The non-RMW ops are (typically) regular LOADs and STOREs and are canonically
implemented using READ_ONCE(), WRITE_ONCE(), smp_load_acquire() and
-smp_store_release() respectively.
+smp_store_release() respectively. Therefore, if you find yourself only using
+the Non-RMW operations of atomic_t, you do not in fact need atomic_t at all
+and are doing it wrong.
-The one detail to this is that atomic_set{}() should be observable to the RMW
+A subtle detail of atomic_set{}() is that it should be observable to the RMW
ops. That is:
C atomic-set
ordering on their SMP atomic primitives. For example our TSO architectures
provide full ordered atomics and these barriers are no-ops.
+NOTE: when the atomic RmW ops are fully ordered, they should also imply a
+compiler barrier.
+
Thus:
atomic_fetch_add();
struct is one class, while each inode has its own instantiation of that
lock class.
-The validator tracks the 'state' of lock-classes, and it tracks
-dependencies between different lock-classes. The validator maintains a
-rolling proof that the state and the dependencies are correct.
-
-Unlike an lock instantiation, the lock-class itself never goes away: when
-a lock-class is used for the first time after bootup it gets registered,
-and all subsequent uses of that lock-class will be attached to this
-lock-class.
+The validator tracks the 'usage state' of lock-classes, and it tracks
+the dependencies between different lock-classes. Lock usage indicates
+how a lock is used with regard to its IRQ contexts, while lock
+dependency can be understood as lock order, where L1 -> L2 suggests that
+a task is attempting to acquire L2 while holding L1. From lockdep's
+perspective, the two locks (L1 and L2) are not necessarily related; that
+dependency just means the order ever happened. The validator maintains a
+continuing effort to prove lock usages and dependencies are correct or
+the validator will shoot a splat if incorrect.
+
+A lock-class's behavior is constructed by its instances collectively:
+when the first instance of a lock-class is used after bootup the class
+gets registered, then all (subsequent) instances will be mapped to the
+class and hence their usages and dependecies will contribute to those of
+the class. A lock-class does not go away when a lock instance does, but
+it can be removed if the memory space of the lock class (static or
+dynamic) is reclaimed, this happens for example when a module is
+unloaded or a workqueue is destroyed.
State
-----
-The validator tracks lock-class usage history into 4 * nSTATEs + 1 separate
-state bits:
+The validator tracks lock-class usage history and divides the usage into
+(4 usages * n STATEs + 1) categories:
+where the 4 usages can be:
- 'ever held in STATE context'
- 'ever held as readlock in STATE context'
- 'ever held with STATE enabled'
- 'ever held as readlock with STATE enabled'
-Where STATE can be either one of (kernel/locking/lockdep_states.h)
- - hardirq
- - softirq
+where the n STATEs are coded in kernel/locking/lockdep_states.h and as of
+now they include:
+- hardirq
+- softirq
+where the last 1 category is:
- 'ever used' [ == !unused ]
-When locking rules are violated, these state bits are presented in the
-locking error messages, inside curlies. A contrived example:
+When locking rules are violated, these usage bits are presented in the
+locking error messages, inside curlies, with a total of 2 * n STATEs bits.
+A contrived example:
modprobe/2287 is trying to acquire lock:
(&sio_locks[i].lock){-.-.}, at: [<c02867fd>] mutex_lock+0x21/0x24
(&sio_locks[i].lock){-.-.}, at: [<c02867fd>] mutex_lock+0x21/0x24
-The bit position indicates STATE, STATE-read, for each of the states listed
-above, and the character displayed in each indicates:
+For a given lock, the bit positions from left to right indicate the usage
+of the lock and readlock (if exists), for each of the n STATEs listed
+above respectively, and the character displayed at each bit position
+indicates:
'.' acquired while irqs disabled and not in irq context
'-' acquired in irq context
'+' acquired with irqs enabled
'?' acquired in irq context with irqs enabled.
-Unused mutexes cannot be part of the cause of an error.
+The bits are illustrated with an example:
+
+ (&sio_locks[i].lock){-.-.}, at: [<c02867fd>] mutex_lock+0x21/0x24
+ ||||
+ ||| \-> softirq disabled and not in softirq context
+ || \--> acquired in softirq context
+ | \---> hardirq disabled and not in hardirq context
+ \----> acquired in hardirq context
+
+
+For a given STATE, whether the lock is ever acquired in that STATE
+context and whether that STATE is enabled yields four possible cases as
+shown in the table below. The bit character is able to indicate which
+exact case is for the lock as of the reporting time.
+
+ -------------------------------------------
+ | | irq enabled | irq disabled |
+ |-------------------------------------------|
+ | ever in irq | ? | - |
+ |-------------------------------------------|
+ | never in irq | + | . |
+ -------------------------------------------
+
+The character '-' suggests irq is disabled because if otherwise the
+charactor '?' would have been shown instead. Similar deduction can be
+applied for '+' too.
+
+Unused locks (e.g., mutexes) cannot be part of the cause of an error.
Single-lock state rules:
------------------------
+A lock is irq-safe means it was ever used in an irq context, while a lock
+is irq-unsafe means it was ever acquired with irq enabled.
+
A softirq-unsafe lock-class is automatically hardirq-unsafe as well. The
-following states are exclusive, and only one of them is allowed to be
-set for any lock-class:
+following states must be exclusive: only one of them is allowed to be set
+for any lock-class based on its usage:
+
+ <hardirq-safe> or <hardirq-unsafe>
+ <softirq-safe> or <softirq-unsafe>
- <hardirq-safe> and <hardirq-unsafe>
- <softirq-safe> and <softirq-unsafe>
+This is because if a lock can be used in irq context (irq-safe) then it
+cannot be ever acquired with irq enabled (irq-unsafe). Otherwise, a
+deadlock may happen. For example, in the scenario that after this lock
+was acquired but before released, if the context is interrupted this
+lock will be attempted to acquire twice, which creates a deadlock,
+referred to as lock recursion deadlock.
-The validator detects and reports lock usage that violate these
+The validator detects and reports lock usage that violates these
single-lock state rules.
Multi-lock dependency rules:
The same lock-class must not be acquired twice, because this could lead
to lock recursion deadlocks.
-Furthermore, two locks may not be taken in different order:
+Furthermore, two locks can not be taken in inverse order:
<L1> -> <L2>
<L2> -> <L1>
-because this could lead to lock inversion deadlocks. (The validator
-finds such dependencies in arbitrary complexity, i.e. there can be any
-other locking sequence between the acquire-lock operations, the
-validator will still track all dependencies between locks.)
+because this could lead to a deadlock - referred to as lock inversion
+deadlock - as attempts to acquire the two locks form a circle which
+could lead to the two contexts waiting for each other permanently. The
+validator will find such dependency circle in arbitrary complexity,
+i.e., there can be any other locking sequence between the acquire-lock
+operations; the validator will still find whether these locks can be
+acquired in a circular fashion.
Furthermore, the following usage based lock dependencies are not allowed
between any two lock-classes:
}
#define ATOMIC64_OP(op, asm_op) \
-static __inline__ void atomic64_##op(long i, atomic64_t * v) \
+static __inline__ void atomic64_##op(s64 i, atomic64_t * v) \
{ \
- unsigned long temp; \
+ s64 temp; \
__asm__ __volatile__( \
"1: ldq_l %0,%1\n" \
" " #asm_op " %0,%2,%0\n" \
} \
#define ATOMIC64_OP_RETURN(op, asm_op) \
-static __inline__ long atomic64_##op##_return_relaxed(long i, atomic64_t * v) \
+static __inline__ s64 atomic64_##op##_return_relaxed(s64 i, atomic64_t * v) \
{ \
- long temp, result; \
+ s64 temp, result; \
__asm__ __volatile__( \
"1: ldq_l %0,%1\n" \
" " #asm_op " %0,%3,%2\n" \
}
#define ATOMIC64_FETCH_OP(op, asm_op) \
-static __inline__ long atomic64_fetch_##op##_relaxed(long i, atomic64_t * v) \
+static __inline__ s64 atomic64_fetch_##op##_relaxed(s64 i, atomic64_t * v) \
{ \
- long temp, result; \
+ s64 temp, result; \
__asm__ __volatile__( \
"1: ldq_l %2,%1\n" \
" " #asm_op " %2,%3,%0\n" \
* Atomically adds @a to @v, so long as it was not @u.
* Returns the old value of @v.
*/
-static __inline__ long atomic64_fetch_add_unless(atomic64_t *v, long a, long u)
+static __inline__ s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
{
- long c, new, old;
+ s64 c, new, old;
smp_mb();
__asm__ __volatile__(
"1: ldq_l %[old],%[mem]\n"
* The function returns the old value of *v minus 1, even if
* the atomic variable, v, was not decremented.
*/
-static inline long atomic64_dec_if_positive(atomic64_t *v)
+static inline s64 atomic64_dec_if_positive(atomic64_t *v)
{
- long old, tmp;
+ s64 old, tmp;
smp_mb();
__asm__ __volatile__(
"1: ldq_l %[old],%[mem]\n"
*/
typedef struct {
- aligned_u64 counter;
+ s64 __aligned(8) counter;
} atomic64_t;
#define ATOMIC64_INIT(a) { (a) }
-static inline long long atomic64_read(const atomic64_t *v)
+static inline s64 atomic64_read(const atomic64_t *v)
{
- unsigned long long val;
+ s64 val;
__asm__ __volatile__(
" ldd %0, [%1] \n"
return val;
}
-static inline void atomic64_set(atomic64_t *v, long long a)
+static inline void atomic64_set(atomic64_t *v, s64 a)
{
/*
* This could have been a simple assignment in "C" but would need
}
#define ATOMIC64_OP(op, op1, op2) \
-static inline void atomic64_##op(long long a, atomic64_t *v) \
+static inline void atomic64_##op(s64 a, atomic64_t *v) \
{ \
- unsigned long long val; \
+ s64 val; \
\
__asm__ __volatile__( \
"1: \n" \
" bnz 1b \n" \
: "=&r"(val) \
: "r"(&v->counter), "ir"(a) \
- : "cc"); \
+ : "cc"); \
} \
#define ATOMIC64_OP_RETURN(op, op1, op2) \
-static inline long long atomic64_##op##_return(long long a, atomic64_t *v) \
+static inline s64 atomic64_##op##_return(s64 a, atomic64_t *v) \
{ \
- unsigned long long val; \
+ s64 val; \
\
smp_mb(); \
\
}
#define ATOMIC64_FETCH_OP(op, op1, op2) \
-static inline long long atomic64_fetch_##op(long long a, atomic64_t *v) \
+static inline s64 atomic64_fetch_##op(s64 a, atomic64_t *v) \
{ \
- unsigned long long val, orig; \
+ s64 val, orig; \
\
smp_mb(); \
\
#undef ATOMIC64_OP_RETURN
#undef ATOMIC64_OP
-static inline long long
-atomic64_cmpxchg(atomic64_t *ptr, long long expected, long long new)
+static inline s64
+atomic64_cmpxchg(atomic64_t *ptr, s64 expected, s64 new)
{
- long long prev;
+ s64 prev;
smp_mb();
return prev;
}
-static inline long long atomic64_xchg(atomic64_t *ptr, long long new)
+static inline s64 atomic64_xchg(atomic64_t *ptr, s64 new)
{
- long long prev;
+ s64 prev;
smp_mb();
* the atomic variable, v, was not decremented.
*/
-static inline long long atomic64_dec_if_positive(atomic64_t *v)
+static inline s64 atomic64_dec_if_positive(atomic64_t *v)
{
- long long val;
+ s64 val;
smp_mb();
* Atomically adds @a to @v, if it was not @u.
* Returns the old value of @v
*/
-static inline long long atomic64_fetch_add_unless(atomic64_t *v, long long a,
- long long u)
+static inline s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
{
- long long old, temp;
+ s64 old, temp;
smp_mb();
#ifndef CONFIG_GENERIC_ATOMIC64
typedef struct {
- long long counter;
+ s64 counter;
} atomic64_t;
#define ATOMIC64_INIT(i) { (i) }
#ifdef CONFIG_ARM_LPAE
-static inline long long atomic64_read(const atomic64_t *v)
+static inline s64 atomic64_read(const atomic64_t *v)
{
- long long result;
+ s64 result;
__asm__ __volatile__("@ atomic64_read\n"
" ldrd %0, %H0, [%1]"
return result;
}
-static inline void atomic64_set(atomic64_t *v, long long i)
+static inline void atomic64_set(atomic64_t *v, s64 i)
{
__asm__ __volatile__("@ atomic64_set\n"
" strd %2, %H2, [%1]"
);
}
#else
-static inline long long atomic64_read(const atomic64_t *v)
+static inline s64 atomic64_read(const atomic64_t *v)
{
- long long result;
+ s64 result;
__asm__ __volatile__("@ atomic64_read\n"
" ldrexd %0, %H0, [%1]"
return result;
}
-static inline void atomic64_set(atomic64_t *v, long long i)
+static inline void atomic64_set(atomic64_t *v, s64 i)
{
- long long tmp;
+ s64 tmp;
prefetchw(&v->counter);
__asm__ __volatile__("@ atomic64_set\n"
#endif
#define ATOMIC64_OP(op, op1, op2) \
-static inline void atomic64_##op(long long i, atomic64_t *v) \
+static inline void atomic64_##op(s64 i, atomic64_t *v) \
{ \
- long long result; \
+ s64 result; \
unsigned long tmp; \
\
prefetchw(&v->counter); \
} \
#define ATOMIC64_OP_RETURN(op, op1, op2) \
-static inline long long \
-atomic64_##op##_return_relaxed(long long i, atomic64_t *v) \
+static inline s64 \
+atomic64_##op##_return_relaxed(s64 i, atomic64_t *v) \
{ \
- long long result; \
+ s64 result; \
unsigned long tmp; \
\
prefetchw(&v->counter); \
}
#define ATOMIC64_FETCH_OP(op, op1, op2) \
-static inline long long \
-atomic64_fetch_##op##_relaxed(long long i, atomic64_t *v) \
+static inline s64 \
+atomic64_fetch_##op##_relaxed(s64 i, atomic64_t *v) \
{ \
- long long result, val; \
+ s64 result, val; \
unsigned long tmp; \
\
prefetchw(&v->counter); \
#undef ATOMIC64_OP_RETURN
#undef ATOMIC64_OP
-static inline long long
-atomic64_cmpxchg_relaxed(atomic64_t *ptr, long long old, long long new)
+static inline s64 atomic64_cmpxchg_relaxed(atomic64_t *ptr, s64 old, s64 new)
{
- long long oldval;
+ s64 oldval;
unsigned long res;
prefetchw(&ptr->counter);
}
#define atomic64_cmpxchg_relaxed atomic64_cmpxchg_relaxed
-static inline long long atomic64_xchg_relaxed(atomic64_t *ptr, long long new)
+static inline s64 atomic64_xchg_relaxed(atomic64_t *ptr, s64 new)
{
- long long result;
+ s64 result;
unsigned long tmp;
prefetchw(&ptr->counter);
}
#define atomic64_xchg_relaxed atomic64_xchg_relaxed
-static inline long long atomic64_dec_if_positive(atomic64_t *v)
+static inline s64 atomic64_dec_if_positive(atomic64_t *v)
{
- long long result;
+ s64 result;
unsigned long tmp;
smp_mb();
}
#define atomic64_dec_if_positive atomic64_dec_if_positive
-static inline long long atomic64_fetch_add_unless(atomic64_t *v, long long a,
- long long u)
+static inline s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
{
- long long oldval, newval;
+ s64 oldval, newval;
unsigned long tmp;
smp_mb();
#define ATOMIC64_OP(op, asm_op) \
__LL_SC_INLINE void \
-__LL_SC_PREFIX(arch_atomic64_##op(long i, atomic64_t *v)) \
+__LL_SC_PREFIX(arch_atomic64_##op(s64 i, atomic64_t *v)) \
{ \
- long result; \
+ s64 result; \
unsigned long tmp; \
\
asm volatile("// atomic64_" #op "\n" \
__LL_SC_EXPORT(arch_atomic64_##op);
#define ATOMIC64_OP_RETURN(name, mb, acq, rel, cl, op, asm_op) \
-__LL_SC_INLINE long \
-__LL_SC_PREFIX(arch_atomic64_##op##_return##name(long i, atomic64_t *v))\
+__LL_SC_INLINE s64 \
+__LL_SC_PREFIX(arch_atomic64_##op##_return##name(s64 i, atomic64_t *v))\
{ \
- long result; \
+ s64 result; \
unsigned long tmp; \
\
asm volatile("// atomic64_" #op "_return" #name "\n" \
__LL_SC_EXPORT(arch_atomic64_##op##_return##name);
#define ATOMIC64_FETCH_OP(name, mb, acq, rel, cl, op, asm_op) \
-__LL_SC_INLINE long \
-__LL_SC_PREFIX(arch_atomic64_fetch_##op##name(long i, atomic64_t *v)) \
+__LL_SC_INLINE s64 \
+__LL_SC_PREFIX(arch_atomic64_fetch_##op##name(s64 i, atomic64_t *v)) \
{ \
- long result, val; \
+ s64 result, val; \
unsigned long tmp; \
\
asm volatile("// atomic64_fetch_" #op #name "\n" \
#undef ATOMIC64_OP_RETURN
#undef ATOMIC64_OP
-__LL_SC_INLINE long
+__LL_SC_INLINE s64
__LL_SC_PREFIX(arch_atomic64_dec_if_positive(atomic64_t *v))
{
- long result;
+ s64 result;
unsigned long tmp;
asm volatile("// atomic64_dec_if_positive\n"
#define __LL_SC_ATOMIC64(op) __LL_SC_CALL(arch_atomic64_##op)
#define ATOMIC64_OP(op, asm_op) \
-static inline void arch_atomic64_##op(long i, atomic64_t *v) \
+static inline void arch_atomic64_##op(s64 i, atomic64_t *v) \
{ \
- register long x0 asm ("x0") = i; \
+ register s64 x0 asm ("x0") = i; \
register atomic64_t *x1 asm ("x1") = v; \
\
asm volatile(ARM64_LSE_ATOMIC_INSN(__LL_SC_ATOMIC64(op), \
#undef ATOMIC64_OP
#define ATOMIC64_FETCH_OP(name, mb, op, asm_op, cl...) \
-static inline long arch_atomic64_fetch_##op##name(long i, atomic64_t *v)\
+static inline s64 arch_atomic64_fetch_##op##name(s64 i, atomic64_t *v) \
{ \
- register long x0 asm ("x0") = i; \
+ register s64 x0 asm ("x0") = i; \
register atomic64_t *x1 asm ("x1") = v; \
\
asm volatile(ARM64_LSE_ATOMIC_INSN( \
#undef ATOMIC64_FETCH_OPS
#define ATOMIC64_OP_ADD_RETURN(name, mb, cl...) \
-static inline long arch_atomic64_add_return##name(long i, atomic64_t *v)\
+static inline s64 arch_atomic64_add_return##name(s64 i, atomic64_t *v) \
{ \
- register long x0 asm ("x0") = i; \
+ register s64 x0 asm ("x0") = i; \
register atomic64_t *x1 asm ("x1") = v; \
\
asm volatile(ARM64_LSE_ATOMIC_INSN( \
#undef ATOMIC64_OP_ADD_RETURN
-static inline void arch_atomic64_and(long i, atomic64_t *v)
+static inline void arch_atomic64_and(s64 i, atomic64_t *v)
{
- register long x0 asm ("x0") = i;
+ register s64 x0 asm ("x0") = i;
register atomic64_t *x1 asm ("x1") = v;
asm volatile(ARM64_LSE_ATOMIC_INSN(
}
#define ATOMIC64_FETCH_OP_AND(name, mb, cl...) \
-static inline long arch_atomic64_fetch_and##name(long i, atomic64_t *v) \
+static inline s64 arch_atomic64_fetch_and##name(s64 i, atomic64_t *v) \
{ \
- register long x0 asm ("x0") = i; \
+ register s64 x0 asm ("x0") = i; \
register atomic64_t *x1 asm ("x1") = v; \
\
asm volatile(ARM64_LSE_ATOMIC_INSN( \
#undef ATOMIC64_FETCH_OP_AND
-static inline void arch_atomic64_sub(long i, atomic64_t *v)
+static inline void arch_atomic64_sub(s64 i, atomic64_t *v)
{
- register long x0 asm ("x0") = i;
+ register s64 x0 asm ("x0") = i;
register atomic64_t *x1 asm ("x1") = v;
asm volatile(ARM64_LSE_ATOMIC_INSN(
}
#define ATOMIC64_OP_SUB_RETURN(name, mb, cl...) \
-static inline long arch_atomic64_sub_return##name(long i, atomic64_t *v)\
+static inline s64 arch_atomic64_sub_return##name(s64 i, atomic64_t *v) \
{ \
- register long x0 asm ("x0") = i; \
+ register s64 x0 asm ("x0") = i; \
register atomic64_t *x1 asm ("x1") = v; \
\
asm volatile(ARM64_LSE_ATOMIC_INSN( \
#undef ATOMIC64_OP_SUB_RETURN
#define ATOMIC64_FETCH_OP_SUB(name, mb, cl...) \
-static inline long arch_atomic64_fetch_sub##name(long i, atomic64_t *v) \
+static inline s64 arch_atomic64_fetch_sub##name(s64 i, atomic64_t *v) \
{ \
- register long x0 asm ("x0") = i; \
+ register s64 x0 asm ("x0") = i; \
register atomic64_t *x1 asm ("x1") = v; \
\
asm volatile(ARM64_LSE_ATOMIC_INSN( \
#undef ATOMIC64_FETCH_OP_SUB
-static inline long arch_atomic64_dec_if_positive(atomic64_t *v)
+static inline s64 arch_atomic64_dec_if_positive(atomic64_t *v)
{
register long x0 asm ("x0") = (long)v;
#undef ATOMIC_OP
#define ATOMIC64_OP(op, c_op) \
-static __inline__ long \
-ia64_atomic64_##op (__s64 i, atomic64_t *v) \
+static __inline__ s64 \
+ia64_atomic64_##op (s64 i, atomic64_t *v) \
{ \
- __s64 old, new; \
+ s64 old, new; \
CMPXCHG_BUGCHECK_DECL \
\
do { \
}
#define ATOMIC64_FETCH_OP(op, c_op) \
-static __inline__ long \
-ia64_atomic64_fetch_##op (__s64 i, atomic64_t *v) \
+static __inline__ s64 \
+ia64_atomic64_fetch_##op (s64 i, atomic64_t *v) \
{ \
- __s64 old, new; \
+ s64 old, new; \
CMPXCHG_BUGCHECK_DECL \
\
do { \
#define atomic64_add_return(i,v) \
({ \
- long __ia64_aar_i = (i); \
+ s64 __ia64_aar_i = (i); \
__ia64_atomic_const(i) \
? ia64_fetch_and_add(__ia64_aar_i, &(v)->counter) \
: ia64_atomic64_add(__ia64_aar_i, v); \
#define atomic64_sub_return(i,v) \
({ \
- long __ia64_asr_i = (i); \
+ s64 __ia64_asr_i = (i); \
__ia64_atomic_const(i) \
? ia64_fetch_and_add(-__ia64_asr_i, &(v)->counter) \
: ia64_atomic64_sub(__ia64_asr_i, v); \
#define atomic64_fetch_add(i,v) \
({ \
- long __ia64_aar_i = (i); \
+ s64 __ia64_aar_i = (i); \
__ia64_atomic_const(i) \
? ia64_fetchadd(__ia64_aar_i, &(v)->counter, acq) \
: ia64_atomic64_fetch_add(__ia64_aar_i, v); \
#define atomic64_fetch_sub(i,v) \
({ \
- long __ia64_asr_i = (i); \
+ s64 __ia64_asr_i = (i); \
__ia64_atomic_const(i) \
? ia64_fetchadd(-__ia64_asr_i, &(v)->counter, acq) \
: ia64_atomic64_fetch_sub(__ia64_asr_i, v); \
#define atomic64_set(v, i) WRITE_ONCE((v)->counter, (i))
#define ATOMIC64_OP(op, c_op, asm_op) \
-static __inline__ void atomic64_##op(long i, atomic64_t * v) \
+static __inline__ void atomic64_##op(s64 i, atomic64_t * v) \
{ \
if (kernel_uses_llsc) { \
- long temp; \
+ s64 temp; \
\
loongson_llsc_mb(); \
__asm__ __volatile__( \
}
#define ATOMIC64_OP_RETURN(op, c_op, asm_op) \
-static __inline__ long atomic64_##op##_return_relaxed(long i, atomic64_t * v) \
+static __inline__ s64 atomic64_##op##_return_relaxed(s64 i, atomic64_t * v) \
{ \
- long result; \
+ s64 result; \
\
if (kernel_uses_llsc) { \
- long temp; \
+ s64 temp; \
\
loongson_llsc_mb(); \
__asm__ __volatile__( \
}
#define ATOMIC64_FETCH_OP(op, c_op, asm_op) \
-static __inline__ long atomic64_fetch_##op##_relaxed(long i, atomic64_t * v) \
+static __inline__ s64 atomic64_fetch_##op##_relaxed(s64 i, atomic64_t * v) \
{ \
- long result; \
+ s64 result; \
\
if (kernel_uses_llsc) { \
- long temp; \
+ s64 temp; \
\
loongson_llsc_mb(); \
__asm__ __volatile__( \
* Atomically test @v and subtract @i if @v is greater or equal than @i.
* The function returns the old value of @v minus @i.
*/
-static __inline__ long atomic64_sub_if_positive(long i, atomic64_t * v)
+static __inline__ s64 atomic64_sub_if_positive(s64 i, atomic64_t * v)
{
- long result;
+ s64 result;
smp_mb__before_llsc();
if (kernel_uses_llsc) {
- long temp;
+ s64 temp;
__asm__ __volatile__(
" .set push \n"
#define ATOMIC64_INIT(i) { (i) }
-static __inline__ long atomic64_read(const atomic64_t *v)
+static __inline__ s64 atomic64_read(const atomic64_t *v)
{
- long t;
+ s64 t;
__asm__ __volatile__("ld%U1%X1 %0,%1" : "=r"(t) : "m"(v->counter));
return t;
}
-static __inline__ void atomic64_set(atomic64_t *v, long i)
+static __inline__ void atomic64_set(atomic64_t *v, s64 i)
{
__asm__ __volatile__("std%U0%X0 %1,%0" : "=m"(v->counter) : "r"(i));
}
#define ATOMIC64_OP(op, asm_op) \
-static __inline__ void atomic64_##op(long a, atomic64_t *v) \
+static __inline__ void atomic64_##op(s64 a, atomic64_t *v) \
{ \
- long t; \
+ s64 t; \
\
__asm__ __volatile__( \
"1: ldarx %0,0,%3 # atomic64_" #op "\n" \
}
#define ATOMIC64_OP_RETURN_RELAXED(op, asm_op) \
-static inline long \
-atomic64_##op##_return_relaxed(long a, atomic64_t *v) \
+static inline s64 \
+atomic64_##op##_return_relaxed(s64 a, atomic64_t *v) \
{ \
- long t; \
+ s64 t; \
\
__asm__ __volatile__( \
"1: ldarx %0,0,%3 # atomic64_" #op "_return_relaxed\n" \
}
#define ATOMIC64_FETCH_OP_RELAXED(op, asm_op) \
-static inline long \
-atomic64_fetch_##op##_relaxed(long a, atomic64_t *v) \
+static inline s64 \
+atomic64_fetch_##op##_relaxed(s64 a, atomic64_t *v) \
{ \
- long res, t; \
+ s64 res, t; \
\
__asm__ __volatile__( \
"1: ldarx %0,0,%4 # atomic64_fetch_" #op "_relaxed\n" \
static __inline__ void atomic64_inc(atomic64_t *v)
{
- long t;
+ s64 t;
__asm__ __volatile__(
"1: ldarx %0,0,%2 # atomic64_inc\n\
}
#define atomic64_inc atomic64_inc
-static __inline__ long atomic64_inc_return_relaxed(atomic64_t *v)
+static __inline__ s64 atomic64_inc_return_relaxed(atomic64_t *v)
{
- long t;
+ s64 t;
__asm__ __volatile__(
"1: ldarx %0,0,%2 # atomic64_inc_return_relaxed\n"
static __inline__ void atomic64_dec(atomic64_t *v)
{
- long t;
+ s64 t;
__asm__ __volatile__(
"1: ldarx %0,0,%2 # atomic64_dec\n\
}
#define atomic64_dec atomic64_dec
-static __inline__ long atomic64_dec_return_relaxed(atomic64_t *v)
+static __inline__ s64 atomic64_dec_return_relaxed(atomic64_t *v)
{
- long t;
+ s64 t;
__asm__ __volatile__(
"1: ldarx %0,0,%2 # atomic64_dec_return_relaxed\n"
* Atomically test *v and decrement if it is greater than 0.
* The function returns the old value of *v minus 1.
*/
-static __inline__ long atomic64_dec_if_positive(atomic64_t *v)
+static __inline__ s64 atomic64_dec_if_positive(atomic64_t *v)
{
- long t;
+ s64 t;
__asm__ __volatile__(
PPC_ATOMIC_ENTRY_BARRIER
* Atomically adds @a to @v, so long as it was not @u.
* Returns the old value of @v.
*/
-static __inline__ long atomic64_fetch_add_unless(atomic64_t *v, long a, long u)
+static __inline__ s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
{
- long t;
+ s64 t;
__asm__ __volatile__ (
PPC_ATOMIC_ENTRY_BARRIER
*/
static __inline__ int atomic64_inc_not_zero(atomic64_t *v)
{
- long t1, t2;
+ s64 t1, t2;
__asm__ __volatile__ (
PPC_ATOMIC_ENTRY_BARRIER
#ifndef CONFIG_GENERIC_ATOMIC64
#define ATOMIC64_INIT(i) { (i) }
-static __always_inline long atomic64_read(const atomic64_t *v)
+static __always_inline s64 atomic64_read(const atomic64_t *v)
{
return READ_ONCE(v->counter);
}
-static __always_inline void atomic64_set(atomic64_t *v, long i)
+static __always_inline void atomic64_set(atomic64_t *v, s64 i)
{
WRITE_ONCE(v->counter, i);
}
#ifdef CONFIG_GENERIC_ATOMIC64
#define ATOMIC_OPS(op, asm_op, I) \
- ATOMIC_OP (op, asm_op, I, w, int, )
+ ATOMIC_OP (op, asm_op, I, w, int, )
#else
#define ATOMIC_OPS(op, asm_op, I) \
- ATOMIC_OP (op, asm_op, I, w, int, ) \
- ATOMIC_OP (op, asm_op, I, d, long, 64)
+ ATOMIC_OP (op, asm_op, I, w, int, ) \
+ ATOMIC_OP (op, asm_op, I, d, s64, 64)
#endif
ATOMIC_OPS(add, add, i)
#ifdef CONFIG_GENERIC_ATOMIC64
#define ATOMIC_OPS(op, asm_op, c_op, I) \
- ATOMIC_FETCH_OP( op, asm_op, I, w, int, ) \
- ATOMIC_OP_RETURN(op, asm_op, c_op, I, w, int, )
+ ATOMIC_FETCH_OP( op, asm_op, I, w, int, ) \
+ ATOMIC_OP_RETURN(op, asm_op, c_op, I, w, int, )
#else
#define ATOMIC_OPS(op, asm_op, c_op, I) \
- ATOMIC_FETCH_OP( op, asm_op, I, w, int, ) \
- ATOMIC_OP_RETURN(op, asm_op, c_op, I, w, int, ) \
- ATOMIC_FETCH_OP( op, asm_op, I, d, long, 64) \
- ATOMIC_OP_RETURN(op, asm_op, c_op, I, d, long, 64)
+ ATOMIC_FETCH_OP( op, asm_op, I, w, int, ) \
+ ATOMIC_OP_RETURN(op, asm_op, c_op, I, w, int, ) \
+ ATOMIC_FETCH_OP( op, asm_op, I, d, s64, 64) \
+ ATOMIC_OP_RETURN(op, asm_op, c_op, I, d, s64, 64)
#endif
ATOMIC_OPS(add, add, +, i)
#ifdef CONFIG_GENERIC_ATOMIC64
#define ATOMIC_OPS(op, asm_op, I) \
- ATOMIC_FETCH_OP(op, asm_op, I, w, int, )
+ ATOMIC_FETCH_OP(op, asm_op, I, w, int, )
#else
#define ATOMIC_OPS(op, asm_op, I) \
- ATOMIC_FETCH_OP(op, asm_op, I, w, int, ) \
- ATOMIC_FETCH_OP(op, asm_op, I, d, long, 64)
+ ATOMIC_FETCH_OP(op, asm_op, I, w, int, ) \
+ ATOMIC_FETCH_OP(op, asm_op, I, d, s64, 64)
#endif
ATOMIC_OPS(and, and, i)
#define atomic_fetch_add_unless atomic_fetch_add_unless
#ifndef CONFIG_GENERIC_ATOMIC64
-static __always_inline long atomic64_fetch_add_unless(atomic64_t *v, long a, long u)
+static __always_inline s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
{
- long prev, rc;
+ s64 prev;
+ long rc;
__asm__ __volatile__ (
"0: lr.d %[p], %[c]\n"
#ifdef CONFIG_GENERIC_ATOMIC64
#define ATOMIC_OPS() \
- ATOMIC_OP( int, , 4)
+ ATOMIC_OP(int, , 4)
#else
#define ATOMIC_OPS() \
- ATOMIC_OP( int, , 4) \
- ATOMIC_OP(long, 64, 8)
+ ATOMIC_OP(int, , 4) \
+ ATOMIC_OP(s64, 64, 8)
#endif
ATOMIC_OPS()
#define atomic_dec_if_positive(v) atomic_sub_if_positive(v, 1)
#ifndef CONFIG_GENERIC_ATOMIC64
-static __always_inline long atomic64_sub_if_positive(atomic64_t *v, int offset)
+static __always_inline s64 atomic64_sub_if_positive(atomic64_t *v, s64 offset)
{
- long prev, rc;
+ s64 prev;
+ long rc;
__asm__ __volatile__ (
"0: lr.d %[p], %[c]\n"
#define ATOMIC64_INIT(i) { (i) }
-static inline long atomic64_read(const atomic64_t *v)
+static inline s64 atomic64_read(const atomic64_t *v)
{
- long c;
+ s64 c;
asm volatile(
" lg %0,%1\n"
return c;
}
-static inline void atomic64_set(atomic64_t *v, long i)
+static inline void atomic64_set(atomic64_t *v, s64 i)
{
asm volatile(
" stg %1,%0\n"
: "=Q" (v->counter) : "d" (i));
}
-static inline long atomic64_add_return(long i, atomic64_t *v)
+static inline s64 atomic64_add_return(s64 i, atomic64_t *v)
{
- return __atomic64_add_barrier(i, &v->counter) + i;
+ return __atomic64_add_barrier(i, (long *)&v->counter) + i;
}
-static inline long atomic64_fetch_add(long i, atomic64_t *v)
+static inline s64 atomic64_fetch_add(s64 i, atomic64_t *v)
{
- return __atomic64_add_barrier(i, &v->counter);
+ return __atomic64_add_barrier(i, (long *)&v->counter);
}
-static inline void atomic64_add(long i, atomic64_t *v)
+static inline void atomic64_add(s64 i, atomic64_t *v)
{
#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
if (__builtin_constant_p(i) && (i > -129) && (i < 128)) {
- __atomic64_add_const(i, &v->counter);
+ __atomic64_add_const(i, (long *)&v->counter);
return;
}
#endif
- __atomic64_add(i, &v->counter);
+ __atomic64_add(i, (long *)&v->counter);
}
#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
-static inline long atomic64_cmpxchg(atomic64_t *v, long old, long new)
+static inline s64 atomic64_cmpxchg(atomic64_t *v, s64 old, s64 new)
{
- return __atomic64_cmpxchg(&v->counter, old, new);
+ return __atomic64_cmpxchg((long *)&v->counter, old, new);
}
#define ATOMIC64_OPS(op) \
-static inline void atomic64_##op(long i, atomic64_t *v) \
+static inline void atomic64_##op(s64 i, atomic64_t *v) \
{ \
- __atomic64_##op(i, &v->counter); \
+ __atomic64_##op(i, (long *)&v->counter); \
} \
-static inline long atomic64_fetch_##op(long i, atomic64_t *v) \
+static inline long atomic64_fetch_##op(s64 i, atomic64_t *v) \
{ \
- return __atomic64_##op##_barrier(i, &v->counter); \
+ return __atomic64_##op##_barrier(i, (long *)&v->counter); \
}
ATOMIC64_OPS(and)
#undef ATOMIC64_OPS
-#define atomic64_sub_return(_i, _v) atomic64_add_return(-(long)(_i), _v)
-#define atomic64_fetch_sub(_i, _v) atomic64_fetch_add(-(long)(_i), _v)
-#define atomic64_sub(_i, _v) atomic64_add(-(long)(_i), _v)
+#define atomic64_sub_return(_i, _v) atomic64_add_return(-(s64)(_i), _v)
+#define atomic64_fetch_sub(_i, _v) atomic64_fetch_add(-(s64)(_i), _v)
+#define atomic64_sub(_i, _v) atomic64_add(-(s64)(_i), _v)
#endif /* __ARCH_S390_ATOMIC__ */
int i;
for (i = 0; i < ARRAY_SIZE(pci_sw_names); i++, counter++)
- seq_printf(m, "%26s:\t%lu\n", pci_sw_names[i],
+ seq_printf(m, "%26s:\t%llu\n", pci_sw_names[i],
atomic64_read(counter));
}
#define ATOMIC_OP(op) \
void atomic_##op(int, atomic_t *); \
-void atomic64_##op(long, atomic64_t *);
+void atomic64_##op(s64, atomic64_t *);
#define ATOMIC_OP_RETURN(op) \
int atomic_##op##_return(int, atomic_t *); \
-long atomic64_##op##_return(long, atomic64_t *);
+s64 atomic64_##op##_return(s64, atomic64_t *);
#define ATOMIC_FETCH_OP(op) \
int atomic_fetch_##op(int, atomic_t *); \
-long atomic64_fetch_##op(long, atomic64_t *);
+s64 atomic64_fetch_##op(s64, atomic64_t *);
#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op)
((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
-long atomic64_dec_if_positive(atomic64_t *v);
+s64 atomic64_dec_if_positive(atomic64_t *v);
#define atomic64_dec_if_positive atomic64_dec_if_positive
#endif /* !(__ARCH_SPARC64_ATOMIC__) */
* For now, this can't happen because all callers hold mmap_sem
* for write. If this changes, we'll need a different solution.
*/
- lockdep_assert_held_exclusive(&mm->mmap_sem);
+ lockdep_assert_held_write(&mm->mmap_sem);
if (atomic_inc_return(&mm->context.perf_rdpmc_allowed) == 1)
on_each_cpu_mask(mm_cpumask(mm), refresh_pce, NULL, 1);
{
asm volatile(LOCK_PREFIX "addl %1,%0"
: "+m" (v->counter)
- : "ir" (i));
+ : "ir" (i) : "memory");
}
/**
{
asm volatile(LOCK_PREFIX "subl %1,%0"
: "+m" (v->counter)
- : "ir" (i));
+ : "ir" (i) : "memory");
}
/**
static __always_inline void arch_atomic_inc(atomic_t *v)
{
asm volatile(LOCK_PREFIX "incl %0"
- : "+m" (v->counter));
+ : "+m" (v->counter) :: "memory");
}
#define arch_atomic_inc arch_atomic_inc
static __always_inline void arch_atomic_dec(atomic_t *v)
{
asm volatile(LOCK_PREFIX "decl %0"
- : "+m" (v->counter));
+ : "+m" (v->counter) :: "memory");
}
#define arch_atomic_dec arch_atomic_dec
/* An 64bit atomic type */
typedef struct {
- u64 __aligned(8) counter;
+ s64 __aligned(8) counter;
} atomic64_t;
#define ATOMIC64_INIT(val) { (val) }
* the old value.
*/
-static inline long long arch_atomic64_cmpxchg(atomic64_t *v, long long o,
- long long n)
+static inline s64 arch_atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n)
{
return arch_cmpxchg64(&v->counter, o, n);
}
* Atomically xchgs the value of @v to @n and returns
* the old value.
*/
-static inline long long arch_atomic64_xchg(atomic64_t *v, long long n)
+static inline s64 arch_atomic64_xchg(atomic64_t *v, s64 n)
{
- long long o;
+ s64 o;
unsigned high = (unsigned)(n >> 32);
unsigned low = (unsigned)n;
alternative_atomic64(xchg, "=&A" (o),
*
* Atomically sets the value of @v to @n.
*/
-static inline void arch_atomic64_set(atomic64_t *v, long long i)
+static inline void arch_atomic64_set(atomic64_t *v, s64 i)
{
unsigned high = (unsigned)(i >> 32);
unsigned low = (unsigned)i;
*
* Atomically reads the value of @v and returns it.
*/
-static inline long long arch_atomic64_read(const atomic64_t *v)
+static inline s64 arch_atomic64_read(const atomic64_t *v)
{
- long long r;
+ s64 r;
alternative_atomic64(read, "=&A" (r), "c" (v) : "memory");
return r;
}
*
* Atomically adds @i to @v and returns @i + *@v
*/
-static inline long long arch_atomic64_add_return(long long i, atomic64_t *v)
+static inline s64 arch_atomic64_add_return(s64 i, atomic64_t *v)
{
alternative_atomic64(add_return,
ASM_OUTPUT2("+A" (i), "+c" (v)),
/*
* Other variants with different arithmetic operators:
*/
-static inline long long arch_atomic64_sub_return(long long i, atomic64_t *v)
+static inline s64 arch_atomic64_sub_return(s64 i, atomic64_t *v)
{
alternative_atomic64(sub_return,
ASM_OUTPUT2("+A" (i), "+c" (v)),
return i;
}
-static inline long long arch_atomic64_inc_return(atomic64_t *v)
+static inline s64 arch_atomic64_inc_return(atomic64_t *v)
{
- long long a;
+ s64 a;
alternative_atomic64(inc_return, "=&A" (a),
"S" (v) : "memory", "ecx");
return a;
}
#define arch_atomic64_inc_return arch_atomic64_inc_return
-static inline long long arch_atomic64_dec_return(atomic64_t *v)
+static inline s64 arch_atomic64_dec_return(atomic64_t *v)
{
- long long a;
+ s64 a;
alternative_atomic64(dec_return, "=&A" (a),
"S" (v) : "memory", "ecx");
return a;
*
* Atomically adds @i to @v.
*/
-static inline long long arch_atomic64_add(long long i, atomic64_t *v)
+static inline s64 arch_atomic64_add(s64 i, atomic64_t *v)
{
__alternative_atomic64(add, add_return,
ASM_OUTPUT2("+A" (i), "+c" (v)),
*
* Atomically subtracts @i from @v.
*/
-static inline long long arch_atomic64_sub(long long i, atomic64_t *v)
+static inline s64 arch_atomic64_sub(s64 i, atomic64_t *v)
{
__alternative_atomic64(sub, sub_return,
ASM_OUTPUT2("+A" (i), "+c" (v)),
* Atomically adds @a to @v, so long as it was not @u.
* Returns non-zero if the add was done, zero otherwise.
*/
-static inline int arch_atomic64_add_unless(atomic64_t *v, long long a,
- long long u)
+static inline int arch_atomic64_add_unless(atomic64_t *v, s64 a, s64 u)
{
unsigned low = (unsigned)u;
unsigned high = (unsigned)(u >> 32);
}
#define arch_atomic64_inc_not_zero arch_atomic64_inc_not_zero
-static inline long long arch_atomic64_dec_if_positive(atomic64_t *v)
+static inline s64 arch_atomic64_dec_if_positive(atomic64_t *v)
{
- long long r;
+ s64 r;
alternative_atomic64(dec_if_positive, "=&A" (r),
"S" (v) : "ecx", "memory");
return r;
#undef alternative_atomic64
#undef __alternative_atomic64
-static inline void arch_atomic64_and(long long i, atomic64_t *v)
+static inline void arch_atomic64_and(s64 i, atomic64_t *v)
{
- long long old, c = 0;
+ s64 old, c = 0;
while ((old = arch_atomic64_cmpxchg(v, c, c & i)) != c)
c = old;
}
-static inline long long arch_atomic64_fetch_and(long long i, atomic64_t *v)
+static inline s64 arch_atomic64_fetch_and(s64 i, atomic64_t *v)
{
- long long old, c = 0;
+ s64 old, c = 0;
while ((old = arch_atomic64_cmpxchg(v, c, c & i)) != c)
c = old;
return old;
}
-static inline void arch_atomic64_or(long long i, atomic64_t *v)
+static inline void arch_atomic64_or(s64 i, atomic64_t *v)
{
- long long old, c = 0;
+ s64 old, c = 0;
while ((old = arch_atomic64_cmpxchg(v, c, c | i)) != c)
c = old;
}
-static inline long long arch_atomic64_fetch_or(long long i, atomic64_t *v)
+static inline s64 arch_atomic64_fetch_or(s64 i, atomic64_t *v)
{
- long long old, c = 0;
+ s64 old, c = 0;
while ((old = arch_atomic64_cmpxchg(v, c, c | i)) != c)
c = old;
return old;
}
-static inline void arch_atomic64_xor(long long i, atomic64_t *v)
+static inline void arch_atomic64_xor(s64 i, atomic64_t *v)
{
- long long old, c = 0;
+ s64 old, c = 0;
while ((old = arch_atomic64_cmpxchg(v, c, c ^ i)) != c)
c = old;
}
-static inline long long arch_atomic64_fetch_xor(long long i, atomic64_t *v)
+static inline s64 arch_atomic64_fetch_xor(s64 i, atomic64_t *v)
{
- long long old, c = 0;
+ s64 old, c = 0;
while ((old = arch_atomic64_cmpxchg(v, c, c ^ i)) != c)
c = old;
return old;
}
-static inline long long arch_atomic64_fetch_add(long long i, atomic64_t *v)
+static inline s64 arch_atomic64_fetch_add(s64 i, atomic64_t *v)
{
- long long old, c = 0;
+ s64 old, c = 0;
while ((old = arch_atomic64_cmpxchg(v, c, c + i)) != c)
c = old;
* Atomically reads the value of @v.
* Doesn't imply a read memory barrier.
*/
-static inline long arch_atomic64_read(const atomic64_t *v)
+static inline s64 arch_atomic64_read(const atomic64_t *v)
{
return READ_ONCE((v)->counter);
}
*
* Atomically sets the value of @v to @i.
*/
-static inline void arch_atomic64_set(atomic64_t *v, long i)
+static inline void arch_atomic64_set(atomic64_t *v, s64 i)
{
WRITE_ONCE(v->counter, i);
}
*
* Atomically adds @i to @v.
*/
-static __always_inline void arch_atomic64_add(long i, atomic64_t *v)
+static __always_inline void arch_atomic64_add(s64 i, atomic64_t *v)
{
asm volatile(LOCK_PREFIX "addq %1,%0"
: "=m" (v->counter)
- : "er" (i), "m" (v->counter));
+ : "er" (i), "m" (v->counter) : "memory");
}
/**
*
* Atomically subtracts @i from @v.
*/
-static inline void arch_atomic64_sub(long i, atomic64_t *v)
+static inline void arch_atomic64_sub(s64 i, atomic64_t *v)
{
asm volatile(LOCK_PREFIX "subq %1,%0"
: "=m" (v->counter)
- : "er" (i), "m" (v->counter));
+ : "er" (i), "m" (v->counter) : "memory");
}
/**
* true if the result is zero, or false for all
* other cases.
*/
-static inline bool arch_atomic64_sub_and_test(long i, atomic64_t *v)
+static inline bool arch_atomic64_sub_and_test(s64 i, atomic64_t *v)
{
return GEN_BINARY_RMWcc(LOCK_PREFIX "subq", v->counter, e, "er", i);
}
{
asm volatile(LOCK_PREFIX "incq %0"
: "=m" (v->counter)
- : "m" (v->counter));
+ : "m" (v->counter) : "memory");
}
#define arch_atomic64_inc arch_atomic64_inc
{
asm volatile(LOCK_PREFIX "decq %0"
: "=m" (v->counter)
- : "m" (v->counter));
+ : "m" (v->counter) : "memory");
}
#define arch_atomic64_dec arch_atomic64_dec
* if the result is negative, or false when
* result is greater than or equal to zero.
*/
-static inline bool arch_atomic64_add_negative(long i, atomic64_t *v)
+static inline bool arch_atomic64_add_negative(s64 i, atomic64_t *v)
{
return GEN_BINARY_RMWcc(LOCK_PREFIX "addq", v->counter, s, "er", i);
}
*
* Atomically adds @i to @v and returns @i + @v
*/
-static __always_inline long arch_atomic64_add_return(long i, atomic64_t *v)
+static __always_inline s64 arch_atomic64_add_return(s64 i, atomic64_t *v)
{
return i + xadd(&v->counter, i);
}
-static inline long arch_atomic64_sub_return(long i, atomic64_t *v)
+static inline s64 arch_atomic64_sub_return(s64 i, atomic64_t *v)
{
return arch_atomic64_add_return(-i, v);
}
-static inline long arch_atomic64_fetch_add(long i, atomic64_t *v)
+static inline s64 arch_atomic64_fetch_add(s64 i, atomic64_t *v)
{
return xadd(&v->counter, i);
}
-static inline long arch_atomic64_fetch_sub(long i, atomic64_t *v)
+static inline s64 arch_atomic64_fetch_sub(s64 i, atomic64_t *v)
{
return xadd(&v->counter, -i);
}
-static inline long arch_atomic64_cmpxchg(atomic64_t *v, long old, long new)
+static inline s64 arch_atomic64_cmpxchg(atomic64_t *v, s64 old, s64 new)
{
return arch_cmpxchg(&v->counter, old, new);
}
#define arch_atomic64_try_cmpxchg arch_atomic64_try_cmpxchg
-static __always_inline bool arch_atomic64_try_cmpxchg(atomic64_t *v, s64 *old, long new)
+static __always_inline bool arch_atomic64_try_cmpxchg(atomic64_t *v, s64 *old, s64 new)
{
return try_cmpxchg(&v->counter, old, new);
}
-static inline long arch_atomic64_xchg(atomic64_t *v, long new)
+static inline s64 arch_atomic64_xchg(atomic64_t *v, s64 new)
{
return arch_xchg(&v->counter, new);
}
-static inline void arch_atomic64_and(long i, atomic64_t *v)
+static inline void arch_atomic64_and(s64 i, atomic64_t *v)
{
asm volatile(LOCK_PREFIX "andq %1,%0"
: "+m" (v->counter)
: "memory");
}
-static inline long arch_atomic64_fetch_and(long i, atomic64_t *v)
+static inline s64 arch_atomic64_fetch_and(s64 i, atomic64_t *v)
{
s64 val = arch_atomic64_read(v);
return val;
}
-static inline void arch_atomic64_or(long i, atomic64_t *v)
+static inline void arch_atomic64_or(s64 i, atomic64_t *v)
{
asm volatile(LOCK_PREFIX "orq %1,%0"
: "+m" (v->counter)
: "memory");
}
-static inline long arch_atomic64_fetch_or(long i, atomic64_t *v)
+static inline s64 arch_atomic64_fetch_or(s64 i, atomic64_t *v)
{
s64 val = arch_atomic64_read(v);
return val;
}
-static inline void arch_atomic64_xor(long i, atomic64_t *v)
+static inline void arch_atomic64_xor(s64 i, atomic64_t *v)
{
asm volatile(LOCK_PREFIX "xorq %1,%0"
: "+m" (v->counter)
: "memory");
}
-static inline long arch_atomic64_fetch_xor(long i, atomic64_t *v)
+static inline s64 arch_atomic64_fetch_xor(s64 i, atomic64_t *v)
{
s64 val = arch_atomic64_read(v);
})
/* Atomic operations are already serializing on x86 */
-#define __smp_mb__before_atomic() barrier()
-#define __smp_mb__after_atomic() barrier()
+#define __smp_mb__before_atomic() do { } while (0)
+#define __smp_mb__after_atomic() do { } while (0)
#include <asm-generic/barrier.h>
static inline struct pt_regs *get_irq_regs(void)
{
- return this_cpu_read(irq_regs);
+ return __this_cpu_read(irq_regs);
}
static inline struct pt_regs *set_irq_regs(struct pt_regs *new_regs)
struct pt_regs *old_regs;
old_regs = get_irq_regs();
- this_cpu_write(irq_regs, new_regs);
+ __this_cpu_write(irq_regs, new_regs);
return old_regs;
}
#ifndef _ASM_X86_JUMP_LABEL_H
#define _ASM_X86_JUMP_LABEL_H
+#define HAVE_JUMP_LABEL_BATCH
+
#define JUMP_LABEL_NOP_SIZE 5
#ifdef CONFIG_X86_64
* don't give an lvalue though). */
extern void __bad_percpu_size(void);
-#define percpu_to_op(op, var, val) \
+#define percpu_to_op(qual, op, var, val) \
do { \
typedef typeof(var) pto_T__; \
if (0) { \
} \
switch (sizeof(var)) { \
case 1: \
- asm(op "b %1,"__percpu_arg(0) \
+ asm qual (op "b %1,"__percpu_arg(0) \
: "+m" (var) \
: "qi" ((pto_T__)(val))); \
break; \
case 2: \
- asm(op "w %1,"__percpu_arg(0) \
+ asm qual (op "w %1,"__percpu_arg(0) \
: "+m" (var) \
: "ri" ((pto_T__)(val))); \
break; \
case 4: \
- asm(op "l %1,"__percpu_arg(0) \
+ asm qual (op "l %1,"__percpu_arg(0) \
: "+m" (var) \
: "ri" ((pto_T__)(val))); \
break; \
case 8: \
- asm(op "q %1,"__percpu_arg(0) \
+ asm qual (op "q %1,"__percpu_arg(0) \
: "+m" (var) \
: "re" ((pto_T__)(val))); \
break; \
* Generate a percpu add to memory instruction and optimize code
* if one is added or subtracted.
*/
-#define percpu_add_op(var, val) \
+#define percpu_add_op(qual, var, val) \
do { \
typedef typeof(var) pao_T__; \
const int pao_ID__ = (__builtin_constant_p(val) && \
switch (sizeof(var)) { \
case 1: \
if (pao_ID__ == 1) \
- asm("incb "__percpu_arg(0) : "+m" (var)); \
+ asm qual ("incb "__percpu_arg(0) : "+m" (var)); \
else if (pao_ID__ == -1) \
- asm("decb "__percpu_arg(0) : "+m" (var)); \
+ asm qual ("decb "__percpu_arg(0) : "+m" (var)); \
else \
- asm("addb %1, "__percpu_arg(0) \
+ asm qual ("addb %1, "__percpu_arg(0) \
: "+m" (var) \
: "qi" ((pao_T__)(val))); \
break; \
case 2: \
if (pao_ID__ == 1) \
- asm("incw "__percpu_arg(0) : "+m" (var)); \
+ asm qual ("incw "__percpu_arg(0) : "+m" (var)); \
else if (pao_ID__ == -1) \
- asm("decw "__percpu_arg(0) : "+m" (var)); \
+ asm qual ("decw "__percpu_arg(0) : "+m" (var)); \
else \
- asm("addw %1, "__percpu_arg(0) \
+ asm qual ("addw %1, "__percpu_arg(0) \
: "+m" (var) \
: "ri" ((pao_T__)(val))); \
break; \
case 4: \
if (pao_ID__ == 1) \
- asm("incl "__percpu_arg(0) : "+m" (var)); \
+ asm qual ("incl "__percpu_arg(0) : "+m" (var)); \
else if (pao_ID__ == -1) \
- asm("decl "__percpu_arg(0) : "+m" (var)); \
+ asm qual ("decl "__percpu_arg(0) : "+m" (var)); \
else \
- asm("addl %1, "__percpu_arg(0) \
+ asm qual ("addl %1, "__percpu_arg(0) \
: "+m" (var) \
: "ri" ((pao_T__)(val))); \
break; \
case 8: \
if (pao_ID__ == 1) \
- asm("incq "__percpu_arg(0) : "+m" (var)); \
+ asm qual ("incq "__percpu_arg(0) : "+m" (var)); \
else if (pao_ID__ == -1) \
- asm("decq "__percpu_arg(0) : "+m" (var)); \
+ asm qual ("decq "__percpu_arg(0) : "+m" (var)); \
else \
- asm("addq %1, "__percpu_arg(0) \
+ asm qual ("addq %1, "__percpu_arg(0) \
: "+m" (var) \
: "re" ((pao_T__)(val))); \
break; \
} \
} while (0)
-#define percpu_from_op(op, var) \
+#define percpu_from_op(qual, op, var) \
({ \
typeof(var) pfo_ret__; \
switch (sizeof(var)) { \
case 1: \
- asm volatile(op "b "__percpu_arg(1)",%0"\
+ asm qual (op "b "__percpu_arg(1)",%0" \
: "=q" (pfo_ret__) \
: "m" (var)); \
break; \
case 2: \
- asm volatile(op "w "__percpu_arg(1)",%0"\
+ asm qual (op "w "__percpu_arg(1)",%0" \
: "=r" (pfo_ret__) \
: "m" (var)); \
break; \
case 4: \
- asm volatile(op "l "__percpu_arg(1)",%0"\
+ asm qual (op "l "__percpu_arg(1)",%0" \
: "=r" (pfo_ret__) \
: "m" (var)); \
break; \
case 8: \
- asm volatile(op "q "__percpu_arg(1)",%0"\
+ asm qual (op "q "__percpu_arg(1)",%0" \
: "=r" (pfo_ret__) \
: "m" (var)); \
break; \
pfo_ret__; \
})
-#define percpu_unary_op(op, var) \
+#define percpu_unary_op(qual, op, var) \
({ \
switch (sizeof(var)) { \
case 1: \
- asm(op "b "__percpu_arg(0) \
+ asm qual (op "b "__percpu_arg(0) \
: "+m" (var)); \
break; \
case 2: \
- asm(op "w "__percpu_arg(0) \
+ asm qual (op "w "__percpu_arg(0) \
: "+m" (var)); \
break; \
case 4: \
- asm(op "l "__percpu_arg(0) \
+ asm qual (op "l "__percpu_arg(0) \
: "+m" (var)); \
break; \
case 8: \
- asm(op "q "__percpu_arg(0) \
+ asm qual (op "q "__percpu_arg(0) \
: "+m" (var)); \
break; \
default: __bad_percpu_size(); \
/*
* Add return operation
*/
-#define percpu_add_return_op(var, val) \
+#define percpu_add_return_op(qual, var, val) \
({ \
typeof(var) paro_ret__ = val; \
switch (sizeof(var)) { \
case 1: \
- asm("xaddb %0, "__percpu_arg(1) \
+ asm qual ("xaddb %0, "__percpu_arg(1) \
: "+q" (paro_ret__), "+m" (var) \
: : "memory"); \
break; \
case 2: \
- asm("xaddw %0, "__percpu_arg(1) \
+ asm qual ("xaddw %0, "__percpu_arg(1) \
: "+r" (paro_ret__), "+m" (var) \
: : "memory"); \
break; \
case 4: \
- asm("xaddl %0, "__percpu_arg(1) \
+ asm qual ("xaddl %0, "__percpu_arg(1) \
: "+r" (paro_ret__), "+m" (var) \
: : "memory"); \
break; \
case 8: \
- asm("xaddq %0, "__percpu_arg(1) \
+ asm qual ("xaddq %0, "__percpu_arg(1) \
: "+re" (paro_ret__), "+m" (var) \
: : "memory"); \
break; \
* expensive due to the implied lock prefix. The processor cannot prefetch
* cachelines if xchg is used.
*/
-#define percpu_xchg_op(var, nval) \
+#define percpu_xchg_op(qual, var, nval) \
({ \
typeof(var) pxo_ret__; \
typeof(var) pxo_new__ = (nval); \
switch (sizeof(var)) { \
case 1: \
- asm("\n\tmov "__percpu_arg(1)",%%al" \
+ asm qual ("\n\tmov "__percpu_arg(1)",%%al" \
"\n1:\tcmpxchgb %2, "__percpu_arg(1) \
"\n\tjnz 1b" \
: "=&a" (pxo_ret__), "+m" (var) \
: "memory"); \
break; \
case 2: \
- asm("\n\tmov "__percpu_arg(1)",%%ax" \
+ asm qual ("\n\tmov "__percpu_arg(1)",%%ax" \
"\n1:\tcmpxchgw %2, "__percpu_arg(1) \
"\n\tjnz 1b" \
: "=&a" (pxo_ret__), "+m" (var) \
: "memory"); \
break; \
case 4: \
- asm("\n\tmov "__percpu_arg(1)",%%eax" \
+ asm qual ("\n\tmov "__percpu_arg(1)",%%eax" \
"\n1:\tcmpxchgl %2, "__percpu_arg(1) \
"\n\tjnz 1b" \
: "=&a" (pxo_ret__), "+m" (var) \
: "memory"); \
break; \
case 8: \
- asm("\n\tmov "__percpu_arg(1)",%%rax" \
+ asm qual ("\n\tmov "__percpu_arg(1)",%%rax" \
"\n1:\tcmpxchgq %2, "__percpu_arg(1) \
"\n\tjnz 1b" \
: "=&a" (pxo_ret__), "+m" (var) \
* cmpxchg has no such implied lock semantics as a result it is much
* more efficient for cpu local operations.
*/
-#define percpu_cmpxchg_op(var, oval, nval) \
+#define percpu_cmpxchg_op(qual, var, oval, nval) \
({ \
typeof(var) pco_ret__; \
typeof(var) pco_old__ = (oval); \
typeof(var) pco_new__ = (nval); \
switch (sizeof(var)) { \
case 1: \
- asm("cmpxchgb %2, "__percpu_arg(1) \
+ asm qual ("cmpxchgb %2, "__percpu_arg(1) \
: "=a" (pco_ret__), "+m" (var) \
: "q" (pco_new__), "0" (pco_old__) \
: "memory"); \
break; \
case 2: \
- asm("cmpxchgw %2, "__percpu_arg(1) \
+ asm qual ("cmpxchgw %2, "__percpu_arg(1) \
: "=a" (pco_ret__), "+m" (var) \
: "r" (pco_new__), "0" (pco_old__) \
: "memory"); \
break; \
case 4: \
- asm("cmpxchgl %2, "__percpu_arg(1) \
+ asm qual ("cmpxchgl %2, "__percpu_arg(1) \
: "=a" (pco_ret__), "+m" (var) \
: "r" (pco_new__), "0" (pco_old__) \
: "memory"); \
break; \
case 8: \
- asm("cmpxchgq %2, "__percpu_arg(1) \
+ asm qual ("cmpxchgq %2, "__percpu_arg(1) \
: "=a" (pco_ret__), "+m" (var) \
: "r" (pco_new__), "0" (pco_old__) \
: "memory"); \
*/
#define this_cpu_read_stable(var) percpu_stable_op("mov", var)
-#define raw_cpu_read_1(pcp) percpu_from_op("mov", pcp)
-#define raw_cpu_read_2(pcp) percpu_from_op("mov", pcp)
-#define raw_cpu_read_4(pcp) percpu_from_op("mov", pcp)
-
-#define raw_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val)
-#define raw_cpu_write_2(pcp, val) percpu_to_op("mov", (pcp), val)
-#define raw_cpu_write_4(pcp, val) percpu_to_op("mov", (pcp), val)
-#define raw_cpu_add_1(pcp, val) percpu_add_op((pcp), val)
-#define raw_cpu_add_2(pcp, val) percpu_add_op((pcp), val)
-#define raw_cpu_add_4(pcp, val) percpu_add_op((pcp), val)
-#define raw_cpu_and_1(pcp, val) percpu_to_op("and", (pcp), val)
-#define raw_cpu_and_2(pcp, val) percpu_to_op("and", (pcp), val)
-#define raw_cpu_and_4(pcp, val) percpu_to_op("and", (pcp), val)
-#define raw_cpu_or_1(pcp, val) percpu_to_op("or", (pcp), val)
-#define raw_cpu_or_2(pcp, val) percpu_to_op("or", (pcp), val)
-#define raw_cpu_or_4(pcp, val) percpu_to_op("or", (pcp), val)
-#define raw_cpu_xchg_1(pcp, val) percpu_xchg_op(pcp, val)
-#define raw_cpu_xchg_2(pcp, val) percpu_xchg_op(pcp, val)
-#define raw_cpu_xchg_4(pcp, val) percpu_xchg_op(pcp, val)
-
-#define this_cpu_read_1(pcp) percpu_from_op("mov", pcp)
-#define this_cpu_read_2(pcp) percpu_from_op("mov", pcp)
-#define this_cpu_read_4(pcp) percpu_from_op("mov", pcp)
-#define this_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val)
-#define this_cpu_write_2(pcp, val) percpu_to_op("mov", (pcp), val)
-#define this_cpu_write_4(pcp, val) percpu_to_op("mov", (pcp), val)
-#define this_cpu_add_1(pcp, val) percpu_add_op((pcp), val)
-#define this_cpu_add_2(pcp, val) percpu_add_op((pcp), val)
-#define this_cpu_add_4(pcp, val) percpu_add_op((pcp), val)
-#define this_cpu_and_1(pcp, val) percpu_to_op("and", (pcp), val)
-#define this_cpu_and_2(pcp, val) percpu_to_op("and", (pcp), val)
-#define this_cpu_and_4(pcp, val) percpu_to_op("and", (pcp), val)
-#define this_cpu_or_1(pcp, val) percpu_to_op("or", (pcp), val)
-#define this_cpu_or_2(pcp, val) percpu_to_op("or", (pcp), val)
-#define this_cpu_or_4(pcp, val) percpu_to_op("or", (pcp), val)
-#define this_cpu_xchg_1(pcp, nval) percpu_xchg_op(pcp, nval)
-#define this_cpu_xchg_2(pcp, nval) percpu_xchg_op(pcp, nval)
-#define this_cpu_xchg_4(pcp, nval) percpu_xchg_op(pcp, nval)
-
-#define raw_cpu_add_return_1(pcp, val) percpu_add_return_op(pcp, val)
-#define raw_cpu_add_return_2(pcp, val) percpu_add_return_op(pcp, val)
-#define raw_cpu_add_return_4(pcp, val) percpu_add_return_op(pcp, val)
-#define raw_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
-#define raw_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
-#define raw_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
-
-#define this_cpu_add_return_1(pcp, val) percpu_add_return_op(pcp, val)
-#define this_cpu_add_return_2(pcp, val) percpu_add_return_op(pcp, val)
-#define this_cpu_add_return_4(pcp, val) percpu_add_return_op(pcp, val)
-#define this_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
-#define this_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
-#define this_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
+#define raw_cpu_read_1(pcp) percpu_from_op(, "mov", pcp)
+#define raw_cpu_read_2(pcp) percpu_from_op(, "mov", pcp)
+#define raw_cpu_read_4(pcp) percpu_from_op(, "mov", pcp)
+
+#define raw_cpu_write_1(pcp, val) percpu_to_op(, "mov", (pcp), val)
+#define raw_cpu_write_2(pcp, val) percpu_to_op(, "mov", (pcp), val)
+#define raw_cpu_write_4(pcp, val) percpu_to_op(, "mov", (pcp), val)
+#define raw_cpu_add_1(pcp, val) percpu_add_op(, (pcp), val)
+#define raw_cpu_add_2(pcp, val) percpu_add_op(, (pcp), val)
+#define raw_cpu_add_4(pcp, val) percpu_add_op(, (pcp), val)
+#define raw_cpu_and_1(pcp, val) percpu_to_op(, "and", (pcp), val)
+#define raw_cpu_and_2(pcp, val) percpu_to_op(, "and", (pcp), val)
+#define raw_cpu_and_4(pcp, val) percpu_to_op(, "and", (pcp), val)
+#define raw_cpu_or_1(pcp, val) percpu_to_op(, "or", (pcp), val)
+#define raw_cpu_or_2(pcp, val) percpu_to_op(, "or", (pcp), val)
+#define raw_cpu_or_4(pcp, val) percpu_to_op(, "or", (pcp), val)
+
+/*
+ * raw_cpu_xchg() can use a load-store since it is not required to be
+ * IRQ-safe.
+ */
+#define raw_percpu_xchg_op(var, nval) \
+({ \
+ typeof(var) pxo_ret__ = raw_cpu_read(var); \
+ raw_cpu_write(var, (nval)); \
+ pxo_ret__; \
+})
+
+#define raw_cpu_xchg_1(pcp, val) raw_percpu_xchg_op(pcp, val)
+#define raw_cpu_xchg_2(pcp, val) raw_percpu_xchg_op(pcp, val)
+#define raw_cpu_xchg_4(pcp, val) raw_percpu_xchg_op(pcp, val)
+
+#define this_cpu_read_1(pcp) percpu_from_op(volatile, "mov", pcp)
+#define this_cpu_read_2(pcp) percpu_from_op(volatile, "mov", pcp)
+#define this_cpu_read_4(pcp) percpu_from_op(volatile, "mov", pcp)
+#define this_cpu_write_1(pcp, val) percpu_to_op(volatile, "mov", (pcp), val)
+#define this_cpu_write_2(pcp, val) percpu_to_op(volatile, "mov", (pcp), val)
+#define this_cpu_write_4(pcp, val) percpu_to_op(volatile, "mov", (pcp), val)
+#define this_cpu_add_1(pcp, val) percpu_add_op(volatile, (pcp), val)
+#define this_cpu_add_2(pcp, val) percpu_add_op(volatile, (pcp), val)
+#define this_cpu_add_4(pcp, val) percpu_add_op(volatile, (pcp), val)
+#define this_cpu_and_1(pcp, val) percpu_to_op(volatile, "and", (pcp), val)
+#define this_cpu_and_2(pcp, val) percpu_to_op(volatile, "and", (pcp), val)
+#define this_cpu_and_4(pcp, val) percpu_to_op(volatile, "and", (pcp), val)
+#define this_cpu_or_1(pcp, val) percpu_to_op(volatile, "or", (pcp), val)
+#define this_cpu_or_2(pcp, val) percpu_to_op(volatile, "or", (pcp), val)
+#define this_cpu_or_4(pcp, val) percpu_to_op(volatile, "or", (pcp), val)
+#define this_cpu_xchg_1(pcp, nval) percpu_xchg_op(volatile, pcp, nval)
+#define this_cpu_xchg_2(pcp, nval) percpu_xchg_op(volatile, pcp, nval)
+#define this_cpu_xchg_4(pcp, nval) percpu_xchg_op(volatile, pcp, nval)
+
+#define raw_cpu_add_return_1(pcp, val) percpu_add_return_op(, pcp, val)
+#define raw_cpu_add_return_2(pcp, val) percpu_add_return_op(, pcp, val)
+#define raw_cpu_add_return_4(pcp, val) percpu_add_return_op(, pcp, val)
+#define raw_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(, pcp, oval, nval)
+#define raw_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(, pcp, oval, nval)
+#define raw_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(, pcp, oval, nval)
+
+#define this_cpu_add_return_1(pcp, val) percpu_add_return_op(volatile, pcp, val)
+#define this_cpu_add_return_2(pcp, val) percpu_add_return_op(volatile, pcp, val)
+#define this_cpu_add_return_4(pcp, val) percpu_add_return_op(volatile, pcp, val)
+#define this_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(volatile, pcp, oval, nval)
+#define this_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(volatile, pcp, oval, nval)
+#define this_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(volatile, pcp, oval, nval)
#ifdef CONFIG_X86_CMPXCHG64
#define percpu_cmpxchg8b_double(pcp1, pcp2, o1, o2, n1, n2) \
* 32 bit must fall back to generic operations.
*/
#ifdef CONFIG_X86_64
-#define raw_cpu_read_8(pcp) percpu_from_op("mov", pcp)
-#define raw_cpu_write_8(pcp, val) percpu_to_op("mov", (pcp), val)
-#define raw_cpu_add_8(pcp, val) percpu_add_op((pcp), val)
-#define raw_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val)
-#define raw_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val)
-#define raw_cpu_add_return_8(pcp, val) percpu_add_return_op(pcp, val)
-#define raw_cpu_xchg_8(pcp, nval) percpu_xchg_op(pcp, nval)
-#define raw_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
-
-#define this_cpu_read_8(pcp) percpu_from_op("mov", pcp)
-#define this_cpu_write_8(pcp, val) percpu_to_op("mov", (pcp), val)
-#define this_cpu_add_8(pcp, val) percpu_add_op((pcp), val)
-#define this_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val)
-#define this_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val)
-#define this_cpu_add_return_8(pcp, val) percpu_add_return_op(pcp, val)
-#define this_cpu_xchg_8(pcp, nval) percpu_xchg_op(pcp, nval)
-#define this_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
+#define raw_cpu_read_8(pcp) percpu_from_op(, "mov", pcp)
+#define raw_cpu_write_8(pcp, val) percpu_to_op(, "mov", (pcp), val)
+#define raw_cpu_add_8(pcp, val) percpu_add_op(, (pcp), val)
+#define raw_cpu_and_8(pcp, val) percpu_to_op(, "and", (pcp), val)
+#define raw_cpu_or_8(pcp, val) percpu_to_op(, "or", (pcp), val)
+#define raw_cpu_add_return_8(pcp, val) percpu_add_return_op(, pcp, val)
+#define raw_cpu_xchg_8(pcp, nval) raw_percpu_xchg_op(pcp, nval)
+#define raw_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(, pcp, oval, nval)
+
+#define this_cpu_read_8(pcp) percpu_from_op(volatile, "mov", pcp)
+#define this_cpu_write_8(pcp, val) percpu_to_op(volatile, "mov", (pcp), val)
+#define this_cpu_add_8(pcp, val) percpu_add_op(volatile, (pcp), val)
+#define this_cpu_and_8(pcp, val) percpu_to_op(volatile, "and", (pcp), val)
+#define this_cpu_or_8(pcp, val) percpu_to_op(volatile, "or", (pcp), val)
+#define this_cpu_add_return_8(pcp, val) percpu_add_return_op(volatile, pcp, val)
+#define this_cpu_xchg_8(pcp, nval) percpu_xchg_op(volatile, pcp, nval)
+#define this_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(volatile, pcp, oval, nval)
/*
* Pretty complex macro to generate cmpxchg16 instruction. The instruction
* from the initial startup. We map APIC_BASE very early in page_setup(),
* so this is correct in the x86 case.
*/
-#define raw_smp_processor_id() (this_cpu_read(cpu_number))
+#define raw_smp_processor_id() this_cpu_read(cpu_number)
+#define __smp_processor_id() __this_cpu_read(cpu_number)
#ifdef CONFIG_X86_32
extern int safe_smp_processor_id(void);
#define __parainstructions_end NULL
#endif
+/*
+ * Currently, the max observed size in the kernel code is
+ * JUMP_LABEL_NOP_SIZE/RELATIVEJUMP_SIZE, which are 5.
+ * Raise it if needed.
+ */
+#define POKE_MAX_OPCODE_SIZE 5
+
+struct text_poke_loc {
+ void *detour;
+ void *addr;
+ size_t len;
+ const char opcode[POKE_MAX_OPCODE_SIZE];
+};
+
extern void text_poke_early(void *addr, const void *opcode, size_t len);
/*
extern void *text_poke_kgdb(void *addr, const void *opcode, size_t len);
extern int poke_int3_handler(struct pt_regs *regs);
extern void text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
+extern void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries);
extern int after_bootmem;
extern __ro_after_init struct mm_struct *poking_mm;
extern __ro_after_init unsigned long poking_addr;
#include <linux/kdebug.h>
#include <linux/kprobes.h>
#include <linux/mmu_context.h>
+#include <linux/bsearch.h>
#include <asm/text-patching.h>
#include <asm/alternative.h>
#include <asm/sections.h>
sync_core();
}
-static bool bp_patching_in_progress;
-static void *bp_int3_handler, *bp_int3_addr;
+static struct bp_patching_desc {
+ struct text_poke_loc *vec;
+ int nr_entries;
+} bp_patching;
+
+static int patch_cmp(const void *key, const void *elt)
+{
+ struct text_poke_loc *tp = (struct text_poke_loc *) elt;
+
+ if (key < tp->addr)
+ return -1;
+ if (key > tp->addr)
+ return 1;
+ return 0;
+}
+NOKPROBE_SYMBOL(patch_cmp);
int poke_int3_handler(struct pt_regs *regs)
{
+ struct text_poke_loc *tp;
+ unsigned char int3 = 0xcc;
+ void *ip;
+
/*
* Having observed our INT3 instruction, we now must observe
- * bp_patching_in_progress.
+ * bp_patching.nr_entries.
*
- * in_progress = TRUE INT3
+ * nr_entries != 0 INT3
* WMB RMB
- * write INT3 if (in_progress)
+ * write INT3 if (nr_entries)
*
- * Idem for bp_int3_handler.
+ * Idem for other elements in bp_patching.
*/
smp_rmb();
- if (likely(!bp_patching_in_progress))
+ if (likely(!bp_patching.nr_entries))
return 0;
- if (user_mode(regs) || regs->ip != (unsigned long)bp_int3_addr)
+ if (user_mode(regs))
return 0;
- /* set up the specified breakpoint handler */
- regs->ip = (unsigned long) bp_int3_handler;
+ /*
+ * Discount the sizeof(int3). See text_poke_bp_batch().
+ */
+ ip = (void *) regs->ip - sizeof(int3);
+
+ /*
+ * Skip the binary search if there is a single member in the vector.
+ */
+ if (unlikely(bp_patching.nr_entries > 1)) {
+ tp = bsearch(ip, bp_patching.vec, bp_patching.nr_entries,
+ sizeof(struct text_poke_loc),
+ patch_cmp);
+ if (!tp)
+ return 0;
+ } else {
+ tp = bp_patching.vec;
+ if (tp->addr != ip)
+ return 0;
+ }
+
+ /* set up the specified breakpoint detour */
+ regs->ip = (unsigned long) tp->detour;
return 1;
}
NOKPROBE_SYMBOL(poke_int3_handler);
/**
- * text_poke_bp() -- update instructions on live kernel on SMP
- * @addr: address to patch
- * @opcode: opcode of new instruction
- * @len: length to copy
- * @handler: address to jump to when the temporary breakpoint is hit
+ * text_poke_bp_batch() -- update instructions on live kernel on SMP
+ * @tp: vector of instructions to patch
+ * @nr_entries: number of entries in the vector
*
* Modify multi-byte instruction by using int3 breakpoint on SMP.
* We completely avoid stop_machine() here, and achieve the
* synchronization using int3 breakpoint.
*
* The way it is done:
- * - add a int3 trap to the address that will be patched
+ * - For each entry in the vector:
+ * - add a int3 trap to the address that will be patched
* - sync cores
- * - update all but the first byte of the patched range
+ * - For each entry in the vector:
+ * - update all but the first byte of the patched range
* - sync cores
- * - replace the first byte (int3) by the first byte of
- * replacing opcode
+ * - For each entry in the vector:
+ * - replace the first byte (int3) by the first byte of
+ * replacing opcode
* - sync cores
*/
-void text_poke_bp(void *addr, const void *opcode, size_t len, void *handler)
+void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries)
{
+ int patched_all_but_first = 0;
unsigned char int3 = 0xcc;
-
- bp_int3_handler = handler;
- bp_int3_addr = (u8 *)addr + sizeof(int3);
- bp_patching_in_progress = true;
+ unsigned int i;
lockdep_assert_held(&text_mutex);
+ bp_patching.vec = tp;
+ bp_patching.nr_entries = nr_entries;
+
/*
* Corresponding read barrier in int3 notifier for making sure the
- * in_progress and handler are correctly ordered wrt. patching.
+ * nr_entries and handler are correctly ordered wrt. patching.
*/
smp_wmb();
- text_poke(addr, &int3, sizeof(int3));
+ /*
+ * First step: add a int3 trap to the address that will be patched.
+ */
+ for (i = 0; i < nr_entries; i++)
+ text_poke(tp[i].addr, &int3, sizeof(int3));
on_each_cpu(do_sync_core, NULL, 1);
- if (len - sizeof(int3) > 0) {
- /* patch all but the first byte */
- text_poke((char *)addr + sizeof(int3),
- (const char *) opcode + sizeof(int3),
- len - sizeof(int3));
+ /*
+ * Second step: update all but the first byte of the patched range.
+ */
+ for (i = 0; i < nr_entries; i++) {
+ if (tp[i].len - sizeof(int3) > 0) {
+ text_poke((char *)tp[i].addr + sizeof(int3),
+ (const char *)tp[i].opcode + sizeof(int3),
+ tp[i].len - sizeof(int3));
+ patched_all_but_first++;
+ }
+ }
+
+ if (patched_all_but_first) {
/*
* According to Intel, this core syncing is very likely
* not necessary and we'd be safe even without it. But
on_each_cpu(do_sync_core, NULL, 1);
}
- /* patch the first byte */
- text_poke(addr, opcode, sizeof(int3));
+ /*
+ * Third step: replace the first byte (int3) by the first byte of
+ * replacing opcode.
+ */
+ for (i = 0; i < nr_entries; i++)
+ text_poke(tp[i].addr, tp[i].opcode, sizeof(int3));
on_each_cpu(do_sync_core, NULL, 1);
/*
* sync_core() implies an smp_mb() and orders this store against
* the writing of the new instruction.
*/
- bp_patching_in_progress = false;
+ bp_patching.vec = NULL;
+ bp_patching.nr_entries = 0;
}
+/**
+ * text_poke_bp() -- update instructions on live kernel on SMP
+ * @addr: address to patch
+ * @opcode: opcode of new instruction
+ * @len: length to copy
+ * @handler: address to jump to when the temporary breakpoint is hit
+ *
+ * Update a single instruction with the vector in the stack, avoiding
+ * dynamically allocated memory. This function should be used when it is
+ * not possible to allocate memory.
+ */
+void text_poke_bp(void *addr, const void *opcode, size_t len, void *handler)
+{
+ struct text_poke_loc tp = {
+ .detour = handler,
+ .addr = addr,
+ .len = len,
+ };
+
+ if (len > POKE_MAX_OPCODE_SIZE) {
+ WARN_ONCE(1, "len is larger than %d\n", POKE_MAX_OPCODE_SIZE);
+ return;
+ }
+
+ memcpy((void *)tp.opcode, opcode, len);
+
+ text_poke_bp_batch(&tp, 1);
+}
BUG();
}
-static void __ref __jump_label_transform(struct jump_entry *entry,
- enum jump_label_type type,
- int init)
+static void __jump_label_set_jump_code(struct jump_entry *entry,
+ enum jump_label_type type,
+ union jump_code_union *code,
+ int init)
{
- union jump_code_union jmp;
const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP };
const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5];
- const void *expect, *code;
+ const void *expect;
int line;
- jmp.jump = 0xe9;
- jmp.offset = jump_entry_target(entry) -
- (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE);
+ code->jump = 0xe9;
+ code->offset = jump_entry_target(entry) -
+ (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE);
- if (type == JUMP_LABEL_JMP) {
- if (init) {
- expect = default_nop; line = __LINE__;
- } else {
- expect = ideal_nop; line = __LINE__;
- }
-
- code = &jmp.code;
+ if (init) {
+ expect = default_nop; line = __LINE__;
+ } else if (type == JUMP_LABEL_JMP) {
+ expect = ideal_nop; line = __LINE__;
} else {
- if (init) {
- expect = default_nop; line = __LINE__;
- } else {
- expect = &jmp.code; line = __LINE__;
- }
-
- code = ideal_nop;
+ expect = code->code; line = __LINE__;
}
if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE))
bug_at((void *)jump_entry_code(entry), line);
+ if (type == JUMP_LABEL_NOP)
+ memcpy(code, ideal_nop, JUMP_LABEL_NOP_SIZE);
+}
+
+static void __ref __jump_label_transform(struct jump_entry *entry,
+ enum jump_label_type type,
+ int init)
+{
+ union jump_code_union code;
+
+ __jump_label_set_jump_code(entry, type, &code, init);
+
/*
* As long as only a single processor is running and the code is still
* not marked as RO, text_poke_early() can be used; Checking that
* always nop being the 'currently valid' instruction
*/
if (init || system_state == SYSTEM_BOOTING) {
- text_poke_early((void *)jump_entry_code(entry), code,
+ text_poke_early((void *)jump_entry_code(entry), &code,
JUMP_LABEL_NOP_SIZE);
return;
}
- text_poke_bp((void *)jump_entry_code(entry), code, JUMP_LABEL_NOP_SIZE,
+ text_poke_bp((void *)jump_entry_code(entry), &code, JUMP_LABEL_NOP_SIZE,
(void *)jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE);
}
mutex_unlock(&text_mutex);
}
+#define TP_VEC_MAX (PAGE_SIZE / sizeof(struct text_poke_loc))
+static struct text_poke_loc tp_vec[TP_VEC_MAX];
+static int tp_vec_nr;
+
+bool arch_jump_label_transform_queue(struct jump_entry *entry,
+ enum jump_label_type type)
+{
+ struct text_poke_loc *tp;
+ void *entry_code;
+
+ if (system_state == SYSTEM_BOOTING) {
+ /*
+ * Fallback to the non-batching mode.
+ */
+ arch_jump_label_transform(entry, type);
+ return true;
+ }
+
+ /*
+ * No more space in the vector, tell upper layer to apply
+ * the queue before continuing.
+ */
+ if (tp_vec_nr == TP_VEC_MAX)
+ return false;
+
+ tp = &tp_vec[tp_vec_nr];
+
+ entry_code = (void *)jump_entry_code(entry);
+
+ /*
+ * The INT3 handler will do a bsearch in the queue, so we need entries
+ * to be sorted. We can survive an unsorted list by rejecting the entry,
+ * forcing the generic jump_label code to apply the queue. Warning once,
+ * to raise the attention to the case of an unsorted entry that is
+ * better not happen, because, in the worst case we will perform in the
+ * same way as we do without batching - with some more overhead.
+ */
+ if (tp_vec_nr > 0) {
+ int prev = tp_vec_nr - 1;
+ struct text_poke_loc *prev_tp = &tp_vec[prev];
+
+ if (WARN_ON_ONCE(prev_tp->addr > entry_code))
+ return false;
+ }
+
+ __jump_label_set_jump_code(entry, type,
+ (union jump_code_union *) &tp->opcode, 0);
+
+ tp->addr = entry_code;
+ tp->detour = entry_code + JUMP_LABEL_NOP_SIZE;
+ tp->len = JUMP_LABEL_NOP_SIZE;
+
+ tp_vec_nr++;
+
+ return true;
+}
+
+void arch_jump_label_transform_apply(void)
+{
+ if (!tp_vec_nr)
+ return;
+
+ mutex_lock(&text_mutex);
+ text_poke_bp_batch(tp_vec, tp_vec_nr);
+ mutex_unlock(&text_mutex);
+
+ tp_vec_nr = 0;
+}
+
static enum {
JL_STATE_START,
JL_STATE_NO_UPDATE,
rcu_read_lock(); \
local_devdata = rcu_dereference(devdata); \
if (local_devdata) \
- p = snprintf(buf, PAGE_SIZE, "%ld\n", \
+ p = snprintf(buf, PAGE_SIZE, "%lld\n", \
atomic64_read(&local_devdata->counters->_name)); \
rcu_read_unlock(); \
return p; \
}
for (i = 0; i < (NX842_HIST_SLOTS - 2); i++) {
- bytes = snprintf(p, bytes_remain, "%u-%uus:\t%ld\n",
+ bytes = snprintf(p, bytes_remain, "%u-%uus:\t%lld\n",
i ? (2<<(i-1)) : 0, (2<<i)-1,
atomic64_read(×[i]));
bytes_remain -= bytes;
}
/* The last bucket holds everything over
* 2<<(NX842_HIST_SLOTS - 2) us */
- bytes = snprintf(p, bytes_remain, "%uus - :\t%ld\n",
+ bytes = snprintf(p, bytes_remain, "%uus - :\t%lld\n",
2<<(NX842_HIST_SLOTS - 2),
atomic64_read(×[(NX842_HIST_SLOTS - 1)]));
p += bytes;
int rc;
int i;
- lockdep_assert_held_exclusive(&devices_rwsem);
+ lockdep_assert_held_write(&devices_rwsem);
ida_init(&inuse);
xa_for_each (&devices, index, device) {
char buf[IB_DEVICE_NAME_MAX];
static void tty_ldisc_close(struct tty_struct *tty, struct tty_ldisc *ld)
{
- lockdep_assert_held_exclusive(&tty->ldisc_sem);
+ lockdep_assert_held_write(&tty->ldisc_sem);
WARN_ON(!test_bit(TTY_LDISC_OPEN, &tty->flags));
clear_bit(TTY_LDISC_OPEN, &tty->flags);
if (ld->ops->close)
struct tty_ldisc *disc = tty_ldisc_get(tty, ld);
int r;
- lockdep_assert_held_exclusive(&tty->ldisc_sem);
+ lockdep_assert_held_write(&tty->ldisc_sem);
if (IS_ERR(disc))
return PTR_ERR(disc);
tty->ldisc = disc;
*/
static void tty_ldisc_kill(struct tty_struct *tty)
{
- lockdep_assert_held_exclusive(&tty->ldisc_sem);
+ lockdep_assert_held_write(&tty->ldisc_sem);
if (!tty->ldisc)
return;
/*
struct tty_ldisc *ld;
int retval;
- lockdep_assert_held_exclusive(&tty->ldisc_sem);
+ lockdep_assert_held_write(&tty->ldisc_sem);
ld = tty_ldisc_get(tty, disc);
if (IS_ERR(ld)) {
BUG_ON(disc == N_TTY);
unsigned flags = 0;
if (iov_iter_rw(iter) == WRITE) {
- lockdep_assert_held_exclusive(&inode->i_rwsem);
+ lockdep_assert_held_write(&inode->i_rwsem);
flags |= IOMAP_WRITE;
} else {
lockdep_assert_held(&inode->i_rwsem);
#include <linux/types.h>
typedef struct {
- long long counter;
+ s64 counter;
} atomic64_t;
#define ATOMIC64_INIT(i) { (i) }
-extern long long atomic64_read(const atomic64_t *v);
-extern void atomic64_set(atomic64_t *v, long long i);
+extern s64 atomic64_read(const atomic64_t *v);
+extern void atomic64_set(atomic64_t *v, s64 i);
#define atomic64_set_release(v, i) atomic64_set((v), (i))
#define ATOMIC64_OP(op) \
-extern void atomic64_##op(long long a, atomic64_t *v);
+extern void atomic64_##op(s64 a, atomic64_t *v);
#define ATOMIC64_OP_RETURN(op) \
-extern long long atomic64_##op##_return(long long a, atomic64_t *v);
+extern s64 atomic64_##op##_return(s64 a, atomic64_t *v);
#define ATOMIC64_FETCH_OP(op) \
-extern long long atomic64_fetch_##op(long long a, atomic64_t *v);
+extern s64 atomic64_fetch_##op(s64 a, atomic64_t *v);
#define ATOMIC64_OPS(op) ATOMIC64_OP(op) ATOMIC64_OP_RETURN(op) ATOMIC64_FETCH_OP(op)
#undef ATOMIC64_OP_RETURN
#undef ATOMIC64_OP
-extern long long atomic64_dec_if_positive(atomic64_t *v);
+extern s64 atomic64_dec_if_positive(atomic64_t *v);
#define atomic64_dec_if_positive atomic64_dec_if_positive
-extern long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n);
-extern long long atomic64_xchg(atomic64_t *v, long long new);
-extern long long atomic64_fetch_add_unless(atomic64_t *v, long long a, long long u);
+extern s64 atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n);
+extern s64 atomic64_xchg(atomic64_t *v, s64 new);
+extern s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u);
#define atomic64_fetch_add_unless atomic64_fetch_add_unless
#endif /* _ASM_GENERIC_ATOMIC64_H */
enum jump_label_type type);
extern void arch_jump_label_transform_static(struct jump_entry *entry,
enum jump_label_type type);
+extern bool arch_jump_label_transform_queue(struct jump_entry *entry,
+ enum jump_label_type type);
+extern void arch_jump_label_transform_apply(void);
extern int jump_label_text_reserved(void *start, void *end);
extern void static_key_slow_inc(struct static_key *key);
extern void static_key_slow_dec(struct static_key *key);
struct lock_list *parent;
};
-/*
- * We record lock dependency chains, so that we can cache them:
+/**
+ * struct lock_chain - lock dependency chain record
+ *
+ * @irq_context: the same as irq_context in held_lock below
+ * @depth: the number of held locks in this chain
+ * @base: the index in chain_hlocks for this chain
+ * @entry: the collided lock chains in lock_chain hash list
+ * @chain_key: the hash key of this lock_chain
*/
struct lock_chain {
- /* see BUILD_BUG_ON()s in lookup_chain_cache() */
+ /* see BUILD_BUG_ON()s in add_chain_cache() */
unsigned int irq_context : 2,
depth : 6,
base : 24;
};
#define MAX_LOCKDEP_KEYS_BITS 13
-/*
- * Subtract one because we offset hlock->class_idx by 1 in order
- * to make 0 mean no class. This avoids overflowing the class_idx
- * bitfield and hitting the BUG in hlock_class().
- */
-#define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1)
+#define MAX_LOCKDEP_KEYS (1UL << MAX_LOCKDEP_KEYS_BITS)
+#define INITIAL_CHAIN_KEY -1
struct held_lock {
/*
u64 waittime_stamp;
u64 holdtime_stamp;
#endif
+ /*
+ * class_idx is zero-indexed; it points to the element in
+ * lock_classes this held lock instance belongs to. class_idx is in
+ * the range from 0 to (MAX_LOCKDEP_KEYS-1) inclusive.
+ */
unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS;
/*
* The lock-stack is unified in that the lock chains of interrupt
extern asmlinkage void lockdep_sys_exit(void);
extern void lockdep_set_selftest_task(struct task_struct *task);
+extern void lockdep_init_task(struct task_struct *task);
+
extern void lockdep_off(void);
extern void lockdep_on(void);
WARN_ON(debug_locks && !lockdep_is_held(l)); \
} while (0)
-#define lockdep_assert_held_exclusive(l) do { \
+#define lockdep_assert_held_write(l) do { \
WARN_ON(debug_locks && !lockdep_is_held_type(l, 0)); \
} while (0)
#else /* !CONFIG_LOCKDEP */
+static inline void lockdep_init_task(struct task_struct *task)
+{
+}
+
static inline void lockdep_off(void)
{
}
#define lockdep_is_held_type(l, r) (1)
#define lockdep_assert_held(l) do { (void)(l); } while (0)
-#define lockdep_assert_held_exclusive(l) do { (void)(l); } while (0)
+#define lockdep_assert_held_write(l) do { (void)(l); } while (0)
#define lockdep_assert_held_read(l) do { (void)(l); } while (0)
#define lockdep_assert_held_once(l) do { (void)(l); } while (0)
{ .name = (_name), .key = (void *)(_key), }
static inline void lockdep_invariant_state(bool force) {}
-static inline void lockdep_init_task(struct task_struct *task) {}
static inline void lockdep_free_task(struct task_struct *task) {}
#ifdef CONFIG_LOCK_STAT
lock_release(&sem->rw_sem.dep_map, 1, ip);
#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
if (!read)
- sem->rw_sem.owner = RWSEM_OWNER_UNKNOWN;
+ atomic_long_set(&sem->rw_sem.owner, RWSEM_OWNER_UNKNOWN);
#endif
}
lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip);
#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
if (!read)
- sem->rw_sem.owner = current;
+ atomic_long_set(&sem->rw_sem.owner, (long)current);
#endif
}
*/
struct rw_semaphore {
atomic_long_t count;
-#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
/*
- * Write owner. Used as a speculative check to see
- * if the owner is running on the cpu.
+ * Write owner or one of the read owners as well flags regarding
+ * the current state of the rwsem. Can be used as a speculative
+ * check to see if the write owner is running on the cpu.
*/
- struct task_struct *owner;
+ atomic_long_t owner;
+#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
struct optimistic_spin_queue osq; /* spinner MCS lock */
#endif
raw_spinlock_t wait_lock;
};
/*
- * Setting bit 1 of the owner field but not bit 0 will indicate
+ * Setting all bits of the owner field except bit 0 will indicate
* that the rwsem is writer-owned with an unknown owner.
*/
-#define RWSEM_OWNER_UNKNOWN ((struct task_struct *)-2L)
+#define RWSEM_OWNER_UNKNOWN (-2L)
/* In all implementations count != 0 means locked */
static inline int rwsem_is_locked(struct rw_semaphore *sem)
#endif
#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
-#define __RWSEM_OPT_INIT(lockname) , .osq = OSQ_LOCK_UNLOCKED, .owner = NULL
+#define __RWSEM_OPT_INIT(lockname) , .osq = OSQ_LOCK_UNLOCKED
#else
#define __RWSEM_OPT_INIT(lockname)
#endif
#define __RWSEM_INITIALIZER(name) \
{ __RWSEM_INIT_COUNT(name), \
+ .owner = ATOMIC_LONG_INIT(0), \
.wait_list = LIST_HEAD_INIT((name).wait_list), \
.wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock) \
__RWSEM_OPT_INIT(name) \
head->lastp = &head->first;
}
+static inline bool wake_q_empty(struct wake_q_head *head)
+{
+ return head->first == WAKE_Q_TAIL;
+}
+
extern void wake_q_add(struct wake_q_head *head, struct task_struct *task);
extern void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task);
extern void wake_up_q(struct wake_q_head *head);
#endif /* !SMP */
-/*
- * smp_processor_id(): get the current CPU ID.
+/**
+ * raw_processor_id() - get the current (unstable) CPU id
+ *
+ * For then you know what you are doing and need an unstable
+ * CPU id.
+ */
+
+/**
+ * smp_processor_id() - get the current (stable) CPU id
+ *
+ * This is the normal accessor to the CPU id and should be used
+ * whenever possible.
+ *
+ * The CPU id is stable when:
*
- * if DEBUG_PREEMPT is enabled then we check whether it is
- * used in a preemption-safe way. (smp_processor_id() is safe
- * if it's used in a preemption-off critical section, or in
- * a thread that is bound to the current CPU.)
+ * - IRQs are disabled;
+ * - preemption is disabled;
+ * - the task is CPU affine.
*
- * NOTE: raw_smp_processor_id() is for internal use only
- * (smp_processor_id() is the preferred variant), but in rare
- * instances it might also be used to turn off false positives
- * (i.e. smp_processor_id() use that the debugging code reports but
- * which use for some reason is legal). Don't use this to hack around
- * the warning message, as your code might not work under PREEMPT.
+ * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
+ * when smp_processor_id() is used when the CPU id is not stable.
*/
+
+/*
+ * Allow the architecture to differentiate between a stable and unstable read.
+ * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
+ * regular asm read for the stable.
+ */
+#ifndef __smp_processor_id
+#define __smp_processor_id(x) raw_smp_processor_id(x)
+#endif
+
#ifdef CONFIG_DEBUG_PREEMPT
extern unsigned int debug_smp_processor_id(void);
# define smp_processor_id() debug_smp_processor_id()
#else
-# define smp_processor_id() raw_smp_processor_id()
+# define smp_processor_id() __smp_processor_id()
#endif
-#define get_cpu() ({ preempt_disable(); smp_processor_id(); })
+#define get_cpu() ({ preempt_disable(); __smp_processor_id(); })
#define put_cpu() preempt_enable()
/*
#ifdef CONFIG_64BIT
typedef struct {
- long counter;
+ s64 counter;
} atomic64_t;
#endif
.softirqs_enabled = 1,
#endif
#ifdef CONFIG_LOCKDEP
+ .lockdep_depth = 0, /* no locks held yet */
+ .curr_chain_key = INITIAL_CHAIN_KEY,
.lockdep_recursion = 0,
#endif
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
p->pagefault_disabled = 0;
#ifdef CONFIG_LOCKDEP
- p->lockdep_depth = 0; /* no locks held yet */
- p->curr_chain_key = 0;
- p->lockdep_recursion = 0;
lockdep_init_task(p);
#endif
FUTEX_WRITE
};
+/**
+ * futex_setup_timer - set up the sleeping hrtimer.
+ * @time: ptr to the given timeout value
+ * @timeout: the hrtimer_sleeper structure to be set up
+ * @flags: futex flags
+ * @range_ns: optional range in ns
+ *
+ * Return: Initialized hrtimer_sleeper structure or NULL if no timeout
+ * value given
+ */
+static inline struct hrtimer_sleeper *
+futex_setup_timer(ktime_t *time, struct hrtimer_sleeper *timeout,
+ int flags, u64 range_ns)
+{
+ if (!time)
+ return NULL;
+
+ hrtimer_init_on_stack(&timeout->timer, (flags & FLAGS_CLOCKRT) ?
+ CLOCK_REALTIME : CLOCK_MONOTONIC,
+ HRTIMER_MODE_ABS);
+ hrtimer_init_sleeper(timeout, current);
+
+ /*
+ * If range_ns is 0, calling hrtimer_set_expires_range_ns() is
+ * effectively the same as calling hrtimer_set_expires().
+ */
+ hrtimer_set_expires_range_ns(&timeout->timer, *time, range_ns);
+
+ return timeout;
+}
+
/**
* get_futex_key() - Get parameters which are the keys for a futex
* @uaddr: virtual address of the futex
static int futex_wait(u32 __user *uaddr, unsigned int flags, u32 val,
ktime_t *abs_time, u32 bitset)
{
- struct hrtimer_sleeper timeout, *to = NULL;
+ struct hrtimer_sleeper timeout, *to;
struct restart_block *restart;
struct futex_hash_bucket *hb;
struct futex_q q = futex_q_init;
return -EINVAL;
q.bitset = bitset;
- if (abs_time) {
- to = &timeout;
-
- hrtimer_init_on_stack(&to->timer, (flags & FLAGS_CLOCKRT) ?
- CLOCK_REALTIME : CLOCK_MONOTONIC,
- HRTIMER_MODE_ABS);
- hrtimer_init_sleeper(to, current);
- hrtimer_set_expires_range_ns(&to->timer, *abs_time,
- current->timer_slack_ns);
- }
-
+ to = futex_setup_timer(abs_time, &timeout, flags,
+ current->timer_slack_ns);
retry:
/*
* Prepare to wait on uaddr. On success, holds hb lock and increments
static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
ktime_t *time, int trylock)
{
- struct hrtimer_sleeper timeout, *to = NULL;
+ struct hrtimer_sleeper timeout, *to;
struct futex_pi_state *pi_state = NULL;
struct rt_mutex_waiter rt_waiter;
struct futex_hash_bucket *hb;
if (refill_pi_state_cache())
return -ENOMEM;
- if (time) {
- to = &timeout;
- hrtimer_init_on_stack(&to->timer, CLOCK_REALTIME,
- HRTIMER_MODE_ABS);
- hrtimer_init_sleeper(to, current);
- hrtimer_set_expires(&to->timer, *time);
- }
+ to = futex_setup_timer(time, &timeout, FLAGS_CLOCKRT, 0);
retry:
ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q.key, FUTEX_WRITE);
u32 val, ktime_t *abs_time, u32 bitset,
u32 __user *uaddr2)
{
- struct hrtimer_sleeper timeout, *to = NULL;
+ struct hrtimer_sleeper timeout, *to;
struct futex_pi_state *pi_state = NULL;
struct rt_mutex_waiter rt_waiter;
struct futex_hash_bucket *hb;
if (!bitset)
return -EINVAL;
- if (abs_time) {
- to = &timeout;
- hrtimer_init_on_stack(&to->timer, (flags & FLAGS_CLOCKRT) ?
- CLOCK_REALTIME : CLOCK_MONOTONIC,
- HRTIMER_MODE_ABS);
- hrtimer_init_sleeper(to, current);
- hrtimer_set_expires_range_ns(&to->timer, *abs_time,
- current->timer_slack_ns);
- }
+ to = futex_setup_timer(abs_time, &timeout, flags,
+ current->timer_slack_ns);
/*
* The waiter is allocated on our stack, manipulated by the requeue
const struct jump_entry *jea = a;
const struct jump_entry *jeb = b;
+ /*
+ * Entrires are sorted by key.
+ */
if (jump_entry_key(jea) < jump_entry_key(jeb))
return -1;
if (jump_entry_key(jea) > jump_entry_key(jeb))
return 1;
+ /*
+ * In the batching mode, entries should also be sorted by the code
+ * inside the already sorted list of entries, enabling a bsearch in
+ * the vector.
+ */
+ if (jump_entry_code(jea) < jump_entry_code(jeb))
+ return -1;
+
+ if (jump_entry_code(jea) > jump_entry_code(jeb))
+ return 1;
+
return 0;
}
return enabled ^ branch;
}
+static bool jump_label_can_update(struct jump_entry *entry, bool init)
+{
+ /*
+ * Cannot update code that was in an init text area.
+ */
+ if (!init && jump_entry_is_init(entry))
+ return false;
+
+ if (!kernel_text_address(jump_entry_code(entry))) {
+ WARN_ONCE(1, "can't patch jump_label at %pS", (void *)jump_entry_code(entry));
+ return false;
+ }
+
+ return true;
+}
+
+#ifndef HAVE_JUMP_LABEL_BATCH
static void __jump_label_update(struct static_key *key,
struct jump_entry *entry,
struct jump_entry *stop,
bool init)
{
for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
- /*
- * An entry->code of 0 indicates an entry which has been
- * disabled because it was in an init text area.
- */
- if (init || !jump_entry_is_init(entry)) {
- if (kernel_text_address(jump_entry_code(entry)))
- arch_jump_label_transform(entry, jump_label_type(entry));
- else
- WARN_ONCE(1, "can't patch jump_label at %pS",
- (void *)jump_entry_code(entry));
+ if (jump_label_can_update(entry, init))
+ arch_jump_label_transform(entry, jump_label_type(entry));
+ }
+}
+#else
+static void __jump_label_update(struct static_key *key,
+ struct jump_entry *entry,
+ struct jump_entry *stop,
+ bool init)
+{
+ for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
+
+ if (!jump_label_can_update(entry, init))
+ continue;
+
+ if (!arch_jump_label_transform_queue(entry, jump_label_type(entry))) {
+ /*
+ * Queue is full: Apply the current queue and try again.
+ */
+ arch_jump_label_transform_apply();
+ BUG_ON(!arch_jump_label_transform_queue(entry, jump_label_type(entry)));
}
}
+ arch_jump_label_transform_apply();
}
+#endif
void __init jump_label_init(void)
{
# and is generally not a function of system call inputs.
KCOV_INSTRUMENT := n
-obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o rwsem-xadd.o
+obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o
ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_lockdep.o = $(CC_FLAGS_FTRACE)
DECLARE_PER_CPU(unsigned long, lockevents[lockevent_num]);
/*
- * The purpose of the lock event counting subsystem is to provide a low
- * overhead way to record the number of specific locking events by using
- * percpu counters. It is the percpu sum that matters, not specifically
- * how many of them happens in each cpu.
- *
- * It is possible that the same percpu counter may be modified in both
- * the process and interrupt contexts. For architectures that perform
- * percpu operation with multiple instructions, it is possible to lose
- * count if a process context percpu update is interrupted in the middle
- * and the same counter is updated in the interrupt context. Therefore,
- * the generated percpu sum may not be precise. The error, if any, should
- * be small and insignificant.
- *
- * For those architectures that do multi-instruction percpu operation,
- * preemption in the middle and moving the task to another cpu may cause
- * a larger error in the count. Again, this will be few and far between.
- * Given the imprecise nature of the count and the possibility of resetting
- * the count and doing the measurement again, this is not really a big
- * problem.
- *
- * To get a better picture of what is happening under the hood, it is
- * suggested that a few measurements should be taken with the counts
- * reset in between to stamp out outliner because of these possible
- * error conditions.
- *
- * To minimize overhead, we use __this_cpu_*() in all cases except when
- * CONFIG_DEBUG_PREEMPT is defined. In this particular case, this_cpu_*()
- * will be used to avoid the appearance of unwanted BUG messages.
- */
-#ifdef CONFIG_DEBUG_PREEMPT
-#define lockevent_percpu_inc(x) this_cpu_inc(x)
-#define lockevent_percpu_add(x, v) this_cpu_add(x, v)
-#else
-#define lockevent_percpu_inc(x) __this_cpu_inc(x)
-#define lockevent_percpu_add(x, v) __this_cpu_add(x, v)
-#endif
-
-/*
- * Increment the PV qspinlock statistical counters
+ * Increment the statistical counters. use raw_cpu_inc() because of lower
+ * overhead and we don't care if we loose the occasional update.
*/
static inline void __lockevent_inc(enum lock_events event, bool cond)
{
if (cond)
- lockevent_percpu_inc(lockevents[event]);
+ raw_cpu_inc(lockevents[event]);
}
#define lockevent_inc(ev) __lockevent_inc(LOCKEVENT_ ##ev, true)
static inline void __lockevent_add(enum lock_events event, int inc)
{
- lockevent_percpu_add(lockevents[event], inc);
+ raw_cpu_add(lockevents[event], inc);
}
#define lockevent_add(ev, c) __lockevent_add(LOCKEVENT_ ##ev, c)
LOCK_EVENT(rwsem_sleep_writer) /* # of writer sleeps */
LOCK_EVENT(rwsem_wake_reader) /* # of reader wakeups */
LOCK_EVENT(rwsem_wake_writer) /* # of writer wakeups */
-LOCK_EVENT(rwsem_opt_wlock) /* # of write locks opt-spin acquired */
-LOCK_EVENT(rwsem_opt_fail) /* # of failed opt-spinnings */
+LOCK_EVENT(rwsem_opt_rlock) /* # of opt-acquired read locks */
+LOCK_EVENT(rwsem_opt_wlock) /* # of opt-acquired write locks */
+LOCK_EVENT(rwsem_opt_fail) /* # of failed optspins */
+LOCK_EVENT(rwsem_opt_nospin) /* # of disabled optspins */
+LOCK_EVENT(rwsem_opt_norspin) /* # of disabled reader-only optspins */
+LOCK_EVENT(rwsem_opt_rlock2) /* # of opt-acquired 2ndary read locks */
LOCK_EVENT(rwsem_rlock) /* # of read locks acquired */
LOCK_EVENT(rwsem_rlock_fast) /* # of fast read locks acquired */
LOCK_EVENT(rwsem_rlock_fail) /* # of failed read lock acquisitions */
-LOCK_EVENT(rwsem_rtrylock) /* # of read trylock calls */
+LOCK_EVENT(rwsem_rlock_handoff) /* # of read lock handoffs */
LOCK_EVENT(rwsem_wlock) /* # of write locks acquired */
LOCK_EVENT(rwsem_wlock_fail) /* # of failed write lock acquisitions */
-LOCK_EVENT(rwsem_wtrylock) /* # of write trylock calls */
+LOCK_EVENT(rwsem_wlock_handoff) /* # of write lock handoffs */
static
#endif
struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
+static DECLARE_BITMAP(lock_classes_in_use, MAX_LOCKDEP_KEYS);
static inline struct lock_class *hlock_class(struct held_lock *hlock)
{
- if (!hlock->class_idx) {
+ unsigned int class_idx = hlock->class_idx;
+
+ /* Don't re-read hlock->class_idx, can't use READ_ONCE() on bitfield */
+ barrier();
+
+ if (!test_bit(class_idx, lock_classes_in_use)) {
/*
* Someone passed in garbage, we give up.
*/
DEBUG_LOCKS_WARN_ON(1);
return NULL;
}
- return lock_classes + hlock->class_idx - 1;
+
+ /*
+ * At this point, if the passed hlock->class_idx is still garbage,
+ * we just have to live with it
+ */
+ return lock_classes + class_idx;
}
#ifdef CONFIG_LOCK_STAT
return k0 | (u64)k1 << 32;
}
+void lockdep_init_task(struct task_struct *task)
+{
+ task->lockdep_depth = 0; /* no locks held yet */
+ task->curr_chain_key = INITIAL_CHAIN_KEY;
+ task->lockdep_recursion = 0;
+}
+
void lockdep_off(void)
{
current->lockdep_recursion++;
return 0;
}
-/*
- * Stack-trace: tightly packed array of stack backtrace
- * addresses. Protected by the graph_lock.
- */
-unsigned long nr_stack_trace_entries;
-static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
-
static void print_lockdep_off(const char *bug_msg)
{
printk(KERN_DEBUG "%s\n", bug_msg);
#endif
}
+unsigned long nr_stack_trace_entries;
+
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
+/*
+ * Stack-trace: tightly packed array of stack backtrace
+ * addresses. Protected by the graph_lock.
+ */
+static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
+
static int save_trace(struct lock_trace *trace)
{
unsigned long *entries = stack_trace + nr_stack_trace_entries;
return 1;
}
+#endif
unsigned int nr_hardirq_chains;
unsigned int nr_softirq_chains;
DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
#endif
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
/*
* Locking printouts:
*/
#undef LOCKDEP_STATE
[LOCK_USED] = "INITIAL USE",
};
+#endif
const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
{
static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
{
+ /*
+ * The usage character defaults to '.' (i.e., irqs disabled and not in
+ * irq context), which is the safest usage category.
+ */
char c = '.';
- if (class->usage_mask & lock_flag(bit + LOCK_USAGE_DIR_MASK))
+ /*
+ * The order of the following usage checks matters, which will
+ * result in the outcome character as follows:
+ *
+ * - '+': irq is enabled and not in irq context
+ * - '-': in irq context and irq is disabled
+ * - '?': in irq context and irq is enabled
+ */
+ if (class->usage_mask & lock_flag(bit + LOCK_USAGE_DIR_MASK)) {
c = '+';
- if (class->usage_mask & lock_flag(bit)) {
- c = '-';
- if (class->usage_mask & lock_flag(bit + LOCK_USAGE_DIR_MASK))
+ if (class->usage_mask & lock_flag(bit))
c = '?';
- }
+ } else if (class->usage_mask & lock_flag(bit))
+ c = '-';
return c;
}
/*
* We can be called locklessly through debug_show_all_locks() so be
* extra careful, the hlock might have been released and cleared.
+ *
+ * If this indeed happens, lets pretend it does not hurt to continue
+ * to print the lock unless the hlock class_idx does not point to a
+ * registered class. The rationale here is: since we don't attempt
+ * to distinguish whether we are in this situation, if it just
+ * happened we can't count on class_idx to tell either.
*/
- unsigned int class_idx = hlock->class_idx;
-
- /* Don't re-read hlock->class_idx, can't use READ_ONCE() on bitfields: */
- barrier();
+ struct lock_class *lock = hlock_class(hlock);
- if (!class_idx || (class_idx - 1) >= MAX_LOCKDEP_KEYS) {
+ if (!lock) {
printk(KERN_CONT "<RELEASED>\n");
return;
}
printk(KERN_CONT "%p", hlock->instance);
- print_lock_name(lock_classes + class_idx - 1);
+ print_lock_name(lock);
printk(KERN_CONT ", at: %pS\n", (void *)hlock->acquire_ip);
}
* Huh! same key, different name? Did someone trample
* on some memory? We're most confused.
*/
- WARN_ON_ONCE(class->name != lock->name);
+ WARN_ON_ONCE(class->name != lock->name &&
+ lock->key != &__lockdep_no_validate__);
return class;
}
}
static bool check_lock_chain_key(struct lock_chain *chain)
{
#ifdef CONFIG_PROVE_LOCKING
- u64 chain_key = 0;
+ u64 chain_key = INITIAL_CHAIN_KEY;
int i;
for (i = chain->base; i < chain->base + chain->depth; i++)
- chain_key = iterate_chain_key(chain_key, chain_hlocks[i] + 1);
+ chain_key = iterate_chain_key(chain_key, chain_hlocks[i]);
/*
* The 'unsigned long long' casts avoid that a compiler warning
* is reported when building tools/lib/lockdep.
return NULL;
}
nr_lock_classes++;
+ __set_bit(class - lock_classes, lock_classes_in_use);
debug_atomic_inc(nr_unused_locks);
class->key = key;
class->name = lock->name;
#define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1)
/*
- * The circular_queue and helpers is used to implement the
- * breadth-first search(BFS)algorithem, by which we can build
- * the shortest path from the next lock to be acquired to the
- * previous held lock if there is a circular between them.
+ * The circular_queue and helpers are used to implement graph
+ * breadth-first search (BFS) algorithm, by which we can determine
+ * whether there is a path from a lock to another. In deadlock checks,
+ * a path from the next lock to be acquired to a previous held lock
+ * indicates that adding the <prev> -> <next> lock dependency will
+ * produce a circle in the graph. Breadth-first search instead of
+ * depth-first search is used in order to find the shortest (circular)
+ * path.
*/
struct circular_queue {
- unsigned long element[MAX_CIRCULAR_QUEUE_SIZE];
+ struct lock_list *element[MAX_CIRCULAR_QUEUE_SIZE];
unsigned int front, rear;
};
return ((cq->rear + 1) & CQ_MASK) == cq->front;
}
-static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem)
+static inline int __cq_enqueue(struct circular_queue *cq, struct lock_list *elem)
{
if (__cq_full(cq))
return -1;
return 0;
}
-static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem)
+/*
+ * Dequeue an element from the circular_queue, return a lock_list if
+ * the queue is not empty, or NULL if otherwise.
+ */
+static inline struct lock_list * __cq_dequeue(struct circular_queue *cq)
{
+ struct lock_list * lock;
+
if (__cq_empty(cq))
- return -1;
+ return NULL;
- *elem = cq->element[cq->front];
+ lock = cq->element[cq->front];
cq->front = (cq->front + 1) & CQ_MASK;
- return 0;
+
+ return lock;
}
static inline unsigned int __cq_get_elem_count(struct circular_queue *cq)
return depth;
}
+/*
+ * Return the forward or backward dependency list.
+ *
+ * @lock: the lock_list to get its class's dependency list
+ * @offset: the offset to struct lock_class to determine whether it is
+ * locks_after or locks_before
+ */
+static inline struct list_head *get_dep_list(struct lock_list *lock, int offset)
+{
+ void *lock_class = lock->class;
+
+ return lock_class + offset;
+}
+
+/*
+ * Forward- or backward-dependency search, used for both circular dependency
+ * checking and hardirq-unsafe/softirq-unsafe checking.
+ */
static int __bfs(struct lock_list *source_entry,
void *data,
int (*match)(struct lock_list *entry, void *data),
struct lock_list **target_entry,
- int forward)
+ int offset)
{
struct lock_list *entry;
+ struct lock_list *lock;
struct list_head *head;
struct circular_queue *cq = &lock_cq;
int ret = 1;
goto exit;
}
- if (forward)
- head = &source_entry->class->locks_after;
- else
- head = &source_entry->class->locks_before;
-
+ head = get_dep_list(source_entry, offset);
if (list_empty(head))
goto exit;
__cq_init(cq);
- __cq_enqueue(cq, (unsigned long)source_entry);
+ __cq_enqueue(cq, source_entry);
- while (!__cq_empty(cq)) {
- struct lock_list *lock;
-
- __cq_dequeue(cq, (unsigned long *)&lock);
+ while ((lock = __cq_dequeue(cq))) {
if (!lock->class) {
ret = -2;
goto exit;
}
- if (forward)
- head = &lock->class->locks_after;
- else
- head = &lock->class->locks_before;
+ head = get_dep_list(lock, offset);
DEBUG_LOCKS_WARN_ON(!irqs_disabled());
goto exit;
}
- if (__cq_enqueue(cq, (unsigned long)entry)) {
+ if (__cq_enqueue(cq, entry)) {
ret = -1;
goto exit;
}
int (*match)(struct lock_list *entry, void *data),
struct lock_list **target_entry)
{
- return __bfs(src_entry, data, match, target_entry, 1);
+ return __bfs(src_entry, data, match, target_entry,
+ offsetof(struct lock_class, locks_after));
}
int (*match)(struct lock_list *entry, void *data),
struct lock_list **target_entry)
{
- return __bfs(src_entry, data, match, target_entry, 0);
+ return __bfs(src_entry, data, match, target_entry,
+ offsetof(struct lock_class, locks_before));
}
-/*
- * Recursive, forwards-direction lock-dependency checking, used for
- * both noncyclic checking and for hardirq-unsafe/softirq-unsafe
- * checking.
- */
-
static void print_lock_trace(struct lock_trace *trace, unsigned int spaces)
{
unsigned long *entries = stack_trace + trace->offset;
* Print a dependency chain entry (this is only done when a deadlock
* has been detected):
*/
-static noinline int
+static noinline void
print_circular_bug_entry(struct lock_list *target, int depth)
{
if (debug_locks_silent)
- return 0;
+ return;
printk("\n-> #%u", depth);
print_lock_name(target->class);
printk(KERN_CONT ":\n");
print_lock_trace(&target->trace, 6);
- return 0;
}
static void
* When a circular dependency is detected, print the
* header first:
*/
-static noinline int
+static noinline void
print_circular_bug_header(struct lock_list *entry, unsigned int depth,
struct held_lock *check_src,
struct held_lock *check_tgt)
struct task_struct *curr = current;
if (debug_locks_silent)
- return 0;
+ return;
pr_warn("\n");
pr_warn("======================================================\n");
pr_warn("\nthe existing dependency chain (in reverse order) is:\n");
print_circular_bug_entry(entry, depth);
-
- return 0;
}
static inline int class_equal(struct lock_list *entry, void *data)
return entry->class == data;
}
-static noinline int print_circular_bug(struct lock_list *this,
- struct lock_list *target,
- struct held_lock *check_src,
- struct held_lock *check_tgt)
+static noinline void print_circular_bug(struct lock_list *this,
+ struct lock_list *target,
+ struct held_lock *check_src,
+ struct held_lock *check_tgt)
{
struct task_struct *curr = current;
struct lock_list *parent;
int depth;
if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
+ return;
if (!save_trace(&this->trace))
- return 0;
+ return;
depth = get_lock_depth(target);
printk("\nstack backtrace:\n");
dump_stack();
-
- return 0;
}
-static noinline int print_bfs_bug(int ret)
+static noinline void print_bfs_bug(int ret)
{
if (!debug_locks_off_graph_unlock())
- return 0;
+ return;
/*
* Breadth-first-search failed, graph got corrupted?
*/
WARN(1, "lockdep bfs error:%d\n", ret);
-
- return 0;
}
static int noop_count(struct lock_list *entry, void *data)
}
/*
- * Prove that the dependency graph starting at <entry> can not
- * lead to <target>. Print an error and return 0 if it does.
+ * Check that the dependency graph starting at <src> can lead to
+ * <target> or not. Print an error and return 0 if it does.
*/
static noinline int
-check_noncircular(struct lock_list *root, struct lock_class *target,
- struct lock_list **target_entry)
+check_path(struct lock_class *target, struct lock_list *src_entry,
+ struct lock_list **target_entry)
{
- int result;
+ int ret;
+
+ ret = __bfs_forwards(src_entry, (void *)target, class_equal,
+ target_entry);
+
+ if (unlikely(ret < 0))
+ print_bfs_bug(ret);
+
+ return ret;
+}
+
+/*
+ * Prove that the dependency graph starting at <src> can not
+ * lead to <target>. If it can, there is a circle when adding
+ * <target> -> <src> dependency.
+ *
+ * Print an error and return 0 if it does.
+ */
+static noinline int
+check_noncircular(struct held_lock *src, struct held_lock *target,
+ struct lock_trace *trace)
+{
+ int ret;
+ struct lock_list *uninitialized_var(target_entry);
+ struct lock_list src_entry = {
+ .class = hlock_class(src),
+ .parent = NULL,
+ };
debug_atomic_inc(nr_cyclic_checks);
- result = __bfs_forwards(root, target, class_equal, target_entry);
+ ret = check_path(hlock_class(target), &src_entry, &target_entry);
- return result;
+ if (unlikely(!ret)) {
+ if (!trace->nr_entries) {
+ /*
+ * If save_trace fails here, the printing might
+ * trigger a WARN but because of the !nr_entries it
+ * should not do bad things.
+ */
+ save_trace(trace);
+ }
+
+ print_circular_bug(&src_entry, target_entry, src, target);
+ }
+
+ return ret;
}
+#ifdef CONFIG_LOCKDEP_SMALL
+/*
+ * Check that the dependency graph starting at <src> can lead to
+ * <target> or not. If it can, <src> -> <target> dependency is already
+ * in the graph.
+ *
+ * Print an error and return 2 if it does or 1 if it does not.
+ */
static noinline int
-check_redundant(struct lock_list *root, struct lock_class *target,
- struct lock_list **target_entry)
+check_redundant(struct held_lock *src, struct held_lock *target)
{
- int result;
+ int ret;
+ struct lock_list *uninitialized_var(target_entry);
+ struct lock_list src_entry = {
+ .class = hlock_class(src),
+ .parent = NULL,
+ };
debug_atomic_inc(nr_redundant_checks);
- result = __bfs_forwards(root, target, class_equal, target_entry);
+ ret = check_path(hlock_class(target), &src_entry, &target_entry);
- return result;
+ if (!ret) {
+ debug_atomic_inc(nr_redundant);
+ ret = 2;
+ } else if (ret < 0)
+ ret = 0;
+
+ return ret;
}
+#endif
-#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
+#ifdef CONFIG_TRACE_IRQFLAGS
static inline int usage_accumulate(struct lock_list *entry, void *mask)
{
*/
static void __used
print_shortest_lock_dependencies(struct lock_list *leaf,
- struct lock_list *root)
+ struct lock_list *root)
{
struct lock_list *entry = leaf;
int depth;
entry = get_lock_parent(entry);
depth--;
} while (entry && (depth >= 0));
-
- return;
}
static void
printk("\n *** DEADLOCK ***\n\n");
}
-static int
+static void
print_bad_irq_dependency(struct task_struct *curr,
struct lock_list *prev_root,
struct lock_list *next_root,
const char *irqclass)
{
if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
+ return;
pr_warn("\n");
pr_warn("=====================================================\n");
pr_warn("\nthe dependencies between %s-irq-safe lock and the holding lock:\n", irqclass);
if (!save_trace(&prev_root->trace))
- return 0;
+ return;
print_shortest_lock_dependencies(backwards_entry, prev_root);
pr_warn("\nthe dependencies between the lock to be acquired");
pr_warn(" and %s-irq-unsafe lock:\n", irqclass);
if (!save_trace(&next_root->trace))
- return 0;
+ return;
print_shortest_lock_dependencies(forwards_entry, next_root);
pr_warn("\nstack backtrace:\n");
dump_stack();
-
- return 0;
}
static const char *state_names[] = {
this.class = hlock_class(prev);
ret = __bfs_backwards(&this, &usage_mask, usage_accumulate, NULL);
- if (ret < 0)
- return print_bfs_bug(ret);
+ if (ret < 0) {
+ print_bfs_bug(ret);
+ return 0;
+ }
usage_mask &= LOCKF_USED_IN_IRQ_ALL;
if (!usage_mask)
that.class = hlock_class(next);
ret = find_usage_forwards(&that, forward_mask, &target_entry1);
- if (ret < 0)
- return print_bfs_bug(ret);
+ if (ret < 0) {
+ print_bfs_bug(ret);
+ return 0;
+ }
if (ret == 1)
return ret;
backward_mask = original_mask(target_entry1->class->usage_mask);
ret = find_usage_backwards(&this, backward_mask, &target_entry);
- if (ret < 0)
- return print_bfs_bug(ret);
+ if (ret < 0) {
+ print_bfs_bug(ret);
+ return 0;
+ }
if (DEBUG_LOCKS_WARN_ON(ret == 1))
return 1;
if (DEBUG_LOCKS_WARN_ON(ret == -1))
return 1;
- return print_bad_irq_dependency(curr, &this, &that,
- target_entry, target_entry1,
- prev, next,
- backward_bit, forward_bit,
- state_name(backward_bit));
+ print_bad_irq_dependency(curr, &this, &that,
+ target_entry, target_entry1,
+ prev, next,
+ backward_bit, forward_bit,
+ state_name(backward_bit));
+
+ return 0;
}
static void inc_chains(void)
nr_process_chains++;
}
-#endif
+#endif /* CONFIG_TRACE_IRQFLAGS */
static void
-print_deadlock_scenario(struct held_lock *nxt,
- struct held_lock *prv)
+print_deadlock_scenario(struct held_lock *nxt, struct held_lock *prv)
{
struct lock_class *next = hlock_class(nxt);
struct lock_class *prev = hlock_class(prv);
printk(" May be due to missing lock nesting notation\n\n");
}
-static int
+static void
print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
struct held_lock *next)
{
if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
+ return;
pr_warn("\n");
pr_warn("============================================\n");
pr_warn("\nstack backtrace:\n");
dump_stack();
-
- return 0;
}
/*
* Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read
*/
static int
-check_deadlock(struct task_struct *curr, struct held_lock *next,
- struct lockdep_map *next_instance, int read)
+check_deadlock(struct task_struct *curr, struct held_lock *next)
{
struct held_lock *prev;
struct held_lock *nest = NULL;
* Allow read-after-read recursion of the same
* lock class (i.e. read_lock(lock)+read_lock(lock)):
*/
- if ((read == 2) && prev->read)
+ if ((next->read == 2) && prev->read)
return 2;
/*
if (nest)
return 2;
- return print_deadlock_bug(curr, prev, next);
+ print_deadlock_bug(curr, prev, next);
+ return 0;
}
return 1;
}
/*
* There was a chain-cache miss, and we are about to add a new dependency
- * to a previous lock. We recursively validate the following rules:
+ * to a previous lock. We validate the following rules:
*
* - would the adding of the <prev> -> <next> dependency create a
* circular dependency in the graph? [== circular deadlock]
check_prev_add(struct task_struct *curr, struct held_lock *prev,
struct held_lock *next, int distance, struct lock_trace *trace)
{
- struct lock_list *uninitialized_var(target_entry);
struct lock_list *entry;
- struct lock_list this;
int ret;
if (!hlock_class(prev)->key || !hlock_class(next)->key) {
/*
* Prove that the new <prev> -> <next> dependency would not
* create a circular dependency in the graph. (We do this by
- * forward-recursing into the graph starting at <next>, and
- *
checking whether we can reach <prev>.)
+ * a breadth-first search into the graph starting at <next>,
+ *
and check whether we can reach <prev>.)
*
- * We are using global variables to control the recursion, to
- * keep the stackframe size of the recursive functions low:
+ * The search is limited by the size of the circular queue (i.e.,
+ * MAX_CIRCULAR_QUEUE_SIZE) which keeps track of a breadth of nodes
+ * in the graph whose neighbours are to be checked.
*/
- this.class = hlock_class(next);
- this.parent = NULL;
- ret = check_noncircular(&this, hlock_class(prev), &target_entry);
- if (unlikely(!ret)) {
- if (!trace->nr_entries) {
- /*
- * If save_trace fails here, the printing might
- * trigger a WARN but because of the !nr_entries it
- * should not do bad things.
- */
- save_trace(trace);
- }
- return print_circular_bug(&this, target_entry, next, prev);
- }
- else if (unlikely(ret < 0))
- return print_bfs_bug(ret);
+ ret = check_noncircular(next, prev, trace);
+ if (unlikely(ret <= 0))
+ return 0;
if (!check_irq_usage(curr, prev, next))
return 0;
}
}
+#ifdef CONFIG_LOCKDEP_SMALL
/*
* Is the <prev> -> <next> link redundant?
*/
- this.class = hlock_class(prev);
- this.parent = NULL;
- ret = check_redundant(&this, hlock_class(next), &target_entry);
- if (!ret) {
- debug_atomic_inc(nr_redundant);
- return 2;
- }
- if (ret < 0)
- return print_bfs_bug(ret);
-
+ ret = check_redundant(prev, next);
+ if (ret != 1)
+ return ret;
+#endif
if (!trace->nr_entries && !save_trace(trace))
return 0;
print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next)
{
struct held_lock *hlock;
- u64 chain_key = 0;
+ u64 chain_key = INITIAL_CHAIN_KEY;
int depth = curr->lockdep_depth;
- int i;
+ int i = get_first_held_lock(curr, hlock_next);
- printk("depth: %u\n", depth + 1);
- for (i = get_first_held_lock(curr, hlock_next); i < depth; i++) {
+ printk("depth: %u (irq_context %u)\n", depth - i + 1,
+ hlock_next->irq_context);
+ for (; i < depth; i++) {
hlock = curr->held_locks + i;
chain_key = print_chain_key_iteration(hlock->class_idx, chain_key);
static void print_chain_keys_chain(struct lock_chain *chain)
{
int i;
- u64 chain_key = 0;
+ u64 chain_key = INITIAL_CHAIN_KEY;
int class_id;
printk("depth: %u\n", chain->depth);
for (i = 0; i < chain->depth; i++) {
class_id = chain_hlocks[chain->base + i];
- chain_key = print_chain_key_iteration(class_id + 1, chain_key);
+ chain_key = print_chain_key_iteration(class_id, chain_key);
print_lock_name(lock_classes + class_id);
printk("\n");
}
for (j = 0; j < chain->depth - 1; j++, i++) {
- id = curr->held_locks[i].class_idx - 1;
+ id = curr->held_locks[i].class_idx;
if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) {
print_collision(curr, hlock, chain);
if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
chain->base = nr_chain_hlocks;
for (j = 0; j < chain->depth - 1; j++, i++) {
- int lock_id = curr->held_locks[i].class_idx - 1;
+ int lock_id = curr->held_locks[i].class_idx;
chain_hlocks[chain->base + j] = lock_id;
}
chain_hlocks[chain->base + j] = class - lock_classes;
return 1;
}
-static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
- struct held_lock *hlock, int chain_head, u64 chain_key)
+static int validate_chain(struct task_struct *curr,
+ struct held_lock *hlock,
+ int chain_head, u64 chain_key)
{
/*
* Trylock needs to maintain the stack of held locks, but it
* - is softirq-safe, if this lock is hardirq-unsafe
*
* And check whether the new lock's dependency graph
- * could lead back to the previous lock.
+ * could lead back to the previous lock:
*
- * any of these scenarios could lead to a deadlock. If
- * All validations
+ * - within the current held-lock stack
+ * - across our accumulated lock dependency records
+ *
+ * any of these scenarios could lead to a deadlock.
*/
- int ret = check_deadlock(curr, hlock, lock, hlock->read);
+ /*
+ * The simple case: does the current hold the same lock
+ * already?
+ */
+ int ret = check_deadlock(curr, hlock);
if (!ret)
return 0;
}
#else
static inline int validate_chain(struct task_struct *curr,
- struct lockdep_map *lock, struct held_lock *hlock,
- int chain_head, u64 chain_key)
+ struct held_lock *hlock,
+ int chain_head, u64 chain_key)
{
return 1;
}
-
-static void print_lock_trace(struct lock_trace *trace, unsigned int spaces)
-{
-}
-#endif
+#endif /* CONFIG_PROVE_LOCKING */
/*
* We are building curr_chain_key incrementally, so double-check
#ifdef CONFIG_DEBUG_LOCKDEP
struct held_lock *hlock, *prev_hlock = NULL;
unsigned int i;
- u64 chain_key = 0;
+ u64 chain_key = INITIAL_CHAIN_KEY;
for (i = 0; i < curr->lockdep_depth; i++) {
hlock = curr->held_locks + i;
(unsigned long long)hlock->prev_chain_key);
return;
}
+
/*
- * Whoops ran out of static storage again?
+ * hlock->class_idx can't go beyond MAX_LOCKDEP_KEYS, but is
+ * it registered lock class index?
*/
- if (DEBUG_LOCKS_WARN_ON(hlock->class_idx > MAX_LOCKDEP_KEYS))
+ if (DEBUG_LOCKS_WARN_ON(!test_bit(hlock->class_idx, lock_classes_in_use)))
return;
if (prev_hlock && (prev_hlock->irq_context !=
hlock->irq_context))
- chain_key = 0;
+ chain_key = INITIAL_CHAIN_KEY;
chain_key = iterate_chain_key(chain_key, hlock->class_idx);
prev_hlock = hlock;
}
#endif
}
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
static int mark_lock(struct task_struct *curr, struct held_lock *this,
enum lock_usage_bit new_bit);
-#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
-
-
-static void
-print_usage_bug_scenario(struct held_lock *lock)
+static void print_usage_bug_scenario(struct held_lock *lock)
{
struct lock_class *class = hlock_class(lock);
printk("\n *** DEADLOCK ***\n\n");
}
-static int
+static void
print_usage_bug(struct task_struct *curr, struct held_lock *this,
enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
{
if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
+ return;
pr_warn("\n");
pr_warn("================================\n");
pr_warn("\nstack backtrace:\n");
dump_stack();
-
- return 0;
}
/*
valid_state(struct task_struct *curr, struct held_lock *this,
enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
{
- if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit)))
- return print_usage_bug(curr, this, bad_bit, new_bit);
+ if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) {
+ print_usage_bug(curr, this, bad_bit, new_bit);
+ return 0;
+ }
return 1;
}
/*
* print irq inversion bug:
*/
-static int
+static void
print_irq_inversion_bug(struct task_struct *curr,
struct lock_list *root, struct lock_list *other,
struct held_lock *this, int forwards,
int depth;
if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
+ return;
pr_warn("\n");
pr_warn("========================================================\n");
pr_warn("\nthe shortest dependencies between 2nd lock and 1st lock:\n");
if (!save_trace(&root->trace))
- return 0;
+ return;
print_shortest_lock_dependencies(other, root);
pr_warn("\nstack backtrace:\n");
dump_stack();
-
- return 0;
}
/*
root.parent = NULL;
root.class = hlock_class(this);
ret = find_usage_forwards(&root, lock_flag(bit), &target_entry);
- if (ret < 0)
- return print_bfs_bug(ret);
+ if (ret < 0) {
+ print_bfs_bug(ret);
+ return 0;
+ }
if (ret == 1)
return ret;
- return print_irq_inversion_bug(curr, &root, target_entry,
- this, 1, irqclass);
+ print_irq_inversion_bug(curr, &root, target_entry,
+ this, 1, irqclass);
+ return 0;
}
/*
root.parent = NULL;
root.class = hlock_class(this);
ret = find_usage_backwards(&root, lock_flag(bit), &target_entry);
- if (ret < 0)
- return print_bfs_bug(ret);
+ if (ret < 0) {
+ print_bfs_bug(ret);
+ return 0;
+ }
if (ret == 1)
return ret;
- return print_irq_inversion_bug(curr, &root, target_entry,
- this, 0, irqclass);
+ print_irq_inversion_bug(curr, &root, target_entry,
+ this, 0, irqclass);
+ return 0;
}
void print_irqtrace_events(struct task_struct *curr)
* Validate that the lock dependencies don't have conflicting usage
* states.
*/
- if ((!read || !dir || STRICT_READ_CHECKS) &&
+ if ((!read || STRICT_READ_CHECKS) &&
!usage(curr, this, excl_bit, state_name(new_bit & ~LOCK_USAGE_READ_MASK)))
return 0;
debug_atomic_inc(redundant_softirqs_off);
}
-static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
+static int
+mark_usage(struct task_struct *curr, struct held_lock *hlock, int check)
{
+ if (!check)
+ goto lock_used;
+
/*
* If non-trylock use in a hardirq or softirq context, then
* mark the lock as used in these contexts:
}
}
+lock_used:
+ /* mark it as used: */
+ if (!mark_lock(curr, hlock, LOCK_USED))
+ return 0;
+
return 1;
}
return 0;
}
-#else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
-
-static inline
-int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit)
-{
- WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */
- return 1;
-}
-
-static inline int mark_irqflags(struct task_struct *curr,
- struct held_lock *hlock)
-{
- return 1;
-}
-
-static inline unsigned int task_irq_context(struct task_struct *task)
-{
- return 0;
-}
-
-static inline int separate_irq_context(struct task_struct *curr,
- struct held_lock *hlock)
-{
- return 0;
-}
-
-#endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
-
/*
* Mark a lock with a usage bit, and validate the state transition:
*/
{
unsigned int new_mask = 1 << new_bit, ret = 1;
+ if (new_bit >= LOCK_USAGE_STATES) {
+ DEBUG_LOCKS_WARN_ON(1);
+ return 0;
+ }
+
/*
* If already set then do not dirty the cacheline,
* nor do any checks:
return 0;
switch (new_bit) {
-#define LOCKDEP_STATE(__STATE) \
- case LOCK_USED_IN_##__STATE: \
- case LOCK_USED_IN_##__STATE##_READ: \
- case LOCK_ENABLED_##__STATE: \
- case LOCK_ENABLED_##__STATE##_READ:
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
- ret = mark_lock_irq(curr, this, new_bit);
- if (!ret)
- return 0;
- break;
case LOCK_USED:
debug_atomic_dec(nr_unused_locks);
break;
default:
- if (!debug_locks_off_graph_unlock())
+ ret = mark_lock_irq(curr, this, new_bit);
+ if (!ret)
return 0;
- WARN_ON(1);
- return 0;
}
graph_unlock();
return ret;
}
+#else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
+
+static inline int
+mark_usage(struct task_struct *curr, struct held_lock *hlock, int check)
+{
+ return 1;
+}
+
+static inline unsigned int task_irq_context(struct task_struct *task)
+{
+ return 0;
+}
+
+static inline int separate_irq_context(struct task_struct *curr,
+ struct held_lock *hlock)
+{
+ return 0;
+}
+
+#endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
+
/*
* Initialize a lock instance's lock-class mapping info:
*/
struct lock_class_key __lockdep_no_validate__;
EXPORT_SYMBOL_GPL(__lockdep_no_validate__);
-static int
+static void
print_lock_nested_lock_not_held(struct task_struct *curr,
struct held_lock *hlock,
unsigned long ip)
{
if (!debug_locks_off())
- return 0;
+ return;
if (debug_locks_silent)
- return 0;
+ return;
pr_warn("\n");
pr_warn("==================================\n");
pr_warn("\nstack backtrace:\n");
dump_stack();
-
- return 0;
}
static int __lock_is_held(const struct lockdep_map *lock, int read);
if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
return 0;
- class_idx = class - lock_classes + 1;
+ class_idx = class - lock_classes;
if (depth) {
hlock = curr->held_locks + depth - 1;
if (hlock->class_idx == class_idx && nest_lock) {
- if (hlock->references) {
- /*
- * Check: unsigned int references:12, overflow.
- */
- if (DEBUG_LOCKS_WARN_ON(hlock->references == (1 << 12)-1))
- return 0;
+ if (!references)
+ references++;
+ if (!hlock->references)
hlock->references++;
- } else {
- hlock->references = 2;
- }
- return 1;
+ hlock->references += references;
+
+ /* Overflow */
+ if (DEBUG_LOCKS_WARN_ON(hlock->references < references))
+ return 0;
+
+ return 2;
}
}
#endif
hlock->pin_count = pin_count;
- if (check && !mark_irqflags(curr, hlock))
- return 0;
-
- /* mark it as used: */
- if (!mark_lock(curr, hlock, LOCK_USED))
+ /* Initialize the lock usage bit */
+ if (!mark_usage(curr, hlock, check))
return 0;
/*
* the hash, not class->key.
*/
/*
- * Whoops, we did it again.. ran straight out of our static allocation.
+ * Whoops, we did it again.. class_idx is invalid.
*/
- if (DEBUG_LOCKS_WARN_ON(class_idx > MAX_LOCKDEP_KEYS))
+ if (DEBUG_LOCKS_WARN_ON(!test_bit(class_idx, lock_classes_in_use)))
return 0;
chain_key = curr->curr_chain_key;
/*
* How can we have a chain hash when we ain't got no keys?!
*/
- if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
+ if (DEBUG_LOCKS_WARN_ON(chain_key != INITIAL_CHAIN_KEY))
return 0;
chain_head = 1;
}
hlock->prev_chain_key = chain_key;
if (separate_irq_context(curr, hlock)) {
- chain_key = 0;
+ chain_key = INITIAL_CHAIN_KEY;
chain_head = 1;
}
chain_key = iterate_chain_key(chain_key, class_idx);
- if (nest_lock && !__lock_is_held(nest_lock, -1))
- return print_lock_nested_lock_not_held(curr, hlock, ip);
+ if (nest_lock && !__lock_is_held(nest_lock, -1)) {
+ print_lock_nested_lock_not_held(curr, hlock, ip);
+ return 0;
+ }
if (!debug_locks_silent) {
WARN_ON_ONCE(depth && !hlock_class(hlock - 1)->key);
WARN_ON_ONCE(!hlock_class(hlock)->key);
}
- if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
+ if (!validate_chain(curr, hlock, chain_head, chain_key))
return 0;
curr->curr_chain_key = chain_key;
return 1;
}
-static int
-print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
- unsigned long ip)
+static void print_unlock_imbalance_bug(struct task_struct *curr,
+ struct lockdep_map *lock,
+ unsigned long ip)
{
if (!debug_locks_off())
- return 0;
+ return;
if (debug_locks_silent)
- return 0;
+ return;
pr_warn("\n");
pr_warn("=====================================\n");
pr_warn("\nstack backtrace:\n");
dump_stack();
-
- return 0;
}
static int match_held_lock(const struct held_lock *hlock,
if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock))
return 0;
- if (hlock->class_idx == class - lock_classes + 1)
+ if (hlock->class_idx == class - lock_classes)
return 1;
}
}
static int reacquire_held_locks(struct task_struct *curr, unsigned int depth,
- int idx)
+ int idx, unsigned int *merged)
{
struct held_lock *hlock;
+ int first_idx = idx;
if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
return 0;
for (hlock = curr->held_locks + idx; idx < depth; idx++, hlock++) {
- if (!__lock_acquire(hlock->instance,
+ switch (__lock_acquire(hlock->instance,
hlock_class(hlock)->subclass,
hlock->trylock,
hlock->read, hlock->check,
hlock->hardirqs_off,
hlock->nest_lock, hlock->acquire_ip,
- hlock->references, hlock->pin_count))
+ hlock->references, hlock->pin_count)) {
+ case 0:
return 1;
+ case 1:
+ break;
+ case 2:
+ *merged += (idx == first_idx);
+ break;
+ default:
+ WARN_ON(1);
+ return 0;
+ }
}
return 0;
}
unsigned long ip)
{
struct task_struct *curr = current;
+ unsigned int depth, merged = 0;
struct held_lock *hlock;
struct lock_class *class;
- unsigned int depth;
int i;
if (unlikely(!debug_locks))
return 0;
hlock = find_held_lock(curr, lock, depth, &i);
- if (!hlock)
- return print_unlock_imbalance_bug(curr, lock, ip);
+ if (!hlock) {
+ print_unlock_imbalance_bug(curr, lock, ip);
+ return 0;
+ }
lockdep_init_map(lock, name, key, 0);
class = register_lock_class(lock, subclass, 0);
- hlock->class_idx = class - lock_classes + 1;
+ hlock->class_idx = class - lock_classes;
curr->lockdep_depth = i;
curr->curr_chain_key = hlock->prev_chain_key;
- if (reacquire_held_locks(curr, depth, i))
+ if (reacquire_held_locks(curr, depth, i, &merged))
return 0;
/*
* I took it apart and put it back together again, except now I have
* these 'spare' parts.. where shall I put them.
*/
- if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
+ if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - merged))
return 0;
return 1;
}
static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip)
{
struct task_struct *curr = current;
+ unsigned int depth, merged = 0;
struct held_lock *hlock;
- unsigned int depth;
int i;
if (unlikely(!debug_locks))
return 0;
hlock = find_held_lock(curr, lock, depth, &i);
- if (!hlock)
- return print_unlock_imbalance_bug(curr, lock, ip);
+ if (!hlock) {
+ print_unlock_imbalance_bug(curr, lock, ip);
+ return 0;
+ }
curr->lockdep_depth = i;
curr->curr_chain_key = hlock->prev_chain_key;
hlock->read = 1;
hlock->acquire_ip = ip;
- if (reacquire_held_locks(curr, depth, i))
+ if (reacquire_held_locks(curr, depth, i, &merged))
+ return 0;
+
+ /* Merging can't happen with unchanged classes.. */
+ if (DEBUG_LOCKS_WARN_ON(merged))
return 0;
/*
*/
if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
return 0;
+
return 1;
}
* @nested is an hysterical artifact, needs a tree wide cleanup.
*/
static int
-__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
+__lock_release(struct lockdep_map *lock, unsigned long ip)
{
struct task_struct *curr = current;
+ unsigned int depth, merged = 1;
struct held_lock *hlock;
- unsigned int depth;
int i;
if (unlikely(!debug_locks))
* So we're all set to release this lock.. wait what lock? We don't
* own any locks, you've been drinking again?
*/
- if (DEBUG_LOCKS_WARN_ON(depth <= 0))
- return print_unlock_imbalance_bug(curr, lock, ip);
+ if (depth <= 0) {
+ print_unlock_imbalance_bug(curr, lock, ip);
+ return 0;
+ }
/*
* Check whether the lock exists in the current stack
* of held locks:
*/
hlock = find_held_lock(curr, lock, depth, &i);
- if (!hlock)
- return print_unlock_imbalance_bug(curr, lock, ip);
+ if (!hlock) {
+ print_unlock_imbalance_bug(curr, lock, ip);
+ return 0;
+ }
if (hlock->instance == lock)
lock_release_holdtime(hlock);
if (i == depth-1)
return 1;
- if (reacquire_held_locks(curr, depth, i + 1))
+ if (reacquire_held_locks(curr, depth, i + 1, &merged))
return 0;
/*
* We had N bottles of beer on the wall, we drank one, but now
* there's not N-1 bottles of beer left on the wall...
+ * Pouring two of the bottles together is acceptable.
*/
- DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth-1);
+ DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - merged);
/*
* Since reacquire_held_locks() would have called check_chain_key()
check_flags(flags);
current->lockdep_recursion = 1;
trace_lock_release(lock, ip);
- if (__lock_release(lock, nested, ip))
+ if (__lock_release(lock, ip))
check_chain_key(current);
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
EXPORT_SYMBOL_GPL(lock_unpin_lock);
#ifdef CONFIG_LOCK_STAT
-static int
-print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
- unsigned long ip)
+static void print_lock_contention_bug(struct task_struct *curr,
+ struct lockdep_map *lock,
+ unsigned long ip)
{
if (!debug_locks_off())
- return 0;
+ return;
if (debug_locks_silent)
- return 0;
+ return;
pr_warn("\n");
pr_warn("=================================\n");
pr_warn("\nstack backtrace:\n");
dump_stack();
-
- return 0;
}
static void
int i;
raw_local_irq_save(flags);
- current->curr_chain_key = 0;
- current->lockdep_depth = 0;
- current->lockdep_recursion = 0;
+ lockdep_init_task(current);
memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
nr_hardirq_chains = 0;
nr_softirq_chains = 0;
return;
recalc:
- chain_key = 0;
+ chain_key = INITIAL_CHAIN_KEY;
for (i = chain->base; i < chain->base + chain->depth; i++)
- chain_key = iterate_chain_key(chain_key, chain_hlocks[i] + 1);
+ chain_key = iterate_chain_key(chain_key, chain_hlocks[i]);
if (chain->depth && chain->chain_key == chain_key)
return;
/* Overwrite the chain key for concurrent RCU readers. */
WRITE_ONCE(class->key, NULL);
WRITE_ONCE(class->name, NULL);
nr_lock_classes--;
+ __clear_bit(class - lock_classes, lock_classes_in_use);
} else {
WARN_ONCE(true, "%s() failed for class %s\n", __func__,
class->name);
printk(" memory used by lock dependency info: %zu kB\n",
(sizeof(lock_classes) +
+ sizeof(lock_classes_in_use) +
sizeof(classhash_table) +
sizeof(list_entries) +
sizeof(list_entries_in_use) +
extern unsigned int nr_softirq_chains;
extern unsigned int nr_process_chains;
extern unsigned int max_lockdep_depth;
-extern unsigned int max_recursion_depth;
extern unsigned int max_bfs_queue_depth;
* and we want to avoid too much cache bouncing.
*/
struct lockdep_stats {
- int chain_lookup_hits;
- int chain_lookup_misses;
- int hardirqs_on_events;
- int hardirqs_off_events;
- int redundant_hardirqs_on;
- int redundant_hardirqs_off;
- int softirqs_on_events;
- int softirqs_off_events;
- int redundant_softirqs_on;
- int redundant_softirqs_off;
- int nr_unused_locks;
- int nr_redundant_checks;
- int nr_redundant;
- int nr_cyclic_checks;
- int nr_cyclic_check_recursions;
- int nr_find_usage_forwards_checks;
- int nr_find_usage_forwards_recursions;
- int nr_find_usage_backwards_checks;
- int nr_find_usage_backwards_recursions;
+ unsigned long chain_lookup_hits;
+ unsigned int chain_lookup_misses;
+ unsigned long hardirqs_on_events;
+ unsigned long hardirqs_off_events;
+ unsigned long redundant_hardirqs_on;
+ unsigned long redundant_hardirqs_off;
+ unsigned long softirqs_on_events;
+ unsigned long softirqs_off_events;
+ unsigned long redundant_softirqs_on;
+ unsigned long redundant_softirqs_off;
+ int nr_unused_locks;
+ unsigned int nr_redundant_checks;
+ unsigned int nr_redundant;
+ unsigned int nr_cyclic_checks;
+ unsigned int nr_find_usage_forwards_checks;
+ unsigned int nr_find_usage_backwards_checks;
/*
* Per lock class locking operation stat counts
+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0
-/* rwsem.c: R/W semaphores: contention handling functions
- *
- * Written by David Howells (dhowells@redhat.com).
- * Derived from arch/i386/kernel/semaphore.c
- *
- * Writer lock-stealing by Alex Shi <alex.shi@intel.com>
- * and Michel Lespinasse <walken@google.com>
- *
- * Optimistic spinning by Tim Chen <tim.c.chen@intel.com>
- * and Davidlohr Bueso <davidlohr@hp.com>. Based on mutexes.
- */
-#include <linux/rwsem.h>
-#include <linux/init.h>
-#include <linux/export.h>
-#include <linux/sched/signal.h>
-#include <linux/sched/rt.h>
-#include <linux/sched/wake_q.h>
-#include <linux/sched/debug.h>
-#include <linux/osq_lock.h>
-
-#include "rwsem.h"
-
-/*
- * Guide to the rw_semaphore's count field for common values.
- * (32-bit case illustrated, similar for 64-bit)
- *
- * 0x0000000X (1) X readers active or attempting lock, no writer waiting
- * X = #active_readers + #readers attempting to lock
- * (X*ACTIVE_BIAS)
- *
- * 0x00000000 rwsem is unlocked, and no one is waiting for the lock or
- * attempting to read lock or write lock.
- *
- * 0xffff000X (1) X readers active or attempting lock, with waiters for lock
- * X = #active readers + # readers attempting lock
- * (X*ACTIVE_BIAS + WAITING_BIAS)
- * (2) 1 writer attempting lock, no waiters for lock
- * X-1 = #active readers + #readers attempting lock
- * ((X-1)*ACTIVE_BIAS + ACTIVE_WRITE_BIAS)
- * (3) 1 writer active, no waiters for lock
- * X-1 = #active readers + #readers attempting lock
- * ((X-1)*ACTIVE_BIAS + ACTIVE_WRITE_BIAS)
- *
- * 0xffff0001 (1) 1 reader active or attempting lock, waiters for lock
- * (WAITING_BIAS + ACTIVE_BIAS)
- * (2) 1 writer active or attempting lock, no waiters for lock
- * (ACTIVE_WRITE_BIAS)
- *
- * 0xffff0000 (1) There are writers or readers queued but none active
- * or in the process of attempting lock.
- * (WAITING_BIAS)
- * Note: writer can attempt to steal lock for this count by adding
- * ACTIVE_WRITE_BIAS in cmpxchg and checking the old count
- *
- * 0xfffe0001 (1) 1 writer active, or attempting lock. Waiters on queue.
- * (ACTIVE_WRITE_BIAS + WAITING_BIAS)
- *
- * Note: Readers attempt to lock by adding ACTIVE_BIAS in down_read and checking
- * the count becomes more than 0 for successful lock acquisition,
- * i.e. the case where there are only readers or nobody has lock.
- * (1st and 2nd case above).
- *
- * Writers attempt to lock by adding ACTIVE_WRITE_BIAS in down_write and
- * checking the count becomes ACTIVE_WRITE_BIAS for successful lock
- * acquisition (i.e. nobody else has lock or attempts lock). If
- * unsuccessful, in rwsem_down_write_failed, we'll check to see if there
- * are only waiters but none active (5th case above), and attempt to
- * steal the lock.
- *
- */
-
-/*
- * Initialize an rwsem:
- */
-void __init_rwsem(struct rw_semaphore *sem, const char *name,
- struct lock_class_key *key)
-{
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
- /*
- * Make sure we are not reinitializing a held semaphore:
- */
- debug_check_no_locks_freed((void *)sem, sizeof(*sem));
- lockdep_init_map(&sem->dep_map, name, key, 0);
-#endif
- atomic_long_set(&sem->count, RWSEM_UNLOCKED_VALUE);
- raw_spin_lock_init(&sem->wait_lock);
- INIT_LIST_HEAD(&sem->wait_list);
-#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
- sem->owner = NULL;
- osq_lock_init(&sem->osq);
-#endif
-}
-
-EXPORT_SYMBOL(__init_rwsem);
-
-enum rwsem_waiter_type {
- RWSEM_WAITING_FOR_WRITE,
- RWSEM_WAITING_FOR_READ
-};
-
-struct rwsem_waiter {
- struct list_head list;
- struct task_struct *task;
- enum rwsem_waiter_type type;
-};
-
-enum rwsem_wake_type {
- RWSEM_WAKE_ANY, /* Wake whatever's at head of wait list */
- RWSEM_WAKE_READERS, /* Wake readers only */
- RWSEM_WAKE_READ_OWNED /* Waker thread holds the read lock */
-};
-
-/*
- * handle the lock release when processes blocked on it that can now run
- * - if we come here from up_xxxx(), then:
- * - the 'active part' of count (&0x0000ffff) reached 0 (but may have changed)
- * - the 'waiting part' of count (&0xffff0000) is -ve (and will still be so)
- * - there must be someone on the queue
- * - the wait_lock must be held by the caller
- * - tasks are marked for wakeup, the caller must later invoke wake_up_q()
- * to actually wakeup the blocked task(s) and drop the reference count,
- * preferably when the wait_lock is released
- * - woken process blocks are discarded from the list after having task zeroed
- * - writers are only marked woken if downgrading is false
- */
-static void __rwsem_mark_wake(struct rw_semaphore *sem,
- enum rwsem_wake_type wake_type,
- struct wake_q_head *wake_q)
-{
- struct rwsem_waiter *waiter, *tmp;
- long oldcount, woken = 0, adjustment = 0;
- struct list_head wlist;
-
- /*
- * Take a peek at the queue head waiter such that we can determine
- * the wakeup(s) to perform.
- */
- waiter = list_first_entry(&sem->wait_list, struct rwsem_waiter, list);
-
- if (waiter->type == RWSEM_WAITING_FOR_WRITE) {
- if (wake_type == RWSEM_WAKE_ANY) {
- /*
- * Mark writer at the front of the queue for wakeup.
- * Until the task is actually later awoken later by
- * the caller, other writers are able to steal it.
- * Readers, on the other hand, will block as they
- * will notice the queued writer.
- */
- wake_q_add(wake_q, waiter->task);
- lockevent_inc(rwsem_wake_writer);
- }
-
- return;
- }
-
- /*
- * Writers might steal the lock before we grant it to the next reader.
- * We prefer to do the first reader grant before counting readers
- * so we can bail out early if a writer stole the lock.
- */
- if (wake_type != RWSEM_WAKE_READ_OWNED) {
- adjustment = RWSEM_ACTIVE_READ_BIAS;
- try_reader_grant:
- oldcount = atomic_long_fetch_add(adjustment, &sem->count);
- if (unlikely(oldcount < RWSEM_WAITING_BIAS)) {
- /*
- * If the count is still less than RWSEM_WAITING_BIAS
- * after removing the adjustment, it is assumed that
- * a writer has stolen the lock. We have to undo our
- * reader grant.
- */
- if (atomic_long_add_return(-adjustment, &sem->count) <
- RWSEM_WAITING_BIAS)
- return;
-
- /* Last active locker left. Retry waking readers. */
- goto try_reader_grant;
- }
- /*
- * Set it to reader-owned to give spinners an early
- * indication that readers now have the lock.
- */
- __rwsem_set_reader_owned(sem, waiter->task);
- }
-
- /*
- * Grant an infinite number of read locks to the readers at the front
- * of the queue. We know that woken will be at least 1 as we accounted
- * for above. Note we increment the 'active part' of the count by the
- * number of readers before waking any processes up.
- *
- * We have to do wakeup in 2 passes to prevent the possibility that
- * the reader count may be decremented before it is incremented. It
- * is because the to-be-woken waiter may not have slept yet. So it
- * may see waiter->task got cleared, finish its critical section and
- * do an unlock before the reader count increment.
- *
- * 1) Collect the read-waiters in a separate list, count them and
- * fully increment the reader count in rwsem.
- * 2) For each waiters in the new list, clear waiter->task and
- * put them into wake_q to be woken up later.
- */
- list_for_each_entry(waiter, &sem->wait_list, list) {
- if (waiter->type == RWSEM_WAITING_FOR_WRITE)
- break;
-
- woken++;
- }
- list_cut_before(&wlist, &sem->wait_list, &waiter->list);
-
- adjustment = woken * RWSEM_ACTIVE_READ_BIAS - adjustment;
- lockevent_cond_inc(rwsem_wake_reader, woken);
- if (list_empty(&sem->wait_list)) {
- /* hit end of list above */
- adjustment -= RWSEM_WAITING_BIAS;
- }
-
- if (adjustment)
- atomic_long_add(adjustment, &sem->count);
-
- /* 2nd pass */
- list_for_each_entry_safe(waiter, tmp, &wlist, list) {
- struct task_struct *tsk;
-
- tsk = waiter->task;
- get_task_struct(tsk);
-
- /*
- * Ensure calling get_task_struct() before setting the reader
- * waiter to nil such that rwsem_down_read_failed() cannot
- * race with do_exit() by always holding a reference count
- * to the task to wakeup.
- */
- smp_store_release(&waiter->task, NULL);
- /*
- * Ensure issuing the wakeup (either by us or someone else)
- * after setting the reader waiter to nil.
- */
- wake_q_add_safe(wake_q, tsk);
- }
-}
-
-/*
- * This function must be called with the sem->wait_lock held to prevent
- * race conditions between checking the rwsem wait list and setting the
- * sem->count accordingly.
- */
-static inline bool rwsem_try_write_lock(long count, struct rw_semaphore *sem)
-{
- /*
- * Avoid trying to acquire write lock if count isn't RWSEM_WAITING_BIAS.
- */
- if (count != RWSEM_WAITING_BIAS)
- return false;
-
- /*
- * Acquire the lock by trying to set it to ACTIVE_WRITE_BIAS. If there
- * are other tasks on the wait list, we need to add on WAITING_BIAS.
- */
- count = list_is_singular(&sem->wait_list) ?
- RWSEM_ACTIVE_WRITE_BIAS :
- RWSEM_ACTIVE_WRITE_BIAS + RWSEM_WAITING_BIAS;
-
- if (atomic_long_cmpxchg_acquire(&sem->count, RWSEM_WAITING_BIAS, count)
- == RWSEM_WAITING_BIAS) {
- rwsem_set_owner(sem);
- return true;
- }
-
- return false;
-}
-
-#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
-/*
- * Try to acquire write lock before the writer has been put on wait queue.
- */
-static inline bool rwsem_try_write_lock_unqueued(struct rw_semaphore *sem)
-{
- long count = atomic_long_read(&sem->count);
-
- while (!count || count == RWSEM_WAITING_BIAS) {
- if (atomic_long_try_cmpxchg_acquire(&sem->count, &count,
- count + RWSEM_ACTIVE_WRITE_BIAS)) {
- rwsem_set_owner(sem);
- lockevent_inc(rwsem_opt_wlock);
- return true;
- }
- }
- return false;
-}
-
-static inline bool owner_on_cpu(struct task_struct *owner)
-{
- /*
- * As lock holder preemption issue, we both skip spinning if
- * task is not on cpu or its cpu is preempted
- */
- return owner->on_cpu && !vcpu_is_preempted(task_cpu(owner));
-}
-
-static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
-{
- struct task_struct *owner;
- bool ret = true;
-
- BUILD_BUG_ON(!rwsem_has_anonymous_owner(RWSEM_OWNER_UNKNOWN));
-
- if (need_resched())
- return false;
-
- rcu_read_lock();
- owner = READ_ONCE(sem->owner);
- if (owner) {
- ret = is_rwsem_owner_spinnable(owner) &&
- owner_on_cpu(owner);
- }
- rcu_read_unlock();
- return ret;
-}
-
-/*
- * Return true only if we can still spin on the owner field of the rwsem.
- */
-static noinline bool rwsem_spin_on_owner(struct rw_semaphore *sem)
-{
- struct task_struct *owner = READ_ONCE(sem->owner);
-
- if (!is_rwsem_owner_spinnable(owner))
- return false;
-
- rcu_read_lock();
- while (owner && (READ_ONCE(sem->owner) == owner)) {
- /*
- * Ensure we emit the owner->on_cpu, dereference _after_
- * checking sem->owner still matches owner, if that fails,
- * owner might point to free()d memory, if it still matches,
- * the rcu_read_lock() ensures the memory stays valid.
- */
- barrier();
-
- /*
- * abort spinning when need_resched or owner is not running or
- * owner's cpu is preempted.
- */
- if (need_resched() || !owner_on_cpu(owner)) {
- rcu_read_unlock();
- return false;
- }
-
- cpu_relax();
- }
- rcu_read_unlock();
-
- /*
- * If there is a new owner or the owner is not set, we continue
- * spinning.
- */
- return is_rwsem_owner_spinnable(READ_ONCE(sem->owner));
-}
-
-static bool rwsem_optimistic_spin(struct rw_semaphore *sem)
-{
- bool taken = false;
-
- preempt_disable();
-
- /* sem->wait_lock should not be held when doing optimistic spinning */
- if (!rwsem_can_spin_on_owner(sem))
- goto done;
-
- if (!osq_lock(&sem->osq))
- goto done;
-
- /*
- * Optimistically spin on the owner field and attempt to acquire the
- * lock whenever the owner changes. Spinning will be stopped when:
- * 1) the owning writer isn't running; or
- * 2) readers own the lock as we can't determine if they are
- * actively running or not.
- */
- while (rwsem_spin_on_owner(sem)) {
- /*
- * Try to acquire the lock
- */
- if (rwsem_try_write_lock_unqueued(sem)) {
- taken = true;
- break;
- }
-
- /*
- * When there's no owner, we might have preempted between the
- * owner acquiring the lock and setting the owner field. If
- * we're an RT task that will live-lock because we won't let
- * the owner complete.
- */
- if (!sem->owner && (need_resched() || rt_task(current)))
- break;
-
- /*
- * The cpu_relax() call is a compiler barrier which forces
- * everything in this loop to be re-loaded. We don't need
- * memory barriers as we'll eventually observe the right
- * values at the cost of a few extra spins.
- */
- cpu_relax();
- }
- osq_unlock(&sem->osq);
-done:
- preempt_enable();
- lockevent_cond_inc(rwsem_opt_fail, !taken);
- return taken;
-}
-
-/*
- * Return true if the rwsem has active spinner
- */
-static inline bool rwsem_has_spinner(struct rw_semaphore *sem)
-{
- return osq_is_locked(&sem->osq);
-}
-
-#else
-static bool rwsem_optimistic_spin(struct rw_semaphore *sem)
-{
- return false;
-}
-
-static inline bool rwsem_has_spinner(struct rw_semaphore *sem)
-{
- return false;
-}
-#endif
-
-/*
- * Wait for the read lock to be granted
- */
-static inline struct rw_semaphore __sched *
-__rwsem_down_read_failed_common(struct rw_semaphore *sem, int state)
-{
- long count, adjustment = -RWSEM_ACTIVE_READ_BIAS;
- struct rwsem_waiter waiter;
- DEFINE_WAKE_Q(wake_q);
-
- waiter.task = current;
- waiter.type = RWSEM_WAITING_FOR_READ;
-
- raw_spin_lock_irq(&sem->wait_lock);
- if (list_empty(&sem->wait_list)) {
- /*
- * In case the wait queue is empty and the lock isn't owned
- * by a writer, this reader can exit the slowpath and return
- * immediately as its RWSEM_ACTIVE_READ_BIAS has already
- * been set in the count.
- */
- if (atomic_long_read(&sem->count) >= 0) {
- raw_spin_unlock_irq(&sem->wait_lock);
- rwsem_set_reader_owned(sem);
- lockevent_inc(rwsem_rlock_fast);
- return sem;
- }
- adjustment += RWSEM_WAITING_BIAS;
- }
- list_add_tail(&waiter.list, &sem->wait_list);
-
- /* we're now waiting on the lock, but no longer actively locking */
- count = atomic_long_add_return(adjustment, &sem->count);
-
- /*
- * If there are no active locks, wake the front queued process(es).
- *
- * If there are no writers and we are first in the queue,
- * wake our own waiter to join the existing active readers !
- */
- if (count == RWSEM_WAITING_BIAS ||
- (count > RWSEM_WAITING_BIAS &&
- adjustment != -RWSEM_ACTIVE_READ_BIAS))
- __rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q);
-
- raw_spin_unlock_irq(&sem->wait_lock);
- wake_up_q(&wake_q);
-
- /* wait to be given the lock */
- while (true) {
- set_current_state(state);
- if (!waiter.task)
- break;
- if (signal_pending_state(state, current)) {
- raw_spin_lock_irq(&sem->wait_lock);
- if (waiter.task)
- goto out_nolock;
- raw_spin_unlock_irq(&sem->wait_lock);
- break;
- }
- schedule();
- lockevent_inc(rwsem_sleep_reader);
- }
-
- __set_current_state(TASK_RUNNING);
- lockevent_inc(rwsem_rlock);
- return sem;
-out_nolock:
- list_del(&waiter.list);
- if (list_empty(&sem->wait_list))
- atomic_long_add(-RWSEM_WAITING_BIAS, &sem->count);
- raw_spin_unlock_irq(&sem->wait_lock);
- __set_current_state(TASK_RUNNING);
- lockevent_inc(rwsem_rlock_fail);
- return ERR_PTR(-EINTR);
-}
-
-__visible struct rw_semaphore * __sched
-rwsem_down_read_failed(struct rw_semaphore *sem)
-{
- return __rwsem_down_read_failed_common(sem, TASK_UNINTERRUPTIBLE);
-}
-EXPORT_SYMBOL(rwsem_down_read_failed);
-
-__visible struct rw_semaphore * __sched
-rwsem_down_read_failed_killable(struct rw_semaphore *sem)
-{
- return __rwsem_down_read_failed_common(sem, TASK_KILLABLE);
-}
-EXPORT_SYMBOL(rwsem_down_read_failed_killable);
-
-/*
- * Wait until we successfully acquire the write lock
- */
-static inline struct rw_semaphore *
-__rwsem_down_write_failed_common(struct rw_semaphore *sem, int state)
-{
- long count;
- bool waiting = true; /* any queued threads before us */
- struct rwsem_waiter waiter;
- struct rw_semaphore *ret = sem;
- DEFINE_WAKE_Q(wake_q);
-
- /* undo write bias from down_write operation, stop active locking */
- count = atomic_long_sub_return(RWSEM_ACTIVE_WRITE_BIAS, &sem->count);
-
- /* do optimistic spinning and steal lock if possible */
- if (rwsem_optimistic_spin(sem))
- return sem;
-
- /*
- * Optimistic spinning failed, proceed to the slowpath
- * and block until we can acquire the sem.
- */
- waiter.task = current;
- waiter.type = RWSEM_WAITING_FOR_WRITE;
-
- raw_spin_lock_irq(&sem->wait_lock);
-
- /* account for this before adding a new element to the list */
- if (list_empty(&sem->wait_list))
- waiting = false;
-
- list_add_tail(&waiter.list, &sem->wait_list);
-
- /* we're now waiting on the lock, but no longer actively locking */
- if (waiting) {
- count = atomic_long_read(&sem->count);
-
- /*
- * If there were already threads queued before us and there are
- * no active writers, the lock must be read owned; so we try to
- * wake any read locks that were queued ahead of us.
- */
- if (count > RWSEM_WAITING_BIAS) {
- __rwsem_mark_wake(sem, RWSEM_WAKE_READERS, &wake_q);
- /*
- * The wakeup is normally called _after_ the wait_lock
- * is released, but given that we are proactively waking
- * readers we can deal with the wake_q overhead as it is
- * similar to releasing and taking the wait_lock again
- * for attempting rwsem_try_write_lock().
- */
- wake_up_q(&wake_q);
-
- /*
- * Reinitialize wake_q after use.
- */
- wake_q_init(&wake_q);
- }
-
- } else
- count = atomic_long_add_return(RWSEM_WAITING_BIAS, &sem->count);
-
- /* wait until we successfully acquire the lock */
- set_current_state(state);
- while (true) {
- if (rwsem_try_write_lock(count, sem))
- break;
- raw_spin_unlock_irq(&sem->wait_lock);
-
- /* Block until there are no active lockers. */
- do {
- if (signal_pending_state(state, current))
- goto out_nolock;
-
- schedule();
- lockevent_inc(rwsem_sleep_writer);
- set_current_state(state);
- } while ((count = atomic_long_read(&sem->count)) & RWSEM_ACTIVE_MASK);
-
- raw_spin_lock_irq(&sem->wait_lock);
- }
- __set_current_state(TASK_RUNNING);
- list_del(&waiter.list);
- raw_spin_unlock_irq(&sem->wait_lock);
- lockevent_inc(rwsem_wlock);
-
- return ret;
-
-out_nolock:
- __set_current_state(TASK_RUNNING);
- raw_spin_lock_irq(&sem->wait_lock);
- list_del(&waiter.list);
- if (list_empty(&sem->wait_list))
- atomic_long_add(-RWSEM_WAITING_BIAS, &sem->count);
- else
- __rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q);
- raw_spin_unlock_irq(&sem->wait_lock);
- wake_up_q(&wake_q);
- lockevent_inc(rwsem_wlock_fail);
-
- return ERR_PTR(-EINTR);
-}
-
-__visible struct rw_semaphore * __sched
-rwsem_down_write_failed(struct rw_semaphore *sem)
-{
- return __rwsem_down_write_failed_common(sem, TASK_UNINTERRUPTIBLE);
-}
-EXPORT_SYMBOL(rwsem_down_write_failed);
-
-__visible struct rw_semaphore * __sched
-rwsem_down_write_failed_killable(struct rw_semaphore *sem)
-{
- return __rwsem_down_write_failed_common(sem, TASK_KILLABLE);
-}
-EXPORT_SYMBOL(rwsem_down_write_failed_killable);
-
-/*
- * handle waking up a waiter on the semaphore
- * - up_read/up_write has decremented the active part of count if we come here
- */
-__visible
-struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)
-{
- unsigned long flags;
- DEFINE_WAKE_Q(wake_q);
-
- /*
- * __rwsem_down_write_failed_common(sem)
- * rwsem_optimistic_spin(sem)
- * osq_unlock(sem->osq)
- * ...
- * atomic_long_add_return(&sem->count)
- *
- * - VS -
- *
- * __up_write()
- * if (atomic_long_sub_return_release(&sem->count) < 0)
- * rwsem_wake(sem)
- * osq_is_locked(&sem->osq)
- *
- * And __up_write() must observe !osq_is_locked() when it observes the
- * atomic_long_add_return() in order to not miss a wakeup.
- *
- * This boils down to:
- *
- * [S.rel] X = 1 [RmW] r0 = (Y += 0)
- * MB RMB
- * [RmW] Y += 1 [L] r1 = X
- *
- * exists (r0=1 /\ r1=0)
- */
- smp_rmb();
-
- /*
- * If a spinner is present, it is not necessary to do the wakeup.
- * Try to do wakeup only if the trylock succeeds to minimize
- * spinlock contention which may introduce too much delay in the
- * unlock operation.
- *
- * spinning writer up_write/up_read caller
- * --------------- -----------------------
- * [S] osq_unlock() [L] osq
- * MB RMB
- * [RmW] rwsem_try_write_lock() [RmW] spin_trylock(wait_lock)
- *
- * Here, it is important to make sure that there won't be a missed
- * wakeup while the rwsem is free and the only spinning writer goes
- * to sleep without taking the rwsem. Even when the spinning writer
- * is just going to break out of the waiting loop, it will still do
- * a trylock in rwsem_down_write_failed() before sleeping. IOW, if
- * rwsem_has_spinner() is true, it will guarantee at least one
- * trylock attempt on the rwsem later on.
- */
- if (rwsem_has_spinner(sem)) {
- /*
- * The smp_rmb() here is to make sure that the spinner
- * state is consulted before reading the wait_lock.
- */
- smp_rmb();
- if (!raw_spin_trylock_irqsave(&sem->wait_lock, flags))
- return sem;
- goto locked;
- }
- raw_spin_lock_irqsave(&sem->wait_lock, flags);
-locked:
-
- if (!list_empty(&sem->wait_list))
- __rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q);
-
- raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
- wake_up_q(&wake_q);
-
- return sem;
-}
-EXPORT_SYMBOL(rwsem_wake);
-
-/*
- * downgrade a write lock into a read lock
- * - caller incremented waiting part of count and discovered it still negative
- * - just wake up any readers at the front of the queue
- */
-__visible
-struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem)
-{
- unsigned long flags;
- DEFINE_WAKE_Q(wake_q);
-
- raw_spin_lock_irqsave(&sem->wait_lock, flags);
-
- if (!list_empty(&sem->wait_list))
- __rwsem_mark_wake(sem, RWSEM_WAKE_READ_OWNED, &wake_q);
-
- raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
- wake_up_q(&wake_q);
-
- return sem;
-}
-EXPORT_SYMBOL(rwsem_downgrade_wake);
*
* Written by David Howells (dhowells@redhat.com).
* Derived from asm-i386/semaphore.h
+ *
+ * Writer lock-stealing by Alex Shi <alex.shi@intel.com>
+ * and Michel Lespinasse <walken@google.com>
+ *
+ * Optimistic spinning by Tim Chen <tim.c.chen@intel.com>
+ * and Davidlohr Bueso <davidlohr@hp.com>. Based on mutexes.
+ *
+ * Rwsem count bit fields re-definition and rwsem rearchitecture by
+ * Waiman Long <longman@redhat.com> and
+ * Peter Zijlstra <peterz@infradead.org>.
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
+#include <linux/sched/rt.h>
+#include <linux/sched/task.h>
#include <linux/sched/debug.h>
+#include <linux/sched/wake_q.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/clock.h>
#include <linux/export.h>
#include <linux/rwsem.h>
#include <linux/atomic.h>
#include "rwsem.h"
+#include "lock_events.h"
+
+/*
+ * The least significant 3 bits of the owner value has the following
+ * meanings when set.
+ * - Bit 0: RWSEM_READER_OWNED - The rwsem is owned by readers
+ * - Bit 1: RWSEM_RD_NONSPINNABLE - Readers cannot spin on this lock.
+ * - Bit 2: RWSEM_WR_NONSPINNABLE - Writers cannot spin on this lock.
+ *
+ * When the rwsem is either owned by an anonymous writer, or it is
+ * reader-owned, but a spinning writer has timed out, both nonspinnable
+ * bits will be set to disable optimistic spinning by readers and writers.
+ * In the later case, the last unlocking reader should then check the
+ * writer nonspinnable bit and clear it only to give writers preference
+ * to acquire the lock via optimistic spinning, but not readers. Similar
+ * action is also done in the reader slowpath.
+
+ * When a writer acquires a rwsem, it puts its task_struct pointer
+ * into the owner field. It is cleared after an unlock.
+ *
+ * When a reader acquires a rwsem, it will also puts its task_struct
+ * pointer into the owner field with the RWSEM_READER_OWNED bit set.
+ * On unlock, the owner field will largely be left untouched. So
+ * for a free or reader-owned rwsem, the owner value may contain
+ * information about the last reader that acquires the rwsem.
+ *
+ * That information may be helpful in debugging cases where the system
+ * seems to hang on a reader owned rwsem especially if only one reader
+ * is involved. Ideally we would like to track all the readers that own
+ * a rwsem, but the overhead is simply too big.
+ *
+ * Reader optimistic spinning is helpful when the reader critical section
+ * is short and there aren't that many readers around. It makes readers
+ * relatively more preferred than writers. When a writer times out spinning
+ * on a reader-owned lock and set the nospinnable bits, there are two main
+ * reasons for that.
+ *
+ * 1) The reader critical section is long, perhaps the task sleeps after
+ * acquiring the read lock.
+ * 2) There are just too many readers contending the lock causing it to
+ * take a while to service all of them.
+ *
+ * In the former case, long reader critical section will impede the progress
+ * of writers which is usually more important for system performance. In
+ * the later case, reader optimistic spinning tends to make the reader
+ * groups that contain readers that acquire the lock together smaller
+ * leading to more of them. That may hurt performance in some cases. In
+ * other words, the setting of nonspinnable bits indicates that reader
+ * optimistic spinning may not be helpful for those workloads that cause
+ * it.
+ *
+ * Therefore, any writers that had observed the setting of the writer
+ * nonspinnable bit for a given rwsem after they fail to acquire the lock
+ * via optimistic spinning will set the reader nonspinnable bit once they
+ * acquire the write lock. Similarly, readers that observe the setting
+ * of reader nonspinnable bit at slowpath entry will set the reader
+ * nonspinnable bits when they acquire the read lock via the wakeup path.
+ *
+ * Once the reader nonspinnable bit is on, it will only be reset when
+ * a writer is able to acquire the rwsem in the fast path or somehow a
+ * reader or writer in the slowpath doesn't observe the nonspinable bit.
+ *
+ * This is to discourage reader optmistic spinning on that particular
+ * rwsem and make writers more preferred. This adaptive disabling of reader
+ * optimistic spinning will alleviate the negative side effect of this
+ * feature.
+ */
+#define RWSEM_READER_OWNED (1UL << 0)
+#define RWSEM_RD_NONSPINNABLE (1UL << 1)
+#define RWSEM_WR_NONSPINNABLE (1UL << 2)
+#define RWSEM_NONSPINNABLE (RWSEM_RD_NONSPINNABLE | RWSEM_WR_NONSPINNABLE)
+#define RWSEM_OWNER_FLAGS_MASK (RWSEM_READER_OWNED | RWSEM_NONSPINNABLE)
+
+#ifdef CONFIG_DEBUG_RWSEMS
+# define DEBUG_RWSEMS_WARN_ON(c, sem) do { \
+ if (!debug_locks_silent && \
+ WARN_ONCE(c, "DEBUG_RWSEMS_WARN_ON(%s): count = 0x%lx, owner = 0x%lx, curr 0x%lx, list %sempty\n",\
+ #c, atomic_long_read(&(sem)->count), \
+ atomic_long_read(&(sem)->owner), (long)current, \
+ list_empty(&(sem)->wait_list) ? "" : "not ")) \
+ debug_locks_off(); \
+ } while (0)
+#else
+# define DEBUG_RWSEMS_WARN_ON(c, sem)
+#endif
+
+/*
+ * On 64-bit architectures, the bit definitions of the count are:
+ *
+ * Bit 0 - writer locked bit
+ * Bit 1 - waiters present bit
+ * Bit 2 - lock handoff bit
+ * Bits 3-7 - reserved
+ * Bits 8-62 - 55-bit reader count
+ * Bit 63 - read fail bit
+ *
+ * On 32-bit architectures, the bit definitions of the count are:
+ *
+ * Bit 0 - writer locked bit
+ * Bit 1 - waiters present bit
+ * Bit 2 - lock handoff bit
+ * Bits 3-7 - reserved
+ * Bits 8-30 - 23-bit reader count
+ * Bit 31 - read fail bit
+ *
+ * It is not likely that the most significant bit (read fail bit) will ever
+ * be set. This guard bit is still checked anyway in the down_read() fastpath
+ * just in case we need to use up more of the reader bits for other purpose
+ * in the future.
+ *
+ * atomic_long_fetch_add() is used to obtain reader lock, whereas
+ * atomic_long_cmpxchg() will be used to obtain writer lock.
+ *
+ * There are three places where the lock handoff bit may be set or cleared.
+ * 1) rwsem_mark_wake() for readers.
+ * 2) rwsem_try_write_lock() for writers.
+ * 3) Error path of rwsem_down_write_slowpath().
+ *
+ * For all the above cases, wait_lock will be held. A writer must also
+ * be the first one in the wait_list to be eligible for setting the handoff
+ * bit. So concurrent setting/clearing of handoff bit is not possible.
+ */
+#define RWSEM_WRITER_LOCKED (1UL << 0)
+#define RWSEM_FLAG_WAITERS (1UL << 1)
+#define RWSEM_FLAG_HANDOFF (1UL << 2)
+#define RWSEM_FLAG_READFAIL (1UL << (BITS_PER_LONG - 1))
+
+#define RWSEM_READER_SHIFT 8
+#define RWSEM_READER_BIAS (1UL << RWSEM_READER_SHIFT)
+#define RWSEM_READER_MASK (~(RWSEM_READER_BIAS - 1))
+#define RWSEM_WRITER_MASK RWSEM_WRITER_LOCKED
+#define RWSEM_LOCK_MASK (RWSEM_WRITER_MASK|RWSEM_READER_MASK)
+#define RWSEM_READ_FAILED_MASK (RWSEM_WRITER_MASK|RWSEM_FLAG_WAITERS|\
+ RWSEM_FLAG_HANDOFF|RWSEM_FLAG_READFAIL)
+
+/*
+ * All writes to owner are protected by WRITE_ONCE() to make sure that
+ * store tearing can't happen as optimistic spinners may read and use
+ * the owner value concurrently without lock. Read from owner, however,
+ * may not need READ_ONCE() as long as the pointer value is only used
+ * for comparison and isn't being dereferenced.
+ */
+static inline void rwsem_set_owner(struct rw_semaphore *sem)
+{
+ atomic_long_set(&sem->owner, (long)current);
+}
+
+static inline void rwsem_clear_owner(struct rw_semaphore *sem)
+{
+ atomic_long_set(&sem->owner, 0);
+}
+
+/*
+ * Test the flags in the owner field.
+ */
+static inline bool rwsem_test_oflags(struct rw_semaphore *sem, long flags)
+{
+ return atomic_long_read(&sem->owner) & flags;
+}
+
+/*
+ * The task_struct pointer of the last owning reader will be left in
+ * the owner field.
+ *
+ * Note that the owner value just indicates the task has owned the rwsem
+ * previously, it may not be the real owner or one of the real owners
+ * anymore when that field is examined, so take it with a grain of salt.
+ *
+ * The reader non-spinnable bit is preserved.
+ */
+static inline void __rwsem_set_reader_owned(struct rw_semaphore *sem,
+ struct task_struct *owner)
+{
+ unsigned long val = (unsigned long)owner | RWSEM_READER_OWNED |
+ (atomic_long_read(&sem->owner) & RWSEM_RD_NONSPINNABLE);
+
+ atomic_long_set(&sem->owner, val);
+}
+
+static inline void rwsem_set_reader_owned(struct rw_semaphore *sem)
+{
+ __rwsem_set_reader_owned(sem, current);
+}
+
+/*
+ * Return true if the rwsem is owned by a reader.
+ */
+static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
+{
+#ifdef CONFIG_DEBUG_RWSEMS
+ /*
+ * Check the count to see if it is write-locked.
+ */
+ long count = atomic_long_read(&sem->count);
+
+ if (count & RWSEM_WRITER_MASK)
+ return false;
+#endif
+ return rwsem_test_oflags(sem, RWSEM_READER_OWNED);
+}
+
+#ifdef CONFIG_DEBUG_RWSEMS
+/*
+ * With CONFIG_DEBUG_RWSEMS configured, it will make sure that if there
+ * is a task pointer in owner of a reader-owned rwsem, it will be the
+ * real owner or one of the real owners. The only exception is when the
+ * unlock is done by up_read_non_owner().
+ */
+static inline void rwsem_clear_reader_owned(struct rw_semaphore *sem)
+{
+ unsigned long val = atomic_long_read(&sem->owner);
+
+ while ((val & ~RWSEM_OWNER_FLAGS_MASK) == (unsigned long)current) {
+ if (atomic_long_try_cmpxchg(&sem->owner, &val,
+ val & RWSEM_OWNER_FLAGS_MASK))
+ return;
+ }
+}
+#else
+static inline void rwsem_clear_reader_owned(struct rw_semaphore *sem)
+{
+}
+#endif
+
+/*
+ * Set the RWSEM_NONSPINNABLE bits if the RWSEM_READER_OWNED flag
+ * remains set. Otherwise, the operation will be aborted.
+ */
+static inline void rwsem_set_nonspinnable(struct rw_semaphore *sem)
+{
+ unsigned long owner = atomic_long_read(&sem->owner);
+
+ do {
+ if (!(owner & RWSEM_READER_OWNED))
+ break;
+ if (owner & RWSEM_NONSPINNABLE)
+ break;
+ } while (!atomic_long_try_cmpxchg(&sem->owner, &owner,
+ owner | RWSEM_NONSPINNABLE));
+}
+
+static inline bool rwsem_read_trylock(struct rw_semaphore *sem)
+{
+ long cnt = atomic_long_add_return_acquire(RWSEM_READER_BIAS, &sem->count);
+ if (WARN_ON_ONCE(cnt < 0))
+ rwsem_set_nonspinnable(sem);
+ return !(cnt & RWSEM_READ_FAILED_MASK);
+}
+
+/*
+ * Return just the real task structure pointer of the owner
+ */
+static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
+{
+ return (struct task_struct *)
+ (atomic_long_read(&sem->owner) & ~RWSEM_OWNER_FLAGS_MASK);
+}
+
+/*
+ * Return the real task structure pointer of the owner and the embedded
+ * flags in the owner. pflags must be non-NULL.
+ */
+static inline struct task_struct *
+rwsem_owner_flags(struct rw_semaphore *sem, unsigned long *pflags)
+{
+ unsigned long owner = atomic_long_read(&sem->owner);
+
+ *pflags = owner & RWSEM_OWNER_FLAGS_MASK;
+ return (struct task_struct *)(owner & ~RWSEM_OWNER_FLAGS_MASK);
+}
+
+/*
+ * Guide to the rw_semaphore's count field.
+ *
+ * When the RWSEM_WRITER_LOCKED bit in count is set, the lock is owned
+ * by a writer.
+ *
+ * The lock is owned by readers when
+ * (1) the RWSEM_WRITER_LOCKED isn't set in count,
+ * (2) some of the reader bits are set in count, and
+ * (3) the owner field has RWSEM_READ_OWNED bit set.
+ *
+ * Having some reader bits set is not enough to guarantee a readers owned
+ * lock as the readers may be in the process of backing out from the count
+ * and a writer has just released the lock. So another writer may steal
+ * the lock immediately after that.
+ */
+
+/*
+ * Initialize an rwsem:
+ */
+void __init_rwsem(struct rw_semaphore *sem, const char *name,
+ struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ /*
+ * Make sure we are not reinitializing a held semaphore:
+ */
+ debug_check_no_locks_freed((void *)sem, sizeof(*sem));
+ lockdep_init_map(&sem->dep_map, name, key, 0);
+#endif
+ atomic_long_set(&sem->count, RWSEM_UNLOCKED_VALUE);
+ raw_spin_lock_init(&sem->wait_lock);
+ INIT_LIST_HEAD(&sem->wait_list);
+ atomic_long_set(&sem->owner, 0L);
+#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
+ osq_lock_init(&sem->osq);
+#endif
+}
+EXPORT_SYMBOL(__init_rwsem);
+
+enum rwsem_waiter_type {
+ RWSEM_WAITING_FOR_WRITE,
+ RWSEM_WAITING_FOR_READ
+};
+
+struct rwsem_waiter {
+ struct list_head list;
+ struct task_struct *task;
+ enum rwsem_waiter_type type;
+ unsigned long timeout;
+ unsigned long last_rowner;
+};
+#define rwsem_first_waiter(sem) \
+ list_first_entry(&sem->wait_list, struct rwsem_waiter, list)
+
+enum rwsem_wake_type {
+ RWSEM_WAKE_ANY, /* Wake whatever's at head of wait list */
+ RWSEM_WAKE_READERS, /* Wake readers only */
+ RWSEM_WAKE_READ_OWNED /* Waker thread holds the read lock */
+};
+
+enum writer_wait_state {
+ WRITER_NOT_FIRST, /* Writer is not first in wait list */
+ WRITER_FIRST, /* Writer is first in wait list */
+ WRITER_HANDOFF /* Writer is first & handoff needed */
+};
+
+/*
+ * The typical HZ value is either 250 or 1000. So set the minimum waiting
+ * time to at least 4ms or 1 jiffy (if it is higher than 4ms) in the wait
+ * queue before initiating the handoff protocol.
+ */
+#define RWSEM_WAIT_TIMEOUT DIV_ROUND_UP(HZ, 250)
+
+/*
+ * Magic number to batch-wakeup waiting readers, even when writers are
+ * also present in the queue. This both limits the amount of work the
+ * waking thread must do and also prevents any potential counter overflow,
+ * however unlikely.
+ */
+#define MAX_READERS_WAKEUP 0x100
+
+/*
+ * handle the lock release when processes blocked on it that can now run
+ * - if we come here from up_xxxx(), then the RWSEM_FLAG_WAITERS bit must
+ * have been set.
+ * - there must be someone on the queue
+ * - the wait_lock must be held by the caller
+ * - tasks are marked for wakeup, the caller must later invoke wake_up_q()
+ * to actually wakeup the blocked task(s) and drop the reference count,
+ * preferably when the wait_lock is released
+ * - woken process blocks are discarded from the list after having task zeroed
+ * - writers are only marked woken if downgrading is false
+ */
+static void rwsem_mark_wake(struct rw_semaphore *sem,
+ enum rwsem_wake_type wake_type,
+ struct wake_q_head *wake_q)
+{
+ struct rwsem_waiter *waiter, *tmp;
+ long oldcount, woken = 0, adjustment = 0;
+ struct list_head wlist;
+
+ lockdep_assert_held(&sem->wait_lock);
+
+ /*
+ * Take a peek at the queue head waiter such that we can determine
+ * the wakeup(s) to perform.
+ */
+ waiter = rwsem_first_waiter(sem);
+
+ if (waiter->type == RWSEM_WAITING_FOR_WRITE) {
+ if (wake_type == RWSEM_WAKE_ANY) {
+ /*
+ * Mark writer at the front of the queue for wakeup.
+ * Until the task is actually later awoken later by
+ * the caller, other writers are able to steal it.
+ * Readers, on the other hand, will block as they
+ * will notice the queued writer.
+ */
+ wake_q_add(wake_q, waiter->task);
+ lockevent_inc(rwsem_wake_writer);
+ }
+
+ return;
+ }
+
+ /*
+ * No reader wakeup if there are too many of them already.
+ */
+ if (unlikely(atomic_long_read(&sem->count) < 0))
+ return;
+
+ /*
+ * Writers might steal the lock before we grant it to the next reader.
+ * We prefer to do the first reader grant before counting readers
+ * so we can bail out early if a writer stole the lock.
+ */
+ if (wake_type != RWSEM_WAKE_READ_OWNED) {
+ struct task_struct *owner;
+
+ adjustment = RWSEM_READER_BIAS;
+ oldcount = atomic_long_fetch_add(adjustment, &sem->count);
+ if (unlikely(oldcount & RWSEM_WRITER_MASK)) {
+ /*
+ * When we've been waiting "too" long (for writers
+ * to give up the lock), request a HANDOFF to
+ * force the issue.
+ */
+ if (!(oldcount & RWSEM_FLAG_HANDOFF) &&
+ time_after(jiffies, waiter->timeout)) {
+ adjustment -= RWSEM_FLAG_HANDOFF;
+ lockevent_inc(rwsem_rlock_handoff);
+ }
+
+ atomic_long_add(-adjustment, &sem->count);
+ return;
+ }
+ /*
+ * Set it to reader-owned to give spinners an early
+ * indication that readers now have the lock.
+ * The reader nonspinnable bit seen at slowpath entry of
+ * the reader is copied over.
+ */
+ owner = waiter->task;
+ if (waiter->last_rowner & RWSEM_RD_NONSPINNABLE) {
+ owner = (void *)((unsigned long)owner | RWSEM_RD_NONSPINNABLE);
+ lockevent_inc(rwsem_opt_norspin);
+ }
+ __rwsem_set_reader_owned(sem, owner);
+ }
+
+ /*
+ * Grant up to MAX_READERS_WAKEUP read locks to all the readers in the
+ * queue. We know that the woken will be at least 1 as we accounted
+ * for above. Note we increment the 'active part' of the count by the
+ * number of readers before waking any processes up.
+ *
+ * This is an adaptation of the phase-fair R/W locks where at the
+ * reader phase (first waiter is a reader), all readers are eligible
+ * to acquire the lock at the same time irrespective of their order
+ * in the queue. The writers acquire the lock according to their
+ * order in the queue.
+ *
+ * We have to do wakeup in 2 passes to prevent the possibility that
+ * the reader count may be decremented before it is incremented. It
+ * is because the to-be-woken waiter may not have slept yet. So it
+ * may see waiter->task got cleared, finish its critical section and
+ * do an unlock before the reader count increment.
+ *
+ * 1) Collect the read-waiters in a separate list, count them and
+ * fully increment the reader count in rwsem.
+ * 2) For each waiters in the new list, clear waiter->task and
+ * put them into wake_q to be woken up later.
+ */
+ INIT_LIST_HEAD(&wlist);
+ list_for_each_entry_safe(waiter, tmp, &sem->wait_list, list) {
+ if (waiter->type == RWSEM_WAITING_FOR_WRITE)
+ continue;
+
+ woken++;
+ list_move_tail(&waiter->list, &wlist);
+
+ /*
+ * Limit # of readers that can be woken up per wakeup call.
+ */
+ if (woken >= MAX_READERS_WAKEUP)
+ break;
+ }
+
+ adjustment = woken * RWSEM_READER_BIAS - adjustment;
+ lockevent_cond_inc(rwsem_wake_reader, woken);
+ if (list_empty(&sem->wait_list)) {
+ /* hit end of list above */
+ adjustment -= RWSEM_FLAG_WAITERS;
+ }
+
+ /*
+ * When we've woken a reader, we no longer need to force writers
+ * to give up the lock and we can clear HANDOFF.
+ */
+ if (woken && (atomic_long_read(&sem->count) & RWSEM_FLAG_HANDOFF))
+ adjustment -= RWSEM_FLAG_HANDOFF;
+
+ if (adjustment)
+ atomic_long_add(adjustment, &sem->count);
+
+ /* 2nd pass */
+ list_for_each_entry_safe(waiter, tmp, &wlist, list) {
+ struct task_struct *tsk;
+
+ tsk = waiter->task;
+ get_task_struct(tsk);
+
+ /*
+ * Ensure calling get_task_struct() before setting the reader
+ * waiter to nil such that rwsem_down_read_slowpath() cannot
+ * race with do_exit() by always holding a reference count
+ * to the task to wakeup.
+ */
+ smp_store_release(&waiter->task, NULL);
+ /*
+ * Ensure issuing the wakeup (either by us or someone else)
+ * after setting the reader waiter to nil.
+ */
+ wake_q_add_safe(wake_q, tsk);
+ }
+}
+
+/*
+ * This function must be called with the sem->wait_lock held to prevent
+ * race conditions between checking the rwsem wait list and setting the
+ * sem->count accordingly.
+ *
+ * If wstate is WRITER_HANDOFF, it will make sure that either the handoff
+ * bit is set or the lock is acquired with handoff bit cleared.
+ */
+static inline bool rwsem_try_write_lock(struct rw_semaphore *sem,
+ enum writer_wait_state wstate)
+{
+ long count, new;
+
+ lockdep_assert_held(&sem->wait_lock);
+
+ count = atomic_long_read(&sem->count);
+ do {
+ bool has_handoff = !!(count & RWSEM_FLAG_HANDOFF);
+
+ if (has_handoff && wstate == WRITER_NOT_FIRST)
+ return false;
+
+ new = count;
+
+ if (count & RWSEM_LOCK_MASK) {
+ if (has_handoff || (wstate != WRITER_HANDOFF))
+ return false;
+
+ new |= RWSEM_FLAG_HANDOFF;
+ } else {
+ new |= RWSEM_WRITER_LOCKED;
+ new &= ~RWSEM_FLAG_HANDOFF;
+
+ if (list_is_singular(&sem->wait_list))
+ new &= ~RWSEM_FLAG_WAITERS;
+ }
+ } while (!atomic_long_try_cmpxchg_acquire(&sem->count, &count, new));
+
+ /*
+ * We have either acquired the lock with handoff bit cleared or
+ * set the handoff bit.
+ */
+ if (new & RWSEM_FLAG_HANDOFF)
+ return false;
+
+ rwsem_set_owner(sem);
+ return true;
+}
+
+#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
+/*
+ * Try to acquire read lock before the reader is put on wait queue.
+ * Lock acquisition isn't allowed if the rwsem is locked or a writer handoff
+ * is ongoing.
+ */
+static inline bool rwsem_try_read_lock_unqueued(struct rw_semaphore *sem)
+{
+ long count = atomic_long_read(&sem->count);
+
+ if (count & (RWSEM_WRITER_MASK | RWSEM_FLAG_HANDOFF))
+ return false;
+
+ count = atomic_long_fetch_add_acquire(RWSEM_READER_BIAS, &sem->count);
+ if (!(count & (RWSEM_WRITER_MASK | RWSEM_FLAG_HANDOFF))) {
+ rwsem_set_reader_owned(sem);
+ lockevent_inc(rwsem_opt_rlock);
+ return true;
+ }
+
+ /* Back out the change */
+ atomic_long_add(-RWSEM_READER_BIAS, &sem->count);
+ return false;
+}
+
+/*
+ * Try to acquire write lock before the writer has been put on wait queue.
+ */
+static inline bool rwsem_try_write_lock_unqueued(struct rw_semaphore *sem)
+{
+ long count = atomic_long_read(&sem->count);
+
+ while (!(count & (RWSEM_LOCK_MASK|RWSEM_FLAG_HANDOFF))) {
+ if (atomic_long_try_cmpxchg_acquire(&sem->count, &count,
+ count | RWSEM_WRITER_LOCKED)) {
+ rwsem_set_owner(sem);
+ lockevent_inc(rwsem_opt_wlock);
+ return true;
+ }
+ }
+ return false;
+}
+
+static inline bool owner_on_cpu(struct task_struct *owner)
+{
+ /*
+ * As lock holder preemption issue, we both skip spinning if
+ * task is not on cpu or its cpu is preempted
+ */
+ return owner->on_cpu && !vcpu_is_preempted(task_cpu(owner));
+}
+
+static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem,
+ unsigned long nonspinnable)
+{
+ struct task_struct *owner;
+ unsigned long flags;
+ bool ret = true;
+
+ BUILD_BUG_ON(!(RWSEM_OWNER_UNKNOWN & RWSEM_NONSPINNABLE));
+
+ if (need_resched()) {
+ lockevent_inc(rwsem_opt_fail);
+ return false;
+ }
+
+ preempt_disable();
+ rcu_read_lock();
+ owner = rwsem_owner_flags(sem, &flags);
+ if ((flags & nonspinnable) || (owner && !owner_on_cpu(owner)))
+ ret = false;
+ rcu_read_unlock();
+ preempt_enable();
+
+ lockevent_cond_inc(rwsem_opt_fail, !ret);
+ return ret;
+}
+
+/*
+ * The rwsem_spin_on_owner() function returns the folowing 4 values
+ * depending on the lock owner state.
+ * OWNER_NULL : owner is currently NULL
+ * OWNER_WRITER: when owner changes and is a writer
+ * OWNER_READER: when owner changes and the new owner may be a reader.
+ * OWNER_NONSPINNABLE:
+ * when optimistic spinning has to stop because either the
+ * owner stops running, is unknown, or its timeslice has
+ * been used up.
+ */
+enum owner_state {
+ OWNER_NULL = 1 << 0,
+ OWNER_WRITER = 1 << 1,
+ OWNER_READER = 1 << 2,
+ OWNER_NONSPINNABLE = 1 << 3,
+};
+#define OWNER_SPINNABLE (OWNER_NULL | OWNER_WRITER | OWNER_READER)
+
+static inline enum owner_state
+rwsem_owner_state(struct task_struct *owner, unsigned long flags, unsigned long nonspinnable)
+{
+ if (flags & nonspinnable)
+ return OWNER_NONSPINNABLE;
+
+ if (flags & RWSEM_READER_OWNED)
+ return OWNER_READER;
+
+ return owner ? OWNER_WRITER : OWNER_NULL;
+}
+
+static noinline enum owner_state
+rwsem_spin_on_owner(struct rw_semaphore *sem, unsigned long nonspinnable)
+{
+ struct task_struct *new, *owner;
+ unsigned long flags, new_flags;
+ enum owner_state state;
+
+ owner = rwsem_owner_flags(sem, &flags);
+ state = rwsem_owner_state(owner, flags, nonspinnable);
+ if (state != OWNER_WRITER)
+ return state;
+
+ rcu_read_lock();
+ for (;;) {
+ if (atomic_long_read(&sem->count) & RWSEM_FLAG_HANDOFF) {
+ state = OWNER_NONSPINNABLE;
+ break;
+ }
+
+ new = rwsem_owner_flags(sem, &new_flags);
+ if ((new != owner) || (new_flags != flags)) {
+ state = rwsem_owner_state(new, new_flags, nonspinnable);
+ break;
+ }
+
+ /*
+ * Ensure we emit the owner->on_cpu, dereference _after_
+ * checking sem->owner still matches owner, if that fails,
+ * owner might point to free()d memory, if it still matches,
+ * the rcu_read_lock() ensures the memory stays valid.
+ */
+ barrier();
+
+ if (need_resched() || !owner_on_cpu(owner)) {
+ state = OWNER_NONSPINNABLE;
+ break;
+ }
+
+ cpu_relax();
+ }
+ rcu_read_unlock();
+
+ return state;
+}
+
+/*
+ * Calculate reader-owned rwsem spinning threshold for writer
+ *
+ * The more readers own the rwsem, the longer it will take for them to
+ * wind down and free the rwsem. So the empirical formula used to
+ * determine the actual spinning time limit here is:
+ *
+ * Spinning threshold = (10 + nr_readers/2)us
+ *
+ * The limit is capped to a maximum of 25us (30 readers). This is just
+ * a heuristic and is subjected to change in the future.
+ */
+static inline u64 rwsem_rspin_threshold(struct rw_semaphore *sem)
+{
+ long count = atomic_long_read(&sem->count);
+ int readers = count >> RWSEM_READER_SHIFT;
+ u64 delta;
+
+ if (readers > 30)
+ readers = 30;
+ delta = (20 + readers) * NSEC_PER_USEC / 2;
+
+ return sched_clock() + delta;
+}
+
+static bool rwsem_optimistic_spin(struct rw_semaphore *sem, bool wlock)
+{
+ bool taken = false;
+ int prev_owner_state = OWNER_NULL;
+ int loop = 0;
+ u64 rspin_threshold = 0;
+ unsigned long nonspinnable = wlock ? RWSEM_WR_NONSPINNABLE
+ : RWSEM_RD_NONSPINNABLE;
+
+ preempt_disable();
+
+ /* sem->wait_lock should not be held when doing optimistic spinning */
+ if (!osq_lock(&sem->osq))
+ goto done;
+
+ /*
+ * Optimistically spin on the owner field and attempt to acquire the
+ * lock whenever the owner changes. Spinning will be stopped when:
+ * 1) the owning writer isn't running; or
+ * 2) readers own the lock and spinning time has exceeded limit.
+ */
+ for (;;) {
+ enum owner_state owner_state;
+
+ owner_state = rwsem_spin_on_owner(sem, nonspinnable);
+ if (!(owner_state & OWNER_SPINNABLE))
+ break;
+
+ /*
+ * Try to acquire the lock
+ */
+ taken = wlock ? rwsem_try_write_lock_unqueued(sem)
+ : rwsem_try_read_lock_unqueued(sem);
+
+ if (taken)
+ break;
+
+ /*
+ * Time-based reader-owned rwsem optimistic spinning
+ */
+ if (wlock && (owner_state == OWNER_READER)) {
+ /*
+ * Re-initialize rspin_threshold every time when
+ * the owner state changes from non-reader to reader.
+ * This allows a writer to steal the lock in between
+ * 2 reader phases and have the threshold reset at
+ * the beginning of the 2nd reader phase.
+ */
+ if (prev_owner_state != OWNER_READER) {
+ if (rwsem_test_oflags(sem, nonspinnable))
+ break;
+ rspin_threshold = rwsem_rspin_threshold(sem);
+ loop = 0;
+ }
+
+ /*
+ * Check time threshold once every 16 iterations to
+ * avoid calling sched_clock() too frequently so
+ * as to reduce the average latency between the times
+ * when the lock becomes free and when the spinner
+ * is ready to do a trylock.
+ */
+ else if (!(++loop & 0xf) && (sched_clock() > rspin_threshold)) {
+ rwsem_set_nonspinnable(sem);
+ lockevent_inc(rwsem_opt_nospin);
+ break;
+ }
+ }
+
+ /*
+ * An RT task cannot do optimistic spinning if it cannot
+ * be sure the lock holder is running or live-lock may
+ * happen if the current task and the lock holder happen
+ * to run in the same CPU. However, aborting optimistic
+ * spinning while a NULL owner is detected may miss some
+ * opportunity where spinning can continue without causing
+ * problem.
+ *
+ * There are 2 possible cases where an RT task may be able
+ * to continue spinning.
+ *
+ * 1) The lock owner is in the process of releasing the
+ * lock, sem->owner is cleared but the lock has not
+ * been released yet.
+ * 2) The lock was free and owner cleared, but another
+ * task just comes in and acquire the lock before
+ * we try to get it. The new owner may be a spinnable
+ * writer.
+ *
+ * To take advantage of two scenarios listed agove, the RT
+ * task is made to retry one more time to see if it can
+ * acquire the lock or continue spinning on the new owning
+ * writer. Of course, if the time lag is long enough or the
+ * new owner is not a writer or spinnable, the RT task will
+ * quit spinning.
+ *
+ * If the owner is a writer, the need_resched() check is
+ * done inside rwsem_spin_on_owner(). If the owner is not
+ * a writer, need_resched() check needs to be done here.
+ */
+ if (owner_state != OWNER_WRITER) {
+ if (need_resched())
+ break;
+ if (rt_task(current) &&
+ (prev_owner_state != OWNER_WRITER))
+ break;
+ }
+ prev_owner_state = owner_state;
+
+ /*
+ * The cpu_relax() call is a compiler barrier which forces
+ * everything in this loop to be re-loaded. We don't need
+ * memory barriers as we'll eventually observe the right
+ * values at the cost of a few extra spins.
+ */
+ cpu_relax();
+ }
+ osq_unlock(&sem->osq);
+done:
+ preempt_enable();
+ lockevent_cond_inc(rwsem_opt_fail, !taken);
+ return taken;
+}
+
+/*
+ * Clear the owner's RWSEM_WR_NONSPINNABLE bit if it is set. This should
+ * only be called when the reader count reaches 0.
+ *
+ * This give writers better chance to acquire the rwsem first before
+ * readers when the rwsem was being held by readers for a relatively long
+ * period of time. Race can happen that an optimistic spinner may have
+ * just stolen the rwsem and set the owner, but just clearing the
+ * RWSEM_WR_NONSPINNABLE bit will do no harm anyway.
+ */
+static inline void clear_wr_nonspinnable(struct rw_semaphore *sem)
+{
+ if (rwsem_test_oflags(sem, RWSEM_WR_NONSPINNABLE))
+ atomic_long_andnot(RWSEM_WR_NONSPINNABLE, &sem->owner);
+}
+
+/*
+ * This function is called when the reader fails to acquire the lock via
+ * optimistic spinning. In this case we will still attempt to do a trylock
+ * when comparing the rwsem state right now with the state when entering
+ * the slowpath indicates that the reader is still in a valid reader phase.
+ * This happens when the following conditions are true:
+ *
+ * 1) The lock is currently reader owned, and
+ * 2) The lock is previously not reader-owned or the last read owner changes.
+ *
+ * In the former case, we have transitioned from a writer phase to a
+ * reader-phase while spinning. In the latter case, it means the reader
+ * phase hasn't ended when we entered the optimistic spinning loop. In
+ * both cases, the reader is eligible to acquire the lock. This is the
+ * secondary path where a read lock is acquired optimistically.
+ *
+ * The reader non-spinnable bit wasn't set at time of entry or it will
+ * not be here at all.
+ */
+static inline bool rwsem_reader_phase_trylock(struct rw_semaphore *sem,
+ unsigned long last_rowner)
+{
+ unsigned long owner = atomic_long_read(&sem->owner);
+
+ if (!(owner & RWSEM_READER_OWNED))
+ return false;
+
+ if (((owner ^ last_rowner) & ~RWSEM_OWNER_FLAGS_MASK) &&
+ rwsem_try_read_lock_unqueued(sem)) {
+ lockevent_inc(rwsem_opt_rlock2);
+ lockevent_add(rwsem_opt_fail, -1);
+ return true;
+ }
+ return false;
+}
+#else
+static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem,
+ unsigned long nonspinnable)
+{
+ return false;
+}
+
+static inline bool rwsem_optimistic_spin(struct rw_semaphore *sem, bool wlock)
+{
+ return false;
+}
+
+static inline void clear_wr_nonspinnable(struct rw_semaphore *sem) { }
+
+static inline bool rwsem_reader_phase_trylock(struct rw_semaphore *sem,
+ unsigned long last_rowner)
+{
+ return false;
+}
+#endif
+
+/*
+ * Wait for the read lock to be granted
+ */
+static struct rw_semaphore __sched *
+rwsem_down_read_slowpath(struct rw_semaphore *sem, int state)
+{
+ long count, adjustment = -RWSEM_READER_BIAS;
+ struct rwsem_waiter waiter;
+ DEFINE_WAKE_Q(wake_q);
+ bool wake = false;
+
+ /*
+ * Save the current read-owner of rwsem, if available, and the
+ * reader nonspinnable bit.
+ */
+ waiter.last_rowner = atomic_long_read(&sem->owner);
+ if (!(waiter.last_rowner & RWSEM_READER_OWNED))
+ waiter.last_rowner &= RWSEM_RD_NONSPINNABLE;
+
+ if (!rwsem_can_spin_on_owner(sem, RWSEM_RD_NONSPINNABLE))
+ goto queue;
+
+ /*
+ * Undo read bias from down_read() and do optimistic spinning.
+ */
+ atomic_long_add(-RWSEM_READER_BIAS, &sem->count);
+ adjustment = 0;
+ if (rwsem_optimistic_spin(sem, false)) {
+ /*
+ * Wake up other readers in the wait list if the front
+ * waiter is a reader.
+ */
+ if ((atomic_long_read(&sem->count) & RWSEM_FLAG_WAITERS)) {
+ raw_spin_lock_irq(&sem->wait_lock);
+ if (!list_empty(&sem->wait_list))
+ rwsem_mark_wake(sem, RWSEM_WAKE_READ_OWNED,
+ &wake_q);
+ raw_spin_unlock_irq(&sem->wait_lock);
+ wake_up_q(&wake_q);
+ }
+ return sem;
+ } else if (rwsem_reader_phase_trylock(sem, waiter.last_rowner)) {
+ return sem;
+ }
+
+queue:
+ waiter.task = current;
+ waiter.type = RWSEM_WAITING_FOR_READ;
+ waiter.timeout = jiffies + RWSEM_WAIT_TIMEOUT;
+
+ raw_spin_lock_irq(&sem->wait_lock);
+ if (list_empty(&sem->wait_list)) {
+ /*
+ * In case the wait queue is empty and the lock isn't owned
+ * by a writer or has the handoff bit set, this reader can
+ * exit the slowpath and return immediately as its
+ * RWSEM_READER_BIAS has already been set in the count.
+ */
+ if (adjustment && !(atomic_long_read(&sem->count) &
+ (RWSEM_WRITER_MASK | RWSEM_FLAG_HANDOFF))) {
+ raw_spin_unlock_irq(&sem->wait_lock);
+ rwsem_set_reader_owned(sem);
+ lockevent_inc(rwsem_rlock_fast);
+ return sem;
+ }
+ adjustment += RWSEM_FLAG_WAITERS;
+ }
+ list_add_tail(&waiter.list, &sem->wait_list);
+
+ /* we're now waiting on the lock, but no longer actively locking */
+ if (adjustment)
+ count = atomic_long_add_return(adjustment, &sem->count);
+ else
+ count = atomic_long_read(&sem->count);
+
+ /*
+ * If there are no active locks, wake the front queued process(es).
+ *
+ * If there are no writers and we are first in the queue,
+ * wake our own waiter to join the existing active readers !
+ */
+ if (!(count & RWSEM_LOCK_MASK)) {
+ clear_wr_nonspinnable(sem);
+ wake = true;
+ }
+ if (wake || (!(count & RWSEM_WRITER_MASK) &&
+ (adjustment & RWSEM_FLAG_WAITERS)))
+ rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q);
+
+ raw_spin_unlock_irq(&sem->wait_lock);
+ wake_up_q(&wake_q);
+
+ /* wait to be given the lock */
+ while (true) {
+ set_current_state(state);
+ if (!waiter.task)
+ break;
+ if (signal_pending_state(state, current)) {
+ raw_spin_lock_irq(&sem->wait_lock);
+ if (waiter.task)
+ goto out_nolock;
+ raw_spin_unlock_irq(&sem->wait_lock);
+ break;
+ }
+ schedule();
+ lockevent_inc(rwsem_sleep_reader);
+ }
+
+ __set_current_state(TASK_RUNNING);
+ lockevent_inc(rwsem_rlock);
+ return sem;
+out_nolock:
+ list_del(&waiter.list);
+ if (list_empty(&sem->wait_list)) {
+ atomic_long_andnot(RWSEM_FLAG_WAITERS|RWSEM_FLAG_HANDOFF,
+ &sem->count);
+ }
+ raw_spin_unlock_irq(&sem->wait_lock);
+ __set_current_state(TASK_RUNNING);
+ lockevent_inc(rwsem_rlock_fail);
+ return ERR_PTR(-EINTR);
+}
+
+/*
+ * This function is called by the a write lock owner. So the owner value
+ * won't get changed by others.
+ */
+static inline void rwsem_disable_reader_optspin(struct rw_semaphore *sem,
+ bool disable)
+{
+ if (unlikely(disable)) {
+ atomic_long_or(RWSEM_RD_NONSPINNABLE, &sem->owner);
+ lockevent_inc(rwsem_opt_norspin);
+ }
+}
+
+/*
+ * Wait until we successfully acquire the write lock
+ */
+static struct rw_semaphore *
+rwsem_down_write_slowpath(struct rw_semaphore *sem, int state)
+{
+ long count;
+ bool disable_rspin;
+ enum writer_wait_state wstate;
+ struct rwsem_waiter waiter;
+ struct rw_semaphore *ret = sem;
+ DEFINE_WAKE_Q(wake_q);
+
+ /* do optimistic spinning and steal lock if possible */
+ if (rwsem_can_spin_on_owner(sem, RWSEM_WR_NONSPINNABLE) &&
+ rwsem_optimistic_spin(sem, true))
+ return sem;
+
+ /*
+ * Disable reader optimistic spinning for this rwsem after
+ * acquiring the write lock when the setting of the nonspinnable
+ * bits are observed.
+ */
+ disable_rspin = atomic_long_read(&sem->owner) & RWSEM_NONSPINNABLE;
+
+ /*
+ * Optimistic spinning failed, proceed to the slowpath
+ * and block until we can acquire the sem.
+ */
+ waiter.task = current;
+ waiter.type = RWSEM_WAITING_FOR_WRITE;
+ waiter.timeout = jiffies + RWSEM_WAIT_TIMEOUT;
+
+ raw_spin_lock_irq(&sem->wait_lock);
+
+ /* account for this before adding a new element to the list */
+ wstate = list_empty(&sem->wait_list) ? WRITER_FIRST : WRITER_NOT_FIRST;
+
+ list_add_tail(&waiter.list, &sem->wait_list);
+
+ /* we're now waiting on the lock */
+ if (wstate == WRITER_NOT_FIRST) {
+ count = atomic_long_read(&sem->count);
+
+ /*
+ * If there were already threads queued before us and:
+ * 1) there are no no active locks, wake the front
+ * queued process(es) as the handoff bit might be set.
+ * 2) there are no active writers and some readers, the lock
+ * must be read owned; so we try to wake any read lock
+ * waiters that were queued ahead of us.
+ */
+ if (count & RWSEM_WRITER_MASK)
+ goto wait;
+
+ rwsem_mark_wake(sem, (count & RWSEM_READER_MASK)
+ ? RWSEM_WAKE_READERS
+ : RWSEM_WAKE_ANY, &wake_q);
+
+ if (!wake_q_empty(&wake_q)) {
+ /*
+ * We want to minimize wait_lock hold time especially
+ * when a large number of readers are to be woken up.
+ */
+ raw_spin_unlock_irq(&sem->wait_lock);
+ wake_up_q(&wake_q);
+ wake_q_init(&wake_q); /* Used again, reinit */
+ raw_spin_lock_irq(&sem->wait_lock);
+ }
+ } else {
+ atomic_long_or(RWSEM_FLAG_WAITERS, &sem->count);
+ }
+
+wait:
+ /* wait until we successfully acquire the lock */
+ set_current_state(state);
+ while (true) {
+ if (rwsem_try_write_lock(sem, wstate))
+ break;
+
+ raw_spin_unlock_irq(&sem->wait_lock);
+
+ /* Block until there are no active lockers. */
+ for (;;) {
+ if (signal_pending_state(state, current))
+ goto out_nolock;
+
+ schedule();
+ lockevent_inc(rwsem_sleep_writer);
+ set_current_state(state);
+ /*
+ * If HANDOFF bit is set, unconditionally do
+ * a trylock.
+ */
+ if (wstate == WRITER_HANDOFF)
+ break;
+
+ if ((wstate == WRITER_NOT_FIRST) &&
+ (rwsem_first_waiter(sem) == &waiter))
+ wstate = WRITER_FIRST;
+
+ count = atomic_long_read(&sem->count);
+ if (!(count & RWSEM_LOCK_MASK))
+ break;
+
+ /*
+ * The setting of the handoff bit is deferred
+ * until rwsem_try_write_lock() is called.
+ */
+ if ((wstate == WRITER_FIRST) && (rt_task(current) ||
+ time_after(jiffies, waiter.timeout))) {
+ wstate = WRITER_HANDOFF;
+ lockevent_inc(rwsem_wlock_handoff);
+ break;
+ }
+ }
+
+ raw_spin_lock_irq(&sem->wait_lock);
+ }
+ __set_current_state(TASK_RUNNING);
+ list_del(&waiter.list);
+ rwsem_disable_reader_optspin(sem, disable_rspin);
+ raw_spin_unlock_irq(&sem->wait_lock);
+ lockevent_inc(rwsem_wlock);
+
+ return ret;
+
+out_nolock:
+ __set_current_state(TASK_RUNNING);
+ raw_spin_lock_irq(&sem->wait_lock);
+ list_del(&waiter.list);
+
+ if (unlikely(wstate == WRITER_HANDOFF))
+ atomic_long_add(-RWSEM_FLAG_HANDOFF, &sem->count);
+
+ if (list_empty(&sem->wait_list))
+ atomic_long_andnot(RWSEM_FLAG_WAITERS, &sem->count);
+ else
+ rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q);
+ raw_spin_unlock_irq(&sem->wait_lock);
+ wake_up_q(&wake_q);
+ lockevent_inc(rwsem_wlock_fail);
+
+ return ERR_PTR(-EINTR);
+}
+
+/*
+ * handle waking up a waiter on the semaphore
+ * - up_read/up_write has decremented the active part of count if we come here
+ */
+static struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem, long count)
+{
+ unsigned long flags;
+ DEFINE_WAKE_Q(wake_q);
+
+ raw_spin_lock_irqsave(&sem->wait_lock, flags);
+
+ if (!list_empty(&sem->wait_list))
+ rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q);
+
+ raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
+ wake_up_q(&wake_q);
+
+ return sem;
+}
+
+/*
+ * downgrade a write lock into a read lock
+ * - caller incremented waiting part of count and discovered it still negative
+ * - just wake up any readers at the front of the queue
+ */
+static struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem)
+{
+ unsigned long flags;
+ DEFINE_WAKE_Q(wake_q);
+
+ raw_spin_lock_irqsave(&sem->wait_lock, flags);
+
+ if (!list_empty(&sem->wait_list))
+ rwsem_mark_wake(sem, RWSEM_WAKE_READ_OWNED, &wake_q);
+
+ raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
+ wake_up_q(&wake_q);
+
+ return sem;
+}
+
+/*
+ * lock for reading
+ */
+inline void __down_read(struct rw_semaphore *sem)
+{
+ if (!rwsem_read_trylock(sem)) {
+ rwsem_down_read_slowpath(sem, TASK_UNINTERRUPTIBLE);
+ DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
+ } else {
+ rwsem_set_reader_owned(sem);
+ }
+}
+
+static inline int __down_read_killable(struct rw_semaphore *sem)
+{
+ if (!rwsem_read_trylock(sem)) {
+ if (IS_ERR(rwsem_down_read_slowpath(sem, TASK_KILLABLE)))
+ return -EINTR;
+ DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
+ } else {
+ rwsem_set_reader_owned(sem);
+ }
+ return 0;
+}
+
+static inline int __down_read_trylock(struct rw_semaphore *sem)
+{
+ /*
+ * Optimize for the case when the rwsem is not locked at all.
+ */
+ long tmp = RWSEM_UNLOCKED_VALUE;
+
+ do {
+ if (atomic_long_try_cmpxchg_acquire(&sem->count, &tmp,
+ tmp + RWSEM_READER_BIAS)) {
+ rwsem_set_reader_owned(sem);
+ return 1;
+ }
+ } while (!(tmp & RWSEM_READ_FAILED_MASK));
+ return 0;
+}
+
+/*
+ * lock for writing
+ */
+static inline void __down_write(struct rw_semaphore *sem)
+{
+ long tmp = RWSEM_UNLOCKED_VALUE;
+
+ if (unlikely(!atomic_long_try_cmpxchg_acquire(&sem->count, &tmp,
+ RWSEM_WRITER_LOCKED)))
+ rwsem_down_write_slowpath(sem, TASK_UNINTERRUPTIBLE);
+ else
+ rwsem_set_owner(sem);
+}
+
+static inline int __down_write_killable(struct rw_semaphore *sem)
+{
+ long tmp = RWSEM_UNLOCKED_VALUE;
+
+ if (unlikely(!atomic_long_try_cmpxchg_acquire(&sem->count, &tmp,
+ RWSEM_WRITER_LOCKED))) {
+ if (IS_ERR(rwsem_down_write_slowpath(sem, TASK_KILLABLE)))
+ return -EINTR;
+ } else {
+ rwsem_set_owner(sem);
+ }
+ return 0;
+}
+
+static inline int __down_write_trylock(struct rw_semaphore *sem)
+{
+ long tmp = RWSEM_UNLOCKED_VALUE;
+
+ if (atomic_long_try_cmpxchg_acquire(&sem->count, &tmp,
+ RWSEM_WRITER_LOCKED)) {
+ rwsem_set_owner(sem);
+ return true;
+ }
+ return false;
+}
+
+/*
+ * unlock after reading
+ */
+inline void __up_read(struct rw_semaphore *sem)
+{
+ long tmp;
+
+ DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
+ rwsem_clear_reader_owned(sem);
+ tmp = atomic_long_add_return_release(-RWSEM_READER_BIAS, &sem->count);
+ DEBUG_RWSEMS_WARN_ON(tmp < 0, sem);
+ if (unlikely((tmp & (RWSEM_LOCK_MASK|RWSEM_FLAG_WAITERS)) ==
+ RWSEM_FLAG_WAITERS)) {
+ clear_wr_nonspinnable(sem);
+ rwsem_wake(sem, tmp);
+ }
+}
+
+/*
+ * unlock after writing
+ */
+static inline void __up_write(struct rw_semaphore *sem)
+{
+ long tmp;
+
+ /*
+ * sem->owner may differ from current if the ownership is transferred
+ * to an anonymous writer by setting the RWSEM_NONSPINNABLE bits.
+ */
+ DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) &&
+ !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE), sem);
+ rwsem_clear_owner(sem);
+ tmp = atomic_long_fetch_add_release(-RWSEM_WRITER_LOCKED, &sem->count);
+ if (unlikely(tmp & RWSEM_FLAG_WAITERS))
+ rwsem_wake(sem, tmp);
+}
+
+/*
+ * downgrade write lock to read lock
+ */
+static inline void __downgrade_write(struct rw_semaphore *sem)
+{
+ long tmp;
+
+ /*
+ * When downgrading from exclusive to shared ownership,
+ * anything inside the write-locked region cannot leak
+ * into the read side. In contrast, anything in the
+ * read-locked region is ok to be re-ordered into the
+ * write side. As such, rely on RELEASE semantics.
+ */
+ DEBUG_RWSEMS_WARN_ON(rwsem_owner(sem) != current, sem);
+ tmp = atomic_long_fetch_add_release(
+ -RWSEM_WRITER_LOCKED+RWSEM_READER_BIAS, &sem->count);
+ rwsem_set_reader_owned(sem);
+ if (tmp & RWSEM_FLAG_WAITERS)
+ rwsem_downgrade_wake(sem);
+}
/*
* lock for reading
LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
}
-
EXPORT_SYMBOL(down_read);
int __sched down_read_killable(struct rw_semaphore *sem)
return 0;
}
-
EXPORT_SYMBOL(down_read_killable);
/*
rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_);
return ret;
}
-
EXPORT_SYMBOL(down_read_trylock);
/*
{
might_sleep();
rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
-
LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
}
-
EXPORT_SYMBOL(down_write);
/*
might_sleep();
rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
- if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock, __down_write_killable)) {
+ if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock,
+ __down_write_killable)) {
rwsem_release(&sem->dep_map, 1, _RET_IP_);
return -EINTR;
}
return 0;
}
-
EXPORT_SYMBOL(down_write_killable);
/*
return ret;
}
-
EXPORT_SYMBOL(down_write_trylock);
/*
void up_read(struct rw_semaphore *sem)
{
rwsem_release(&sem->dep_map, 1, _RET_IP_);
-
__up_read(sem);
}
-
EXPORT_SYMBOL(up_read);
/*
void up_write(struct rw_semaphore *sem)
{
rwsem_release(&sem->dep_map, 1, _RET_IP_);
-
__up_write(sem);
}
-
EXPORT_SYMBOL(up_write);
/*
void downgrade_write(struct rw_semaphore *sem)
{
lock_downgrade(&sem->dep_map, _RET_IP_);
-
__downgrade_write(sem);
}
-
EXPORT_SYMBOL(downgrade_write);
#ifdef CONFIG_DEBUG_LOCK_ALLOC
{
might_sleep();
rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_);
-
LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
}
-
EXPORT_SYMBOL(down_read_nested);
void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest)
{
might_sleep();
rwsem_acquire_nest(&sem->dep_map, 0, 0, nest, _RET_IP_);
-
LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
}
-
EXPORT_SYMBOL(_down_write_nest_lock);
void down_read_non_owner(struct rw_semaphore *sem)
{
might_sleep();
-
__down_read(sem);
__rwsem_set_reader_owned(sem, NULL);
}
-
EXPORT_SYMBOL(down_read_non_owner);
void down_write_nested(struct rw_semaphore *sem, int subclass)
{
might_sleep();
rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_);
-
LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
}
-
EXPORT_SYMBOL(down_write_nested);
int __sched down_write_killable_nested(struct rw_semaphore *sem, int subclass)
might_sleep();
rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_);
- if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock, __down_write_killable)) {
+ if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock,
+ __down_write_killable)) {
rwsem_release(&sem->dep_map, 1, _RET_IP_);
return -EINTR;
}
return 0;
}
-
EXPORT_SYMBOL(down_write_killable_nested);
void up_read_non_owner(struct rw_semaphore *sem)
{
- DEBUG_RWSEMS_WARN_ON(!((unsigned long)sem->owner & RWSEM_READER_OWNED),
- sem);
+ DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
__up_read(sem);
}
-
EXPORT_SYMBOL(up_read_non_owner);
#endif
/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * The least significant 2 bits of the owner value has the following
- * meanings when set.
- * - RWSEM_READER_OWNED (bit 0): The rwsem is owned by readers
- * - RWSEM_ANONYMOUSLY_OWNED (bit 1): The rwsem is anonymously owned,
- * i.e. the owner(s) cannot be readily determined. It can be reader
- * owned or the owning writer is indeterminate.
- *
- * When a writer acquires a rwsem, it puts its task_struct pointer
- * into the owner field. It is cleared after an unlock.
- *
- * When a reader acquires a rwsem, it will also puts its task_struct
- * pointer into the owner field with both the RWSEM_READER_OWNED and
- * RWSEM_ANONYMOUSLY_OWNED bits set. On unlock, the owner field will
- * largely be left untouched. So for a free or reader-owned rwsem,
- * the owner value may contain information about the last reader that
- * acquires the rwsem. The anonymous bit is set because that particular
- * reader may or may not still own the lock.
- *
- * That information may be helpful in debugging cases where the system
- * seems to hang on a reader owned rwsem especially if only one reader
- * is involved. Ideally we would like to track all the readers that own
- * a rwsem, but the overhead is simply too big.
- */
-#include "lock_events.h"
-#define RWSEM_READER_OWNED (1UL << 0)
-#define RWSEM_ANONYMOUSLY_OWNED (1UL << 1)
+#ifndef __INTERNAL_RWSEM_H
+#define __INTERNAL_RWSEM_H
+#include <linux/rwsem.h>
-#ifdef CONFIG_DEBUG_RWSEMS
-# define DEBUG_RWSEMS_WARN_ON(c, sem) do { \
- if (!debug_locks_silent && \
- WARN_ONCE(c, "DEBUG_RWSEMS_WARN_ON(%s): count = 0x%lx, owner = 0x%lx, curr 0x%lx, list %sempty\n",\
- #c, atomic_long_read(&(sem)->count), \
- (long)((sem)->owner), (long)current, \
- list_empty(&(sem)->wait_list) ? "" : "not ")) \
- debug_locks_off(); \
- } while (0)
-#else
-# define DEBUG_RWSEMS_WARN_ON(c, sem)
-#endif
+extern void __down_read(struct rw_semaphore *sem);
+extern void __up_read(struct rw_semaphore *sem);
-/*
- * R/W semaphores originally for PPC using the stuff in lib/rwsem.c.
- * Adapted largely from include/asm-i386/rwsem.h
- * by Paul Mackerras <paulus@samba.org>.
- */
-
-/*
- * the semaphore definition
- */
-#ifdef CONFIG_64BIT
-# define RWSEM_ACTIVE_MASK 0xffffffffL
-#else
-# define RWSEM_ACTIVE_MASK 0x0000ffffL
-#endif
-
-#define RWSEM_ACTIVE_BIAS 0x00000001L
-#define RWSEM_WAITING_BIAS (-RWSEM_ACTIVE_MASK-1)
-#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
-#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
-
-#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
-/*
- * All writes to owner are protected by WRITE_ONCE() to make sure that
- * store tearing can't happen as optimistic spinners may read and use
- * the owner value concurrently without lock. Read from owner, however,
- * may not need READ_ONCE() as long as the pointer value is only used
- * for comparison and isn't being dereferenced.
- */
-static inline void rwsem_set_owner(struct rw_semaphore *sem)
-{
- WRITE_ONCE(sem->owner, current);
-}
-
-static inline void rwsem_clear_owner(struct rw_semaphore *sem)
-{
- WRITE_ONCE(sem->owner, NULL);
-}
-
-/*
- * The task_struct pointer of the last owning reader will be left in
- * the owner field.
- *
- * Note that the owner value just indicates the task has owned the rwsem
- * previously, it may not be the real owner or one of the real owners
- * anymore when that field is examined, so take it with a grain of salt.
- */
-static inline void __rwsem_set_reader_owned(struct rw_semaphore *sem,
- struct task_struct *owner)
-{
- unsigned long val = (unsigned long)owner | RWSEM_READER_OWNED
- | RWSEM_ANONYMOUSLY_OWNED;
-
- WRITE_ONCE(sem->owner, (struct task_struct *)val);
-}
-
-static inline void rwsem_set_reader_owned(struct rw_semaphore *sem)
-{
- __rwsem_set_reader_owned(sem, current);
-}
-
-/*
- * Return true if the a rwsem waiter can spin on the rwsem's owner
- * and steal the lock, i.e. the lock is not anonymously owned.
- * N.B. !owner is considered spinnable.
- */
-static inline bool is_rwsem_owner_spinnable(struct task_struct *owner)
-{
- return !((unsigned long)owner & RWSEM_ANONYMOUSLY_OWNED);
-}
-
-/*
- * Return true if rwsem is owned by an anonymous writer or readers.
- */
-static inline bool rwsem_has_anonymous_owner(struct task_struct *owner)
-{
- return (unsigned long)owner & RWSEM_ANONYMOUSLY_OWNED;
-}
-
-#ifdef CONFIG_DEBUG_RWSEMS
-/*
- * With CONFIG_DEBUG_RWSEMS configured, it will make sure that if there
- * is a task pointer in owner of a reader-owned rwsem, it will be the
- * real owner or one of the real owners. The only exception is when the
- * unlock is done by up_read_non_owner().
- */
-#define rwsem_clear_reader_owned rwsem_clear_reader_owned
-static inline void rwsem_clear_reader_owned(struct rw_semaphore *sem)
-{
- unsigned long val = (unsigned long)current | RWSEM_READER_OWNED
- | RWSEM_ANONYMOUSLY_OWNED;
- if (READ_ONCE(sem->owner) == (struct task_struct *)val)
- cmpxchg_relaxed((unsigned long *)&sem->owner, val,
- RWSEM_READER_OWNED | RWSEM_ANONYMOUSLY_OWNED);
-}
-#endif
-
-#else
-static inline void rwsem_set_owner(struct rw_semaphore *sem)
-{
-}
-
-static inline void rwsem_clear_owner(struct rw_semaphore *sem)
-{
-}
-
-static inline void __rwsem_set_reader_owned(struct rw_semaphore *sem,
- struct task_struct *owner)
-{
-}
-
-static inline void rwsem_set_reader_owned(struct rw_semaphore *sem)
-{
-}
-#endif
-
-#ifndef rwsem_clear_reader_owned
-static inline void rwsem_clear_reader_owned(struct rw_semaphore *sem)
-{
-}
-#endif
-
-extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_down_read_failed_killable(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_down_write_failed_killable(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem);
-extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem);
-
-/*
- * lock for reading
- */
-static inline void __down_read(struct rw_semaphore *sem)
-{
- if (unlikely(atomic_long_inc_return_acquire(&sem->count) <= 0)) {
- rwsem_down_read_failed(sem);
- DEBUG_RWSEMS_WARN_ON(!((unsigned long)sem->owner &
- RWSEM_READER_OWNED), sem);
- } else {
- rwsem_set_reader_owned(sem);
- }
-}
-
-static inline int __down_read_killable(struct rw_semaphore *sem)
-{
- if (unlikely(atomic_long_inc_return_acquire(&sem->count) <= 0)) {
- if (IS_ERR(rwsem_down_read_failed_killable(sem)))
- return -EINTR;
- DEBUG_RWSEMS_WARN_ON(!((unsigned long)sem->owner &
- RWSEM_READER_OWNED), sem);
- } else {
- rwsem_set_reader_owned(sem);
- }
- return 0;
-}
-
-static inline int __down_read_trylock(struct rw_semaphore *sem)
-{
- /*
- * Optimize for the case when the rwsem is not locked at all.
- */
- long tmp = RWSEM_UNLOCKED_VALUE;
-
- lockevent_inc(rwsem_rtrylock);
- do {
- if (atomic_long_try_cmpxchg_acquire(&sem->count, &tmp,
- tmp + RWSEM_ACTIVE_READ_BIAS)) {
- rwsem_set_reader_owned(sem);
- return 1;
- }
- } while (tmp >= 0);
- return 0;
-}
-
-/*
- * lock for writing
- */
-static inline void __down_write(struct rw_semaphore *sem)
-{
- long tmp;
-
- tmp = atomic_long_add_return_acquire(RWSEM_ACTIVE_WRITE_BIAS,
- &sem->count);
- if (unlikely(tmp != RWSEM_ACTIVE_WRITE_BIAS))
- rwsem_down_write_failed(sem);
- rwsem_set_owner(sem);
-}
-
-static inline int __down_write_killable(struct rw_semaphore *sem)
-{
- long tmp;
-
- tmp = atomic_long_add_return_acquire(RWSEM_ACTIVE_WRITE_BIAS,
- &sem->count);
- if (unlikely(tmp != RWSEM_ACTIVE_WRITE_BIAS))
- if (IS_ERR(rwsem_down_write_failed_killable(sem)))
- return -EINTR;
- rwsem_set_owner(sem);
- return 0;
-}
-
-static inline int __down_write_trylock(struct rw_semaphore *sem)
-{
- long tmp;
-
- lockevent_inc(rwsem_wtrylock);
- tmp = atomic_long_cmpxchg_acquire(&sem->count, RWSEM_UNLOCKED_VALUE,
- RWSEM_ACTIVE_WRITE_BIAS);
- if (tmp == RWSEM_UNLOCKED_VALUE) {
- rwsem_set_owner(sem);
- return true;
- }
- return false;
-}
-
-/*
- * unlock after reading
- */
-static inline void __up_read(struct rw_semaphore *sem)
-{
- long tmp;
-
- DEBUG_RWSEMS_WARN_ON(!((unsigned long)sem->owner & RWSEM_READER_OWNED),
- sem);
- rwsem_clear_reader_owned(sem);
- tmp = atomic_long_dec_return_release(&sem->count);
- if (unlikely(tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0))
- rwsem_wake(sem);
-}
-
-/*
- * unlock after writing
- */
-static inline void __up_write(struct rw_semaphore *sem)
-{
- DEBUG_RWSEMS_WARN_ON(sem->owner != current, sem);
- rwsem_clear_owner(sem);
- if (unlikely(atomic_long_sub_return_release(RWSEM_ACTIVE_WRITE_BIAS,
- &sem->count) < 0))
- rwsem_wake(sem);
-}
-
-/*
- * downgrade write lock to read lock
- */
-static inline void __downgrade_write(struct rw_semaphore *sem)
-{
- long tmp;
-
- /*
- * When downgrading from exclusive to shared ownership,
- * anything inside the write-locked region cannot leak
- * into the read side. In contrast, anything in the
- * read-locked region is ok to be re-ordered into the
- * write side. As such, rely on RELEASE semantics.
- */
- DEBUG_RWSEMS_WARN_ON(sem->owner != current, sem);
- tmp = atomic_long_add_return_release(-RWSEM_WAITING_BIAS, &sem->count);
- rwsem_set_reader_owned(sem);
- if (tmp < 0)
- rwsem_downgrade_wake(sem);
-}
+#endif /* __INTERNAL_RWSEM_H */
u64 time, cost;
s64 delta;
int cpu, nr = INT_MAX;
+ int this = smp_processor_id();
this_sd = rcu_dereference(*this_cpu_ptr(&sd_llc));
if (!this_sd)
nr = 4;
}
- time = local_clock();
+ time = cpu_clock(this);
for_each_cpu_wrap(cpu, sched_domain_span(sd), target) {
if (!--nr)
break;
}
- time = local_clock() - time;
+ time = cpu_clock(this) - time;
cost = this_sd->avg_scan_cost;
delta = (s64)(time - cost) / 8;
this_sd->avg_scan_cost += delta;
select DEBUG_SPINLOCK
select DEBUG_MUTEXES
select DEBUG_RT_MUTEXES if RT_MUTEXES
- select DEBUG_RWSEMS if RWSEM_SPIN_ON_OWNER
+ select DEBUG_RWSEMS
select DEBUG_WW_MUTEX_SLOWPATH
select DEBUG_LOCK_ALLOC
select TRACE_IRQFLAGS
config DEBUG_RWSEMS
bool "RW Semaphore debugging: basic checks"
- depends on DEBUG_KERNEL && RWSEM_SPIN_ON_OWNER
+ depends on DEBUG_KERNEL
help
- This debugging feature allows mismatched rw semaphore locks and unlocks
- to be detected and reported.
+ This debugging feature allows mismatched rw semaphore locks
+ and unlocks to be detected and reported.
config DEBUG_LOCK_ALLOC
bool "Lock debugging: detect incorrect freeing of live locks"
return &atomic64_lock[addr & (NR_LOCKS - 1)].lock;
}
-long long atomic64_read(const atomic64_t *v)
+s64 atomic64_read(const atomic64_t *v)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
- long long val;
+ s64 val;
raw_spin_lock_irqsave(lock, flags);
val = v->counter;
}
EXPORT_SYMBOL(atomic64_read);
-void atomic64_set(atomic64_t *v, long long i)
+void atomic64_set(atomic64_t *v, s64 i)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
EXPORT_SYMBOL(atomic64_set);
#define ATOMIC64_OP(op, c_op) \
-void atomic64_##op(long long a, atomic64_t *v) \
+void atomic64_##op(s64 a, atomic64_t *v) \
{ \
unsigned long flags; \
raw_spinlock_t *lock = lock_addr(v); \
EXPORT_SYMBOL(atomic64_##op);
#define ATOMIC64_OP_RETURN(op, c_op) \
-long long atomic64_##op##_return(long long a, atomic64_t *v) \
+s64 atomic64_##op##_return(s64 a, atomic64_t *v) \
{ \
unsigned long flags; \
raw_spinlock_t *lock = lock_addr(v); \
- long long val; \
+ s64 val; \
\
raw_spin_lock_irqsave(lock, flags); \
val = (v->counter c_op a); \
EXPORT_SYMBOL(atomic64_##op##_return);
#define ATOMIC64_FETCH_OP(op, c_op) \
-long long atomic64_fetch_##op(long long a, atomic64_t *v) \
+s64 atomic64_fetch_##op(s64 a, atomic64_t *v) \
{ \
unsigned long flags; \
raw_spinlock_t *lock = lock_addr(v); \
- long long val; \
+ s64 val; \
\
raw_spin_lock_irqsave(lock, flags); \
val = v->counter; \
#undef ATOMIC64_OP_RETURN
#undef ATOMIC64_OP
-long long atomic64_dec_if_positive(atomic64_t *v)
+s64 atomic64_dec_if_positive(atomic64_t *v)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
- long long val;
+ s64 val;
raw_spin_lock_irqsave(lock, flags);
val = v->counter - 1;
}
EXPORT_SYMBOL(atomic64_dec_if_positive);
-long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n)
+s64 atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
- long long val;
+ s64 val;
raw_spin_lock_irqsave(lock, flags);
val = v->counter;
}
EXPORT_SYMBOL(atomic64_cmpxchg);
-long long atomic64_xchg(atomic64_t *v, long long new)
+s64 atomic64_xchg(atomic64_t *v, s64 new)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
- long long val;
+ s64 val;
raw_spin_lock_irqsave(lock, flags);
val = v->counter;
}
EXPORT_SYMBOL(atomic64_xchg);
-long long atomic64_fetch_add_unless(atomic64_t *v, long long a, long long u)
+s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
{
unsigned long flags;
raw_spinlock_t *lock = lock_addr(v);
- long long val;
+ s64 val;
raw_spin_lock_irqsave(lock, flags);
val = v->counter;
OLDSUM="$(tail -n 1 ${LINUXDIR}/include/${header})"
OLDSUM="${OLDSUM#// }"
- NEWSUM="$(head -n -1 ${LINUXDIR}/include/${header} | sha1sum)"
+ NEWSUM="$(sed '$d' ${LINUXDIR}/include/${header} | sha1sum)"
NEWSUM="${NEWSUM%% *}"
if [ "${OLDSUM}" != "${NEWSUM}" ]; then
AA_BUG(!orig);
AA_BUG(!new);
- lockdep_assert_held_exclusive(&labels_set(orig)->lock);
+ lockdep_assert_held_write(&labels_set(orig)->lock);
tmp = rcu_dereference_protected(orig->proxy->label,
&labels_ns(orig)->lock);
AA_BUG(!ls);
AA_BUG(!label);
- lockdep_assert_held_exclusive(&ls->lock);
+ lockdep_assert_held_write(&ls->lock);
if (new)
__aa_proxy_redirect(label, new);
AA_BUG(!ls);
AA_BUG(!old);
AA_BUG(!new);
- lockdep_assert_held_exclusive(&ls->lock);
+ lockdep_assert_held_write(&ls->lock);
AA_BUG(new->flags & FLAG_IN_TREE);
if (!label_is_stale(old))
AA_BUG(!ls);
AA_BUG(!label);
AA_BUG(labels_set(label) != ls);
- lockdep_assert_held_exclusive(&ls->lock);
+ lockdep_assert_held_write(&ls->lock);
AA_BUG(label->flags & FLAG_IN_TREE);
/* Figure out where to put new node */
projects / linux-2.6-microblaze.git / commitdiff