rcutorture: Add RCU-bh and RCU-sched support for extended readers

Since there is now a single consolidated RCU flavor, rcutorture
needs to test extending of RCU readers via rcu_read_lock_bh() and
rcu_read_lock_sched().  This commit adds this support, with added checks
(just like for local_bh_enable()) to ensure that rcu_read_unlock_bh()
will not be invoked while interrupts are disabled.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index c55d148..1bc0e37 100644 (file)
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -66,13 +66,16 @@ MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and Josh Triplett <josh@jos
 /* Bits for ->extendables field, extendables param, and related definitions. */
 #define RCUTORTURE_RDR_SHIFT    8      /* Put SRCU index in upper bits. */
 #define RCUTORTURE_RDR_MASK     ((1 << RCUTORTURE_RDR_SHIFT) - 1)
-#define RCUTORTURE_RDR_BH       0x1    /* Extend readers by disabling bh. */
-#define RCUTORTURE_RDR_IRQ      0x2    /*  ... disabling interrupts. */
-#define RCUTORTURE_RDR_PREEMPT  0x4    /*  ... disabling preemption. */
-#define RCUTORTURE_RDR_RCU      0x8    /*  ... entering another RCU reader. */
-#define RCUTORTURE_RDR_NBITS    4      /* Number of bits defined above. */
-#define RCUTORTURE_MAX_EXTEND   (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | \
-                                 RCUTORTURE_RDR_PREEMPT)
+#define RCUTORTURE_RDR_BH       0x01   /* Extend readers by disabling bh. */
+#define RCUTORTURE_RDR_IRQ      0x02   /*  ... disabling interrupts. */
+#define RCUTORTURE_RDR_PREEMPT  0x04   /*  ... disabling preemption. */
+#define RCUTORTURE_RDR_RBH      0x08   /*  ... rcu_read_lock_bh(). */
+#define RCUTORTURE_RDR_SCHED    0x10   /*  ... rcu_read_lock_sched(). */
+#define RCUTORTURE_RDR_RCU      0x20   /*  ... entering another RCU reader. */
+#define RCUTORTURE_RDR_NBITS    6      /* Number of bits defined above. */
+#define RCUTORTURE_MAX_EXTEND   \
+       (RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
+        RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED)
 #define RCUTORTURE_RDR_MAX_LOOPS 0x7   /* Maximum reader extensions. */
                                        /* Must be power of two minus one. */
 
@@ -1217,6 +1220,10 @@ static void rcutorture_one_extend(int *readstate, int newstate,
                local_irq_disable();
        if (statesnew & RCUTORTURE_RDR_PREEMPT)
                preempt_disable();
+       if (statesnew & RCUTORTURE_RDR_RBH)
+               rcu_read_lock_bh();
+       if (statesnew & RCUTORTURE_RDR_SCHED)
+               rcu_read_lock_sched();
        if (statesnew & RCUTORTURE_RDR_RCU)
                idxnew = cur_ops->readlock() << RCUTORTURE_RDR_SHIFT;
 
@@ -1227,6 +1234,10 @@ static void rcutorture_one_extend(int *readstate, int newstate,
                local_bh_enable();
        if (statesold & RCUTORTURE_RDR_PREEMPT)
                preempt_enable();
+       if (statesold & RCUTORTURE_RDR_RBH)
+               rcu_read_unlock_bh();
+       if (statesold & RCUTORTURE_RDR_SCHED)
+               rcu_read_unlock_sched();
        if (statesold & RCUTORTURE_RDR_RCU)
                cur_ops->readunlock(idxold >> RCUTORTURE_RDR_SHIFT);
 
@@ -1269,10 +1280,11 @@ rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
                mask = mask & randmask2;
        else
                mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
+       /* Can't enable bh w/irq disabled. */
        if ((mask & RCUTORTURE_RDR_IRQ) &&
-           !(mask & RCUTORTURE_RDR_BH) &&
-           (oldmask & RCUTORTURE_RDR_BH))
-               mask |= RCUTORTURE_RDR_BH; /* Can't enable bh w/irq disabled. */
+           ((!(mask & RCUTORTURE_RDR_BH) && (oldmask & RCUTORTURE_RDR_BH)) ||
+            (!(mask & RCUTORTURE_RDR_RBH) && (oldmask & RCUTORTURE_RDR_RBH))))
+               mask |= RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
        if ((mask & RCUTORTURE_RDR_IRQ) &&
            !(mask & cur_ops->ext_irq_conflict) &&
            (oldmask & cur_ops->ext_irq_conflict))