parisc: Improve interrupt handling in arch_spin_lock_flags()

Rewrite arch_spin_lock() and arch_spin_lock_flags() to not re-enable and
disable the PSW_SM_I interrupt flag too often.

Signed-off-by: Helge Deller <deller@gmx.de>

diff --git a/arch/parisc/include/asm/spinlock.h b/arch/parisc/include/asm/spinlock.h
index 197d224..51582ea 100644 (file)
--- a/arch/parisc/include/asm/spinlock.h
+++ b/arch/parisc/include/asm/spinlock.h
@@ -10,25 +10,34 @@
 static inline int arch_spin_is_locked(arch_spinlock_t *x)
 {
        volatile unsigned int *a = __ldcw_align(x);
+       smp_mb();
        return *a == 0;
 }
 
-#define arch_spin_lock(lock) arch_spin_lock_flags(lock, 0)
+static inline void arch_spin_lock(arch_spinlock_t *x)
+{
+       volatile unsigned int *a;
+
+       a = __ldcw_align(x);
+       while (__ldcw(a) == 0)
+               while (*a == 0)
+                       cpu_relax();
+}
 
 static inline void arch_spin_lock_flags(arch_spinlock_t *x,
                                         unsigned long flags)
 {
        volatile unsigned int *a;
+       unsigned long flags_dis;
 
        a = __ldcw_align(x);
-       while (__ldcw(a) == 0)
+       while (__ldcw(a) == 0) {
+               local_save_flags(flags_dis);
+               local_irq_restore(flags);
                while (*a == 0)
-                       if (flags & PSW_SM_I) {
-                               local_irq_enable();
-                               cpu_relax();
-                               local_irq_disable();
-                       } else
-                               cpu_relax();
+                       cpu_relax();
+               local_irq_restore(flags_dis);
+       }
 }
 #define arch_spin_lock_flags arch_spin_lock_flags