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-rw-r--r--arch/arm/include/asm/spinlock.h25
1 files changed, 14 insertions, 11 deletions
diff --git a/arch/arm/include/asm/spinlock.h b/arch/arm/include/asm/spinlock.h
index 6220e9fdf4c7..f8b8965666e9 100644
--- a/arch/arm/include/asm/spinlock.h
+++ b/arch/arm/include/asm/spinlock.h
@@ -97,19 +97,22 @@ static inline void arch_spin_lock(arch_spinlock_t *lock)
static inline int arch_spin_trylock(arch_spinlock_t *lock)
{
- unsigned long tmp;
+ unsigned long contended, res;
u32 slock;
- __asm__ __volatile__(
-" ldrex %0, [%2]\n"
-" subs %1, %0, %0, ror #16\n"
-" addeq %0, %0, %3\n"
-" strexeq %1, %0, [%2]"
- : "=&r" (slock), "=&r" (tmp)
- : "r" (&lock->slock), "I" (1 << TICKET_SHIFT)
- : "cc");
-
- if (tmp == 0) {
+ do {
+ __asm__ __volatile__(
+ " ldrex %0, [%3]\n"
+ " mov %2, #0\n"
+ " subs %1, %0, %0, ror #16\n"
+ " addeq %0, %0, %4\n"
+ " strexeq %2, %0, [%3]"
+ : "=&r" (slock), "=&r" (contended), "=r" (res)
+ : "r" (&lock->slock), "I" (1 << TICKET_SHIFT)
+ : "cc");
+ } while (res);
+
+ if (!contended) {
smp_mb();
return 1;
} else {