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| author | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2016-09-27 10:34:19 -0300 |
|---|---|---|
| committer | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2016-09-27 10:34:19 -0300 |
| commit | 1c29f4306f557ef5d9ed515ec8881f4d1735b058 (patch) | |
| tree | 1359b9f8403af67e35bbbaae36e2b60c9bb3d2da /arch/arm64/include/asm/spinlock.h | |
| parent | 5b465b045af3a649a89b8a5c5bfdece20ffc0345 (diff) | |
Linux-libre 4.7.5-gnupck-4.7.5-gnu
Diffstat (limited to 'arch/arm64/include/asm/spinlock.h')
| -rw-r--r-- | arch/arm64/include/asm/spinlock.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/spinlock.h b/arch/arm64/include/asm/spinlock.h index e875a5a55..89206b568 100644 --- a/arch/arm64/include/asm/spinlock.h +++ b/arch/arm64/include/asm/spinlock.h @@ -363,4 +363,14 @@ static inline int arch_read_trylock(arch_rwlock_t *rw) #define arch_read_relax(lock) cpu_relax() #define arch_write_relax(lock) cpu_relax() +/* + * Accesses appearing in program order before a spin_lock() operation + * can be reordered with accesses inside the critical section, by virtue + * of arch_spin_lock being constructed using acquire semantics. + * + * In cases where this is problematic (e.g. try_to_wake_up), an + * smp_mb__before_spinlock() can restore the required ordering. + */ +#define smp_mb__before_spinlock() smp_mb() + #endif /* __ASM_SPINLOCK_H */ |