diff options
| author | Stefan Agner <stefan@agner.ch> | 2017-03-14 13:59:28 -0700 |
|---|---|---|
| committer | Max Krummenacher <max.krummenacher@toradex.com> | 2017-03-15 18:35:51 +0100 |
| commit | 39ac0033f2345ce7b5d8ca4439192407dacb2355 (patch) | |
| tree | 51dc588baa63d31bc406388885f62c1cae068fa3 /arch/arm64/include/asm/spinlock.h | |
| parent | 13f2767f31803754aa883f298737aff866f04628 (diff) | |
| parent | d9e0350d2575a20ee7783427da9bd6b6107eb983 (diff) | |
Merge tag 'v4.1.39' into toradex_vf_4.1-nexttoradex_vf_4.1
Linux 4.1.39
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 cee128732435..d155a9bbfab6 100644 --- a/arch/arm64/include/asm/spinlock.h +++ b/arch/arm64/include/asm/spinlock.h @@ -231,4 +231,14 @@ 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 */ |