diff options
| author | Will Deacon <will.deacon@arm.com> | 2013-01-24 14:47:38 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2013-01-28 15:13:05 +0100 |
| commit | 20e260b6f4f717c100620122f626a2c06a4cfd72 (patch) | |
| tree | b2f0c8c70f86ae41f742604b4eb6c08d75109595 /arch/arm/include/asm/spinlock.h | |
| parent | ARM: smp: remove wrapper functions (diff) | |
| download | linux-20e260b6f4f717c100620122f626a2c06a4cfd72.tar.xz linux-20e260b6f4f717c100620122f626a2c06a4cfd72.zip | |
ARM: 7632/1: spinlock: avoid exclusive accesses on unlock() path
When unlocking a spinlock, all we need to do is increment the owner
field of the lock. Since only one CPU can be performing an unlock()
operation for a given lock, this doesn't need to be exclusive.
This patch simplifies arch_spin_unlock to use non-exclusive accesses
when updating the owner field of the lock.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/include/asm/spinlock.h')
| -rw-r--r-- | arch/arm/include/asm/spinlock.h | 16 |
1 files changed, 1 insertions, 15 deletions
diff --git a/arch/arm/include/asm/spinlock.h b/arch/arm/include/asm/spinlock.h index b4ca707d0a69..6220e9fdf4c7 100644 --- a/arch/arm/include/asm/spinlock.h +++ b/arch/arm/include/asm/spinlock.h @@ -119,22 +119,8 @@ static inline int arch_spin_trylock(arch_spinlock_t *lock) static inline void arch_spin_unlock(arch_spinlock_t *lock) { - unsigned long tmp; - u32 slock; - smp_mb(); - - __asm__ __volatile__( -" mov %1, #1\n" -"1: ldrex %0, [%2]\n" -" uadd16 %0, %0, %1\n" -" strex %1, %0, [%2]\n" -" teq %1, #0\n" -" bne 1b" - : "=&r" (slock), "=&r" (tmp) - : "r" (&lock->slock) - : "cc"); - + lock->tickets.owner++; dsb_sev(); } |