| Message ID | 1357916871-19920-1-git-send-email-will.deacon@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/arch/arm/include/asm/spinlock.h b/arch/arm/include/asm/spinlock.h index b4ca707..6220e9f 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(); }
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> --- arch/arm/include/asm/spinlock.h | 16 +--------------- 1 file changed, 1 insertion(+), 15 deletions(-)