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-rw-r--r--arch/x86/include/asm/rwsem.h28
1 files changed, 21 insertions, 7 deletions
diff --git a/arch/x86/include/asm/rwsem.h b/arch/x86/include/asm/rwsem.h
index 2dbe4a721ce5..cad82c9c2fde 100644
--- a/arch/x86/include/asm/rwsem.h
+++ b/arch/x86/include/asm/rwsem.h
@@ -105,8 +105,8 @@ static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
asm volatile("# beginning down_write\n\t"
LOCK_PREFIX " xadd %1,(%2)\n\t"
/* adds 0xffff0001, returns the old value */
- " test %1,%1\n\t"
- /* was the count 0 before? */
+ " test " __ASM_SEL(%w1,%k1) "," __ASM_SEL(%w1,%k1) "\n\t"
+ /* was the active mask 0 before? */
" jz 1f\n"
" call call_rwsem_down_write_failed\n"
"1:\n"
@@ -126,11 +126,25 @@ static inline void __down_write(struct rw_semaphore *sem)
*/
static inline int __down_write_trylock(struct rw_semaphore *sem)
{
- long ret = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,
- RWSEM_ACTIVE_WRITE_BIAS);
- if (ret == RWSEM_UNLOCKED_VALUE)
- return 1;
- return 0;
+ long result, tmp;
+ asm volatile("# beginning __down_write_trylock\n\t"
+ " mov %0,%1\n\t"
+ "1:\n\t"
+ " test " __ASM_SEL(%w1,%k1) "," __ASM_SEL(%w1,%k1) "\n\t"
+ /* was the active mask 0 before? */
+ " jnz 2f\n\t"
+ " mov %1,%2\n\t"
+ " add %3,%2\n\t"
+ LOCK_PREFIX " cmpxchg %2,%0\n\t"
+ " jnz 1b\n\t"
+ "2:\n\t"
+ " sete %b1\n\t"
+ " movzbl %b1, %k1\n\t"
+ "# ending __down_write_trylock\n\t"
+ : "+m" (sem->count), "=&a" (result), "=&r" (tmp)
+ : "er" (RWSEM_ACTIVE_WRITE_BIAS)
+ : "memory", "cc");
+ return result;
}
/*