---

yaml
---
r: 373757
b: refs/heads/master
c: a31a369
h: refs/heads/master
i:
  373755: dd8ab12
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 25c39325968bbcebe6cd2a1991228c9dfb48d655
+refs/heads/master: a31a369b07cf306ae1de0b2d4a52c3821a570bf6

trunk/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;
 }
 
 /*