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authorAlex Shi <alex.shi@linaro.org>2016-04-21 14:43:36 +0800
committerAlex Shi <alex.shi@linaro.org>2016-04-21 14:43:36 +0800
commit9beee7af111a7afa5f7b787daaf8a6891c05f216 (patch)
tree92fdbea807b9ef2917d1f087355f08617230dd75 /include/asm-generic/bitops/lock.h
parente8490c42825967752fef08dddf37eb3f5f34d753 (diff)
parentfd9302c16fc244139c1ddfdffc145d5b772ed9ce (diff)
Merge branch 'linux-linaro-lsk-v4.1' into linux-linaro-lsk-v4.1-androidlsk-v4.1-16.04-android
Conflicts: keep -fno-pic flag in arch/arm64/Makefile
Diffstat (limited to 'include/asm-generic/bitops/lock.h')
-rw-r--r--include/asm-generic/bitops/lock.h14
1 files changed, 7 insertions, 7 deletions
diff --git a/include/asm-generic/bitops/lock.h b/include/asm-generic/bitops/lock.h
index c30266e94806..8ef0ccbf8167 100644
--- a/include/asm-generic/bitops/lock.h
+++ b/include/asm-generic/bitops/lock.h
@@ -29,16 +29,16 @@ do { \
* @nr: the bit to set
* @addr: the address to start counting from
*
- * This operation is like clear_bit_unlock, however it is not atomic.
- * It does provide release barrier semantics so it can be used to unlock
- * a bit lock, however it would only be used if no other CPU can modify
- * any bits in the memory until the lock is released (a good example is
- * if the bit lock itself protects access to the other bits in the word).
+ * A weaker form of clear_bit_unlock() as used by __bit_lock_unlock(). If all
+ * the bits in the word are protected by this lock some archs can use weaker
+ * ops to safely unlock.
+ *
+ * See for example x86's implementation.
*/
#define __clear_bit_unlock(nr, addr) \
do { \
- smp_mb(); \
- __clear_bit(nr, addr); \
+ smp_mb__before_atomic(); \
+ clear_bit(nr, addr); \
} while (0)
#endif /* _ASM_GENERIC_BITOPS_LOCK_H_ */