Upgrade to 4.4.50-rt62

[kvmfornfv.git] / kernel / include / asm-generic / bitops / lock.h

diff --git a/kernel/include/asm-generic/bitops/lock.h b/kernel/include/asm-generic/bitops/lock.h
index c30266e..8ef0ccb 100644 (file)
--- a/kernel/include/asm-generic/bitops/lock.h
+++ b/kernel/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_ */