fs: buffer lock use lock bitops

trylock_buffer and unlock_buffer open and close a critical section.
Hence, we can use the lock bitops to get the desired memory ordering.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/buffer.c b/fs/buffer.c
index ac78d4c19b3b3b27e812f13c0bd7669e962cea04..6569fda5cfed892c7e4ed53daa2e9677e60c36d5 100644 (file)
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -76,8 +76,7 @@ EXPORT_SYMBOL(__lock_buffer);
 
 void unlock_buffer(struct buffer_head *bh)
 {
-       smp_mb__before_clear_bit();
-       clear_buffer_locked(bh);
+       clear_bit_unlock(BH_Lock, &bh->b_state);
        smp_mb__after_clear_bit();
        wake_up_bit(&bh->b_state, BH_Lock);
 }

diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index eadaab44015f62e4fa04ab003828945d6c6bf503..3ce64b90118c20346a704d1c727ec9450d7ccb95 100644 (file)
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -322,7 +322,7 @@ static inline void wait_on_buffer(struct buffer_head *bh)
 
 static inline int trylock_buffer(struct buffer_head *bh)
 {
-       return likely(!test_and_set_bit(BH_Lock, &bh->b_state));
+       return likely(!test_and_set_bit_lock(BH_Lock, &bh->b_state));
 }
 
 static inline void lock_buffer(struct buffer_head *bh)