From 51b07fc3c5c830bb49c80fc5eac041e1f66a72e7 Mon Sep 17 00:00:00 2001
From: Nick Piggin <npiggin@suse.de>
Date: Sat, 18 Oct 2008 20:27:00 -0700
Subject: [PATCH] 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>
---
fs/buffer.c | 3 +--
include/linux/buffer_head.h | 2 +-
2 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index ac78d4c19b3b3..6569fda5cfed8 100644
--- 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 eadaab44015f6..3ce64b90118c2 100644
--- 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)
--
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