The patch titled
fs: buffer lock use lock bitops
has been added to the -mm tree. Its filename is
fs-buffer-lock-use-lock-bitops.patch
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------------------------------------------------------
Subject: fs: buffer lock use lock bitops
From: Nick Piggin <npiggin@xxxxxxx>
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@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/buffer.c | 3 +--
include/linux/buffer_head.h | 2 +-
2 files changed, 2 insertions(+), 3 deletions(-)
diff -puN fs/buffer.c~fs-buffer-lock-use-lock-bitops fs/buffer.c
--- a/fs/buffer.c~fs-buffer-lock-use-lock-bitops
+++ a/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 -puN include/linux/buffer_head.h~fs-buffer-lock-use-lock-bitops include/linux/buffer_head.h
--- a/include/linux/buffer_head.h~fs-buffer-lock-use-lock-bitops
+++ a/include/linux/buffer_head.h
@@ -322,7 +322,7 @@ static inline void wait_on_buffer(struct
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)
_
Patches currently in -mm which might be from npiggin@xxxxxxx are
origin.patch
linux-next.patch
mm-dirty-page-tracking-race-fix.patch
mm-dirty-page-tracking-race-fix-fix.patch
mm-xip-fix-fault-vs-sparse-page-invalidate-race.patch
mm-xip-ext2-fix-block-allocation-race.patch
vmscan-move-isolate_lru_page-to-vmscanc.patch
mlock-mlocked-pages-are-unevictable.patch
mmap-handle-mlocked-pages-during-map-remap-unmap.patch
vmstat-mlocked-pages-statistics.patch
mm-pagecache-insertion-fewer-atomics.patch
mm-unlockless-reclaim.patch
mm-page-lock-use-lock-bitops.patch
fs-buffer-lock-use-lock-bitops.patch
mm-page-allocator-minor-speedup.patch
reiser4.patch
likeliness-accounting-change-and-cleanup.patch
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