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authorNick Piggin <npiggin@suse.de>2007-11-26 14:58:10 -0600
committerDave Kleikamp <shaggy@linux.vnet.ibm.com>2008-01-03 13:11:44 -0600
commit54af6233d1cb84cdfaa6ea44ea0db0bcf518baac (patch)
tree031f07f853e18e2fe09b054a3a8e432424362e60
parent67e6682f18b3bf812a994ae027ff87174a297ae8 (diff)
downloadop-kernel-dev-54af6233d1cb84cdfaa6ea44ea0db0bcf518baac.zip
op-kernel-dev-54af6233d1cb84cdfaa6ea44ea0db0bcf518baac.tar.gz
JFS is missing a memory barrier
JFS is missing a memory barrier needed to close the critical section before clearing the lock bit. Use lock bitops for this. unlock_page() has a second barrier after clearing the lock, which is required because it checks whether the waitqueue is active without locks. Such a barrier is not required here because the waitqueue spinlock is always taken (something to think about if performance is an issue). Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
-rw-r--r--fs/jfs/jfs_metapage.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index b27fa11..1dfaae5 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -39,11 +39,11 @@ static struct {
#endif
#define metapage_locked(mp) test_bit(META_locked, &(mp)->flag)
-#define trylock_metapage(mp) test_and_set_bit(META_locked, &(mp)->flag)
+#define trylock_metapage(mp) test_and_set_bit_lock(META_locked, &(mp)->flag)
static inline void unlock_metapage(struct metapage *mp)
{
- clear_bit(META_locked, &mp->flag);
+ clear_bit_unlock(META_locked, &mp->flag);
wake_up(&mp->wait);
}
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