From: Milan Broz This patch replaces dm_mutex with _minor_lock in dm_blk_close() and then removes it. During the BKL conversion, commit 6e9624b8caec290d28b4c6d9ec75749df6372b87 (block: push down BKL into .open and .release) pushed lock_kernel() down into dm_blk_open/close calls. Commit 2a48fc0ab24241755dc93bfd4f01d68efab47f5a (block: autoconvert trivial BKL users to private mutex) converted it to a local mutex, but _minor_lock is sufficient. Signed-off-by: Milan Broz Signed-off-by: Alasdair G Kergon --- drivers/md/dm.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) Index: linux-2.6.37/drivers/md/dm.c =================================================================== --- linux-2.6.37.orig/drivers/md/dm.c +++ linux-2.6.37/drivers/md/dm.c @@ -32,7 +32,6 @@ #define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE" #define DM_COOKIE_LENGTH 24 -static DEFINE_MUTEX(dm_mutex); static const char *_name = DM_NAME; static unsigned int major = 0; @@ -328,7 +327,6 @@ static int dm_blk_open(struct block_devi { struct mapped_device *md; - mutex_lock(&dm_mutex); spin_lock(&_minor_lock); md = bdev->bd_disk->private_data; @@ -346,7 +344,6 @@ static int dm_blk_open(struct block_devi out: spin_unlock(&_minor_lock); - mutex_unlock(&dm_mutex); return md ? 0 : -ENXIO; } @@ -355,10 +352,12 @@ static int dm_blk_close(struct gendisk * { struct mapped_device *md = disk->private_data; - mutex_lock(&dm_mutex); + spin_lock(&_minor_lock); + atomic_dec(&md->open_count); dm_put(md); - mutex_unlock(&dm_mutex); + + spin_unlock(&_minor_lock); return 0; }