dm: remove dm_mutex after bkl conversion (4a1aeb98) · Commits · 戴 / test

This patch replaces dm_mutex with _minor_lock in dm_blk_close() and then removes it. During the BKL conversion, commit (block: push down BKL into .open and .release) pushed lock_kernel() down into dm_blk_open/close calls. Commit (block: autoconvert trivial BKL users to private mutex) converted it to a local mutex, but _minor_lock is sufficient. Signed-off-by:

Milan Broz <mbroz@redhat.com> Signed-off-by:

Alasdair G Kergon <agk@redhat.com>

drivers/md/dm.c

+4 −5

Original line number	Diff line number	Diff line
		@@ -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_device *bdev, fmode_t mode)
		{
		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_device *bdev, fmode_t mode)

		out:
		spin_unlock(&_minor_lock);
		mutex_unlock(&dm_mutex);

		return md ? 0 : -ENXIO;
		}
		@@ -355,10 +352,12 @@ static int dm_blk_close(struct gendisk *disk, fmode_t mode)
		{
		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;
		}

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