dm bufio: Fix missing decrement of no_sleep_enabled if dm_bufio_client_create failed

The 'no_sleep_enabled' should be decreased in error handling path
in dm_bufio_client_create() when the DM_BUFIO_CLIENT_NO_SLEEP flag
is set, otherwise static_branch_unlikely() will always return true
even if no dm_bufio_client instances have DM_BUFIO_CLIENT_NO_SLEEP
flag set.

Cc: stable@vger.kernel.org
Fixes: 3c1c875 ("dm bufio: conditionally enable branching for DM_BUFIO_CLIENT_NO_SLEEP")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Author: Zhihao Cheng

drivers/md/dm-bufio.c

@@ -1858,6 +1858,8 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign
 	dm_io_client_destroy(c->dm_io);
 bad_dm_io:
 	mutex_destroy(&c->lock);
+	if (c->no_sleep)
+		static_branch_dec(&no_sleep_enabled);
 	kfree(c);
 bad_client:
 	return ERR_PTR(r);