dm: cleanup close_table_device

Take the list unlink and free into close_table_device so that no half
torn down table_devices exist.  Also remove the check for a NULL bdev
as that can't happen - open_table_device never adds a table_device to
the list that does not have a valid block_device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20221115141054.1051801-5-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 28d7581b6a826b42b53b017647f4791fa24f3965..2917700b1e15c4c5dc1605f62ba6cbe951595be6 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -774,14 +774,11 @@ out_free_td:
  */
 static void close_table_device(struct table_device *td, struct mapped_device *md)
 {
-       if (!td->dm_dev.bdev)
-               return;
-
        bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md));
        blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL);
        put_dax(td->dm_dev.dax_dev);
-       td->dm_dev.bdev = NULL;
-       td->dm_dev.dax_dev = NULL;
+       list_del(&td->list);
+       kfree(td);
 }
 
 static struct table_device *find_table_device(struct list_head *l, dev_t dev,
@@ -823,11 +820,8 @@ void dm_put_table_device(struct mapped_device *md, struct dm_dev *d)
        struct table_device *td = container_of(d, struct table_device, dm_dev);
 
        mutex_lock(&md->table_devices_lock);
-       if (refcount_dec_and_test(&td->count)) {
+       if (refcount_dec_and_test(&td->count))
                close_table_device(td, md);
-               list_del(&td->list);
-               kfree(td);
-       }
        mutex_unlock(&md->table_devices_lock);
 }