[PATCH 6.0 0333/1073] dm: make sure create and remove dm device wont race with open and close table

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From: Yu Kuai <yukuai3@xxxxxxxxxx>

[ Upstream commit d563792c8933a810d28ce0f2831f0726c2b15a31 ]

open_table_device() and close_table_device() is protected by
table_devices_lock, hence use it to protect add_disk() and
del_gendisk().

Prepare to track per-add_disk holder relations in dm.

Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Reviewed-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Link: https://lore.kernel.org/r/20221115141054.1051801-6-yukuai1@xxxxxxxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Stable-dep-of: 1a581b721699 ("dm: track per-add_disk holder relations in DM")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/md/dm.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 620abcef2df5..e7fc2a69633c 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1965,7 +1965,14 @@ static void cleanup_mapped_device(struct mapped_device *md)
 		spin_unlock(&_minor_lock);
 		if (dm_get_md_type(md) != DM_TYPE_NONE) {
 			dm_sysfs_exit(md);
+
+			/*
+			 * Hold lock to make sure del_gendisk() won't concurrent
+			 * with open/close_table_device().
+			 */
+			mutex_lock(&md->table_devices_lock);
 			del_gendisk(md->disk);
+			mutex_unlock(&md->table_devices_lock);
 		}
 		dm_queue_destroy_crypto_profile(md->queue);
 		put_disk(md->disk);
@@ -2325,15 +2332,24 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
 	if (r)
 		return r;
 
+	/*
+	 * Hold lock to make sure add_disk() and del_gendisk() won't concurrent
+	 * with open_table_device() and close_table_device().
+	 */
+	mutex_lock(&md->table_devices_lock);
 	r = add_disk(md->disk);
+	mutex_unlock(&md->table_devices_lock);
 	if (r)
 		return r;
 
 	r = dm_sysfs_init(md);
 	if (r) {
+		mutex_lock(&md->table_devices_lock);
 		del_gendisk(md->disk);
+		mutex_unlock(&md->table_devices_lock);
 		return r;
 	}
+
 	md->type = type;
 	return 0;
 }
-- 
2.35.1






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