[PATCH 6.1 0343/1146] dm: make sure create and remove dm device wont race with open and close table

Greg Kroah-Hartman
2022-12-28T15:43:42Z

From: Yu Kuai <yukuai3@huawei.com>

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

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 8fb0b97b2df1..f10ac680cef4 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