dm: make sure create and remove dm device won't race with open and close table

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>

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 2917700..3728b56 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1952,7 +1952,14 @@ 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);
@@ -2312,15 +2319,24 @@ 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;
 }