Before removing disk from sysfs, userspace still may change queue via
sysfs, such as switching elevator or setting wbt latency, both may
reinitialize wbt, then the warning in blk_free_queue_stats() will be
triggered since rq_qos_exit() is moved to del_gendisk().
Fixes the issue by moving draining queue & tearing down after disk is
removed from sysfs, at that time no one can come into queue's
store()/show().
Reported-by: Yi Zhang <yi.zhang@xxxxxxxxxx>
Tested-by: Yi Zhang <yi.zhang@xxxxxxxxxx>
Fixes: 8e141f9eb803 ("block: drain file system I/O on del_gendisk")
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
block/genhd.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/block/genhd.c b/block/genhd.c
index 64f83c4aee99..2052aeffa39b 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -589,16 +589,6 @@ void del_gendisk(struct gendisk *disk)
* Prevent new I/O from crossing bio_queue_enter().
*/
blk_queue_start_drain(q);
- blk_mq_freeze_queue_wait(q);
-
- rq_qos_exit(q);
- blk_sync_queue(q);
- blk_flush_integrity();
- /*
- * Allow using passthrough request again after the queue is torn down.
- */
- blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q);
- __blk_mq_unfreeze_queue(q, true);
if (!(disk->flags & GENHD_FL_HIDDEN)) {
sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
@@ -621,6 +611,18 @@ void del_gendisk(struct gendisk *disk)
sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);
device_del(disk_to_dev(disk));
+
+ blk_mq_freeze_queue_wait(q);
+
+ rq_qos_exit(q);
+ blk_sync_queue(q);
+ blk_flush_integrity();
+ /*
+ * Allow using passthrough request again after the queue is torn down.
+ */
+ blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q);
+ __blk_mq_unfreeze_queue(q, true);
+
}
EXPORT_SYMBOL(del_gendisk);
--
2.31.1
