From: Ming Lei <ming.lei@redhat.com>
Date: Tue, 26 Oct 2021 18:12:04 +0800
Subject: [PATCH] block: drain queue after disk is removed from sysfs
Git-commit: d308ae0d299a6bb15be4efb91849582d19c23213
Patch-mainline: v5.15
References: jsc#PED-1183
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@redhat.com>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Fixes: 8e141f9eb803 ("block: drain file system I/O on del_gendisk")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211026101204.2897166-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
block/genhd.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/block/genhd.c b/block/genhd.c
index b49858550fa6..ab12ae6e636e 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -588,16 +588,6 @@ 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");
@@ -620,6 +610,18 @@ 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);
--
2.35.3