Commit 24125c44 authored Aug 08, 2023 by Mike Snitzer Committed by Yongqiang Liu Aug 08, 2023

dm: requeue IO if mapping table not yet available

mainline inclusion
from mainline-v5.18-rc1
commit fa247089
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7FI78
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v6.4-rc7&id=fa247089de9936a46e290d4724cb5f0b845600f5



----------------------------------------

Update both bio-based and request-based DM to requeue IO if the
mapping table not available.

This race of IO being submitted before the DM device ready is so
narrow, yet possible for initial table load given that the DM device's
request_queue is created prior, that it best to requeue IO to handle
this unlikely case.

Reported-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>

parent 1ff1a72b

drivers/md/dm-rq.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -752,8 +752,13 @@ static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,

		if (unlikely(!ti)) {
		int srcu_idx;
		struct dm_table *map = dm_get_live_table(md, &srcu_idx);
		struct dm_table *map;

		map = dm_get_live_table(md, &srcu_idx);
		if (unlikely(!map)) {
		dm_put_live_table(md, srcu_idx);
		return BLK_STS_RESOURCE;
		}
		ti = dm_table_find_target(map, 0);
		dm_put_live_table(md, srcu_idx);
		}

drivers/md/dm.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -1781,8 +1781,9 @@ static blk_qc_t dm_make_request(struct request_queue q, struct bio bio)

		map = dm_get_live_table(md, &srcu_idx);

		/* if we're suspended, we have to queue this io for later */
		if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) {
		/* If suspended, or map not yet available, queue this IO for later */
		if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) \|\|
		unlikely(!map)) {
		dm_put_live_table(md, srcu_idx);

		if (!(bio->bi_opf & REQ_RAHEAD))