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: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NLi Lingfeng <lilingfeng3@huawei.com>
Reviewed-by: NYu Kuai <yukuai3@huawei.com>
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>

drivers/md/dm-rq.c

@@ -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

@@ -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))