From b93af3055d6f32d3b0361cfdb110c9399c1241ba Mon Sep 17 00:00:00 2001
From: John Garry <john.garry@huawei.com>
Date: Tue, 27 Jul 2021 17:32:53 +0800
Subject: [PATCH] blk-mq-sched: Fix blk_mq_sched_alloc_tags() error handling
Git-commit: b93af3055d6f32d3b0361cfdb110c9399c1241ba
Patch-mainline: v5.14-rc4
References: bsc#1189506

If the blk_mq_sched_alloc_tags() -> blk_mq_alloc_rqs() call fails, then we
call blk_mq_sched_free_tags() -> blk_mq_free_rqs().

It is incorrect to do so, as any rqs would have already been freed in the
blk_mq_alloc_rqs() call.

Fix by calling blk_mq_free_rq_map() only directly.

Fixes: 6917ff0b5bd41 ("blk-mq-sched: refactor scheduler initialization")
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/1627378373-148090-1-git-send-email-john.garry@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Jan Kara <jack@suse.cz>

---
 block/blk-mq-sched.c |   17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -503,17 +503,6 @@ void blk_mq_sched_insert_requests(struct
 	percpu_ref_put(&q->q_usage_counter);
 }
 
-static void blk_mq_sched_free_tags(struct blk_mq_tag_set *set,
-				   struct blk_mq_hw_ctx *hctx,
-				   unsigned int hctx_idx)
-{
-	if (hctx->sched_tags) {
-		blk_mq_free_rqs(set, hctx->sched_tags, hctx_idx);
-		blk_mq_free_rq_map(hctx->sched_tags);
-		hctx->sched_tags = NULL;
-	}
-}
-
 static int blk_mq_sched_alloc_tags(struct request_queue *q,
 				   struct blk_mq_hw_ctx *hctx,
 				   unsigned int hctx_idx)
@@ -527,8 +516,10 @@ static int blk_mq_sched_alloc_tags(struc
 		return -ENOMEM;
 
 	ret = blk_mq_alloc_rqs(set, hctx->sched_tags, hctx_idx, q->nr_requests);
-	if (ret)
-		blk_mq_sched_free_tags(set, hctx, hctx_idx);
+	if (ret) {
+		blk_mq_free_rq_map(hctx->sched_tags);
+		hctx->sched_tags = NULL;
+	}
 
 	return ret;
 }