blk-mq-sched: Fix blk_mq_sched_alloc_tags() error handling

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>

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index c838d81..0f006ca 100644 (file)
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -515,17 +515,6 @@ void blk_mq_sched_insert_requests(struct blk_mq_hw_ctx *hctx,
        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, set->flags);
-               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)
@@ -539,8 +528,10 @@ static int blk_mq_sched_alloc_tags(struct request_queue *q,
                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, set->flags);
+               hctx->sched_tags = NULL;
+       }
 
        return ret;
 }