nbd: don't start request if nbd_queue_rq() failed

commit 6a468d5990ec ("nbd: don't start req until after the dead
connection logic") move blk_mq_start_request() from nbd_queue_rq()
to nbd_handle_cmd() to skip starting request if the connection is
dead. However, request is still started in other error paths.

Currently, blk_mq_end_request() will be called immediately if
nbd_queue_rq() failed, thus start request in such situation is
useless. So remove blk_mq_start_request() from error paths in
nbd_handle_cmd().

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20210916093350.1410403-5-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 49c501c..87066ca 100644 (file)
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -939,7 +939,6 @@ static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
        if (!refcount_inc_not_zero(&nbd->config_refs)) {
                dev_err_ratelimited(disk_to_dev(nbd->disk),
                                    "Socks array is empty\n");
-               blk_mq_start_request(req);
                return -EINVAL;
        }
        config = nbd->config;
@@ -948,7 +947,6 @@ static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
                dev_err_ratelimited(disk_to_dev(nbd->disk),
                                    "Attempted send on invalid socket\n");
                nbd_config_put(nbd);
-               blk_mq_start_request(req);
                return -EINVAL;
        }
        cmd->status = BLK_STS_OK;
@@ -972,7 +970,6 @@ again:
                         */
                        sock_shutdown(nbd);
                        nbd_config_put(nbd);
-                       blk_mq_start_request(req);
                        return -EIO;
                }
                goto again;