nvme-loop: fix kernel oops in case of unhandled command

BugLink: https://bugs.launchpad.net/bugs/1836802
commit 11d9ea6f2ca69237d35d6c55755beba3e006b106 upstream.

When nvmet_req_init() fails, __nvmet_req_complete() is called
to handle the target request via .queue_response(), so
nvme_loop_queue_response() shouldn't be called again for
handling the failure.

This patch fixes this case by the following way:

- move blk_mq_start_request() before nvmet_req_init(), so
nvme_loop_queue_response() may work well to complete this
host request

- don't call nvme_cleanup_cmd() which is done in nvme_loop_complete_rq()

- don't call nvme_loop_queue_response() which is done via
.queue_response()

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
[trimmed changelog]
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/nvme/target/loop.c b/drivers/nvme/target/loop.c
index fdfcc961029f9844d84114b1c096426cb17e10ae..392ff9f39a7450be018688fad2bb6cdb51f25158 100644 (file)
--- a/drivers/nvme/target/loop.c
+++ b/drivers/nvme/target/loop.c
@@ -174,15 +174,12 @@ static blk_status_t nvme_loop_queue_rq(struct blk_mq_hw_ctx *hctx,
        if (ret)
                return ret;
 
+       blk_mq_start_request(req);
        iod->cmd.common.flags |= NVME_CMD_SGL_METABUF;
        iod->req.port = nvmet_loop_port;
        if (!nvmet_req_init(&iod->req, &queue->nvme_cq,
-                       &queue->nvme_sq, &nvme_loop_ops)) {
-               nvme_cleanup_cmd(req);
-               blk_mq_start_request(req);
-               nvme_loop_queue_response(&iod->req);
+                       &queue->nvme_sq, &nvme_loop_ops))
                return BLK_STS_OK;
-       }
 
        if (blk_rq_bytes(req)) {
                iod->sg_table.sgl = iod->first_sgl;
@@ -196,8 +193,6 @@ static blk_status_t nvme_loop_queue_rq(struct blk_mq_hw_ctx *hctx,
                iod->req.transfer_len = blk_rq_bytes(req);
        }
 
-       blk_mq_start_request(req);
-
        schedule_work(&iod->work);
        return BLK_STS_OK;
 }