scsi: core: set result when the command cannot be dispatched

When SCSI blk-mq is enabled, there is a bug in handling errors in
scsi_queue_rq.  Specifically, the bug is not setting result field of
scsi_request correctly when the dispatch of the command has been
failed. Since the upper layer code including the sg_io ioctl expects to
receive any error status from result field of scsi_request, the error is
silently ignored and this could cause data corruptions for some
applications.

Fixes: d285203cf647 ("scsi: add support for a blk-mq based I/O path.")
Cc: <stable@vger.kernel.org>
Signed-off-by: Jaesoo Lee <jalee@purestorage.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 601b9f1de26758a1d078a69de36469ad4318d39d..07dfc17d48246551a63966444172b4197e30def4 100644 (file)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1706,8 +1706,12 @@ out_put_budget:
                        ret = BLK_STS_DEV_RESOURCE;
                break;
        default:
+               if (unlikely(!scsi_device_online(sdev)))
+                       scsi_req(req)->result = DID_NO_CONNECT << 16;
+               else
+                       scsi_req(req)->result = DID_ERROR << 16;
                /*
-                * Make sure to release all allocated ressources when
+                * Make sure to release all allocated resources when
                 * we hit an error, as we will never see this command
                 * again.
                 */