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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jaesoo Lee <jalee@purestorage.com>,
        Hannes Reinecke <hare@suse.com>,
        Bart Van Assche <bvanassche@acm.org>,
        "Martin K. Petersen" <martin.petersen@oracle.com>
Subject: [PATCH 4.19 58/96] scsi: core: set result when the command cannot be dispatched
Date:   Wed, 24 Apr 2019 19:10:03 +0200
Message-Id: <20190424170923.663054867@linuxfoundation.org>
In-Reply-To: <20190424170919.829037226@linuxfoundation.org>
References: <20190424170919.829037226@linuxfoundation.org>
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From: Jaesoo Lee <jalee@purestorage.com>

commit be549d49115422f846b6d96ee8fd7173a5f7ceb0 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/scsi/scsi_lib.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2149,8 +2149,12 @@ 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.
 		 */