[SCSI] storvsc: Properly handle errors from the host

Hyper-V cannot process some commands like ATA_12 and ATA_16. It also returns a
very generic error when this happens (SRB_STATUS_ERROR).  Most of the time we
treat SRB_STATUS_ERROR as DID_TARGET_FAILURE which causes error handler retry,
but in the case of pass through commands, they'll never succeed (and the error
handler will offline the device), so put a discriminating block in the command
completion routing and send the SRB_STATUS_ERROR upwards with DID_PASSTHROUGH
for commands we know should not be retried.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/storvsc_drv.c

@@ -785,12 +785,22 @@ static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
 	/*
 	 * If there is an error; offline the device since all
 	 * error recovery strategies would have already been
-	 * deployed on the host side.
+	 * deployed on the host side. However, if the command
+	 * were a pass-through command deal with it appropriately.
 	 */
-	if (vm_srb->srb_status == SRB_STATUS_ERROR)
-		scmnd->result = DID_TARGET_FAILURE << 16;
-	else
-		scmnd->result = vm_srb->scsi_status;
+	scmnd->result = vm_srb->scsi_status;
+
+	if (vm_srb->srb_status == SRB_STATUS_ERROR) {
+		switch (scmnd->cmnd[0]) {
+		case ATA_16:
+		case ATA_12:
+			set_host_byte(scmnd, DID_PASSTHROUGH);
+			break;
+		default:
+			set_host_byte(scmnd, DID_TARGET_FAILURE);
+		}
+	}
+
 
 	/*
 	 * If the LUN is invalid; remove the device.