[SCSI] storvsc: Restructure error handling code on command completion

In preparation for handling additional sense codes, restructure and cleanup
the error handling code in the command completion code path.
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

@@ -761,37 +761,23 @@ static int storvsc_channel_init(struct hv_device *device)
 	return ret;
 }
 
-
-static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
+static void storvsc_handle_error(struct vmscsi_request *vm_srb,
+				struct scsi_cmnd *scmnd,
+				struct Scsi_Host *host,
+				u8 asc, u8 ascq)
 {
-	struct scsi_cmnd *scmnd = cmd_request->cmd;
-	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
-	void (*scsi_done_fn)(struct scsi_cmnd *);
-	struct scsi_sense_hdr sense_hdr;
-	struct vmscsi_request *vm_srb;
 	struct storvsc_scan_work *wrk;
-	struct stor_mem_pools *memp = scmnd->device->hostdata;
-
-	vm_srb = &cmd_request->vstor_packet.vm_srb;
-	if (cmd_request->bounce_sgl_count) {
-		if (vm_srb->data_in == READ_TYPE)
-			copy_from_bounce_buffer(scsi_sglist(scmnd),
-					cmd_request->bounce_sgl,
-					scsi_sg_count(scmnd),
-					cmd_request->bounce_sgl_count);
-		destroy_bounce_buffer(cmd_request->bounce_sgl,
-					cmd_request->bounce_sgl_count);
-	}
+	void (*process_err_fn)(struct work_struct *work);
+	bool do_work = false;
 
+	switch (vm_srb->srb_status) {
+	case SRB_STATUS_ERROR:
 		/*
 		 * If there is an error; offline the device since all
 		 * error recovery strategies would have already been
 		 * deployed on the host side. However, if the command
 		 * were a pass-through command deal with it appropriately.
 		 */
-	scmnd->result = vm_srb->scsi_status;
-
-	if (vm_srb->srb_status == SRB_STATUS_ERROR) {
 		switch (scmnd->cmnd[0]) {
 		case ATA_16:
 		case ATA_12:
@@ -800,38 +786,69 @@ static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
 		default:
 			set_host_byte(scmnd, DID_TARGET_FAILURE);
 		}
+		break;
+	case SRB_STATUS_INVALID_LUN:
+		do_work = true;
+		process_err_fn = storvsc_remove_lun;
+		break;
 	}
-
+	if (!do_work)
+		return;
 
 	/*
-	 * If the LUN is invalid; remove the device.
+	 * We need to schedule work to process this error; schedule it.
 	 */
-	if (vm_srb->srb_status == SRB_STATUS_INVALID_LUN) {
+	wrk = kmalloc(sizeof(struct storvsc_scan_work), GFP_ATOMIC);
+	if (!wrk) {
+		set_host_byte(scmnd, DID_TARGET_FAILURE);
+		return;
+	}
+
+	wrk->host = host;
+	wrk->lun = vm_srb->lun;
+	INIT_WORK(&wrk->work, process_err_fn);
+	schedule_work(&wrk->work);
+}
+
+
+static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request)
+{
+	struct scsi_cmnd *scmnd = cmd_request->cmd;
+	struct hv_host_device *host_dev = shost_priv(scmnd->device->host);
+	void (*scsi_done_fn)(struct scsi_cmnd *);
+	struct scsi_sense_hdr sense_hdr;
+	struct vmscsi_request *vm_srb;
+	struct stor_mem_pools *memp = scmnd->device->hostdata;
+	struct Scsi_Host *host;
 	struct storvsc_device *stor_dev;
 	struct hv_device *dev = host_dev->dev;
-		struct Scsi_Host *host;
 
 	stor_dev = get_in_stor_device(dev);
 	host = stor_dev->host;
 
-		wrk = kmalloc(sizeof(struct storvsc_scan_work),
-				GFP_ATOMIC);
-		if (!wrk) {
-			scmnd->result = DID_TARGET_FAILURE << 16;
-		} else {
-			wrk->host = host;
-			wrk->lun = vm_srb->lun;
-			INIT_WORK(&wrk->work, storvsc_remove_lun);
-			schedule_work(&wrk->work);
-		}
+	vm_srb = &cmd_request->vstor_packet.vm_srb;
+	if (cmd_request->bounce_sgl_count) {
+		if (vm_srb->data_in == READ_TYPE)
+			copy_from_bounce_buffer(scsi_sglist(scmnd),
+					cmd_request->bounce_sgl,
+					scsi_sg_count(scmnd),
+					cmd_request->bounce_sgl_count);
+		destroy_bounce_buffer(cmd_request->bounce_sgl,
+					cmd_request->bounce_sgl_count);
 	}
 
+	scmnd->result = vm_srb->scsi_status;
+
 	if (scmnd->result) {
 		if (scsi_normalize_sense(scmnd->sense_buffer,
 				SCSI_SENSE_BUFFERSIZE, &sense_hdr))
 			scsi_print_sense_hdr("storvsc", &sense_hdr);
 	}
 
+	if (vm_srb->srb_status != SRB_STATUS_SUCCESS)
+		storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
+					 sense_hdr.ascq);
+
 	scsi_set_resid(scmnd,
 		cmd_request->data_buffer.len -
 		vm_srb->data_transfer_length);