storvsc: ring buffer failures may result in I/O freeze

commit e86fb5e8 upstream.

When ring buffer returns an error indicating retry, storvsc may not
return a proper error code to SCSI when bounce buffer is not used.
This has introduced I/O freeze on RAID running atop storvsc devices.
This patch fixes it by always returning a proper error code.
Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

drivers/scsi/storvsc_drv.c

@@ -1690,13 +1690,12 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
 	if (ret == -EAGAIN) {
 		/* no more space */
 
-		if (cmd_request->bounce_sgl_count) {
+		if (cmd_request->bounce_sgl_count)
 			destroy_bounce_buffer(cmd_request->bounce_sgl,
 					cmd_request->bounce_sgl_count);
 
-			ret = SCSI_MLQUEUE_DEVICE_BUSY;
-			goto queue_error;
-		}
+		ret = SCSI_MLQUEUE_DEVICE_BUSY;
+		goto queue_error;
 	}
 
 	return 0;