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

longlimsft · Christoph Hellwig · commit e86fb5e8ab95 · 2014-12-15T13:34:29.000+01:00
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 &lt;longli@microsoft.com&gt;
Reviewed-by: K. Y. Srinivasan &lt;kys@microsoft.com&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
cc: stable@vger.kernel.org
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
@@ -1688,13 +1688,12 @@ 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;
