scsi: storvsc: Increase the ring buffer size

Increase the default ring buffer size as this can significantly
improve performance especially on high latency storage back-ends.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

drivers/scsi/storvsc_drv.c

@@ -308,7 +308,7 @@ enum storvsc_request_type {
  * This is the end of Protocol specific defines.
  */
 
-static int storvsc_ringbuffer_size = (20 * PAGE_SIZE);
+static int storvsc_ringbuffer_size = (256 * PAGE_SIZE);
 
 module_param(storvsc_ringbuffer_size, int, S_IRUGO);
 MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");