From 56d8c4364c601895e91edb0ff5ff6779ca21f1bc Mon Sep 17 00:00:00 2001
From: Ian Jackson <iwj@mariner.uk.xensource.com>
Date: Fri, 28 Mar 2008 16:20:45 +0000
Subject: [PATCH] improve DMA transfers by increasing the size of DMA buffers.

Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>

Cross-ported from xen-unstable f4a92f0db20fda98a633c149e3396c005a759a77
---
 hw/scsi-disk.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 91fcc70a..3f781666 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -34,7 +34,12 @@ do { fprintf(stderr, "scsi-disk: " fmt , ##args); } while (0)
 #define SENSE_HARDWARE_ERROR  4
 #define SENSE_ILLEGAL_REQUEST 5
 
-#define SCSI_DMA_BUF_SIZE    65536
+#ifdef CONFIG_STUBDOM
+#include <xen/io/blkif.h>
+#define SCSI_DMA_BUF_SIZE    (BLKIF_MAX_SEGMENTS_PER_REQUEST * TARGET_PAGE_SIZE)
+#else
+#define SCSI_DMA_BUF_SIZE    131072
+#endif
 
 typedef struct SCSIRequest {
     SCSIDeviceState *dev;
-- 
2.39.5