Saner calculation of stubdom IDE_DMA_BUF_SECTORS.

Thanks to Samuel Thibault.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>

diff --git a/hw/ide.c b/hw/ide.c
index 37bcf56bab88dfdbe9146259910aff763dbf27a7..79c52040c2f46b5940cb047e3f74730059c3b791 100644 (file)
--- a/hw/ide.c
+++ b/hw/ide.c
@@ -201,20 +201,10 @@
 
 /* set to 1 set disable mult support */
 #define MAX_MULT_SECTORS 16
-#ifdef CONFIG_STUBDOM
-#include <xen/io/blkif.h>
-#define IDE_DMA_BUF_SIZE (BLKIF_MAX_SEGMENTS_PER_REQUEST * TARGET_PAGE_SIZE)
-#else
-#define IDE_DMA_BUF_SIZE 131072
-#endif
-#if (IDE_DMA_BUF_SIZE < MAX_MULT_SECTORS * 512)
-#error "IDE_DMA_BUF_SIZE must be bigger or equal to MAX_MULT_SECTORS * 512"
-#endif
-
 #ifdef CONFIG_STUBDOM
 #include <xen/io/blkif.h>
 #define IDE_DMA_BUF_SECTORS \
- ((BLKIF_MAX_SEGMENTS_PER_REQUEST * TARGET_PAGE_SIZE) / 512)
+       (((BLKIF_MAX_SEGMENTS_PER_REQUEST - 1 ) * TARGET_PAGE_SIZE) / 512)
 #else
 #define IDE_DMA_BUF_SECTORS 256
 #endif