[PATCH 2/9] xen swiotlb: fixup swiotlb is chunks smaller than MAX_CONTIG_ORDER

From: Jeremy Fitzhardinge
Date: Thu May 07 2009 - 20:38:29 EST


From: Ian Campbell <ian.campbell@xxxxxxxxxx>

Impact: bugfix

Don't attempt to make larger memory ranges than Xen can cope with
contiguous.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
---
drivers/pci/xen-iommu.c | 27 ++++++++++++++++++---------
1 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/xen-iommu.c b/drivers/pci/xen-iommu.c
index c593058..b9b4620 100644
--- a/drivers/pci/xen-iommu.c
+++ b/drivers/pci/xen-iommu.c
@@ -5,6 +5,7 @@
#include <linux/module.h>
#include <linux/version.h>
#include <linux/scatterlist.h>
+#include <linux/swiotlb.h>
#include <linux/io.h>
#include <linux/bug.h>

@@ -36,19 +37,27 @@ do { \
} while (0)


+static int max_dma_bits = 32;
+
void xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
{
- unsigned order = get_order(size);
-
- printk(KERN_DEBUG "xen_swiotlb_fixup: buf=%p size=%zu order=%u\n",
- buf, size, order);
-
- if (WARN_ON(size != (PAGE_SIZE << order)))
- return;
-
- if (xen_create_contiguous_region((unsigned long)buf,
- order, 0xffffffff))
- printk(KERN_ERR "xen_create_contiguous_region failed\n");
+ int i, rc;
+ int dma_bits;
+
+ printk(KERN_DEBUG "xen_swiotlb_fixup: buf=%p size=%zu\n",
+ buf, size);
+
+ dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
+ for (i = 0; i < nslabs; i += IO_TLB_SEGSIZE) {
+ do {
+ rc = xen_create_contiguous_region(
+ (unsigned long)buf + (i << IO_TLB_SHIFT),
+ get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT),
+ dma_bits);
+ } while (rc && dma_bits++ < max_dma_bits);
+ if (rc)
+ panic(KERN_ERR "xen_create_contiguous_region failed\n");
+ }
}
static inline int address_needs_mapping(struct device *hwdev,
dma_addr_t addr)
--
1.6.0.6

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