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Subject[PATCH -mm 06/11] alpha: make pci_iommu respect the segment size limits
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This patch makes pci_iommu respect segment size limits when merging sg
lists.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
---
arch/alpha/kernel/pci_iommu.c | 24 ++++++++++++++++++------
include/asm-alpha/pci.h | 1 +
2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/arch/alpha/kernel/pci_iommu.c b/arch/alpha/kernel/pci_iommu.c
index 2d00a08..26d3789 100644
--- a/arch/alpha/kernel/pci_iommu.c
+++ b/arch/alpha/kernel/pci_iommu.c
@@ -9,6 +9,7 @@
#include <linux/bootmem.h>
#include <linux/scatterlist.h>
#include <linux/log2.h>
+#include <linux/dma-mapping.h>

#include <asm/io.h>
#include <asm/hwrpb.h>
@@ -470,22 +471,29 @@ EXPORT_SYMBOL(pci_free_consistent);
#define SG_ENT_PHYS_ADDRESS(SG) __pa(SG_ENT_VIRT_ADDRESS(SG))

static void
-sg_classify(struct scatterlist *sg, struct scatterlist *end, int virt_ok)
+sg_classify(struct device *dev, struct scatterlist *sg, struct scatterlist *end,
+ int virt_ok)
{
unsigned long next_paddr;
struct scatterlist *leader;
long leader_flag, leader_length;
+ unsigned int max_seg_size;

leader = sg;
leader_flag = 0;
leader_length = leader->length;
next_paddr = SG_ENT_PHYS_ADDRESS(leader) + leader_length;

+ /* we will not marge sg without device. */
+ max_seg_size = dev ? dma_get_max_seg_size(dev) : 0;
for (++sg; sg < end; ++sg) {
unsigned long addr, len;
addr = SG_ENT_PHYS_ADDRESS(sg);
len = sg->length;

+ if (leader_length + len > max_seg_size)
+ goto new_segment;
+
if (next_paddr == addr) {
sg->dma_address = -1;
leader_length += len;
@@ -494,6 +502,7 @@ sg_classify(struct scatterlist *sg, struct scatterlist *end, int virt_ok)
leader_flag = 1;
leader_length += len;
} else {
+new_segment:
leader->dma_address = leader_flag;
leader->dma_length = leader_length;
leader = sg;
@@ -512,7 +521,7 @@ sg_classify(struct scatterlist *sg, struct scatterlist *end, int virt_ok)
in the blanks. */

static int
-sg_fill(struct scatterlist *leader, struct scatterlist *end,
+sg_fill(struct device *dev, struct scatterlist *leader, struct scatterlist *end,
struct scatterlist *out, struct pci_iommu_arena *arena,
dma_addr_t max_dma, int dac_allowed)
{
@@ -562,8 +571,8 @@ sg_fill(struct scatterlist *leader, struct scatterlist *end,

/* Otherwise, break up the remaining virtually contiguous
hunks into individual direct maps and retry. */
- sg_classify(leader, end, 0);
- return sg_fill(leader, end, out, arena, max_dma, dac_allowed);
+ sg_classify(dev, leader, end, 0);
+ return sg_fill(dev, leader, end, out, arena, max_dma, dac_allowed);
}

out->dma_address = arena->dma_base + dma_ofs*PAGE_SIZE + paddr;
@@ -619,12 +628,15 @@ pci_map_sg(struct pci_dev *pdev, struct scatterlist *sg, int nents,
struct pci_iommu_arena *arena;
dma_addr_t max_dma;
int dac_allowed;
+ struct device *dev;

if (direction == PCI_DMA_NONE)
BUG();

dac_allowed = pdev ? pci_dac_dma_supported(pdev, pdev->dma_mask) : 0;

+ dev = pdev ? &pdev->dev : NULL;
+
/* Fast path single entry scatterlists. */
if (nents == 1) {
sg->dma_length = sg->length;
@@ -638,7 +650,7 @@ pci_map_sg(struct pci_dev *pdev, struct scatterlist *sg, int nents,
end = sg + nents;

/* First, prepare information about the entries. */
- sg_classify(sg, end, alpha_mv.mv_pci_tbi != 0);
+ sg_classify(dev, sg, end, alpha_mv.mv_pci_tbi != 0);

/* Second, figure out where we're going to map things. */
if (alpha_mv.mv_pci_tbi) {
@@ -658,7 +670,7 @@ pci_map_sg(struct pci_dev *pdev, struct scatterlist *sg, int nents,
for (out = sg; sg < end; ++sg) {
if ((int) sg->dma_address < 0)
continue;
- if (sg_fill(sg, end, out, arena, max_dma, dac_allowed) < 0)
+ if (sg_fill(dev, sg, end, out, arena, max_dma, dac_allowed) < 0)
goto error;
out++;
}
diff --git a/include/asm-alpha/pci.h b/include/asm-alpha/pci.h
index 30ee766..d5b10ef 100644
--- a/include/asm-alpha/pci.h
+++ b/include/asm-alpha/pci.h
@@ -4,6 +4,7 @@
#ifdef __KERNEL__

#include <linux/spinlock.h>
+#include <linux/dma-mapping.h>
#include <asm/scatterlist.h>
#include <asm/machvec.h>

--
1.5.2.4
-
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