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x86-64: pci-gart iommu sg chaining zeroes wrong sg.

PATCH In review FUJITA Tomonori 2 participants 3 messages Sep 27, 2007 – Sep 30, 2007 SCSI

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FUJITA Tomonori

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#0 lore raw

PATCH 1/1 x86-64: pci-gart iommu sg chaining zeroes wrong sg.

This patch is for Jens' block tree (sg chaining branch).

I don't have the hardware but this looks like a bug.

---
From: FUJITA Tomonori <[email protected]>
Subject: [PATCH] x86-64: pci-gart iommu sg chaining zeroes a wrong sg's dma_length

Needs to zero the end of the list.

Signed-off-by FUJITA Tomonori <[email protected]>
---
 arch/x86_64/kernel/pci-gart.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
arch/x86_64/kernel/pci-gart.c +2 -1
index 27b7db4..a4151a7 100644
@@ -425,9 +425,10 @@ int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
 	if (dma_map_cont(start_sg, i - start, sgmap, pages, need) < 0)
 		goto error;
 	out++;
+	sgmap = sg_next(sgmap);
 	flush_gart();
 	if (out < nents)
-		ps->dma_length = 0;
+		sgmap->dma_length = 0;
 	return out;
 
 error:
Signature · 1 line
1.5.2.4
author
#1 lore raw
Quoted 20 lines · On Fri, 28 Sep 2007 01:38:27 +0900 FUJITA Tomonori <[email protected]> wrote:

This patch is for Jens' block tree (sg chaining branch).

I don't have the hardware but this looks like a bug.

---
From: FUJITA Tomonori <[email protected]>
Subject: [PATCH] x86-64: pci-gart iommu sg chaining zeroes a wrong sg's dma_length

Needs to zero the end of the list.

Signed-off-by FUJITA Tomonori <[email protected]>
---
 arch/x86_64/kernel/pci-gart.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
arch/x86_64/kernel/pci-gart.c +0 -0
index 27b7db4..a4151a7 100644

arch/x86_64/kernel/pci-gart.c int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir) · line 432

Quoted 9 lines
arch/x86_64/kernel/pci-gart.c +2 -1
@@ -425,9 +425,10 @@ int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
 	if (dma_map_cont(start_sg, i - start, sgmap, pages, need) < 0)
 		goto error;
 	out++;
+	sgmap = sg_next(sgmap);
 	flush_gart();
 	if (out < nents)
-		ps->dma_length = 0;
+		sgmap->dma_length = 0;
 	return out;

Sorry, it should be:

arch/x86_64/kernel/pci-gart.c +4 -2
index 27b7db4..cfcc84e 100644
@@ -426,8 +426,10 @@ int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
 		goto error;
 	out++;
 	flush_gart();
-	if (out < nents)
-		ps->dma_length = 0;
+	if (out < nents) {
+		sgmap = sg_next(sgmap);
+		sgmap->dma_length = 0;
+	}
 	return out;
 
 error:
#2 lore raw
Quoted 41 lines · FUJITA Tomonori
Quoted 20 lines · On Fri, 28 Sep 2007 01:38:27 +0900 FUJITA Tomonori <[email protected]> wrote:

This patch is for Jens' block tree (sg chaining branch).

I don't have the hardware but this looks like a bug.

---
From: FUJITA Tomonori <[email protected]>
Subject: [PATCH] x86-64: pci-gart iommu sg chaining zeroes a wrong sg's dma_length

Needs to zero the end of the list.

Signed-off-by FUJITA Tomonori <[email protected]>
---
 arch/x86_64/kernel/pci-gart.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
arch/x86_64/kernel/pci-gart.c +0 -0
index 27b7db4..a4151a7 100644

arch/x86_64/kernel/pci-gart.c int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir) · line 432

Quoted 9 lines
arch/x86_64/kernel/pci-gart.c +2 -1
@@ -425,9 +425,10 @@ int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
 	if (dma_map_cont(start_sg, i - start, sgmap, pages, need) < 0)
 		goto error;
 	out++;
+	sgmap = sg_next(sgmap);
 	flush_gart();
 	if (out < nents)
-		ps->dma_length = 0;
+		sgmap->dma_length = 0;
 	return out;

Sorry, it should be:

arch/x86_64/kernel/pci-gart.c +0 -0
index 27b7db4..cfcc84e 100644

arch/x86_64/kernel/pci-gart.c int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir) · line 432

Quoted 9 lines
arch/x86_64/kernel/pci-gart.c +4 -2
@@ -426,8 +426,10 @@ int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents, int dir)
 		goto error;
 	out++;
 	flush_gart();
-	if (out < nents)
-		ps->dma_length = 0;
+	if (out < nents) {
+		sgmap = sg_next(sgmap);
+		sgmap->dma_length = 0;
+	}

looks correct to me.
ps points at the previous "scanned" sg entry while you want to zero out dma_length at the entry immediately following the last entry mapped (if (out < nents))

the original code before 62296749bd421904dace1e6b0fc3c4538aac7111 was:
- if (out < nents)
- sg[out].dma_length = 0;

Benny

Quoted 8 lines
arch/x86_64/kernel/pci-gart.c +0 -1
 	return out;
 
 error:
-

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