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Commit 0d541064 authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
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[PATCH] x86_64: GART DMA merging fix 



Don't touch the non DMA members in the sg list in dma_map_sg in the IOMMU

Some drivers (in particular ST) ran into problems because they reused the sg
lists after passing them to pci_map_sg().  The merging procedure in the K8
GART IOMMU corrupted the state.  This patch changes it to only touch the dma*
entries during merging, but not the other fields.  Approach suggested by Dave
Miller.

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent a65d17c9

arch/x86_64/kernel/pci-gart.c

+2 −4
Original line number Diff line number Diff line
@@ -310,7 +310,7 @@ void gart_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, int di 


	for (i = 0; i < nents; i++) {

		struct scatterlist *s = &sg[i];

		if (!s->dma_length || !s->length)

		if (!s->dma_length)

			break;

		dma_unmap_single(dev, s->dma_address, s->dma_length, dir);

	}
@@ -364,7 +364,6 @@ static int __dma_map_cont(struct scatterlist *sg, int start, int stopat, 
		

		BUG_ON(i > start && s->offset);

		if (i == start) {

			*sout = *s; 

			sout->dma_address = iommu_bus_base;

			sout->dma_address += iommu_page*PAGE_SIZE + s->offset;

			sout->dma_length = s->length;
@@ -391,7 +390,6 @@ static inline int dma_map_cont(struct scatterlist *sg, int start, int stopat, 
{

	if (!need) { 

		BUG_ON(stopat - start != 1);

		*sout = sg[start]; 

		sout->dma_length = sg[start].length; 

		return 0;

	}