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iommu: Do more input validation in iommu_map_sg()

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The IOMMU-API works on page boundarys, unlike the DMA-API
which can work with sub-page buffers. The sg->offset
field does not make sense on the IOMMU level, so force it to
be 0. Do some error-path consolidation while at it.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Joerg Roedel 2014-11-04 14:53:51 +01:00
parent 315786ebbf
commit 38ec010d9b
1 changed files with 18 additions and 11 deletions
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29
drivers/iommu/iommu.c
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@ -1127,26 +1127,33 @@ EXPORT_SYMBOL_GPL(iommu_unmap);
size_t default_iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
struct scatterlist *sg, unsigned int nents, int prot)
{
int ret;
struct scatterlist *s;
size_t mapped = 0;
unsigned int i;
struct scatterlist *s;
int ret;
for_each_sg(sg, s, nents, i) {
phys_addr_t phys = page_to_phys(sg_page(s));
size_t page_len = s->offset + s->length;
ret = iommu_map(domain, iova + mapped, phys, page_len, prot);
if (ret) {
/* undo mappings already done */
iommu_unmap(domain, iova, mapped);
mapped = 0;
break;
}
mapped += page_len;
/* We are mapping on page boundarys, so offset must be 0 */
if (s->offset)
goto out_err;
ret = iommu_map(domain, iova + mapped, phys, s->length, prot);
if (ret)
goto out_err;
mapped += s->length;
}
return mapped;
out_err:
/* undo mappings already done */
iommu_unmap(domain, iova, mapped);
return 0;
}
EXPORT_SYMBOL_GPL(default_iommu_map_sg);