iommu: add generic helper for mapping sgtable objects

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struct sg_table is a common structure used for describing a memory
buffer. It consists of a scatterlist with memory pages and DMA addresses
(sgl entry), as well as the number of scatterlist entries: CPU pages
(orig_nents entry) and DMA mapped pages (nents entry).

It turned out that it was a common mistake to misuse nents and orig_nents
entries, calling mapping functions with a wrong number of entries.

To avoid such issues, lets introduce a common wrapper operating directly
on the struct sg_table objects, which take care of the proper use of
the nents and orig_nents entries.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

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Marek Szyprowski 2020-05-13 15:32:10 +02:00 • committed by Christoph Hellwig

parent 709d6d73c7

commit 48530d9fab

1 changed files with 16 additions and 0 deletions

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include/linux/iommu.h

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