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| author | FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> | 2010-05-26 14:44:21 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-05-27 09:12:53 -0700 |
| commit | b02de871617be353c941edce5f7c22bb18499b4e (patch) | |
| tree | 5d4d9cc22118ae3f4ecd134d1ce31ae3e95d33e0 /Documentation/DMA-API-HOWTO.txt | |
| parent | 7cdcc8e4762f0e4a94cead6a3b57b5eaa01bd5da (diff) | |
| download | lwn-b02de871617be353c941edce5f7c22bb18499b4e.tar.gz lwn-b02de871617be353c941edce5f7c22bb18499b4e.zip | |
Documentation: update scatterlist struct description in DMA-API-HOWTO
Now we have <asm-generic/scatterlist.h>. Architectures should use it
instead of inventing the own scatterlist struct. Let's update the
description.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/DMA-API-HOWTO.txt')
| -rw-r--r-- | Documentation/DMA-API-HOWTO.txt | 17 |
1 files changed, 4 insertions, 13 deletions
diff --git a/Documentation/DMA-API-HOWTO.txt b/Documentation/DMA-API-HOWTO.txt index a38ddadd208e..c3ab456422f3 100644 --- a/Documentation/DMA-API-HOWTO.txt +++ b/Documentation/DMA-API-HOWTO.txt @@ -703,19 +703,10 @@ to "Closing". 1) Struct scatterlist requirements. - Struct scatterlist must contain, at a minimum, the following - members: - - struct page *page; - unsigned int offset; - unsigned int length; - - The base address is specified by a "page+offset" pair. - - Previous versions of struct scatterlist contained a "void *address" - field that was sometimes used instead of page+offset. As of Linux - 2.5., page+offset is always used, and the "address" field has been - deleted. + Don't invent the architecture specific struct scatterlist; just use + <asm-generic/scatterlist.h>. You need to enable + CONFIG_NEED_SG_DMA_LENGTH if the architecture supports IOMMUs + (including software IOMMU). 2) More to come... |