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| Started by | Andrew Morton <akpm@linux-foundation.org> |
|---|---|
| First post | 2015-08-04 01:20 +0200 |
| Last post | 2015-08-04 01:20 +0200 |
| Articles | 1 — 1 participant |
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Re: [RFC PATCH v2] lib: scatterlist: add sg splitting function Andrew Morton <akpm@linux-foundation.org> - 2015-08-04 01:20 +0200
| From | Andrew Morton <akpm@linux-foundation.org> |
|---|---|
| Date | 2015-08-04 01:20 +0200 |
| Subject | Re: [RFC PATCH v2] lib: scatterlist: add sg splitting function |
| Message-ID | <pTxbr-VO-9@gated-at.bofh.it> |
On Sat, 1 Aug 2015 15:17:13 +0200 Robert Jarzmik <robert.jarzmik@free.fr> wrote: > Sometimes a scatter-gather has to be split into several chunks, or sub scatter > lists. This happens for example if a scatter list will be handled by multiple > DMA channels, each one filling a part of it. > > A concrete example comes with the media V4L2 API, where the scatter list is > allocated from userspace to hold an image, regardless of the knowledge of how > many DMAs will fill it : > - in a simple RGB565 case, one DMA will pump data from the camera ISP to memory > - in the trickier YUV422 case, 3 DMAs will pump data from the camera ISP pipes, > one for pipe Y, one for pipe U and one for pipe V > > For these cases, it is necessary to split the original scatter list into > multiple scatter lists, which is the purpose of this patch. > > ... > > include/linux/scatterlist.h | 5 ++ > lib/scatterlist.c | 189 ++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 194 insertions(+) It's quite a bit of code for a fairly specialised thing. How ugly would it be to put this in a new .c file and have subsystems select it in Kconfig? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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