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authorTomasz Stanislawski <t.stanislaws@samsung.com>2012-06-18 09:25:01 +0200
committerMarek Szyprowski <m.szyprowski@samsung.com>2012-07-30 12:25:44 +0200
commitefc42bc98058a36d761b16a114823db1a902ed05 (patch)
tree3ba9403ec5b4a8619bde6a7fd1eaa3c14843ad3d /include/linux/scatterlist.h
parent28a33cbc24e4256c143dce96c7d93bf423229f92 (diff)
scatterlist: add sg_alloc_table_from_pages function
This patch adds a new constructor for an sg table. The table is constructed from an array of struct pages. All contiguous chunks of the pages are merged into a single sg nodes. A user may provide an offset and a size of a buffer if the buffer is not page-aligned. The function is dedicated for DMABUF exporters which often perform conversion from an page array to a scatterlist. Moreover the scatterlist should be squashed in order to save memory and to speed-up the process of DMA mapping using dma_map_sg. The code is based on the patch 'v4l: vb2-dma-contig: add support for scatterlist in userptr mode' and hints from Laurent Pinchart. Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> CC: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/scatterlist.h')
-rw-r--r--include/linux/scatterlist.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index ac9586dadfa..7b600da9a63 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -214,6 +214,10 @@ void sg_free_table(struct sg_table *);
int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, gfp_t,
sg_alloc_fn *);
int sg_alloc_table(struct sg_table *, unsigned int, gfp_t);
+int sg_alloc_table_from_pages(struct sg_table *sgt,
+ struct page **pages, unsigned int n_pages,
+ unsigned long offset, unsigned long size,
+ gfp_t gfp_mask);
size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents,
void *buf, size_t buflen);