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| author | Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> | 2015-02-11 13:53:14 +0100 |
|---|---|---|
| committer | Marek Szyprowski <m.szyprowski@samsung.com> | 2015-03-09 13:05:47 +0100 |
| commit | 8582e267e9a29ccfd2151c5d74bc2b1440dfb827 (patch) | |
| tree | 3b4cae0c874c6a7299e4e27929e0d972a91d5150 /include | |
| parent | 9eccca0843205f87c00404b663188b88eb248051 (diff) | |
asm/dma-mapping-common: Clarify output of dma_map_sg_attrs
Although dma_map_sg_attrs returns 0 on error and it cannot return a
value < 0, the function returns a signed integer.
Most of the time, this function is used with a scatterlist structure.
This structure uses an unsigned integer for the number of memory.
A dma developer that has not read in detail DMA-API.txt, can wrongly
return a value < 0 on error.
The comment will help the driver developer, and the WARN_ON the dma
developer.
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-generic/dma-mapping-common.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/asm-generic/dma-mapping-common.h b/include/asm-generic/dma-mapping-common.h index 3378dcf4c31e..940d5ec122c9 100644 --- a/include/asm-generic/dma-mapping-common.h +++ b/include/asm-generic/dma-mapping-common.h @@ -39,6 +39,10 @@ static inline void dma_unmap_single_attrs(struct device *dev, dma_addr_t addr, debug_dma_unmap_page(dev, addr, size, dir, true); } +/* + * dma_maps_sg_attrs returns 0 on error and > 0 on success. + * It should never return a value < 0. + */ static inline int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, struct dma_attrs *attrs) @@ -51,6 +55,7 @@ static inline int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, kmemcheck_mark_initialized(sg_virt(s), s->length); BUG_ON(!valid_dma_direction(dir)); ents = ops->map_sg(dev, sg, nents, dir, attrs); + BUG_ON(ents < 0); debug_dma_map_sg(dev, sg, nents, ents, dir); return ents; |