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authorRicardo Ribalda Delgado <ricardo.ribalda@gmail.com>2015-02-11 15:53:15 +0300
committerMarek Szyprowski <m.szyprowski@samsung.com>2015-03-09 15:05:47 +0300
commit04abab698285297115e5096b3100df1064045529 (patch)
treeb81b23e56d884fb10d32ffadec2bc8ae83e7211a /include/linux/dma-mapping.h
parent8582e267e9a29ccfd2151c5d74bc2b1440dfb827 (diff)
downloadlinux-04abab698285297115e5096b3100df1064045529.tar.xz
include/dma-mapping: Clarify output of dma_map_sg
Although dma_map_sg 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. Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Diffstat (limited to 'include/linux/dma-mapping.h')
-rw-r--r--include/linux/dma-mapping.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index c3007cb4bfa6..ac07ff090919 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -34,6 +34,10 @@ struct dma_map_ops {
void (*unmap_page)(struct device *dev, dma_addr_t dma_handle,
size_t size, enum dma_data_direction dir,
struct dma_attrs *attrs);
+ /*
+ * map_sg returns 0 on error and a value > 0 on success.
+ * It should never return a value < 0.
+ */
int (*map_sg)(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction dir,
struct dma_attrs *attrs);