Commit 04abab69 authored Feb 11, 2015 by Ricardo Ribalda Delgado Committed by Marek Szyprowski Mar 09, 2015

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>

parent 8582e267

include/linux/dma-mapping.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -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);