diff options
Diffstat (limited to 'include/linux/scatterlist.h')
| -rw-r--r-- | include/linux/scatterlist.h | 49 |
1 files changed, 40 insertions, 9 deletions
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index b96f0d0b5b8f..b4be960c7e5d 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -339,12 +339,12 @@ int sg_alloc_table_chained(struct sg_table *table, int nents, /* * sg page iterator * - * Iterates over sg entries page-by-page. On each successful iteration, - * you can call sg_page_iter_page(@piter) and sg_page_iter_dma_address(@piter) - * to get the current page and its dma address. @piter->sg will point to the - * sg holding this page and @piter->sg_pgoffset to the page's page offset - * within the sg. The iteration will stop either when a maximum number of sg - * entries was reached or a terminating sg (sg_last(sg) == true) was reached. + * Iterates over sg entries page-by-page. On each successful iteration, you + * can call sg_page_iter_page(@piter) to get the current page and its dma + * address. @piter->sg will point to the sg holding this page and + * @piter->sg_pgoffset to the page's page offset within the sg. The iteration + * will stop either when a maximum number of sg entries was reached or a + * terminating sg (sg_last(sg) == true) was reached. */ struct sg_page_iter { struct scatterlist *sg; /* sg holding the page */ @@ -356,7 +356,19 @@ struct sg_page_iter { * next step */ }; +/* + * sg page iterator for DMA addresses + * + * This is the same as sg_page_iter however you can call + * sg_page_iter_dma_address(@dma_iter) to get the page's DMA + * address. sg_page_iter_page() cannot be called on this iterator. + */ +struct sg_dma_page_iter { + struct sg_page_iter base; +}; + bool __sg_page_iter_next(struct sg_page_iter *piter); +bool __sg_page_iter_dma_next(struct sg_dma_page_iter *dma_iter); void __sg_page_iter_start(struct sg_page_iter *piter, struct scatterlist *sglist, unsigned int nents, unsigned long pgoffset); @@ -372,11 +384,13 @@ static inline struct page *sg_page_iter_page(struct sg_page_iter *piter) /** * sg_page_iter_dma_address - get the dma address of the current page held by * the page iterator. - * @piter: page iterator holding the page + * @dma_iter: page iterator holding the page */ -static inline dma_addr_t sg_page_iter_dma_address(struct sg_page_iter *piter) +static inline dma_addr_t +sg_page_iter_dma_address(struct sg_dma_page_iter *dma_iter) { - return sg_dma_address(piter->sg) + (piter->sg_pgoffset << PAGE_SHIFT); + return sg_dma_address(dma_iter->base.sg) + + (dma_iter->base.sg_pgoffset << PAGE_SHIFT); } /** @@ -385,11 +399,28 @@ static inline dma_addr_t sg_page_iter_dma_address(struct sg_page_iter *piter) * @piter: page iterator to hold current page, sg, sg_pgoffset * @nents: maximum number of sg entries to iterate over * @pgoffset: starting page offset + * + * Callers may use sg_page_iter_page() to get each page pointer. */ #define for_each_sg_page(sglist, piter, nents, pgoffset) \ for (__sg_page_iter_start((piter), (sglist), (nents), (pgoffset)); \ __sg_page_iter_next(piter);) +/** + * for_each_sg_dma_page - iterate over the pages of the given sg list + * @sglist: sglist to iterate over + * @dma_iter: page iterator to hold current page + * @dma_nents: maximum number of sg entries to iterate over, this is the value + * returned from dma_map_sg + * @pgoffset: starting page offset + * + * Callers may use sg_page_iter_dma_address() to get each page's DMA address. + */ +#define for_each_sg_dma_page(sglist, dma_iter, dma_nents, pgoffset) \ + for (__sg_page_iter_start(&(dma_iter)->base, sglist, dma_nents, \ + pgoffset); \ + __sg_page_iter_dma_next(dma_iter);) + /* * Mapping sg iterator * |