diff options
Diffstat (limited to 'include/linux/scatterlist.h')
| -rw-r--r-- | include/linux/scatterlist.h | 44 |
1 files changed, 39 insertions, 5 deletions
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 2d8bdaef9611..5951e3f38878 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -172,6 +172,22 @@ static inline void sg_mark_end(struct scatterlist *sg) } /** + * sg_unmark_end - Undo setting the end of the scatterlist + * @sg: SG entryScatterlist + * + * Description: + * Removes the termination marker from the given entry of the scatterlist. + * + **/ +static inline void sg_unmark_end(struct scatterlist *sg) +{ +#ifdef CONFIG_DEBUG_SG + BUG_ON(sg->sg_magic != SG_MAGIC); +#endif + sg->page_link &= ~0x02; +} + +/** * sg_phys - Return physical address of an sg entry * @sg: SG entry * @@ -235,13 +251,13 @@ size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, * sg page iterator * * Iterates over sg entries page-by-page. On each successful iteration, - * @piter->page points to the current page, @piter->sg 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. + * 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. */ struct sg_page_iter { - struct page *page; /* current page */ struct scatterlist *sg; /* sg holding the page */ unsigned int sg_pgoffset; /* page offset within the sg */ @@ -255,6 +271,24 @@ bool __sg_page_iter_next(struct sg_page_iter *piter); void __sg_page_iter_start(struct sg_page_iter *piter, struct scatterlist *sglist, unsigned int nents, unsigned long pgoffset); +/** + * sg_page_iter_page - get the current page held by the page iterator + * @piter: page iterator holding the page + */ +static inline struct page *sg_page_iter_page(struct sg_page_iter *piter) +{ + return nth_page(sg_page(piter->sg), piter->sg_pgoffset); +} + +/** + * sg_page_iter_dma_address - get the dma address of the current page held by + * the page iterator. + * @piter: page iterator holding the page + */ +static inline dma_addr_t sg_page_iter_dma_address(struct sg_page_iter *piter) +{ + return sg_dma_address(piter->sg) + (piter->sg_pgoffset << PAGE_SHIFT); +} /** * for_each_sg_page - iterate over the pages of the given sg list |