diff options
Diffstat (limited to 'include/linux/scatterlist.h')
| -rw-r--r-- | include/linux/scatterlist.h | 56 |
1 files changed, 47 insertions, 9 deletions
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index ecf87484814f..266754a55327 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -39,6 +39,12 @@ struct sg_table { unsigned int orig_nents; /* original size of list */ }; +struct sg_append_table { + struct sg_table sgt; /* The scatter list table */ + struct scatterlist *prv; /* last populated sge in the table */ + unsigned int total_nents; /* Total entries in the table */ +}; + /* * Notes on SG table design. * @@ -280,19 +286,51 @@ typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t); typedef void (sg_free_fn)(struct scatterlist *, unsigned int); void __sg_free_table(struct sg_table *, unsigned int, unsigned int, - sg_free_fn *); + sg_free_fn *, unsigned int); void sg_free_table(struct sg_table *); +void sg_free_append_table(struct sg_append_table *sgt); int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, struct scatterlist *, unsigned int, gfp_t, sg_alloc_fn *); int sg_alloc_table(struct sg_table *, unsigned int, gfp_t); -struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt, - struct page **pages, unsigned int n_pages, unsigned int offset, - unsigned long size, unsigned int max_segment, - struct scatterlist *prv, unsigned int left_pages, - gfp_t gfp_mask); -int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, - unsigned int n_pages, unsigned int offset, - unsigned long size, gfp_t gfp_mask); +int sg_alloc_append_table_from_pages(struct sg_append_table *sgt, + struct page **pages, unsigned int n_pages, + unsigned int offset, unsigned long size, + unsigned int max_segment, + unsigned int left_pages, gfp_t gfp_mask); +int sg_alloc_table_from_pages_segment(struct sg_table *sgt, struct page **pages, + unsigned int n_pages, unsigned int offset, + unsigned long size, + unsigned int max_segment, gfp_t gfp_mask); + +/** + * sg_alloc_table_from_pages - Allocate and initialize an sg table from + * an array of pages + * @sgt: The sg table header to use + * @pages: Pointer to an array of page pointers + * @n_pages: Number of pages in the pages array + * @offset: Offset from start of the first page to the start of a buffer + * @size: Number of valid bytes in the buffer (after offset) + * @gfp_mask: GFP allocation mask + * + * Description: + * Allocate and initialize an sg table from a list of pages. Contiguous + * ranges of the pages are squashed into a single scatterlist node. A user + * may provide an offset at a start and a size of valid data in a buffer + * specified by the page array. The returned sg table is released by + * sg_free_table. + * + * Returns: + * 0 on success, negative error on failure + */ +static inline int sg_alloc_table_from_pages(struct sg_table *sgt, + struct page **pages, + unsigned int n_pages, + unsigned int offset, + unsigned long size, gfp_t gfp_mask) +{ + return sg_alloc_table_from_pages_segment(sgt, pages, n_pages, offset, + size, UINT_MAX, gfp_mask); +} #ifdef CONFIG_SGL_ALLOC struct scatterlist *sgl_alloc_order(unsigned long long length, |