diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/scatterlist.c | 66 |
1 files changed, 49 insertions, 17 deletions
diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 7b2e74da2c44..7c1c55f7daaa 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -370,35 +370,38 @@ int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) EXPORT_SYMBOL(sg_alloc_table); /** - * 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 + * __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) + * @max_segment: Maximum size of a scatterlist node in bytes (page aligned) + * @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. + * ranges of the pages are squashed into a single scatterlist node up to the + * maximum size specified in @max_segment. An 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 */ -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_table_from_pages(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) { - const unsigned int max_segment = SCATTERLIST_MAX_SEGMENT; unsigned int chunks, cur_page, seg_len, i; int ret; struct scatterlist *s; + if (WARN_ON(!max_segment || offset_in_page(max_segment))) + return -EINVAL; + /* compute number of contiguous chunks */ chunks = 1; seg_len = 0; @@ -440,6 +443,35 @@ int sg_alloc_table_from_pages(struct sg_table *sgt, return 0; } +EXPORT_SYMBOL(__sg_alloc_table_from_pages); + +/** + * 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 + */ +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(sgt, pages, n_pages, offset, size, + SCATTERLIST_MAX_SEGMENT, gfp_mask); +} EXPORT_SYMBOL(sg_alloc_table_from_pages); void __sg_page_iter_start(struct sg_page_iter *piter, |