diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/scatterlist.h | 112 |
1 files changed, 104 insertions, 8 deletions
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 2dc7464cce5..1645795cbb1 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -2,24 +2,37 @@ #define _LINUX_SCATTERLIST_H #include <asm/scatterlist.h> +#include <asm/io.h> #include <linux/mm.h> #include <linux/string.h> +/** + * sg_set_page - Set sg entry to point at given page + * @sg: SG entry + * @page: The page + * + * Description: + * Use this function to set an sg entry pointing at a page, never assign + * the page directly. We encode sg table information in the lower bits + * of the page pointer. See sg_page() for looking up the page belonging + * to an sg entry. + * + **/ +static inline void sg_set_page(struct scatterlist *sg, struct page *page) +{ + sg->page = page; +} + +#define sg_page(sg) ((sg)->page) + static inline void sg_set_buf(struct scatterlist *sg, const void *buf, unsigned int buflen) { - sg->page = virt_to_page(buf); + sg_set_page(sg, virt_to_page(buf)); sg->offset = offset_in_page(buf); sg->length = buflen; } -static inline void sg_init_one(struct scatterlist *sg, const void *buf, - unsigned int buflen) -{ - memset(sg, 0, sizeof(*sg)); - sg_set_buf(sg, buf, buflen); -} - /* * We overload the LSB of the page pointer to indicate whether it's * a valid sg entry, or whether it points to the start of a new scatterlist. @@ -104,4 +117,87 @@ static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, prv[prv_nents - 1].page = (struct page *) ((unsigned long) sgl | 0x01); } +/** + * sg_mark_end - Mark the end of the scatterlist + * @sgl: Scatterlist + * @nents: Number of entries in sgl + * + * Description: + * Marks the last entry as the termination point for sg_next() + * + **/ +static inline void sg_mark_end(struct scatterlist *sgl, unsigned int nents) +{ +} + +static inline void __sg_mark_end(struct scatterlist *sg) +{ +} + + +/** + * sg_init_one - Initialize a single entry sg list + * @sg: SG entry + * @buf: Virtual address for IO + * @buflen: IO length + * + * Notes: + * This should not be used on a single entry that is part of a larger + * table. Use sg_init_table() for that. + * + **/ +static inline void sg_init_one(struct scatterlist *sg, const void *buf, + unsigned int buflen) +{ + memset(sg, 0, sizeof(*sg)); + sg_mark_end(sg, 1); + sg_set_buf(sg, buf, buflen); +} + +/** + * sg_init_table - Initialize SG table + * @sgl: The SG table + * @nents: Number of entries in table + * + * Notes: + * If this is part of a chained sg table, sg_mark_end() should be + * used only on the last table part. + * + **/ +static inline void sg_init_table(struct scatterlist *sgl, unsigned int nents) +{ + memset(sgl, 0, sizeof(*sgl) * nents); + sg_mark_end(sgl, nents); +} + +/** + * sg_phys - Return physical address of an sg entry + * @sg: SG entry + * + * Description: + * This calls page_to_phys() on the page in this sg entry, and adds the + * sg offset. The caller must know that it is legal to call page_to_phys() + * on the sg page. + * + **/ +static inline unsigned long sg_phys(struct scatterlist *sg) +{ + return page_to_phys(sg_page(sg)) + sg->offset; +} + +/** + * sg_virt - Return virtual address of an sg entry + * @sg: SG entry + * + * Description: + * This calls page_address() on the page in this sg entry, and adds the + * sg offset. The caller must know that the sg page has a valid virtual + * mapping. + * + **/ +static inline void *sg_virt(struct scatterlist *sg) +{ + return page_address(sg_page(sg)) + sg->offset; +} + #endif /* _LINUX_SCATTERLIST_H */ |