diff options
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/scatterlist.h | 126 |
1 files changed, 26 insertions, 100 deletions
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index e3ff21dbac5..a3d567a974e 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -7,6 +7,12 @@ #include <linux/string.h> #include <asm/io.h> +struct sg_table { + struct scatterlist *sgl; /* the list */ + unsigned int nents; /* number of mapped entries */ + unsigned int orig_nents; /* original size of list */ +}; + /* * Notes on SG table design. * @@ -106,31 +112,6 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf, sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf)); } -/** - * sg_next - return the next scatterlist entry in a list - * @sg: The current sg entry - * - * Description: - * Usually the next entry will be @sg@ + 1, but if this sg element is part - * of a chained scatterlist, it could jump to the start of a new - * scatterlist array. - * - **/ -static inline struct scatterlist *sg_next(struct scatterlist *sg) -{ -#ifdef CONFIG_DEBUG_SG - BUG_ON(sg->sg_magic != SG_MAGIC); -#endif - if (sg_is_last(sg)) - return NULL; - - sg++; - if (unlikely(sg_is_chain(sg))) - sg = sg_chain_ptr(sg); - - return sg; -} - /* * Loop over each sg element, following the pointer to a new list if necessary */ @@ -138,40 +119,6 @@ static inline struct scatterlist *sg_next(struct scatterlist *sg) for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg)) /** - * sg_last - return the last scatterlist entry in a list - * @sgl: First entry in the scatterlist - * @nents: Number of entries in the scatterlist - * - * Description: - * Should only be used casually, it (currently) scan the entire list - * to get the last entry. - * - * Note that the @sgl@ pointer passed in need not be the first one, - * the important bit is that @nents@ denotes the number of entries that - * exist from @sgl@. - * - **/ -static inline struct scatterlist *sg_last(struct scatterlist *sgl, - unsigned int nents) -{ -#ifndef ARCH_HAS_SG_CHAIN - struct scatterlist *ret = &sgl[nents - 1]; -#else - struct scatterlist *sg, *ret = NULL; - unsigned int i; - - for_each_sg(sgl, sg, nents, i) - ret = sg; - -#endif -#ifdef CONFIG_DEBUG_SG - BUG_ON(sgl[0].sg_magic != SG_MAGIC); - BUG_ON(!sg_is_last(ret)); -#endif - return ret; -} - -/** * sg_chain - Chain two sglists together * @prv: First scatterlist * @prv_nents: Number of entries in prv @@ -223,47 +170,6 @@ static inline void sg_mark_end(struct scatterlist *sg) } /** - * 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); -#ifdef CONFIG_DEBUG_SG - { - unsigned int i; - for (i = 0; i < nents; i++) - sgl[i].sg_magic = SG_MAGIC; - } -#endif - sg_mark_end(&sgl[nents - 1]); -} - -/** - * 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) -{ - sg_init_table(sg, 1); - sg_set_buf(sg, buf, buflen); -} - -/** * sg_phys - Return physical address of an sg entry * @sg: SG entry * @@ -293,4 +199,24 @@ static inline void *sg_virt(struct scatterlist *sg) return page_address(sg_page(sg)) + sg->offset; } +struct scatterlist *sg_next(struct scatterlist *); +struct scatterlist *sg_last(struct scatterlist *s, unsigned int); +void sg_init_table(struct scatterlist *, unsigned int); +void sg_init_one(struct scatterlist *, const void *, unsigned int); + +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, sg_free_fn *); +void sg_free_table(struct sg_table *); +int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, gfp_t, + sg_alloc_fn *); +int sg_alloc_table(struct sg_table *, unsigned int, gfp_t); + +/* + * Maximum number of entries that will be allocated in one piece, if + * a list larger than this is required then chaining will be utilized. + */ +#define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist)) + #endif /* _LINUX_SCATTERLIST_H */ |