| /* SPDX-License-Identifier: GPL-2.0 */ |
| #ifndef _LINUX_SCATTERLIST_H |
| #define _LINUX_SCATTERLIST_H |
| |
| #include <linux/string.h> |
| #include <linux/types.h> |
| #include <linux/bug.h> |
| #include <linux/mm.h> |
| #include <asm/io.h> |
| |
| struct scatterlist { |
| unsigned long page_link; |
| unsigned int offset; |
| unsigned int length; |
| dma_addr_t dma_address; |
| #ifdef CONFIG_NEED_SG_DMA_LENGTH |
| unsigned int dma_length; |
| #endif |
| }; |
| |
| /* |
| * These macros should be used after a dma_map_sg call has been done |
| * to get bus addresses of each of the SG entries and their lengths. |
| * You should only work with the number of sg entries dma_map_sg |
| * returns, or alternatively stop on the first sg_dma_len(sg) which |
| * is 0. |
| */ |
| #define sg_dma_address(sg) ((sg)->dma_address) |
| |
| #ifdef CONFIG_NEED_SG_DMA_LENGTH |
| #define sg_dma_len(sg) ((sg)->dma_length) |
| #else |
| #define sg_dma_len(sg) ((sg)->length) |
| #endif |
| |
| struct sg_table { |
| struct scatterlist *sgl; /* the list */ |
| unsigned int nents; /* number of mapped entries */ |
| 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. |
| * |
| * We use the unsigned long page_link field in the scatterlist struct to place |
| * the page pointer AND encode information about the sg table as well. The two |
| * lower bits are reserved for this information. |
| * |
| * If bit 0 is set, then the page_link contains a pointer to the next sg |
| * table list. Otherwise the next entry is at sg + 1. |
| * |
| * If bit 1 is set, then this sg entry is the last element in a list. |
| * |
| * See sg_next(). |
| * |
| */ |
| |
| #define SG_CHAIN 0x01UL |
| #define SG_END 0x02UL |
| |
| /* |
| * 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. |
| * Those low bits are there for everyone! (thanks mason :-) |
| */ |
| #define sg_is_chain(sg) ((sg)->page_link & SG_CHAIN) |
| #define sg_is_last(sg) ((sg)->page_link & SG_END) |
| #define sg_chain_ptr(sg) \ |
| ((struct scatterlist *) ((sg)->page_link & ~(SG_CHAIN | SG_END))) |
| |
| /** |
| * sg_assign_page - Assign a given page to an SG entry |
| * @sg: SG entry |
| * @page: The page |
| * |
| * Description: |
| * Assign page to sg entry. Also see sg_set_page(), the most commonly used |
| * variant. |
| * |
| **/ |
| static inline void sg_assign_page(struct scatterlist *sg, struct page *page) |
| { |
| unsigned long page_link = sg->page_link & (SG_CHAIN | SG_END); |
| |
| /* |
| * In order for the low bit stealing approach to work, pages |
| * must be aligned at a 32-bit boundary as a minimum. |
| */ |
| BUG_ON((unsigned long) page & (SG_CHAIN | SG_END)); |
| #ifdef CONFIG_DEBUG_SG |
| BUG_ON(sg_is_chain(sg)); |
| #endif |
| sg->page_link = page_link | (unsigned long) page; |
| } |
| |
| /** |
| * sg_set_page - Set sg entry to point at given page |
| * @sg: SG entry |
| * @page: The page |
| * @len: Length of data |
| * @offset: Offset into 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, |
| unsigned int len, unsigned int offset) |
| { |
| sg_assign_page(sg, page); |
| sg->offset = offset; |
| sg->length = len; |
| } |
| |
| static inline struct page *sg_page(struct scatterlist *sg) |
| { |
| #ifdef CONFIG_DEBUG_SG |
| BUG_ON(sg_is_chain(sg)); |
| #endif |
| return (struct page *)((sg)->page_link & ~(SG_CHAIN | SG_END)); |
| } |
| |
| /** |
| * sg_set_buf - Set sg entry to point at given data |
| * @sg: SG entry |
| * @buf: Data |
| * @buflen: Data length |
| * |
| **/ |
| static inline void sg_set_buf(struct scatterlist *sg, const void *buf, |
| unsigned int buflen) |
| { |
| #ifdef CONFIG_DEBUG_SG |
| BUG_ON(!virt_addr_valid(buf)); |
| #endif |
| sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf)); |
| } |
| |
| /* |
| * Loop over each sg element, following the pointer to a new list if necessary |
| */ |
| #define for_each_sg(sglist, sg, nr, __i) \ |
| for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg)) |
| |
| /* |
| * Loop over each sg element in the given sg_table object. |
| */ |
| #define for_each_sgtable_sg(sgt, sg, i) \ |
| for_each_sg((sgt)->sgl, sg, (sgt)->orig_nents, i) |
| |
| /* |
| * Loop over each sg element in the given *DMA mapped* sg_table object. |
| * Please use sg_dma_address(sg) and sg_dma_len(sg) to extract DMA addresses |
| * of the each element. |
| */ |
| #define for_each_sgtable_dma_sg(sgt, sg, i) \ |
| for_each_sg((sgt)->sgl, sg, (sgt)->nents, i) |
| |
| static inline void __sg_chain(struct scatterlist *chain_sg, |
| struct scatterlist *sgl) |
| { |
| /* |
| * offset and length are unused for chain entry. Clear them. |
| */ |
| chain_sg->offset = 0; |
| chain_sg->length = 0; |
| |
| /* |
| * Set lowest bit to indicate a link pointer, and make sure to clear |
| * the termination bit if it happens to be set. |
| */ |
| chain_sg->page_link = ((unsigned long) sgl | SG_CHAIN) & ~SG_END; |
| } |
| |
| /** |
| * sg_chain - Chain two sglists together |
| * @prv: First scatterlist |
| * @prv_nents: Number of entries in prv |
| * @sgl: Second scatterlist |
| * |
| * Description: |
| * Links @prv@ and @sgl@ together, to form a longer scatterlist. |
| * |
| **/ |
| static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, |
| struct scatterlist *sgl) |
| { |
| __sg_chain(&prv[prv_nents - 1], sgl); |
| } |
| |
| /** |
| * sg_mark_end - Mark the end of the scatterlist |
| * @sg: SG entryScatterlist |
| * |
| * Description: |
| * Marks the passed in sg entry as the termination point for the sg |
| * table. A call to sg_next() on this entry will return NULL. |
| * |
| **/ |
| static inline void sg_mark_end(struct scatterlist *sg) |
| { |
| /* |
| * Set termination bit, clear potential chain bit |
| */ |
| sg->page_link |= SG_END; |
| sg->page_link &= ~SG_CHAIN; |
| } |
| |
| /** |
| * 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) |
| { |
| sg->page_link &= ~SG_END; |
| } |
| |
| /** |
| * 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 dma_addr_t 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; |
| } |
| |
| /** |
| * sg_init_marker - Initialize markers in sg table |
| * @sgl: The SG table |
| * @nents: Number of entries in table |
| * |
| **/ |
| static inline void sg_init_marker(struct scatterlist *sgl, |
| unsigned int nents) |
| { |
| sg_mark_end(&sgl[nents - 1]); |
| } |
| |
| int sg_nents(struct scatterlist *sg); |
| int sg_nents_for_len(struct scatterlist *sg, u64 len); |
| 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); |
| int sg_split(struct scatterlist *in, const int in_mapped_nents, |
| const off_t skip, const int nb_splits, |
| const size_t *split_sizes, |
| struct scatterlist **out, int *out_mapped_nents, |
| gfp_t gfp_mask); |
| |
| 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 *, 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); |
| 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, |
| unsigned int order, bool chainable, |
| gfp_t gfp, unsigned int *nent_p); |
| struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp, |
| unsigned int *nent_p); |
| void sgl_free_n_order(struct scatterlist *sgl, int nents, int order); |
| void sgl_free_order(struct scatterlist *sgl, int order); |
| void sgl_free(struct scatterlist *sgl); |
| #endif /* CONFIG_SGL_ALLOC */ |
| |
| size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, |
| size_t buflen, off_t skip, bool to_buffer); |
| |
| size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
| const void *buf, size_t buflen); |
| size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, |
| void *buf, size_t buflen); |
| |
| size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
| const void *buf, size_t buflen, off_t skip); |
| size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, |
| void *buf, size_t buflen, off_t skip); |
| size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, |
| size_t buflen, off_t skip); |
| |
| /* |
| * 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)) |
| |
| /* |
| * The maximum number of SG segments that we will put inside a |
| * scatterlist (unless chaining is used). Should ideally fit inside a |
| * single page, to avoid a higher order allocation. We could define this |
| * to SG_MAX_SINGLE_ALLOC to pack correctly at the highest order. The |
| * minimum value is 32 |
| */ |
| #define SG_CHUNK_SIZE 128 |
| |
| /* |
| * Like SG_CHUNK_SIZE, but for archs that have sg chaining. This limit |
| * is totally arbitrary, a setting of 2048 will get you at least 8mb ios. |
| */ |
| #ifdef CONFIG_ARCH_NO_SG_CHAIN |
| #define SG_MAX_SEGMENTS SG_CHUNK_SIZE |
| #else |
| #define SG_MAX_SEGMENTS 2048 |
| #endif |
| |
| #ifdef CONFIG_SG_POOL |
| void sg_free_table_chained(struct sg_table *table, |
| unsigned nents_first_chunk); |
| int sg_alloc_table_chained(struct sg_table *table, int nents, |
| struct scatterlist *first_chunk, |
| unsigned nents_first_chunk); |
| #endif |
| |
| /* |
| * sg page iterator |
| * |
| * Iterates over sg entries page-by-page. On each successful iteration, you |
| * can call sg_page_iter_page(@piter) to get the current page. |
| * @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 scatterlist *sg; /* sg holding the page */ |
| unsigned int sg_pgoffset; /* page offset within the sg */ |
| |
| /* these are internal states, keep away */ |
| unsigned int __nents; /* remaining sg entries */ |
| int __pg_advance; /* nr pages to advance at the |
| * next step */ |
| }; |
| |
| /* |
| * sg page iterator for DMA addresses |
| * |
| * This is the same as sg_page_iter however you can call |
| * sg_page_iter_dma_address(@dma_iter) to get the page's DMA |
| * address. sg_page_iter_page() cannot be called on this iterator. |
| */ |
| struct sg_dma_page_iter { |
| struct sg_page_iter base; |
| }; |
| |
| bool __sg_page_iter_next(struct sg_page_iter *piter); |
| bool __sg_page_iter_dma_next(struct sg_dma_page_iter *dma_iter); |
| 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. |
| * @dma_iter: page iterator holding the page |
| */ |
| static inline dma_addr_t |
| sg_page_iter_dma_address(struct sg_dma_page_iter *dma_iter) |
| { |
| return sg_dma_address(dma_iter->base.sg) + |
| (dma_iter->base.sg_pgoffset << PAGE_SHIFT); |
| } |
| |
| /** |
| * for_each_sg_page - iterate over the pages of the given sg list |
| * @sglist: sglist to iterate over |
| * @piter: page iterator to hold current page, sg, sg_pgoffset |
| * @nents: maximum number of sg entries to iterate over |
| * @pgoffset: starting page offset (in pages) |
| * |
| * Callers may use sg_page_iter_page() to get each page pointer. |
| * In each loop it operates on PAGE_SIZE unit. |
| */ |
| #define for_each_sg_page(sglist, piter, nents, pgoffset) \ |
| for (__sg_page_iter_start((piter), (sglist), (nents), (pgoffset)); \ |
| __sg_page_iter_next(piter);) |
| |
| /** |
| * for_each_sg_dma_page - iterate over the pages of the given sg list |
| * @sglist: sglist to iterate over |
| * @dma_iter: DMA page iterator to hold current page |
| * @dma_nents: maximum number of sg entries to iterate over, this is the value |
| * returned from dma_map_sg |
| * @pgoffset: starting page offset (in pages) |
| * |
| * Callers may use sg_page_iter_dma_address() to get each page's DMA address. |
| * In each loop it operates on PAGE_SIZE unit. |
| */ |
| #define for_each_sg_dma_page(sglist, dma_iter, dma_nents, pgoffset) \ |
| for (__sg_page_iter_start(&(dma_iter)->base, sglist, dma_nents, \ |
| pgoffset); \ |
| __sg_page_iter_dma_next(dma_iter);) |
| |
| /** |
| * for_each_sgtable_page - iterate over all pages in the sg_table object |
| * @sgt: sg_table object to iterate over |
| * @piter: page iterator to hold current page |
| * @pgoffset: starting page offset (in pages) |
| * |
| * Iterates over the all memory pages in the buffer described by |
| * a scatterlist stored in the given sg_table object. |
| * See also for_each_sg_page(). In each loop it operates on PAGE_SIZE unit. |
| */ |
| #define for_each_sgtable_page(sgt, piter, pgoffset) \ |
| for_each_sg_page((sgt)->sgl, piter, (sgt)->orig_nents, pgoffset) |
| |
| /** |
| * for_each_sgtable_dma_page - iterate over the DMA mapped sg_table object |
| * @sgt: sg_table object to iterate over |
| * @dma_iter: DMA page iterator to hold current page |
| * @pgoffset: starting page offset (in pages) |
| * |
| * Iterates over the all DMA mapped pages in the buffer described by |
| * a scatterlist stored in the given sg_table object. |
| * See also for_each_sg_dma_page(). In each loop it operates on PAGE_SIZE |
| * unit. |
| */ |
| #define for_each_sgtable_dma_page(sgt, dma_iter, pgoffset) \ |
| for_each_sg_dma_page((sgt)->sgl, dma_iter, (sgt)->nents, pgoffset) |
| |
| |
| /* |
| * Mapping sg iterator |
| * |
| * Iterates over sg entries mapping page-by-page. On each successful |
| * iteration, @miter->page points to the mapped page and |
| * @miter->length bytes of data can be accessed at @miter->addr. As |
| * long as an iteration is enclosed between start and stop, the user |
| * is free to choose control structure and when to stop. |
| * |
| * @miter->consumed is set to @miter->length on each iteration. It |
| * can be adjusted if the user can't consume all the bytes in one go. |
| * Also, a stopped iteration can be resumed by calling next on it. |
| * This is useful when iteration needs to release all resources and |
| * continue later (e.g. at the next interrupt). |
| */ |
| |
| #define SG_MITER_ATOMIC (1 << 0) /* use kmap_atomic */ |
| #define SG_MITER_TO_SG (1 << 1) /* flush back to phys on unmap */ |
| #define SG_MITER_FROM_SG (1 << 2) /* nop */ |
| |
| struct sg_mapping_iter { |
| /* the following three fields can be accessed directly */ |
| struct page *page; /* currently mapped page */ |
| void *addr; /* pointer to the mapped area */ |
| size_t length; /* length of the mapped area */ |
| size_t consumed; /* number of consumed bytes */ |
| struct sg_page_iter piter; /* page iterator */ |
| |
| /* these are internal states, keep away */ |
| unsigned int __offset; /* offset within page */ |
| unsigned int __remaining; /* remaining bytes on page */ |
| unsigned int __flags; |
| }; |
| |
| void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, |
| unsigned int nents, unsigned int flags); |
| bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset); |
| bool sg_miter_next(struct sg_mapping_iter *miter); |
| void sg_miter_stop(struct sg_mapping_iter *miter); |
| |
| #endif /* _LINUX_SCATTERLIST_H */ |