/*- * Copyright (c) 2010 Isilon Systems, Inc. * Copyright (c) 2010 iX Systems, Inc. * Copyright (c) 2010 Panasas, Inc. * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd. * Copyright (c) 2015 Matthew Dillon * Copyright (c) 2016 Matt Macy * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice unmodified, this list of conditions, and the following * disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifndef _LINUX_SCATTERLIST_H_ #define _LINUX_SCATTERLIST_H_ #include #include #include #include #include #include /* * SG table design. * * If flags bit 0 is set, then the sg field contains a pointer to the next sg * table list. Otherwise the next entry is at sg + 1, can be determined using * the sg_is_chain() function. * * If flags bit 1 is set, then this sg entry is the last element in a list, * can be determined using the sg_is_last() function. * * See sg_next(). * */ struct scatterlist { union { struct vm_page *page; struct scatterlist *sg; } sl_un; unsigned long offset; uint32_t length; dma_addr_t dma_address; uint32_t flags; }; 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_page_iter { struct scatterlist *sg; unsigned int sg_pgoffset; /* page index */ unsigned int maxents; unsigned int __nents; int __pg_advance; }; /* * 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)) #define sg_dma_address(sg) (sg)->dma_address #define sg_dma_len(sg) (sg)->length #define sg_page(sg) (sg)->sl_un.page #define sg_scatternext(sg) (sg)->sl_un.sg #define SG_END 0x01 #define SG_CHAIN 0x02 static inline void sg_set_page(struct scatterlist *sg, struct vm_page *page, unsigned int len, unsigned int offset) { sg_page(sg) = page; sg_dma_len(sg) = len; sg->offset = offset; if (offset > PAGE_SIZE) panic("sg_set_page: Invalid offset %d\n", offset); } #if 0 static inline void sg_set_buf(struct scatterlist *sg, const void *buf, unsigned int buflen) { sg_set_page(sg, virt_to_page(buf), buflen, ((uintptr_t)buf) & ~PAGE_MASK); } #endif static inline void sg_init_table(struct scatterlist *sg, unsigned int nents) { bzero(sg, sizeof(*sg) * nents); sg[nents - 1].flags = SG_END; } static inline struct scatterlist * sg_next(struct scatterlist *sg) { if (sg->flags & SG_END) return (NULL); sg++; if (sg->flags & SG_CHAIN) sg = sg_scatternext(sg); return (sg); } static inline vm_paddr_t sg_phys(struct scatterlist *sg) { return sg_page(sg)->phys_addr + sg->offset; } /** * 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) { /* * offset and length are unused for chain entry. Clear them. */ struct scatterlist *sg = &prv[prv_nents - 1]; sg->offset = 0; sg->length = 0; /* * Indicate a link pointer, and set the link to the second list. */ sg->flags = SG_CHAIN; sg->sl_un.sg = 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) { sg->flags = SG_END; } /** * __sg_free_table - Free a previously mapped sg table * @table: The sg table header to use * @max_ents: The maximum number of entries per single scatterlist * * Description: * Free an sg table previously allocated and setup with * __sg_alloc_table(). The @max_ents value must be identical to * that previously used with __sg_alloc_table(). * **/ static inline void __sg_free_table(struct sg_table *table, unsigned int max_ents) { struct scatterlist *sgl, *next; if (unlikely(!table->sgl)) return; sgl = table->sgl; while (table->orig_nents) { unsigned int alloc_size = table->orig_nents; unsigned int sg_size; /* * If we have more than max_ents segments left, * then assign 'next' to the sg table after the current one. * sg_size is then one less than alloc size, since the last * element is the chain pointer. */ if (alloc_size > max_ents) { next = sgl[max_ents - 1].sl_un.sg; alloc_size = max_ents; sg_size = alloc_size - 1; } else { sg_size = alloc_size; next = NULL; } table->orig_nents -= sg_size; kfree(sgl); sgl = next; } table->sgl = NULL; } /** * sg_free_table - Free a previously allocated sg table * @table: The mapped sg table header * **/ static inline void sg_free_table(struct sg_table *table) { __sg_free_table(table, SG_MAX_SINGLE_ALLOC); } /** * __sg_alloc_table - Allocate and initialize an sg table with given allocator * @table: The sg table header to use * @nents: Number of entries in sg list * @max_ents: The maximum number of entries the allocator returns per call * @gfp_mask: GFP allocation mask * * Description: * This function returns a @table @nents long. The allocator is * defined to return scatterlist chunks of maximum size @max_ents. * Thus if @nents is bigger than @max_ents, the scatterlists will be * chained in units of @max_ents. * * Notes: * If this function returns non-0 (eg failure), the caller must call * __sg_free_table() to cleanup any leftover allocations. * **/ static inline int __sg_alloc_table(struct sg_table *table, unsigned int nents, unsigned int max_ents, gfp_t gfp_mask) { struct scatterlist *sg, *prv; unsigned int left; memset(table, 0, sizeof(*table)); if (nents == 0) return -EINVAL; left = nents; prv = NULL; do { unsigned int sg_size, alloc_size = left; if (alloc_size > max_ents) { alloc_size = max_ents; sg_size = alloc_size - 1; } else sg_size = alloc_size; left -= sg_size; sg = kmalloc(alloc_size * sizeof(struct scatterlist), M_DRM, gfp_mask); if (unlikely(!sg)) { /* * Adjust entry count to reflect that the last * entry of the previous table won't be used for * linkage. Without this, sg_kfree() may get * confused. */ if (prv) table->nents = ++table->orig_nents; return -ENOMEM; } sg_init_table(sg, alloc_size); table->nents = table->orig_nents += sg_size; /* * If this is the first mapping, assign the sg table header. * If this is not the first mapping, chain previous part. */ if (prv) sg_chain(prv, max_ents, sg); else table->sgl = sg; /* * If no more entries after this one, mark the end */ if (!left) sg_mark_end(&sg[sg_size - 1]); prv = sg; } while (left); return 0; } /** * sg_alloc_table - Allocate and initialize an sg table * @table: The sg table header to use * @nents: Number of entries in sg list * @gfp_mask: GFP allocation mask * * Description: * Allocate and initialize an sg table. If @nents@ is larger than * SG_MAX_SINGLE_ALLOC a chained sg table will be setup. * **/ static inline int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) { int ret; ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC, gfp_mask); if (unlikely(ret)) __sg_free_table(table, SG_MAX_SINGLE_ALLOC); return ret; } static inline int sg_nents(struct scatterlist *sg) { int nents; for (nents = 0; sg; sg = sg_next(sg)) nents++; return nents; } static inline void __sg_page_iter_start(struct sg_page_iter *piter, struct scatterlist *sglist, unsigned int nents, unsigned long pgoffset) { piter->__pg_advance = 0; piter->__nents = nents; piter->sg = sglist; piter->sg_pgoffset = pgoffset; } /* * Iterate pages in sg list. */ static inline void _sg_iter_next(struct sg_page_iter *iter) { struct scatterlist *sg; unsigned int pgcount; sg = iter->sg; pgcount = (sg->offset + sg->length + PAGE_MASK) >> PAGE_SHIFT; ++iter->sg_pgoffset; while (iter->sg_pgoffset >= pgcount) { iter->sg_pgoffset -= pgcount; sg = sg_next(sg); --iter->maxents; if (sg == NULL || iter->maxents == 0) break; pgcount = (sg->offset + sg->length + PAGE_MASK) >> PAGE_SHIFT; } iter->sg = sg; } static inline int sg_page_count(struct scatterlist *sg) { return PAGE_ALIGN(sg->offset + sg->length) >> PAGE_SHIFT; } static inline bool __sg_page_iter_next(struct sg_page_iter *piter) { if (piter->__nents == 0) return (false); if (piter->sg == NULL) return (false); piter->sg_pgoffset += piter->__pg_advance; piter->__pg_advance = 1; while (piter->sg_pgoffset >= sg_page_count(piter->sg)) { piter->sg_pgoffset -= sg_page_count(piter->sg); piter->sg = sg_next(piter->sg); if (--piter->__nents == 0) return (false); if (piter->sg == NULL) return (false); } return (true); } /* * NOTE: pgoffset is really a page index, not a byte offset. */ static inline void _sg_iter_init(struct scatterlist *sgl, struct sg_page_iter *iter, unsigned int nents, unsigned long pgoffset) { if (nents) { /* * Nominal case. Note subtract 1 from starting page index * for initial _sg_iter_next() call. */ iter->sg = sgl; iter->sg_pgoffset = pgoffset - 1; iter->maxents = nents; _sg_iter_next(iter); } else { /* * Degenerate case */ iter->sg = NULL; iter->sg_pgoffset = 0; iter->maxents = 0; } } static inline struct vm_page * sg_page_iter_page(struct sg_page_iter *piter) { return nth_page(sg_page(piter->sg), piter->sg_pgoffset); } static inline dma_addr_t sg_page_iter_dma_address(struct sg_page_iter *spi) { return spi->sg->dma_address + (spi->sg_pgoffset << PAGE_SHIFT); } #define for_each_sg_page(sgl, iter, nents, pgoffset) \ for (_sg_iter_init(sgl, iter, nents, pgoffset); \ (iter)->sg; _sg_iter_next(iter)) #define for_each_sg(sglist, sg, sgmax, _itr) \ for (_itr = 0, sg = (sglist); _itr < (sgmax); _itr++, sg = sg_next(sg)) /* * * XXX please review these */ static inline size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, const void *buf, size_t buflen, off_t skip) { off_t off; int len, curlen, curoff; struct sg_page_iter iter; struct scatterlist *sg; struct vm_page *page; char *vaddr; off = 0; for_each_sg_page(sgl, &iter, nents, 0) { sg = iter.sg; curlen = sg->length; curoff = sg->offset; if (skip && curlen >= skip) { skip -= curlen; continue; } if (skip) { curlen -= skip; curoff += skip; skip = 0; } len = min(curlen, buflen - off); page = sg_page_iter_page(&iter); vaddr = (char *)kmap(page) + sg->offset; memcpy(vaddr, (const char *)buf + off, len); off += len; kunmap(page); } return (off); } static inline size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, const char *buf, size_t buflen) { return (sg_pcopy_from_buffer(sgl, nents, buf, buflen, 0)); } static inline size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, size_t buflen, off_t skip) { off_t off; int len, curlen, curoff; struct sg_page_iter iter; struct scatterlist *sg; struct vm_page *page; char *vaddr; off = 0; for_each_sg_page(sgl, &iter, nents, 0) { sg = iter.sg; curlen = sg->length; curoff = sg->offset; if (skip && curlen >= skip) { skip -= curlen; continue; } if (skip) { curlen -= skip; curoff += skip; skip = 0; } len = min(curlen, buflen - off); page = sg_page_iter_page(&iter); vaddr = (char *)kmap(page) + sg->offset; memcpy((char *)buf + off, vaddr, len); off += len; kunmap(page); } return (off); } static inline size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, char *buf, size_t buflen) { return (sg_pcopy_to_buffer(sgl, nents, buf, buflen, 0)); } #endif /* _LINUX_SCATTERLIST_H_ */