2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013-2017 Mellanox Technologies, Ltd.
6 * Copyright (c) 2015 Matthew Dillon <dillon@backplane.com>
7 * Copyright (c) 2016 Matthew Macy
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice unmodified, this list of conditions, and the following
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 #ifndef _LINUX_SCATTERLIST_H_
34 #define _LINUX_SCATTERLIST_H_
36 #include <sys/types.h>
37 #include <sys/sf_buf.h>
39 #include <linux/page.h>
40 #include <linux/slab.h>
45 unsigned long page_link;
46 #define SG_PAGE_LINK_CHAIN 0x1UL
47 #define SG_PAGE_LINK_LAST 0x2UL
48 #define SG_PAGE_LINK_MASK 0x3UL
51 dma_addr_t dma_address;
52 struct bus_dmamap *dma_map; /* FreeBSD specific */
55 CTASSERT((sizeof(struct scatterlist) & SG_PAGE_LINK_MASK) == 0);
58 struct scatterlist *sgl;
60 unsigned int orig_nents;
64 struct scatterlist *sg;
65 unsigned int sg_pgoffset;
73 struct sg_dma_page_iter {
74 struct sg_page_iter base;
77 #define SCATTERLIST_MAX_SEGMENT (-1U & ~(PAGE_SIZE - 1))
79 #define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist))
81 #define SG_MAGIC 0x87654321UL
82 #define SG_CHAIN SG_PAGE_LINK_CHAIN
83 #define SG_END SG_PAGE_LINK_LAST
85 #define sg_is_chain(sg) ((sg)->page_link & SG_PAGE_LINK_CHAIN)
86 #define sg_is_last(sg) ((sg)->page_link & SG_PAGE_LINK_LAST)
87 #define sg_chain_ptr(sg) \
88 ((struct scatterlist *) ((sg)->page_link & ~SG_PAGE_LINK_MASK))
90 #define sg_dma_address(sg) (sg)->dma_address
91 #define sg_dma_len(sg) (sg)->length
93 #define for_each_sg_page(sgl, iter, nents, pgoffset) \
94 for (_sg_iter_init(sgl, iter, nents, pgoffset); \
95 (iter)->sg; _sg_iter_next(iter))
96 #define for_each_sg_dma_page(sgl, iter, nents, pgoffset) \
97 for_each_sg_page(sgl, &(iter)->base, nents, pgoffset)
99 #define for_each_sg(sglist, sg, sgmax, iter) \
100 for (iter = 0, sg = (sglist); iter < (sgmax); iter++, sg = sg_next(sg))
102 typedef struct scatterlist *(sg_alloc_fn) (unsigned int, gfp_t);
103 typedef void (sg_free_fn) (struct scatterlist *, unsigned int);
106 sg_assign_page(struct scatterlist *sg, struct page *page)
108 unsigned long page_link = sg->page_link & SG_PAGE_LINK_MASK;
110 sg->page_link = page_link | (unsigned long)page;
114 sg_set_page(struct scatterlist *sg, struct page *page, unsigned int len,
117 sg_assign_page(sg, page);
122 static inline struct page *
123 sg_page(struct scatterlist *sg)
125 return ((struct page *)((sg)->page_link & ~SG_PAGE_LINK_MASK));
129 sg_set_buf(struct scatterlist *sg, const void *buf, unsigned int buflen)
131 sg_set_page(sg, virt_to_page(buf), buflen,
132 ((uintptr_t)buf) & (PAGE_SIZE - 1));
135 static inline struct scatterlist *
136 sg_next(struct scatterlist *sg)
142 sg = sg_chain_ptr(sg);
146 static inline vm_paddr_t
147 sg_phys(struct scatterlist *sg)
149 return (VM_PAGE_TO_PHYS(sg_page(sg)) + sg->offset);
153 sg_virt(struct scatterlist *sg)
156 return ((void *)((unsigned long)page_address(sg_page(sg)) + sg->offset));
160 sg_chain(struct scatterlist *prv, unsigned int prv_nents,
161 struct scatterlist *sgl)
163 struct scatterlist *sg = &prv[prv_nents - 1];
167 sg->page_link = ((unsigned long)sgl |
168 SG_PAGE_LINK_CHAIN) & ~SG_PAGE_LINK_LAST;
172 sg_mark_end(struct scatterlist *sg)
174 sg->page_link |= SG_PAGE_LINK_LAST;
175 sg->page_link &= ~SG_PAGE_LINK_CHAIN;
179 sg_init_table(struct scatterlist *sg, unsigned int nents)
181 bzero(sg, sizeof(*sg) * nents);
182 sg_mark_end(&sg[nents - 1]);
186 sg_init_one(struct scatterlist *sg, const void *buf, unsigned int buflen)
188 sg_init_table(sg, 1);
189 sg_set_buf(sg, buf, buflen);
192 static struct scatterlist *
193 sg_kmalloc(unsigned int nents, gfp_t gfp_mask)
195 if (nents == SG_MAX_SINGLE_ALLOC) {
196 return ((void *)__get_free_page(gfp_mask));
198 return (kmalloc(nents * sizeof(struct scatterlist), gfp_mask));
202 sg_kfree(struct scatterlist *sg, unsigned int nents)
204 if (nents == SG_MAX_SINGLE_ALLOC) {
205 free_page((unsigned long)sg);
211 __sg_free_table(struct sg_table *table, unsigned int max_ents,
212 bool skip_first_chunk, sg_free_fn * free_fn)
214 struct scatterlist *sgl, *next;
216 if (unlikely(!table->sgl))
220 while (table->orig_nents) {
221 unsigned int alloc_size = table->orig_nents;
222 unsigned int sg_size;
224 if (alloc_size > max_ents) {
225 next = sg_chain_ptr(&sgl[max_ents - 1]);
226 alloc_size = max_ents;
227 sg_size = alloc_size - 1;
229 sg_size = alloc_size;
233 table->orig_nents -= sg_size;
234 if (skip_first_chunk)
235 skip_first_chunk = 0;
237 free_fn(sgl, alloc_size);
245 sg_free_table(struct sg_table *table)
247 __sg_free_table(table, SG_MAX_SINGLE_ALLOC, 0, sg_kfree);
251 __sg_alloc_table(struct sg_table *table, unsigned int nents,
252 unsigned int max_ents, struct scatterlist *first_chunk,
253 gfp_t gfp_mask, sg_alloc_fn *alloc_fn)
255 struct scatterlist *sg, *prv;
258 memset(table, 0, sizeof(*table));
265 unsigned int sg_size;
266 unsigned int alloc_size = left;
268 if (alloc_size > max_ents) {
269 alloc_size = max_ents;
270 sg_size = alloc_size - 1;
272 sg_size = alloc_size;
280 sg = alloc_fn(alloc_size, gfp_mask);
284 table->nents = ++table->orig_nents;
288 sg_init_table(sg, alloc_size);
289 table->nents = table->orig_nents += sg_size;
292 sg_chain(prv, max_ents, sg);
297 sg_mark_end(&sg[sg_size - 1]);
306 sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask)
310 ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC,
311 NULL, gfp_mask, sg_kmalloc);
313 __sg_free_table(table, SG_MAX_SINGLE_ALLOC, 0, sg_kfree);
319 __sg_alloc_table_from_pages(struct sg_table *sgt,
320 struct page **pages, unsigned int count,
321 unsigned long off, unsigned long size,
322 unsigned int max_segment, gfp_t gfp_mask)
324 unsigned int i, segs, cur, len;
326 struct scatterlist *s;
328 if (__predict_false(!max_segment || offset_in_page(max_segment)))
332 for (segs = i = 1; i < count; ++i) {
334 if (len >= max_segment ||
335 page_to_pfn(pages[i]) != page_to_pfn(pages[i - 1]) + 1) {
340 if (__predict_false((rc = sg_alloc_table(sgt, segs, gfp_mask))))
344 for_each_sg(sgt->sgl, s, sgt->orig_nents, i) {
345 unsigned long seg_size;
349 for (j = cur + 1; j < count; ++j) {
351 if (len >= max_segment || page_to_pfn(pages[j]) !=
352 page_to_pfn(pages[j - 1]) + 1)
356 seg_size = ((j - cur) << PAGE_SHIFT) - off;
357 sg_set_page(s, pages[cur], MIN(size, seg_size), off);
366 sg_alloc_table_from_pages(struct sg_table *sgt,
367 struct page **pages, unsigned int count,
368 unsigned long off, unsigned long size,
372 return (__sg_alloc_table_from_pages(sgt, pages, count, off, size,
373 SCATTERLIST_MAX_SEGMENT, gfp_mask));
377 sg_nents(struct scatterlist *sg)
381 for (nents = 0; sg; sg = sg_next(sg))
387 __sg_page_iter_start(struct sg_page_iter *piter,
388 struct scatterlist *sglist, unsigned int nents,
389 unsigned long pgoffset)
391 piter->internal.pg_advance = 0;
392 piter->internal.nents = nents;
395 piter->sg_pgoffset = pgoffset;
399 _sg_iter_next(struct sg_page_iter *iter)
401 struct scatterlist *sg;
402 unsigned int pgcount;
405 pgcount = (sg->offset + sg->length + PAGE_SIZE - 1) >> PAGE_SHIFT;
408 while (iter->sg_pgoffset >= pgcount) {
409 iter->sg_pgoffset -= pgcount;
412 if (sg == NULL || iter->maxents == 0)
414 pgcount = (sg->offset + sg->length + PAGE_SIZE - 1) >> PAGE_SHIFT;
420 sg_page_count(struct scatterlist *sg)
422 return (PAGE_ALIGN(sg->offset + sg->length) >> PAGE_SHIFT);
424 #define sg_dma_page_count(sg) \
428 __sg_page_iter_next(struct sg_page_iter *piter)
430 unsigned int pgcount;
432 if (piter->internal.nents == 0)
434 if (piter->sg == NULL)
437 piter->sg_pgoffset += piter->internal.pg_advance;
438 piter->internal.pg_advance = 1;
441 pgcount = sg_page_count(piter->sg);
442 if (likely(piter->sg_pgoffset < pgcount))
444 piter->sg_pgoffset -= pgcount;
445 piter->sg = sg_next(piter->sg);
446 if (--piter->internal.nents == 0)
448 if (piter->sg == NULL)
453 #define __sg_page_iter_dma_next(itr) \
454 __sg_page_iter_next(&(itr)->base)
457 _sg_iter_init(struct scatterlist *sgl, struct sg_page_iter *iter,
458 unsigned int nents, unsigned long pgoffset)
462 iter->sg_pgoffset = pgoffset - 1;
463 iter->maxents = nents;
467 iter->sg_pgoffset = 0;
473 * sg_page_iter_dma_address() is implemented as a macro because it
474 * needs to accept two different and identical structure types. This
475 * allows both old and new code to co-exist. The compile time assert
476 * adds some safety, that the structure sizes match.
478 #define sg_page_iter_dma_address(spi) ({ \
479 struct sg_page_iter *__spi = (void *)(spi); \
480 dma_addr_t __dma_address; \
481 CTASSERT(sizeof(*(spi)) == sizeof(*__spi)); \
482 __dma_address = __spi->sg->dma_address + \
483 (__spi->sg_pgoffset << PAGE_SHIFT); \
487 static inline struct page *
488 sg_page_iter_page(struct sg_page_iter *piter)
490 return (nth_page(sg_page(piter->sg), piter->sg_pgoffset));
493 static __inline size_t
494 sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents,
495 const void *buf, size_t buflen, off_t skip)
497 struct sg_page_iter piter;
506 b = __DECONST(char *, buf);
509 for_each_sg_page(sgl, &piter, nents, 0) {
511 /* Skip to the start. */
512 if (piter.sg->length <= skip) {
513 skip -= piter.sg->length;
517 /* See how much to copy. */
518 KASSERT(((piter.sg->length - skip) != 0 && (buflen != 0)),
519 ("%s: sg len %u - skip %ju || buflen %zu is 0\n",
520 __func__, piter.sg->length, (uintmax_t)skip, buflen));
521 len = min(piter.sg->length - skip, buflen);
523 page = sg_page_iter_page(&piter);
524 sf = sf_buf_alloc(page, SFB_CPUPRIVATE | SFB_NOWAIT);
527 p = (char *)sf_buf_kva(sf) + piter.sg_pgoffset + skip;
531 /* We copied so nothing more to skip. */
534 /* Either we exactly filled the page, or we are done. */
546 sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents,
547 const void *buf, size_t buflen)
549 return (sg_pcopy_from_buffer(sgl, nents, buf, buflen, 0));
553 sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents,
554 void *buf, size_t buflen, off_t offset)
556 struct sg_page_iter iter;
557 struct scatterlist *sg;
566 for_each_sg_page(sgl, &iter, nents, 0) {
569 if (offset >= sg->length) {
570 offset -= sg->length;
573 len = ulmin(buflen, sg->length - offset);
577 page = sg_page_iter_page(&iter);
578 if (!PMAP_HAS_DMAP) {
579 sf = sf_buf_alloc(page, SFB_CPUPRIVATE | SFB_NOWAIT);
582 vaddr = (char *)sf_buf_kva(sf);
584 vaddr = (char *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(page));
585 memcpy(buf, vaddr + sg->offset + offset, len);
589 /* start at beginning of next page */
593 buf = (char *)buf + len;
602 #endif /* _LINUX_SCATTERLIST_H_ */