1 /*- 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 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice unmodified, this list of conditions, and the following 14 * disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 * 30 * $FreeBSD$ 31 */ 32 #ifndef _LINUX_SCATTERLIST_H_ 33 #define _LINUX_SCATTERLIST_H_ 34 35 #include <linux/page.h> 36 #include <linux/slab.h> 37 #include <linux/mm.h> 38 39 struct scatterlist { 40 unsigned long page_link; 41 #define SG_PAGE_LINK_CHAIN 0x1UL 42 #define SG_PAGE_LINK_LAST 0x2UL 43 #define SG_PAGE_LINK_MASK 0x3UL 44 unsigned int offset; 45 unsigned int length; 46 dma_addr_t address; 47 }; 48 49 CTASSERT((sizeof(struct scatterlist) & SG_PAGE_LINK_MASK) == 0); 50 51 struct sg_table { 52 struct scatterlist *sgl; 53 unsigned int nents; 54 unsigned int orig_nents; 55 }; 56 57 struct sg_page_iter { 58 struct scatterlist *sg; 59 unsigned int sg_pgoffset; 60 unsigned int maxents; 61 struct { 62 unsigned int nents; 63 int pg_advance; 64 } internal; 65 }; 66 67 #define SCATTERLIST_MAX_SEGMENT (-1U & ~(PAGE_SIZE - 1)) 68 69 #define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist)) 70 71 #define SG_MAGIC 0x87654321UL 72 73 #define sg_is_chain(sg) ((sg)->page_link & SG_PAGE_LINK_CHAIN) 74 #define sg_is_last(sg) ((sg)->page_link & SG_PAGE_LINK_LAST) 75 #define sg_chain_ptr(sg) \ 76 ((struct scatterlist *) ((sg)->page_link & ~SG_PAGE_LINK_MASK)) 77 78 #define sg_dma_address(sg) (sg)->address 79 #define sg_dma_len(sg) (sg)->length 80 81 #define for_each_sg_page(sgl, iter, nents, pgoffset) \ 82 for (_sg_iter_init(sgl, iter, nents, pgoffset); \ 83 (iter)->sg; _sg_iter_next(iter)) 84 85 #define for_each_sg(sglist, sg, sgmax, iter) \ 86 for (iter = 0, sg = (sglist); iter < (sgmax); iter++, sg = sg_next(sg)) 87 88 typedef struct scatterlist *(sg_alloc_fn) (unsigned int, gfp_t); 89 typedef void (sg_free_fn) (struct scatterlist *, unsigned int); 90 91 static inline void 92 sg_assign_page(struct scatterlist *sg, struct page *page) 93 { 94 unsigned long page_link = sg->page_link & SG_PAGE_LINK_MASK; 95 96 sg->page_link = page_link | (unsigned long)page; 97 } 98 99 static inline void 100 sg_set_page(struct scatterlist *sg, struct page *page, unsigned int len, 101 unsigned int offset) 102 { 103 sg_assign_page(sg, page); 104 sg->offset = offset; 105 sg->length = len; 106 } 107 108 static inline struct page * 109 sg_page(struct scatterlist *sg) 110 { 111 return ((struct page *)((sg)->page_link & ~SG_PAGE_LINK_MASK)); 112 } 113 114 static inline void 115 sg_set_buf(struct scatterlist *sg, const void *buf, unsigned int buflen) 116 { 117 sg_set_page(sg, virt_to_page(buf), buflen, 118 ((uintptr_t)buf) & (PAGE_SIZE - 1)); 119 } 120 121 static inline struct scatterlist * 122 sg_next(struct scatterlist *sg) 123 { 124 if (sg_is_last(sg)) 125 return (NULL); 126 sg++; 127 if (sg_is_chain(sg)) 128 sg = sg_chain_ptr(sg); 129 return (sg); 130 } 131 132 static inline vm_paddr_t 133 sg_phys(struct scatterlist *sg) 134 { 135 return (VM_PAGE_TO_PHYS(sg_page(sg)) + sg->offset); 136 } 137 138 static inline void 139 sg_chain(struct scatterlist *prv, unsigned int prv_nents, 140 struct scatterlist *sgl) 141 { 142 struct scatterlist *sg = &prv[prv_nents - 1]; 143 144 sg->offset = 0; 145 sg->length = 0; 146 sg->page_link = ((unsigned long)sgl | 147 SG_PAGE_LINK_CHAIN) & ~SG_PAGE_LINK_LAST; 148 } 149 150 static inline void 151 sg_mark_end(struct scatterlist *sg) 152 { 153 sg->page_link |= SG_PAGE_LINK_LAST; 154 sg->page_link &= ~SG_PAGE_LINK_CHAIN; 155 } 156 157 static inline void 158 sg_init_table(struct scatterlist *sg, unsigned int nents) 159 { 160 bzero(sg, sizeof(*sg) * nents); 161 sg_mark_end(&sg[nents - 1]); 162 } 163 164 static struct scatterlist * 165 sg_kmalloc(unsigned int nents, gfp_t gfp_mask) 166 { 167 if (nents == SG_MAX_SINGLE_ALLOC) { 168 return ((void *)__get_free_page(gfp_mask)); 169 } else 170 return (kmalloc(nents * sizeof(struct scatterlist), gfp_mask)); 171 } 172 173 static inline void 174 sg_kfree(struct scatterlist *sg, unsigned int nents) 175 { 176 if (nents == SG_MAX_SINGLE_ALLOC) { 177 free_page((unsigned long)sg); 178 } else 179 kfree(sg); 180 } 181 182 static inline void 183 __sg_free_table(struct sg_table *table, unsigned int max_ents, 184 bool skip_first_chunk, sg_free_fn * free_fn) 185 { 186 struct scatterlist *sgl, *next; 187 188 if (unlikely(!table->sgl)) 189 return; 190 191 sgl = table->sgl; 192 while (table->orig_nents) { 193 unsigned int alloc_size = table->orig_nents; 194 unsigned int sg_size; 195 196 if (alloc_size > max_ents) { 197 next = sg_chain_ptr(&sgl[max_ents - 1]); 198 alloc_size = max_ents; 199 sg_size = alloc_size - 1; 200 } else { 201 sg_size = alloc_size; 202 next = NULL; 203 } 204 205 table->orig_nents -= sg_size; 206 if (skip_first_chunk) 207 skip_first_chunk = 0; 208 else 209 free_fn(sgl, alloc_size); 210 sgl = next; 211 } 212 213 table->sgl = NULL; 214 } 215 216 static inline void 217 sg_free_table(struct sg_table *table) 218 { 219 __sg_free_table(table, SG_MAX_SINGLE_ALLOC, 0, sg_kfree); 220 } 221 222 static inline int 223 __sg_alloc_table(struct sg_table *table, unsigned int nents, 224 unsigned int max_ents, struct scatterlist *first_chunk, 225 gfp_t gfp_mask, sg_alloc_fn *alloc_fn) 226 { 227 struct scatterlist *sg, *prv; 228 unsigned int left; 229 230 memset(table, 0, sizeof(*table)); 231 232 if (nents == 0) 233 return (-EINVAL); 234 left = nents; 235 prv = NULL; 236 do { 237 unsigned int sg_size; 238 unsigned int alloc_size = left; 239 240 if (alloc_size > max_ents) { 241 alloc_size = max_ents; 242 sg_size = alloc_size - 1; 243 } else 244 sg_size = alloc_size; 245 246 left -= sg_size; 247 248 if (first_chunk) { 249 sg = first_chunk; 250 first_chunk = NULL; 251 } else { 252 sg = alloc_fn(alloc_size, gfp_mask); 253 } 254 if (unlikely(!sg)) { 255 if (prv) 256 table->nents = ++table->orig_nents; 257 258 return (-ENOMEM); 259 } 260 sg_init_table(sg, alloc_size); 261 table->nents = table->orig_nents += sg_size; 262 263 if (prv) 264 sg_chain(prv, max_ents, sg); 265 else 266 table->sgl = sg; 267 268 if (!left) 269 sg_mark_end(&sg[sg_size - 1]); 270 271 prv = sg; 272 } while (left); 273 274 return (0); 275 } 276 277 static inline int 278 sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) 279 { 280 int ret; 281 282 ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC, 283 NULL, gfp_mask, sg_kmalloc); 284 if (unlikely(ret)) 285 __sg_free_table(table, SG_MAX_SINGLE_ALLOC, 0, sg_kfree); 286 287 return (ret); 288 } 289 290 static inline int 291 __sg_alloc_table_from_pages(struct sg_table *sgt, 292 struct page **pages, unsigned int count, 293 unsigned long off, unsigned long size, 294 unsigned int max_segment, gfp_t gfp_mask) 295 { 296 unsigned int i, segs, cur, len; 297 int rc; 298 struct scatterlist *s; 299 300 if (__predict_false(!max_segment || offset_in_page(max_segment))) 301 return (-EINVAL); 302 303 len = 0; 304 for (segs = i = 1; i < count; ++i) { 305 len += PAGE_SIZE; 306 if (len >= max_segment || 307 page_to_pfn(pages[i]) != page_to_pfn(pages[i - 1]) + 1) { 308 ++segs; 309 len = 0; 310 } 311 } 312 if (__predict_false((rc = sg_alloc_table(sgt, segs, gfp_mask)))) 313 return (rc); 314 315 cur = 0; 316 for_each_sg(sgt->sgl, s, sgt->orig_nents, i) { 317 unsigned long seg_size; 318 unsigned int j; 319 320 len = 0; 321 for (j = cur + 1; j < count; ++j) { 322 len += PAGE_SIZE; 323 if (len >= max_segment || page_to_pfn(pages[j]) != 324 page_to_pfn(pages[j - 1]) + 1) 325 break; 326 } 327 328 seg_size = ((j - cur) << PAGE_SHIFT) - off; 329 sg_set_page(s, pages[cur], min(size, seg_size), off); 330 size -= seg_size; 331 off = 0; 332 cur = j; 333 } 334 return (0); 335 } 336 337 static inline int 338 sg_alloc_table_from_pages(struct sg_table *sgt, 339 struct page **pages, unsigned int count, 340 unsigned long off, unsigned long size, 341 gfp_t gfp_mask) 342 { 343 344 return (__sg_alloc_table_from_pages(sgt, pages, count, off, size, 345 SCATTERLIST_MAX_SEGMENT, gfp_mask)); 346 } 347 348 static inline int 349 sg_nents(struct scatterlist *sg) 350 { 351 int nents; 352 353 for (nents = 0; sg; sg = sg_next(sg)) 354 nents++; 355 return (nents); 356 } 357 358 static inline void 359 __sg_page_iter_start(struct sg_page_iter *piter, 360 struct scatterlist *sglist, unsigned int nents, 361 unsigned long pgoffset) 362 { 363 piter->internal.pg_advance = 0; 364 piter->internal.nents = nents; 365 366 piter->sg = sglist; 367 piter->sg_pgoffset = pgoffset; 368 } 369 370 static inline void 371 _sg_iter_next(struct sg_page_iter *iter) 372 { 373 struct scatterlist *sg; 374 unsigned int pgcount; 375 376 sg = iter->sg; 377 pgcount = (sg->offset + sg->length + PAGE_SIZE - 1) >> PAGE_SHIFT; 378 379 ++iter->sg_pgoffset; 380 while (iter->sg_pgoffset >= pgcount) { 381 iter->sg_pgoffset -= pgcount; 382 sg = sg_next(sg); 383 --iter->maxents; 384 if (sg == NULL || iter->maxents == 0) 385 break; 386 pgcount = (sg->offset + sg->length + PAGE_SIZE - 1) >> PAGE_SHIFT; 387 } 388 iter->sg = sg; 389 } 390 391 static inline int 392 sg_page_count(struct scatterlist *sg) 393 { 394 return (PAGE_ALIGN(sg->offset + sg->length) >> PAGE_SHIFT); 395 } 396 397 static inline bool 398 __sg_page_iter_next(struct sg_page_iter *piter) 399 { 400 if (piter->internal.nents == 0) 401 return (0); 402 if (piter->sg == NULL) 403 return (0); 404 405 piter->sg_pgoffset += piter->internal.pg_advance; 406 piter->internal.pg_advance = 1; 407 408 while (piter->sg_pgoffset >= sg_page_count(piter->sg)) { 409 piter->sg_pgoffset -= sg_page_count(piter->sg); 410 piter->sg = sg_next(piter->sg); 411 if (--piter->internal.nents == 0) 412 return (0); 413 if (piter->sg == NULL) 414 return (0); 415 } 416 return (1); 417 } 418 419 static inline void 420 _sg_iter_init(struct scatterlist *sgl, struct sg_page_iter *iter, 421 unsigned int nents, unsigned long pgoffset) 422 { 423 if (nents) { 424 iter->sg = sgl; 425 iter->sg_pgoffset = pgoffset - 1; 426 iter->maxents = nents; 427 _sg_iter_next(iter); 428 } else { 429 iter->sg = NULL; 430 iter->sg_pgoffset = 0; 431 iter->maxents = 0; 432 } 433 } 434 435 static inline dma_addr_t 436 sg_page_iter_dma_address(struct sg_page_iter *spi) 437 { 438 return (spi->sg->address + (spi->sg_pgoffset << PAGE_SHIFT)); 439 } 440 441 static inline struct page * 442 sg_page_iter_page(struct sg_page_iter *piter) 443 { 444 return (nth_page(sg_page(piter->sg), piter->sg_pgoffset)); 445 } 446 447 448 #endif /* _LINUX_SCATTERLIST_H_ */ 449