Blame view
lib/scatterlist.c
15.6 KB
0db9299f4 SG: Move function... |
1 2 3 4 5 6 7 8 |
/* * Copyright (C) 2007 Jens Axboe <jens.axboe@oracle.com> * * Scatterlist handling helpers. * * This source code is licensed under the GNU General Public License, * Version 2. See the file COPYING for more details. */ |
8bc3bcc93 lib: reduce the u... |
9 |
#include <linux/export.h> |
5a0e3ad6a include cleanup: ... |
10 |
#include <linux/slab.h> |
0db9299f4 SG: Move function... |
11 |
#include <linux/scatterlist.h> |
b1adaf65b [SCSI] block: add... |
12 |
#include <linux/highmem.h> |
b94de9bb7 lib/scatterlist: ... |
13 |
#include <linux/kmemleak.h> |
0db9299f4 SG: Move function... |
14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 |
/** * 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. * **/ 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; } EXPORT_SYMBOL(sg_next); /** |
2e4846102 scatterlist: add ... |
42 43 44 45 46 47 48 49 50 51 |
* sg_nents - return total count of entries in scatterlist * @sg: The scatterlist * * Description: * Allows to know how many entries are in sg, taking into acount * chaining as well * **/ int sg_nents(struct scatterlist *sg) { |
232f1b510 scatterlist: refa... |
52 53 |
int nents; for (nents = 0; sg; sg = sg_next(sg)) |
2e4846102 scatterlist: add ... |
54 |
nents++; |
2e4846102 scatterlist: add ... |
55 56 57 58 59 60 |
return nents; } EXPORT_SYMBOL(sg_nents); /** |
0db9299f4 SG: Move function... |
61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 |
* 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) scans 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@. * **/ 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; } EXPORT_SYMBOL(sg_last); /** * 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. * **/ 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]); } EXPORT_SYMBOL(sg_init_table); /** * sg_init_one - Initialize a single entry sg list * @sg: SG entry * @buf: Virtual address for IO * @buflen: IO length * **/ void sg_init_one(struct scatterlist *sg, const void *buf, unsigned int buflen) { sg_init_table(sg, 1); sg_set_buf(sg, buf, buflen); } EXPORT_SYMBOL(sg_init_one); /* * The default behaviour of sg_alloc_table() is to use these kmalloc/kfree * helpers. */ static struct scatterlist *sg_kmalloc(unsigned int nents, gfp_t gfp_mask) { |
b94de9bb7 lib/scatterlist: ... |
138 139 140 141 142 143 144 145 146 147 148 149 150 151 |
if (nents == SG_MAX_SINGLE_ALLOC) { /* * Kmemleak doesn't track page allocations as they are not * commonly used (in a raw form) for kernel data structures. * As we chain together a list of pages and then a normal * kmalloc (tracked by kmemleak), in order to for that last * allocation not to become decoupled (and thus a * false-positive) we need to inform kmemleak of all the * intermediate allocations. */ void *ptr = (void *) __get_free_page(gfp_mask); kmemleak_alloc(ptr, PAGE_SIZE, 1, gfp_mask); return ptr; } else |
0db9299f4 SG: Move function... |
152 153 154 155 156 |
return kmalloc(nents * sizeof(struct scatterlist), gfp_mask); } static void sg_kfree(struct scatterlist *sg, unsigned int nents) { |
b94de9bb7 lib/scatterlist: ... |
157 158 |
if (nents == SG_MAX_SINGLE_ALLOC) { kmemleak_free(sg); |
0db9299f4 SG: Move function... |
159 |
free_page((unsigned long) sg); |
b94de9bb7 lib/scatterlist: ... |
160 |
} else |
0db9299f4 SG: Move function... |
161 162 163 164 165 166 |
kfree(sg); } /** * __sg_free_table - Free a previously mapped sg table * @table: The sg table header to use |
7cedb1f17 SG: work with the... |
167 |
* @max_ents: The maximum number of entries per single scatterlist |
0db9299f4 SG: Move function... |
168 169 170 |
* @free_fn: Free function * * Description: |
7cedb1f17 SG: work with the... |
171 172 173 |
* 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(). |
0db9299f4 SG: Move function... |
174 175 |
* **/ |
7cedb1f17 SG: work with the... |
176 177 |
void __sg_free_table(struct sg_table *table, unsigned int max_ents, sg_free_fn *free_fn) |
0db9299f4 SG: Move function... |
178 179 180 181 182 183 184 185 186 187 188 189 |
{ 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; /* |
7cedb1f17 SG: work with the... |
190 |
* If we have more than max_ents segments left, |
0db9299f4 SG: Move function... |
191 192 193 194 |
* 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. */ |
7cedb1f17 SG: work with the... |
195 196 197 |
if (alloc_size > max_ents) { next = sg_chain_ptr(&sgl[max_ents - 1]); alloc_size = max_ents; |
0db9299f4 SG: Move function... |
198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 |
sg_size = alloc_size - 1; } else { sg_size = alloc_size; next = NULL; } table->orig_nents -= sg_size; free_fn(sgl, alloc_size); sgl = next; } table->sgl = NULL; } EXPORT_SYMBOL(__sg_free_table); /** * sg_free_table - Free a previously allocated sg table * @table: The mapped sg table header * **/ void sg_free_table(struct sg_table *table) { |
7cedb1f17 SG: work with the... |
220 |
__sg_free_table(table, SG_MAX_SINGLE_ALLOC, sg_kfree); |
0db9299f4 SG: Move function... |
221 222 223 224 225 226 227 |
} EXPORT_SYMBOL(sg_free_table); /** * __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 |
7cedb1f17 SG: work with the... |
228 |
* @max_ents: The maximum number of entries the allocator returns per call |
0db9299f4 SG: Move function... |
229 230 231 |
* @gfp_mask: GFP allocation mask * @alloc_fn: Allocator to use * |
7cedb1f17 SG: work with the... |
232 233 234 235 236 237 |
* 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. * |
0db9299f4 SG: Move function... |
238 239 240 241 242 |
* Notes: * If this function returns non-0 (eg failure), the caller must call * __sg_free_table() to cleanup any leftover allocations. * **/ |
7cedb1f17 SG: work with the... |
243 244 |
int __sg_alloc_table(struct sg_table *table, unsigned int nents, unsigned int max_ents, gfp_t gfp_mask, |
0db9299f4 SG: Move function... |
245 246 247 248 249 250 |
sg_alloc_fn *alloc_fn) { struct scatterlist *sg, *prv; unsigned int left; #ifndef ARCH_HAS_SG_CHAIN |
6fd59a83b scatterlist: don'... |
251 252 |
if (WARN_ON_ONCE(nents > max_ents)) return -EINVAL; |
0db9299f4 SG: Move function... |
253 254 255 256 257 258 259 260 |
#endif memset(table, 0, sizeof(*table)); left = nents; prv = NULL; do { unsigned int sg_size, alloc_size = left; |
7cedb1f17 SG: work with the... |
261 262 |
if (alloc_size > max_ents) { alloc_size = max_ents; |
0db9299f4 SG: Move function... |
263 264 265 266 267 268 269 |
sg_size = alloc_size - 1; } else sg_size = alloc_size; left -= sg_size; sg = alloc_fn(alloc_size, gfp_mask); |
edce6820a scatterlist: prev... |
270 271 272 273 274 275 276 277 278 279 280 281 |
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; } |
0db9299f4 SG: Move function... |
282 283 284 285 286 287 288 289 290 |
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) |
7cedb1f17 SG: work with the... |
291 |
sg_chain(prv, max_ents, sg); |
0db9299f4 SG: Move function... |
292 293 294 295 296 297 298 299 |
else table->sgl = sg; /* * If no more entries after this one, mark the end */ if (!left) sg_mark_end(&sg[sg_size - 1]); |
0db9299f4 SG: Move function... |
300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 |
prv = sg; } while (left); return 0; } EXPORT_SYMBOL(__sg_alloc_table); /** * 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. * **/ int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) { int ret; |
7cedb1f17 SG: work with the... |
321 322 |
ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC, gfp_mask, sg_kmalloc); |
0db9299f4 SG: Move function... |
323 |
if (unlikely(ret)) |
7cedb1f17 SG: work with the... |
324 |
__sg_free_table(table, SG_MAX_SINGLE_ALLOC, sg_kfree); |
0db9299f4 SG: Move function... |
325 326 327 328 |
return ret; } EXPORT_SYMBOL(sg_alloc_table); |
b1adaf65b [SCSI] block: add... |
329 330 |
/** |
efc42bc98 scatterlist: add ... |
331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 |
* 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 */ int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, unsigned int n_pages, unsigned long offset, unsigned long size, gfp_t gfp_mask) { unsigned int chunks; unsigned int i; unsigned int cur_page; int ret; struct scatterlist *s; /* compute number of contiguous chunks */ chunks = 1; for (i = 1; i < n_pages; ++i) if (page_to_pfn(pages[i]) != page_to_pfn(pages[i - 1]) + 1) ++chunks; ret = sg_alloc_table(sgt, chunks, gfp_mask); if (unlikely(ret)) return ret; /* merging chunks and putting them into the scatterlist */ cur_page = 0; for_each_sg(sgt->sgl, s, sgt->orig_nents, i) { unsigned long chunk_size; unsigned int j; /* look for the end of the current chunk */ for (j = cur_page + 1; j < n_pages; ++j) if (page_to_pfn(pages[j]) != page_to_pfn(pages[j - 1]) + 1) break; chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset; sg_set_page(s, pages[cur_page], min(size, chunk_size), offset); size -= chunk_size; offset = 0; cur_page = j; } return 0; } EXPORT_SYMBOL(sg_alloc_table_from_pages); |
a321e91b6 lib/scatterlist: ... |
393 394 395 396 397 398 |
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; |
a321e91b6 lib/scatterlist: ... |
399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 |
piter->sg = sglist; piter->sg_pgoffset = pgoffset; } EXPORT_SYMBOL(__sg_page_iter_start); static int sg_page_count(struct scatterlist *sg) { return PAGE_ALIGN(sg->offset + sg->length) >> PAGE_SHIFT; } bool __sg_page_iter_next(struct sg_page_iter *piter) { if (!piter->__nents || !piter->sg) 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 || !piter->sg) return false; } |
a321e91b6 lib/scatterlist: ... |
423 424 425 426 |
return true; } EXPORT_SYMBOL(__sg_page_iter_next); |
efc42bc98 scatterlist: add ... |
427 |
/** |
137d3edb4 sg: reimplement s... |
428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 |
* sg_miter_start - start mapping iteration over a sg list * @miter: sg mapping iter to be started * @sgl: sg list to iterate over * @nents: number of sg entries * * Description: * Starts mapping iterator @miter. * * Context: * Don't care. */ void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, unsigned int nents, unsigned int flags) { memset(miter, 0, sizeof(struct sg_mapping_iter)); |
4225fc855 lib/scatterlist: ... |
443 |
__sg_page_iter_start(&miter->piter, sgl, nents, 0); |
6de7e356f lib/scatterlist: ... |
444 |
WARN_ON(!(flags & (SG_MITER_TO_SG | SG_MITER_FROM_SG))); |
137d3edb4 sg: reimplement s... |
445 446 447 448 449 450 451 452 453 |
miter->__flags = flags; } EXPORT_SYMBOL(sg_miter_start); /** * sg_miter_next - proceed mapping iterator to the next mapping * @miter: sg mapping iter to proceed * * Description: |
8290e2d2d scatterlist: atom... |
454 455 456 |
* Proceeds @miter to the next mapping. @miter should have been started * using sg_miter_start(). On successful return, @miter->page, * @miter->addr and @miter->length point to the current mapping. |
137d3edb4 sg: reimplement s... |
457 458 |
* * Context: |
8290e2d2d scatterlist: atom... |
459 460 |
* Preemption disabled if SG_MITER_ATOMIC. Preemption must stay disabled * till @miter is stopped. May sleep if !SG_MITER_ATOMIC. |
137d3edb4 sg: reimplement s... |
461 462 463 464 465 466 467 |
* * Returns: * true if @miter contains the next mapping. false if end of sg * list is reached. */ bool sg_miter_next(struct sg_mapping_iter *miter) { |
137d3edb4 sg: reimplement s... |
468 |
sg_miter_stop(miter); |
4225fc855 lib/scatterlist: ... |
469 470 471 472 473 474 475 476 477 |
/* * Get to the next page if necessary. * __remaining, __offset is adjusted by sg_miter_stop */ if (!miter->__remaining) { struct scatterlist *sg; unsigned long pgoffset; if (!__sg_page_iter_next(&miter->piter)) |
23c560a99 scatterlist: make... |
478 |
return false; |
137d3edb4 sg: reimplement s... |
479 |
|
4225fc855 lib/scatterlist: ... |
480 481 |
sg = miter->piter.sg; pgoffset = miter->piter.sg_pgoffset; |
137d3edb4 sg: reimplement s... |
482 |
|
4225fc855 lib/scatterlist: ... |
483 484 485 486 487 488 |
miter->__offset = pgoffset ? 0 : sg->offset; miter->__remaining = sg->offset + sg->length - (pgoffset << PAGE_SHIFT) - miter->__offset; miter->__remaining = min_t(unsigned long, miter->__remaining, PAGE_SIZE - miter->__offset); } |
2db76d7c3 lib/scatterlist: ... |
489 |
miter->page = sg_page_iter_page(&miter->piter); |
4225fc855 lib/scatterlist: ... |
490 |
miter->consumed = miter->length = miter->__remaining; |
137d3edb4 sg: reimplement s... |
491 492 |
if (miter->__flags & SG_MITER_ATOMIC) |
4225fc855 lib/scatterlist: ... |
493 |
miter->addr = kmap_atomic(miter->page) + miter->__offset; |
137d3edb4 sg: reimplement s... |
494 |
else |
4225fc855 lib/scatterlist: ... |
495 |
miter->addr = kmap(miter->page) + miter->__offset; |
137d3edb4 sg: reimplement s... |
496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 |
return true; } EXPORT_SYMBOL(sg_miter_next); /** * sg_miter_stop - stop mapping iteration * @miter: sg mapping iter to be stopped * * Description: * Stops mapping iterator @miter. @miter should have been started * started using sg_miter_start(). A stopped iteration can be * resumed by calling sg_miter_next() on it. This is useful when * resources (kmap) need to be released during iteration. * * Context: |
8290e2d2d scatterlist: atom... |
512 513 |
* Preemption disabled if the SG_MITER_ATOMIC is set. Don't care * otherwise. |
137d3edb4 sg: reimplement s... |
514 515 516 517 518 519 520 521 |
*/ void sg_miter_stop(struct sg_mapping_iter *miter) { WARN_ON(miter->consumed > miter->length); /* drop resources from the last iteration */ if (miter->addr) { miter->__offset += miter->consumed; |
4225fc855 lib/scatterlist: ... |
522 |
miter->__remaining -= miter->consumed; |
137d3edb4 sg: reimplement s... |
523 |
|
e14594cd6 lib/scatterlist.c... |
524 525 |
if ((miter->__flags & SG_MITER_TO_SG) && !PageSlab(miter->page)) |
6de7e356f lib/scatterlist: ... |
526 |
flush_kernel_dcache_page(miter->page); |
137d3edb4 sg: reimplement s... |
527 |
if (miter->__flags & SG_MITER_ATOMIC) { |
8290e2d2d scatterlist: atom... |
528 |
WARN_ON_ONCE(preemptible()); |
c3eede8e0 lib: remove the s... |
529 |
kunmap_atomic(miter->addr); |
137d3edb4 sg: reimplement s... |
530 |
} else |
f652c521e lib/scatterlist.c... |
531 |
kunmap(miter->page); |
137d3edb4 sg: reimplement s... |
532 533 534 535 536 537 538 539 540 541 |
miter->page = NULL; miter->addr = NULL; miter->length = 0; miter->consumed = 0; } } EXPORT_SYMBOL(sg_miter_stop); /** |
b1adaf65b [SCSI] block: add... |
542 543 544 545 546 547 548 549 550 551 552 553 554 555 |
* sg_copy_buffer - Copy data between a linear buffer and an SG list * @sgl: The SG list * @nents: Number of SG entries * @buf: Where to copy from * @buflen: The number of bytes to copy * @to_buffer: transfer direction (non zero == from an sg list to a * buffer, 0 == from a buffer to an sg list * * Returns the number of copied bytes. * **/ static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, size_t buflen, int to_buffer) { |
137d3edb4 sg: reimplement s... |
556 557 |
unsigned int offset = 0; struct sg_mapping_iter miter; |
50bed2e28 sg: disable inter... |
558 |
unsigned long flags; |
6de7e356f lib/scatterlist: ... |
559 560 561 562 563 564 |
unsigned int sg_flags = SG_MITER_ATOMIC; if (to_buffer) sg_flags |= SG_MITER_FROM_SG; else sg_flags |= SG_MITER_TO_SG; |
137d3edb4 sg: reimplement s... |
565 |
|
6de7e356f lib/scatterlist: ... |
566 |
sg_miter_start(&miter, sgl, nents, sg_flags); |
137d3edb4 sg: reimplement s... |
567 |
|
50bed2e28 sg: disable inter... |
568 |
local_irq_save(flags); |
137d3edb4 sg: reimplement s... |
569 570 571 572 573 574 575 |
while (sg_miter_next(&miter) && offset < buflen) { unsigned int len; len = min(miter.length, buflen - offset); if (to_buffer) memcpy(buf + offset, miter.addr, len); |
6de7e356f lib/scatterlist: ... |
576 |
else |
137d3edb4 sg: reimplement s... |
577 |
memcpy(miter.addr, buf + offset, len); |
b1adaf65b [SCSI] block: add... |
578 |
|
137d3edb4 sg: reimplement s... |
579 |
offset += len; |
b1adaf65b [SCSI] block: add... |
580 |
} |
137d3edb4 sg: reimplement s... |
581 |
sg_miter_stop(&miter); |
50bed2e28 sg: disable inter... |
582 |
local_irq_restore(flags); |
137d3edb4 sg: reimplement s... |
583 |
return offset; |
b1adaf65b [SCSI] block: add... |
584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 |
} /** * sg_copy_from_buffer - Copy from a linear buffer to an SG list * @sgl: The SG list * @nents: Number of SG entries * @buf: Where to copy from * @buflen: The number of bytes to copy * * Returns the number of copied bytes. * **/ size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, size_t buflen) { return sg_copy_buffer(sgl, nents, buf, buflen, 0); } EXPORT_SYMBOL(sg_copy_from_buffer); /** * sg_copy_to_buffer - Copy from an SG list to a linear buffer * @sgl: The SG list * @nents: Number of SG entries * @buf: Where to copy to * @buflen: The number of bytes to copy * * Returns the number of copied bytes. * **/ size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, size_t buflen) { return sg_copy_buffer(sgl, nents, buf, buflen, 1); } EXPORT_SYMBOL(sg_copy_to_buffer); |