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40b0b3f8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
0db9299f JA |
2 | /* |
3 | * Copyright (C) 2007 Jens Axboe <jens.axboe@oracle.com> | |
4 | * | |
5 | * Scatterlist handling helpers. | |
0db9299f | 6 | */ |
8bc3bcc9 | 7 | #include <linux/export.h> |
5a0e3ad6 | 8 | #include <linux/slab.h> |
0db9299f | 9 | #include <linux/scatterlist.h> |
b1adaf65 | 10 | #include <linux/highmem.h> |
b94de9bb | 11 | #include <linux/kmemleak.h> |
0db9299f JA |
12 | |
13 | /** | |
14 | * sg_next - return the next scatterlist entry in a list | |
15 | * @sg: The current sg entry | |
16 | * | |
17 | * Description: | |
18 | * Usually the next entry will be @sg@ + 1, but if this sg element is part | |
19 | * of a chained scatterlist, it could jump to the start of a new | |
20 | * scatterlist array. | |
21 | * | |
22 | **/ | |
23 | struct scatterlist *sg_next(struct scatterlist *sg) | |
24 | { | |
0db9299f JA |
25 | if (sg_is_last(sg)) |
26 | return NULL; | |
27 | ||
28 | sg++; | |
29 | if (unlikely(sg_is_chain(sg))) | |
30 | sg = sg_chain_ptr(sg); | |
31 | ||
32 | return sg; | |
33 | } | |
34 | EXPORT_SYMBOL(sg_next); | |
35 | ||
2e484610 ML |
36 | /** |
37 | * sg_nents - return total count of entries in scatterlist | |
38 | * @sg: The scatterlist | |
39 | * | |
40 | * Description: | |
41 | * Allows to know how many entries are in sg, taking into acount | |
42 | * chaining as well | |
43 | * | |
44 | **/ | |
45 | int sg_nents(struct scatterlist *sg) | |
46 | { | |
232f1b51 ML |
47 | int nents; |
48 | for (nents = 0; sg; sg = sg_next(sg)) | |
2e484610 | 49 | nents++; |
2e484610 ML |
50 | return nents; |
51 | } | |
52 | EXPORT_SYMBOL(sg_nents); | |
53 | ||
cfaed10d TL |
54 | /** |
55 | * sg_nents_for_len - return total count of entries in scatterlist | |
56 | * needed to satisfy the supplied length | |
57 | * @sg: The scatterlist | |
58 | * @len: The total required length | |
59 | * | |
60 | * Description: | |
61 | * Determines the number of entries in sg that are required to meet | |
62 | * the supplied length, taking into acount chaining as well | |
63 | * | |
64 | * Returns: | |
65 | * the number of sg entries needed, negative error on failure | |
66 | * | |
67 | **/ | |
68 | int sg_nents_for_len(struct scatterlist *sg, u64 len) | |
69 | { | |
70 | int nents; | |
71 | u64 total; | |
72 | ||
73 | if (!len) | |
74 | return 0; | |
75 | ||
76 | for (nents = 0, total = 0; sg; sg = sg_next(sg)) { | |
77 | nents++; | |
78 | total += sg->length; | |
79 | if (total >= len) | |
80 | return nents; | |
81 | } | |
82 | ||
83 | return -EINVAL; | |
84 | } | |
85 | EXPORT_SYMBOL(sg_nents_for_len); | |
2e484610 | 86 | |
0db9299f JA |
87 | /** |
88 | * sg_last - return the last scatterlist entry in a list | |
89 | * @sgl: First entry in the scatterlist | |
90 | * @nents: Number of entries in the scatterlist | |
91 | * | |
92 | * Description: | |
93 | * Should only be used casually, it (currently) scans the entire list | |
94 | * to get the last entry. | |
95 | * | |
96 | * Note that the @sgl@ pointer passed in need not be the first one, | |
97 | * the important bit is that @nents@ denotes the number of entries that | |
98 | * exist from @sgl@. | |
99 | * | |
100 | **/ | |
101 | struct scatterlist *sg_last(struct scatterlist *sgl, unsigned int nents) | |
102 | { | |
0db9299f JA |
103 | struct scatterlist *sg, *ret = NULL; |
104 | unsigned int i; | |
105 | ||
106 | for_each_sg(sgl, sg, nents, i) | |
107 | ret = sg; | |
108 | ||
0db9299f | 109 | BUG_ON(!sg_is_last(ret)); |
0db9299f JA |
110 | return ret; |
111 | } | |
112 | EXPORT_SYMBOL(sg_last); | |
113 | ||
114 | /** | |
115 | * sg_init_table - Initialize SG table | |
116 | * @sgl: The SG table | |
117 | * @nents: Number of entries in table | |
118 | * | |
119 | * Notes: | |
120 | * If this is part of a chained sg table, sg_mark_end() should be | |
121 | * used only on the last table part. | |
122 | * | |
123 | **/ | |
124 | void sg_init_table(struct scatterlist *sgl, unsigned int nents) | |
125 | { | |
126 | memset(sgl, 0, sizeof(*sgl) * nents); | |
f3851786 | 127 | sg_init_marker(sgl, nents); |
0db9299f JA |
128 | } |
129 | EXPORT_SYMBOL(sg_init_table); | |
130 | ||
131 | /** | |
132 | * sg_init_one - Initialize a single entry sg list | |
133 | * @sg: SG entry | |
134 | * @buf: Virtual address for IO | |
135 | * @buflen: IO length | |
136 | * | |
137 | **/ | |
138 | void sg_init_one(struct scatterlist *sg, const void *buf, unsigned int buflen) | |
139 | { | |
140 | sg_init_table(sg, 1); | |
141 | sg_set_buf(sg, buf, buflen); | |
142 | } | |
143 | EXPORT_SYMBOL(sg_init_one); | |
144 | ||
145 | /* | |
146 | * The default behaviour of sg_alloc_table() is to use these kmalloc/kfree | |
147 | * helpers. | |
148 | */ | |
149 | static struct scatterlist *sg_kmalloc(unsigned int nents, gfp_t gfp_mask) | |
150 | { | |
b94de9bb CW |
151 | if (nents == SG_MAX_SINGLE_ALLOC) { |
152 | /* | |
153 | * Kmemleak doesn't track page allocations as they are not | |
154 | * commonly used (in a raw form) for kernel data structures. | |
155 | * As we chain together a list of pages and then a normal | |
156 | * kmalloc (tracked by kmemleak), in order to for that last | |
157 | * allocation not to become decoupled (and thus a | |
158 | * false-positive) we need to inform kmemleak of all the | |
159 | * intermediate allocations. | |
160 | */ | |
161 | void *ptr = (void *) __get_free_page(gfp_mask); | |
162 | kmemleak_alloc(ptr, PAGE_SIZE, 1, gfp_mask); | |
163 | return ptr; | |
164 | } else | |
6da2ec56 KC |
165 | return kmalloc_array(nents, sizeof(struct scatterlist), |
166 | gfp_mask); | |
0db9299f JA |
167 | } |
168 | ||
169 | static void sg_kfree(struct scatterlist *sg, unsigned int nents) | |
170 | { | |
b94de9bb CW |
171 | if (nents == SG_MAX_SINGLE_ALLOC) { |
172 | kmemleak_free(sg); | |
0db9299f | 173 | free_page((unsigned long) sg); |
b94de9bb | 174 | } else |
0db9299f JA |
175 | kfree(sg); |
176 | } | |
177 | ||
178 | /** | |
179 | * __sg_free_table - Free a previously mapped sg table | |
180 | * @table: The sg table header to use | |
7cedb1f1 | 181 | * @max_ents: The maximum number of entries per single scatterlist |
4635873c ML |
182 | * @nents_first_chunk: Number of entries int the (preallocated) first |
183 | * scatterlist chunk, 0 means no such preallocated first chunk | |
0db9299f JA |
184 | * @free_fn: Free function |
185 | * | |
186 | * Description: | |
7cedb1f1 JB |
187 | * Free an sg table previously allocated and setup with |
188 | * __sg_alloc_table(). The @max_ents value must be identical to | |
189 | * that previously used with __sg_alloc_table(). | |
0db9299f JA |
190 | * |
191 | **/ | |
7cedb1f1 | 192 | void __sg_free_table(struct sg_table *table, unsigned int max_ents, |
4635873c | 193 | unsigned int nents_first_chunk, sg_free_fn *free_fn) |
0db9299f JA |
194 | { |
195 | struct scatterlist *sgl, *next; | |
4635873c | 196 | unsigned curr_max_ents = nents_first_chunk ?: max_ents; |
0db9299f JA |
197 | |
198 | if (unlikely(!table->sgl)) | |
199 | return; | |
200 | ||
201 | sgl = table->sgl; | |
202 | while (table->orig_nents) { | |
203 | unsigned int alloc_size = table->orig_nents; | |
204 | unsigned int sg_size; | |
205 | ||
206 | /* | |
7cedb1f1 | 207 | * If we have more than max_ents segments left, |
0db9299f JA |
208 | * then assign 'next' to the sg table after the current one. |
209 | * sg_size is then one less than alloc size, since the last | |
210 | * element is the chain pointer. | |
211 | */ | |
4635873c ML |
212 | if (alloc_size > curr_max_ents) { |
213 | next = sg_chain_ptr(&sgl[curr_max_ents - 1]); | |
214 | alloc_size = curr_max_ents; | |
0db9299f JA |
215 | sg_size = alloc_size - 1; |
216 | } else { | |
217 | sg_size = alloc_size; | |
218 | next = NULL; | |
219 | } | |
220 | ||
221 | table->orig_nents -= sg_size; | |
4635873c ML |
222 | if (nents_first_chunk) |
223 | nents_first_chunk = 0; | |
c21e59d8 TB |
224 | else |
225 | free_fn(sgl, alloc_size); | |
0db9299f | 226 | sgl = next; |
4635873c | 227 | curr_max_ents = max_ents; |
0db9299f JA |
228 | } |
229 | ||
230 | table->sgl = NULL; | |
231 | } | |
232 | EXPORT_SYMBOL(__sg_free_table); | |
233 | ||
234 | /** | |
235 | * sg_free_table - Free a previously allocated sg table | |
236 | * @table: The mapped sg table header | |
237 | * | |
238 | **/ | |
239 | void sg_free_table(struct sg_table *table) | |
240 | { | |
c53c6d6a | 241 | __sg_free_table(table, SG_MAX_SINGLE_ALLOC, false, sg_kfree); |
0db9299f JA |
242 | } |
243 | EXPORT_SYMBOL(sg_free_table); | |
244 | ||
245 | /** | |
246 | * __sg_alloc_table - Allocate and initialize an sg table with given allocator | |
247 | * @table: The sg table header to use | |
248 | * @nents: Number of entries in sg list | |
7cedb1f1 | 249 | * @max_ents: The maximum number of entries the allocator returns per call |
4635873c ML |
250 | * @nents_first_chunk: Number of entries int the (preallocated) first |
251 | * scatterlist chunk, 0 means no such preallocated chunk provided by user | |
0db9299f JA |
252 | * @gfp_mask: GFP allocation mask |
253 | * @alloc_fn: Allocator to use | |
254 | * | |
7cedb1f1 JB |
255 | * Description: |
256 | * This function returns a @table @nents long. The allocator is | |
257 | * defined to return scatterlist chunks of maximum size @max_ents. | |
258 | * Thus if @nents is bigger than @max_ents, the scatterlists will be | |
259 | * chained in units of @max_ents. | |
260 | * | |
0db9299f JA |
261 | * Notes: |
262 | * If this function returns non-0 (eg failure), the caller must call | |
263 | * __sg_free_table() to cleanup any leftover allocations. | |
264 | * | |
265 | **/ | |
7cedb1f1 | 266 | int __sg_alloc_table(struct sg_table *table, unsigned int nents, |
c53c6d6a | 267 | unsigned int max_ents, struct scatterlist *first_chunk, |
4635873c ML |
268 | unsigned int nents_first_chunk, gfp_t gfp_mask, |
269 | sg_alloc_fn *alloc_fn) | |
0db9299f JA |
270 | { |
271 | struct scatterlist *sg, *prv; | |
272 | unsigned int left; | |
4635873c ML |
273 | unsigned curr_max_ents = nents_first_chunk ?: max_ents; |
274 | unsigned prv_max_ents; | |
0db9299f | 275 | |
27daabd9 DC |
276 | memset(table, 0, sizeof(*table)); |
277 | ||
278 | if (nents == 0) | |
279 | return -EINVAL; | |
7c703e54 | 280 | #ifdef CONFIG_ARCH_NO_SG_CHAIN |
6fd59a83 NB |
281 | if (WARN_ON_ONCE(nents > max_ents)) |
282 | return -EINVAL; | |
0db9299f JA |
283 | #endif |
284 | ||
0db9299f JA |
285 | left = nents; |
286 | prv = NULL; | |
287 | do { | |
288 | unsigned int sg_size, alloc_size = left; | |
289 | ||
4635873c ML |
290 | if (alloc_size > curr_max_ents) { |
291 | alloc_size = curr_max_ents; | |
0db9299f JA |
292 | sg_size = alloc_size - 1; |
293 | } else | |
294 | sg_size = alloc_size; | |
295 | ||
296 | left -= sg_size; | |
297 | ||
c53c6d6a CH |
298 | if (first_chunk) { |
299 | sg = first_chunk; | |
300 | first_chunk = NULL; | |
301 | } else { | |
302 | sg = alloc_fn(alloc_size, gfp_mask); | |
303 | } | |
edce6820 JC |
304 | if (unlikely(!sg)) { |
305 | /* | |
306 | * Adjust entry count to reflect that the last | |
307 | * entry of the previous table won't be used for | |
308 | * linkage. Without this, sg_kfree() may get | |
309 | * confused. | |
310 | */ | |
311 | if (prv) | |
312 | table->nents = ++table->orig_nents; | |
313 | ||
4e456fee | 314 | return -ENOMEM; |
edce6820 | 315 | } |
0db9299f JA |
316 | |
317 | sg_init_table(sg, alloc_size); | |
318 | table->nents = table->orig_nents += sg_size; | |
319 | ||
320 | /* | |
321 | * If this is the first mapping, assign the sg table header. | |
322 | * If this is not the first mapping, chain previous part. | |
323 | */ | |
324 | if (prv) | |
4635873c | 325 | sg_chain(prv, prv_max_ents, sg); |
0db9299f JA |
326 | else |
327 | table->sgl = sg; | |
328 | ||
329 | /* | |
330 | * If no more entries after this one, mark the end | |
331 | */ | |
332 | if (!left) | |
333 | sg_mark_end(&sg[sg_size - 1]); | |
334 | ||
0db9299f | 335 | prv = sg; |
4635873c ML |
336 | prv_max_ents = curr_max_ents; |
337 | curr_max_ents = max_ents; | |
0db9299f JA |
338 | } while (left); |
339 | ||
340 | return 0; | |
341 | } | |
342 | EXPORT_SYMBOL(__sg_alloc_table); | |
343 | ||
344 | /** | |
345 | * sg_alloc_table - Allocate and initialize an sg table | |
346 | * @table: The sg table header to use | |
347 | * @nents: Number of entries in sg list | |
348 | * @gfp_mask: GFP allocation mask | |
349 | * | |
350 | * Description: | |
351 | * Allocate and initialize an sg table. If @nents@ is larger than | |
352 | * SG_MAX_SINGLE_ALLOC a chained sg table will be setup. | |
353 | * | |
354 | **/ | |
355 | int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) | |
356 | { | |
357 | int ret; | |
358 | ||
7cedb1f1 | 359 | ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC, |
4635873c | 360 | NULL, 0, gfp_mask, sg_kmalloc); |
0db9299f | 361 | if (unlikely(ret)) |
4635873c | 362 | __sg_free_table(table, SG_MAX_SINGLE_ALLOC, 0, sg_kfree); |
0db9299f JA |
363 | |
364 | return ret; | |
365 | } | |
366 | EXPORT_SYMBOL(sg_alloc_table); | |
b1adaf65 | 367 | |
efc42bc9 | 368 | /** |
89d8589c TU |
369 | * __sg_alloc_table_from_pages - Allocate and initialize an sg table from |
370 | * an array of pages | |
371 | * @sgt: The sg table header to use | |
372 | * @pages: Pointer to an array of page pointers | |
373 | * @n_pages: Number of pages in the pages array | |
374 | * @offset: Offset from start of the first page to the start of a buffer | |
375 | * @size: Number of valid bytes in the buffer (after offset) | |
376 | * @max_segment: Maximum size of a scatterlist node in bytes (page aligned) | |
377 | * @gfp_mask: GFP allocation mask | |
efc42bc9 TS |
378 | * |
379 | * Description: | |
380 | * Allocate and initialize an sg table from a list of pages. Contiguous | |
89d8589c TU |
381 | * ranges of the pages are squashed into a single scatterlist node up to the |
382 | * maximum size specified in @max_segment. An user may provide an offset at a | |
383 | * start and a size of valid data in a buffer specified by the page array. | |
384 | * The returned sg table is released by sg_free_table. | |
efc42bc9 TS |
385 | * |
386 | * Returns: | |
387 | * 0 on success, negative error on failure | |
388 | */ | |
89d8589c TU |
389 | int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, |
390 | unsigned int n_pages, unsigned int offset, | |
391 | unsigned long size, unsigned int max_segment, | |
392 | gfp_t gfp_mask) | |
efc42bc9 | 393 | { |
c125906b | 394 | unsigned int chunks, cur_page, seg_len, i; |
efc42bc9 TS |
395 | int ret; |
396 | struct scatterlist *s; | |
397 | ||
89d8589c TU |
398 | if (WARN_ON(!max_segment || offset_in_page(max_segment))) |
399 | return -EINVAL; | |
400 | ||
efc42bc9 TS |
401 | /* compute number of contiguous chunks */ |
402 | chunks = 1; | |
c125906b TU |
403 | seg_len = 0; |
404 | for (i = 1; i < n_pages; i++) { | |
405 | seg_len += PAGE_SIZE; | |
406 | if (seg_len >= max_segment || | |
407 | page_to_pfn(pages[i]) != page_to_pfn(pages[i - 1]) + 1) { | |
408 | chunks++; | |
409 | seg_len = 0; | |
410 | } | |
411 | } | |
efc42bc9 TS |
412 | |
413 | ret = sg_alloc_table(sgt, chunks, gfp_mask); | |
414 | if (unlikely(ret)) | |
415 | return ret; | |
416 | ||
417 | /* merging chunks and putting them into the scatterlist */ | |
418 | cur_page = 0; | |
419 | for_each_sg(sgt->sgl, s, sgt->orig_nents, i) { | |
c125906b | 420 | unsigned int j, chunk_size; |
efc42bc9 TS |
421 | |
422 | /* look for the end of the current chunk */ | |
c125906b TU |
423 | seg_len = 0; |
424 | for (j = cur_page + 1; j < n_pages; j++) { | |
425 | seg_len += PAGE_SIZE; | |
426 | if (seg_len >= max_segment || | |
427 | page_to_pfn(pages[j]) != | |
efc42bc9 TS |
428 | page_to_pfn(pages[j - 1]) + 1) |
429 | break; | |
c125906b | 430 | } |
efc42bc9 TS |
431 | |
432 | chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset; | |
c125906b TU |
433 | sg_set_page(s, pages[cur_page], |
434 | min_t(unsigned long, size, chunk_size), offset); | |
efc42bc9 TS |
435 | size -= chunk_size; |
436 | offset = 0; | |
437 | cur_page = j; | |
438 | } | |
439 | ||
440 | return 0; | |
441 | } | |
89d8589c TU |
442 | EXPORT_SYMBOL(__sg_alloc_table_from_pages); |
443 | ||
444 | /** | |
445 | * sg_alloc_table_from_pages - Allocate and initialize an sg table from | |
446 | * an array of pages | |
447 | * @sgt: The sg table header to use | |
448 | * @pages: Pointer to an array of page pointers | |
449 | * @n_pages: Number of pages in the pages array | |
450 | * @offset: Offset from start of the first page to the start of a buffer | |
451 | * @size: Number of valid bytes in the buffer (after offset) | |
452 | * @gfp_mask: GFP allocation mask | |
453 | * | |
454 | * Description: | |
455 | * Allocate and initialize an sg table from a list of pages. Contiguous | |
456 | * ranges of the pages are squashed into a single scatterlist node. A user | |
457 | * may provide an offset at a start and a size of valid data in a buffer | |
458 | * specified by the page array. The returned sg table is released by | |
459 | * sg_free_table. | |
460 | * | |
461 | * Returns: | |
462 | * 0 on success, negative error on failure | |
463 | */ | |
464 | int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, | |
465 | unsigned int n_pages, unsigned int offset, | |
466 | unsigned long size, gfp_t gfp_mask) | |
467 | { | |
468 | return __sg_alloc_table_from_pages(sgt, pages, n_pages, offset, size, | |
469 | SCATTERLIST_MAX_SEGMENT, gfp_mask); | |
470 | } | |
efc42bc9 TS |
471 | EXPORT_SYMBOL(sg_alloc_table_from_pages); |
472 | ||
e80a0af4 BVA |
473 | #ifdef CONFIG_SGL_ALLOC |
474 | ||
475 | /** | |
476 | * sgl_alloc_order - allocate a scatterlist and its pages | |
477 | * @length: Length in bytes of the scatterlist. Must be at least one | |
478 | * @order: Second argument for alloc_pages() | |
479 | * @chainable: Whether or not to allocate an extra element in the scatterlist | |
480 | * for scatterlist chaining purposes | |
481 | * @gfp: Memory allocation flags | |
482 | * @nent_p: [out] Number of entries in the scatterlist that have pages | |
483 | * | |
484 | * Returns: A pointer to an initialized scatterlist or %NULL upon failure. | |
485 | */ | |
486 | struct scatterlist *sgl_alloc_order(unsigned long long length, | |
487 | unsigned int order, bool chainable, | |
488 | gfp_t gfp, unsigned int *nent_p) | |
489 | { | |
490 | struct scatterlist *sgl, *sg; | |
491 | struct page *page; | |
492 | unsigned int nent, nalloc; | |
493 | u32 elem_len; | |
494 | ||
495 | nent = round_up(length, PAGE_SIZE << order) >> (PAGE_SHIFT + order); | |
496 | /* Check for integer overflow */ | |
497 | if (length > (nent << (PAGE_SHIFT + order))) | |
498 | return NULL; | |
499 | nalloc = nent; | |
500 | if (chainable) { | |
501 | /* Check for integer overflow */ | |
502 | if (nalloc + 1 < nalloc) | |
503 | return NULL; | |
504 | nalloc++; | |
505 | } | |
506 | sgl = kmalloc_array(nalloc, sizeof(struct scatterlist), | |
507 | (gfp & ~GFP_DMA) | __GFP_ZERO); | |
508 | if (!sgl) | |
509 | return NULL; | |
510 | ||
8c7a8d1c | 511 | sg_init_table(sgl, nalloc); |
e80a0af4 BVA |
512 | sg = sgl; |
513 | while (length) { | |
514 | elem_len = min_t(u64, length, PAGE_SIZE << order); | |
515 | page = alloc_pages(gfp, order); | |
516 | if (!page) { | |
517 | sgl_free(sgl); | |
518 | return NULL; | |
519 | } | |
520 | ||
521 | sg_set_page(sg, page, elem_len, 0); | |
522 | length -= elem_len; | |
523 | sg = sg_next(sg); | |
524 | } | |
8c7a8d1c | 525 | WARN_ONCE(length, "length = %lld\n", length); |
e80a0af4 BVA |
526 | if (nent_p) |
527 | *nent_p = nent; | |
528 | return sgl; | |
529 | } | |
530 | EXPORT_SYMBOL(sgl_alloc_order); | |
531 | ||
532 | /** | |
533 | * sgl_alloc - allocate a scatterlist and its pages | |
534 | * @length: Length in bytes of the scatterlist | |
535 | * @gfp: Memory allocation flags | |
536 | * @nent_p: [out] Number of entries in the scatterlist | |
537 | * | |
538 | * Returns: A pointer to an initialized scatterlist or %NULL upon failure. | |
539 | */ | |
540 | struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp, | |
541 | unsigned int *nent_p) | |
542 | { | |
543 | return sgl_alloc_order(length, 0, false, gfp, nent_p); | |
544 | } | |
545 | EXPORT_SYMBOL(sgl_alloc); | |
546 | ||
547 | /** | |
8c7a8d1c | 548 | * sgl_free_n_order - free a scatterlist and its pages |
e80a0af4 | 549 | * @sgl: Scatterlist with one or more elements |
8c7a8d1c | 550 | * @nents: Maximum number of elements to free |
e80a0af4 | 551 | * @order: Second argument for __free_pages() |
8c7a8d1c BVA |
552 | * |
553 | * Notes: | |
554 | * - If several scatterlists have been chained and each chain element is | |
555 | * freed separately then it's essential to set nents correctly to avoid that a | |
556 | * page would get freed twice. | |
557 | * - All pages in a chained scatterlist can be freed at once by setting @nents | |
558 | * to a high number. | |
e80a0af4 | 559 | */ |
8c7a8d1c | 560 | void sgl_free_n_order(struct scatterlist *sgl, int nents, int order) |
e80a0af4 BVA |
561 | { |
562 | struct scatterlist *sg; | |
563 | struct page *page; | |
8c7a8d1c | 564 | int i; |
e80a0af4 | 565 | |
8c7a8d1c BVA |
566 | for_each_sg(sgl, sg, nents, i) { |
567 | if (!sg) | |
568 | break; | |
e80a0af4 BVA |
569 | page = sg_page(sg); |
570 | if (page) | |
571 | __free_pages(page, order); | |
572 | } | |
573 | kfree(sgl); | |
574 | } | |
8c7a8d1c BVA |
575 | EXPORT_SYMBOL(sgl_free_n_order); |
576 | ||
577 | /** | |
578 | * sgl_free_order - free a scatterlist and its pages | |
579 | * @sgl: Scatterlist with one or more elements | |
580 | * @order: Second argument for __free_pages() | |
581 | */ | |
582 | void sgl_free_order(struct scatterlist *sgl, int order) | |
583 | { | |
584 | sgl_free_n_order(sgl, INT_MAX, order); | |
585 | } | |
e80a0af4 BVA |
586 | EXPORT_SYMBOL(sgl_free_order); |
587 | ||
588 | /** | |
589 | * sgl_free - free a scatterlist and its pages | |
590 | * @sgl: Scatterlist with one or more elements | |
591 | */ | |
592 | void sgl_free(struct scatterlist *sgl) | |
593 | { | |
594 | sgl_free_order(sgl, 0); | |
595 | } | |
596 | EXPORT_SYMBOL(sgl_free); | |
597 | ||
598 | #endif /* CONFIG_SGL_ALLOC */ | |
599 | ||
a321e91b ID |
600 | void __sg_page_iter_start(struct sg_page_iter *piter, |
601 | struct scatterlist *sglist, unsigned int nents, | |
602 | unsigned long pgoffset) | |
603 | { | |
604 | piter->__pg_advance = 0; | |
605 | piter->__nents = nents; | |
606 | ||
a321e91b ID |
607 | piter->sg = sglist; |
608 | piter->sg_pgoffset = pgoffset; | |
609 | } | |
610 | EXPORT_SYMBOL(__sg_page_iter_start); | |
611 | ||
612 | static int sg_page_count(struct scatterlist *sg) | |
613 | { | |
614 | return PAGE_ALIGN(sg->offset + sg->length) >> PAGE_SHIFT; | |
615 | } | |
616 | ||
617 | bool __sg_page_iter_next(struct sg_page_iter *piter) | |
618 | { | |
619 | if (!piter->__nents || !piter->sg) | |
620 | return false; | |
621 | ||
622 | piter->sg_pgoffset += piter->__pg_advance; | |
623 | piter->__pg_advance = 1; | |
624 | ||
625 | while (piter->sg_pgoffset >= sg_page_count(piter->sg)) { | |
626 | piter->sg_pgoffset -= sg_page_count(piter->sg); | |
627 | piter->sg = sg_next(piter->sg); | |
628 | if (!--piter->__nents || !piter->sg) | |
629 | return false; | |
630 | } | |
a321e91b ID |
631 | |
632 | return true; | |
633 | } | |
634 | EXPORT_SYMBOL(__sg_page_iter_next); | |
635 | ||
d901b276 JG |
636 | static int sg_dma_page_count(struct scatterlist *sg) |
637 | { | |
638 | return PAGE_ALIGN(sg->offset + sg_dma_len(sg)) >> PAGE_SHIFT; | |
639 | } | |
640 | ||
641 | bool __sg_page_iter_dma_next(struct sg_dma_page_iter *dma_iter) | |
642 | { | |
643 | struct sg_page_iter *piter = &dma_iter->base; | |
644 | ||
645 | if (!piter->__nents || !piter->sg) | |
646 | return false; | |
647 | ||
648 | piter->sg_pgoffset += piter->__pg_advance; | |
649 | piter->__pg_advance = 1; | |
650 | ||
651 | while (piter->sg_pgoffset >= sg_dma_page_count(piter->sg)) { | |
652 | piter->sg_pgoffset -= sg_dma_page_count(piter->sg); | |
653 | piter->sg = sg_next(piter->sg); | |
654 | if (!--piter->__nents || !piter->sg) | |
655 | return false; | |
656 | } | |
657 | ||
658 | return true; | |
659 | } | |
660 | EXPORT_SYMBOL(__sg_page_iter_dma_next); | |
661 | ||
137d3edb TH |
662 | /** |
663 | * sg_miter_start - start mapping iteration over a sg list | |
664 | * @miter: sg mapping iter to be started | |
665 | * @sgl: sg list to iterate over | |
666 | * @nents: number of sg entries | |
667 | * | |
668 | * Description: | |
669 | * Starts mapping iterator @miter. | |
670 | * | |
671 | * Context: | |
672 | * Don't care. | |
673 | */ | |
674 | void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, | |
675 | unsigned int nents, unsigned int flags) | |
676 | { | |
677 | memset(miter, 0, sizeof(struct sg_mapping_iter)); | |
678 | ||
4225fc85 | 679 | __sg_page_iter_start(&miter->piter, sgl, nents, 0); |
6de7e356 | 680 | WARN_ON(!(flags & (SG_MITER_TO_SG | SG_MITER_FROM_SG))); |
137d3edb TH |
681 | miter->__flags = flags; |
682 | } | |
683 | EXPORT_SYMBOL(sg_miter_start); | |
684 | ||
11052004 AM |
685 | static bool sg_miter_get_next_page(struct sg_mapping_iter *miter) |
686 | { | |
687 | if (!miter->__remaining) { | |
688 | struct scatterlist *sg; | |
11052004 AM |
689 | |
690 | if (!__sg_page_iter_next(&miter->piter)) | |
691 | return false; | |
692 | ||
693 | sg = miter->piter.sg; | |
11052004 | 694 | |
aeb87246 CL |
695 | miter->__offset = miter->piter.sg_pgoffset ? 0 : sg->offset; |
696 | miter->piter.sg_pgoffset += miter->__offset >> PAGE_SHIFT; | |
697 | miter->__offset &= PAGE_SIZE - 1; | |
11052004 | 698 | miter->__remaining = sg->offset + sg->length - |
aeb87246 CL |
699 | (miter->piter.sg_pgoffset << PAGE_SHIFT) - |
700 | miter->__offset; | |
11052004 AM |
701 | miter->__remaining = min_t(unsigned long, miter->__remaining, |
702 | PAGE_SIZE - miter->__offset); | |
703 | } | |
704 | ||
705 | return true; | |
706 | } | |
707 | ||
df642cea AM |
708 | /** |
709 | * sg_miter_skip - reposition mapping iterator | |
710 | * @miter: sg mapping iter to be skipped | |
711 | * @offset: number of bytes to plus the current location | |
712 | * | |
713 | * Description: | |
714 | * Sets the offset of @miter to its current location plus @offset bytes. | |
715 | * If mapping iterator @miter has been proceeded by sg_miter_next(), this | |
716 | * stops @miter. | |
717 | * | |
718 | * Context: | |
719 | * Don't care if @miter is stopped, or not proceeded yet. | |
720 | * Otherwise, preemption disabled if the SG_MITER_ATOMIC is set. | |
721 | * | |
722 | * Returns: | |
723 | * true if @miter contains the valid mapping. false if end of sg | |
724 | * list is reached. | |
725 | */ | |
0d6077f8 | 726 | bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset) |
df642cea AM |
727 | { |
728 | sg_miter_stop(miter); | |
729 | ||
730 | while (offset) { | |
731 | off_t consumed; | |
732 | ||
733 | if (!sg_miter_get_next_page(miter)) | |
734 | return false; | |
735 | ||
736 | consumed = min_t(off_t, offset, miter->__remaining); | |
737 | miter->__offset += consumed; | |
738 | miter->__remaining -= consumed; | |
739 | offset -= consumed; | |
740 | } | |
741 | ||
742 | return true; | |
743 | } | |
0d6077f8 | 744 | EXPORT_SYMBOL(sg_miter_skip); |
df642cea | 745 | |
137d3edb TH |
746 | /** |
747 | * sg_miter_next - proceed mapping iterator to the next mapping | |
748 | * @miter: sg mapping iter to proceed | |
749 | * | |
750 | * Description: | |
8290e2d2 TH |
751 | * Proceeds @miter to the next mapping. @miter should have been started |
752 | * using sg_miter_start(). On successful return, @miter->page, | |
753 | * @miter->addr and @miter->length point to the current mapping. | |
137d3edb TH |
754 | * |
755 | * Context: | |
8290e2d2 TH |
756 | * Preemption disabled if SG_MITER_ATOMIC. Preemption must stay disabled |
757 | * till @miter is stopped. May sleep if !SG_MITER_ATOMIC. | |
137d3edb TH |
758 | * |
759 | * Returns: | |
760 | * true if @miter contains the next mapping. false if end of sg | |
761 | * list is reached. | |
762 | */ | |
763 | bool sg_miter_next(struct sg_mapping_iter *miter) | |
764 | { | |
137d3edb TH |
765 | sg_miter_stop(miter); |
766 | ||
4225fc85 ID |
767 | /* |
768 | * Get to the next page if necessary. | |
769 | * __remaining, __offset is adjusted by sg_miter_stop | |
770 | */ | |
11052004 AM |
771 | if (!sg_miter_get_next_page(miter)) |
772 | return false; | |
137d3edb | 773 | |
2db76d7c | 774 | miter->page = sg_page_iter_page(&miter->piter); |
4225fc85 | 775 | miter->consumed = miter->length = miter->__remaining; |
137d3edb TH |
776 | |
777 | if (miter->__flags & SG_MITER_ATOMIC) | |
4225fc85 | 778 | miter->addr = kmap_atomic(miter->page) + miter->__offset; |
137d3edb | 779 | else |
4225fc85 | 780 | miter->addr = kmap(miter->page) + miter->__offset; |
137d3edb TH |
781 | |
782 | return true; | |
783 | } | |
784 | EXPORT_SYMBOL(sg_miter_next); | |
785 | ||
786 | /** | |
787 | * sg_miter_stop - stop mapping iteration | |
788 | * @miter: sg mapping iter to be stopped | |
789 | * | |
790 | * Description: | |
791 | * Stops mapping iterator @miter. @miter should have been started | |
4ba6a2b2 MY |
792 | * using sg_miter_start(). A stopped iteration can be resumed by |
793 | * calling sg_miter_next() on it. This is useful when resources (kmap) | |
794 | * need to be released during iteration. | |
137d3edb TH |
795 | * |
796 | * Context: | |
8290e2d2 TH |
797 | * Preemption disabled if the SG_MITER_ATOMIC is set. Don't care |
798 | * otherwise. | |
137d3edb TH |
799 | */ |
800 | void sg_miter_stop(struct sg_mapping_iter *miter) | |
801 | { | |
802 | WARN_ON(miter->consumed > miter->length); | |
803 | ||
804 | /* drop resources from the last iteration */ | |
805 | if (miter->addr) { | |
806 | miter->__offset += miter->consumed; | |
4225fc85 | 807 | miter->__remaining -= miter->consumed; |
137d3edb | 808 | |
3d77b50c ML |
809 | if ((miter->__flags & SG_MITER_TO_SG) && |
810 | !PageSlab(miter->page)) | |
6de7e356 SAS |
811 | flush_kernel_dcache_page(miter->page); |
812 | ||
137d3edb | 813 | if (miter->__flags & SG_MITER_ATOMIC) { |
8290e2d2 | 814 | WARN_ON_ONCE(preemptible()); |
c3eede8e | 815 | kunmap_atomic(miter->addr); |
137d3edb | 816 | } else |
f652c521 | 817 | kunmap(miter->page); |
137d3edb TH |
818 | |
819 | miter->page = NULL; | |
820 | miter->addr = NULL; | |
821 | miter->length = 0; | |
822 | miter->consumed = 0; | |
823 | } | |
824 | } | |
825 | EXPORT_SYMBOL(sg_miter_stop); | |
826 | ||
b1adaf65 FT |
827 | /** |
828 | * sg_copy_buffer - Copy data between a linear buffer and an SG list | |
829 | * @sgl: The SG list | |
830 | * @nents: Number of SG entries | |
831 | * @buf: Where to copy from | |
832 | * @buflen: The number of bytes to copy | |
df642cea AM |
833 | * @skip: Number of bytes to skip before copying |
834 | * @to_buffer: transfer direction (true == from an sg list to a | |
6e853185 | 835 | * buffer, false == from a buffer to an sg list) |
b1adaf65 FT |
836 | * |
837 | * Returns the number of copied bytes. | |
838 | * | |
839 | **/ | |
386ecb12 DG |
840 | size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, |
841 | size_t buflen, off_t skip, bool to_buffer) | |
b1adaf65 | 842 | { |
137d3edb TH |
843 | unsigned int offset = 0; |
844 | struct sg_mapping_iter miter; | |
6de7e356 SAS |
845 | unsigned int sg_flags = SG_MITER_ATOMIC; |
846 | ||
847 | if (to_buffer) | |
848 | sg_flags |= SG_MITER_FROM_SG; | |
849 | else | |
850 | sg_flags |= SG_MITER_TO_SG; | |
137d3edb | 851 | |
6de7e356 | 852 | sg_miter_start(&miter, sgl, nents, sg_flags); |
137d3edb | 853 | |
df642cea AM |
854 | if (!sg_miter_skip(&miter, skip)) |
855 | return false; | |
856 | ||
1d5210ef | 857 | while ((offset < buflen) && sg_miter_next(&miter)) { |
137d3edb TH |
858 | unsigned int len; |
859 | ||
860 | len = min(miter.length, buflen - offset); | |
861 | ||
862 | if (to_buffer) | |
863 | memcpy(buf + offset, miter.addr, len); | |
6de7e356 | 864 | else |
137d3edb | 865 | memcpy(miter.addr, buf + offset, len); |
b1adaf65 | 866 | |
137d3edb | 867 | offset += len; |
b1adaf65 FT |
868 | } |
869 | ||
137d3edb TH |
870 | sg_miter_stop(&miter); |
871 | ||
872 | return offset; | |
b1adaf65 | 873 | } |
386ecb12 | 874 | EXPORT_SYMBOL(sg_copy_buffer); |
b1adaf65 FT |
875 | |
876 | /** | |
877 | * sg_copy_from_buffer - Copy from a linear buffer to an SG list | |
878 | * @sgl: The SG list | |
879 | * @nents: Number of SG entries | |
880 | * @buf: Where to copy from | |
881 | * @buflen: The number of bytes to copy | |
882 | * | |
883 | * Returns the number of copied bytes. | |
884 | * | |
885 | **/ | |
886 | size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, | |
2a1bf8f9 | 887 | const void *buf, size_t buflen) |
b1adaf65 | 888 | { |
2a1bf8f9 | 889 | return sg_copy_buffer(sgl, nents, (void *)buf, buflen, 0, false); |
b1adaf65 FT |
890 | } |
891 | EXPORT_SYMBOL(sg_copy_from_buffer); | |
892 | ||
893 | /** | |
894 | * sg_copy_to_buffer - Copy from an SG list to a linear buffer | |
895 | * @sgl: The SG list | |
896 | * @nents: Number of SG entries | |
897 | * @buf: Where to copy to | |
898 | * @buflen: The number of bytes to copy | |
899 | * | |
900 | * Returns the number of copied bytes. | |
901 | * | |
902 | **/ | |
903 | size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, | |
904 | void *buf, size_t buflen) | |
905 | { | |
df642cea | 906 | return sg_copy_buffer(sgl, nents, buf, buflen, 0, true); |
b1adaf65 FT |
907 | } |
908 | EXPORT_SYMBOL(sg_copy_to_buffer); | |
df642cea AM |
909 | |
910 | /** | |
911 | * sg_pcopy_from_buffer - Copy from a linear buffer to an SG list | |
912 | * @sgl: The SG list | |
913 | * @nents: Number of SG entries | |
914 | * @buf: Where to copy from | |
df642cea | 915 | * @buflen: The number of bytes to copy |
4dc7daf8 | 916 | * @skip: Number of bytes to skip before copying |
df642cea AM |
917 | * |
918 | * Returns the number of copied bytes. | |
919 | * | |
920 | **/ | |
921 | size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, | |
2a1bf8f9 | 922 | const void *buf, size_t buflen, off_t skip) |
df642cea | 923 | { |
2a1bf8f9 | 924 | return sg_copy_buffer(sgl, nents, (void *)buf, buflen, skip, false); |
df642cea AM |
925 | } |
926 | EXPORT_SYMBOL(sg_pcopy_from_buffer); | |
927 | ||
928 | /** | |
929 | * sg_pcopy_to_buffer - Copy from an SG list to a linear buffer | |
930 | * @sgl: The SG list | |
931 | * @nents: Number of SG entries | |
932 | * @buf: Where to copy to | |
df642cea | 933 | * @buflen: The number of bytes to copy |
4dc7daf8 | 934 | * @skip: Number of bytes to skip before copying |
df642cea AM |
935 | * |
936 | * Returns the number of copied bytes. | |
937 | * | |
938 | **/ | |
939 | size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, | |
940 | void *buf, size_t buflen, off_t skip) | |
941 | { | |
942 | return sg_copy_buffer(sgl, nents, buf, buflen, skip, true); | |
943 | } | |
944 | EXPORT_SYMBOL(sg_pcopy_to_buffer); | |
0945e569 JT |
945 | |
946 | /** | |
947 | * sg_zero_buffer - Zero-out a part of a SG list | |
948 | * @sgl: The SG list | |
949 | * @nents: Number of SG entries | |
950 | * @buflen: The number of bytes to zero out | |
951 | * @skip: Number of bytes to skip before zeroing | |
952 | * | |
953 | * Returns the number of bytes zeroed. | |
954 | **/ | |
955 | size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, | |
956 | size_t buflen, off_t skip) | |
957 | { | |
958 | unsigned int offset = 0; | |
959 | struct sg_mapping_iter miter; | |
960 | unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG; | |
961 | ||
962 | sg_miter_start(&miter, sgl, nents, sg_flags); | |
963 | ||
964 | if (!sg_miter_skip(&miter, skip)) | |
965 | return false; | |
966 | ||
967 | while (offset < buflen && sg_miter_next(&miter)) { | |
968 | unsigned int len; | |
969 | ||
970 | len = min(miter.length, buflen - offset); | |
971 | memset(miter.addr, 0, len); | |
972 | ||
973 | offset += len; | |
974 | } | |
975 | ||
976 | sg_miter_stop(&miter); | |
977 | return offset; | |
978 | } | |
979 | EXPORT_SYMBOL(sg_zero_buffer); |