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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> |
f5f82cd1 DH |
12 | #include <linux/bvec.h> |
13 | #include <linux/uio.h> | |
0db9299f JA |
14 | |
15 | /** | |
16 | * sg_next - return the next scatterlist entry in a list | |
17 | * @sg: The current sg entry | |
18 | * | |
19 | * Description: | |
20 | * Usually the next entry will be @sg@ + 1, but if this sg element is part | |
21 | * of a chained scatterlist, it could jump to the start of a new | |
22 | * scatterlist array. | |
23 | * | |
24 | **/ | |
25 | struct scatterlist *sg_next(struct scatterlist *sg) | |
26 | { | |
0db9299f JA |
27 | if (sg_is_last(sg)) |
28 | return NULL; | |
29 | ||
30 | sg++; | |
31 | if (unlikely(sg_is_chain(sg))) | |
32 | sg = sg_chain_ptr(sg); | |
33 | ||
34 | return sg; | |
35 | } | |
36 | EXPORT_SYMBOL(sg_next); | |
37 | ||
2e484610 ML |
38 | /** |
39 | * sg_nents - return total count of entries in scatterlist | |
40 | * @sg: The scatterlist | |
41 | * | |
42 | * Description: | |
9dbbc3b9 | 43 | * Allows to know how many entries are in sg, taking into account |
2e484610 ML |
44 | * chaining as well |
45 | * | |
46 | **/ | |
47 | int sg_nents(struct scatterlist *sg) | |
48 | { | |
232f1b51 ML |
49 | int nents; |
50 | for (nents = 0; sg; sg = sg_next(sg)) | |
2e484610 | 51 | nents++; |
2e484610 ML |
52 | return nents; |
53 | } | |
54 | EXPORT_SYMBOL(sg_nents); | |
55 | ||
cfaed10d TL |
56 | /** |
57 | * sg_nents_for_len - return total count of entries in scatterlist | |
58 | * needed to satisfy the supplied length | |
59 | * @sg: The scatterlist | |
60 | * @len: The total required length | |
61 | * | |
62 | * Description: | |
63 | * Determines the number of entries in sg that are required to meet | |
9dbbc3b9 | 64 | * the supplied length, taking into account chaining as well |
cfaed10d TL |
65 | * |
66 | * Returns: | |
67 | * the number of sg entries needed, negative error on failure | |
68 | * | |
69 | **/ | |
70 | int sg_nents_for_len(struct scatterlist *sg, u64 len) | |
71 | { | |
72 | int nents; | |
73 | u64 total; | |
74 | ||
75 | if (!len) | |
76 | return 0; | |
77 | ||
78 | for (nents = 0, total = 0; sg; sg = sg_next(sg)) { | |
79 | nents++; | |
80 | total += sg->length; | |
81 | if (total >= len) | |
82 | return nents; | |
83 | } | |
84 | ||
85 | return -EINVAL; | |
86 | } | |
87 | EXPORT_SYMBOL(sg_nents_for_len); | |
2e484610 | 88 | |
0db9299f JA |
89 | /** |
90 | * sg_last - return the last scatterlist entry in a list | |
91 | * @sgl: First entry in the scatterlist | |
92 | * @nents: Number of entries in the scatterlist | |
93 | * | |
94 | * Description: | |
95 | * Should only be used casually, it (currently) scans the entire list | |
96 | * to get the last entry. | |
97 | * | |
98 | * Note that the @sgl@ pointer passed in need not be the first one, | |
99 | * the important bit is that @nents@ denotes the number of entries that | |
100 | * exist from @sgl@. | |
101 | * | |
102 | **/ | |
103 | struct scatterlist *sg_last(struct scatterlist *sgl, unsigned int nents) | |
104 | { | |
0db9299f JA |
105 | struct scatterlist *sg, *ret = NULL; |
106 | unsigned int i; | |
107 | ||
108 | for_each_sg(sgl, sg, nents, i) | |
109 | ret = sg; | |
110 | ||
0db9299f | 111 | BUG_ON(!sg_is_last(ret)); |
0db9299f JA |
112 | return ret; |
113 | } | |
114 | EXPORT_SYMBOL(sg_last); | |
115 | ||
116 | /** | |
117 | * sg_init_table - Initialize SG table | |
118 | * @sgl: The SG table | |
119 | * @nents: Number of entries in table | |
120 | * | |
121 | * Notes: | |
122 | * If this is part of a chained sg table, sg_mark_end() should be | |
123 | * used only on the last table part. | |
124 | * | |
125 | **/ | |
126 | void sg_init_table(struct scatterlist *sgl, unsigned int nents) | |
127 | { | |
128 | memset(sgl, 0, sizeof(*sgl) * nents); | |
f3851786 | 129 | sg_init_marker(sgl, nents); |
0db9299f JA |
130 | } |
131 | EXPORT_SYMBOL(sg_init_table); | |
132 | ||
133 | /** | |
134 | * sg_init_one - Initialize a single entry sg list | |
135 | * @sg: SG entry | |
136 | * @buf: Virtual address for IO | |
137 | * @buflen: IO length | |
138 | * | |
139 | **/ | |
140 | void sg_init_one(struct scatterlist *sg, const void *buf, unsigned int buflen) | |
141 | { | |
142 | sg_init_table(sg, 1); | |
143 | sg_set_buf(sg, buf, buflen); | |
144 | } | |
145 | EXPORT_SYMBOL(sg_init_one); | |
146 | ||
147 | /* | |
148 | * The default behaviour of sg_alloc_table() is to use these kmalloc/kfree | |
149 | * helpers. | |
150 | */ | |
151 | static struct scatterlist *sg_kmalloc(unsigned int nents, gfp_t gfp_mask) | |
152 | { | |
b94de9bb CW |
153 | if (nents == SG_MAX_SINGLE_ALLOC) { |
154 | /* | |
155 | * Kmemleak doesn't track page allocations as they are not | |
156 | * commonly used (in a raw form) for kernel data structures. | |
157 | * As we chain together a list of pages and then a normal | |
158 | * kmalloc (tracked by kmemleak), in order to for that last | |
159 | * allocation not to become decoupled (and thus a | |
160 | * false-positive) we need to inform kmemleak of all the | |
161 | * intermediate allocations. | |
162 | */ | |
163 | void *ptr = (void *) __get_free_page(gfp_mask); | |
164 | kmemleak_alloc(ptr, PAGE_SIZE, 1, gfp_mask); | |
165 | return ptr; | |
166 | } else | |
6da2ec56 KC |
167 | return kmalloc_array(nents, sizeof(struct scatterlist), |
168 | gfp_mask); | |
0db9299f JA |
169 | } |
170 | ||
171 | static void sg_kfree(struct scatterlist *sg, unsigned int nents) | |
172 | { | |
b94de9bb CW |
173 | if (nents == SG_MAX_SINGLE_ALLOC) { |
174 | kmemleak_free(sg); | |
0db9299f | 175 | free_page((unsigned long) sg); |
b94de9bb | 176 | } else |
0db9299f JA |
177 | kfree(sg); |
178 | } | |
179 | ||
180 | /** | |
181 | * __sg_free_table - Free a previously mapped sg table | |
182 | * @table: The sg table header to use | |
7cedb1f1 | 183 | * @max_ents: The maximum number of entries per single scatterlist |
4635873c ML |
184 | * @nents_first_chunk: Number of entries int the (preallocated) first |
185 | * scatterlist chunk, 0 means no such preallocated first chunk | |
0db9299f | 186 | * @free_fn: Free function |
3e302dbc | 187 | * @num_ents: Number of entries in the table |
0db9299f JA |
188 | * |
189 | * Description: | |
7cedb1f1 JB |
190 | * Free an sg table previously allocated and setup with |
191 | * __sg_alloc_table(). The @max_ents value must be identical to | |
192 | * that previously used with __sg_alloc_table(). | |
0db9299f JA |
193 | * |
194 | **/ | |
7cedb1f1 | 195 | void __sg_free_table(struct sg_table *table, unsigned int max_ents, |
3e302dbc MG |
196 | unsigned int nents_first_chunk, sg_free_fn *free_fn, |
197 | unsigned int num_ents) | |
0db9299f JA |
198 | { |
199 | struct scatterlist *sgl, *next; | |
4635873c | 200 | unsigned curr_max_ents = nents_first_chunk ?: max_ents; |
0db9299f JA |
201 | |
202 | if (unlikely(!table->sgl)) | |
203 | return; | |
204 | ||
205 | sgl = table->sgl; | |
3e302dbc MG |
206 | while (num_ents) { |
207 | unsigned int alloc_size = num_ents; | |
0db9299f JA |
208 | unsigned int sg_size; |
209 | ||
210 | /* | |
7cedb1f1 | 211 | * If we have more than max_ents segments left, |
0db9299f JA |
212 | * then assign 'next' to the sg table after the current one. |
213 | * sg_size is then one less than alloc size, since the last | |
214 | * element is the chain pointer. | |
215 | */ | |
4635873c ML |
216 | if (alloc_size > curr_max_ents) { |
217 | next = sg_chain_ptr(&sgl[curr_max_ents - 1]); | |
218 | alloc_size = curr_max_ents; | |
0db9299f JA |
219 | sg_size = alloc_size - 1; |
220 | } else { | |
221 | sg_size = alloc_size; | |
222 | next = NULL; | |
223 | } | |
224 | ||
3e302dbc | 225 | num_ents -= sg_size; |
4635873c ML |
226 | if (nents_first_chunk) |
227 | nents_first_chunk = 0; | |
c21e59d8 TB |
228 | else |
229 | free_fn(sgl, alloc_size); | |
0db9299f | 230 | sgl = next; |
4635873c | 231 | curr_max_ents = max_ents; |
0db9299f JA |
232 | } |
233 | ||
234 | table->sgl = NULL; | |
235 | } | |
236 | EXPORT_SYMBOL(__sg_free_table); | |
237 | ||
3e302dbc MG |
238 | /** |
239 | * sg_free_append_table - Free a previously allocated append sg table. | |
240 | * @table: The mapped sg append table header | |
241 | * | |
242 | **/ | |
243 | void sg_free_append_table(struct sg_append_table *table) | |
244 | { | |
6d529ea8 | 245 | __sg_free_table(&table->sgt, SG_MAX_SINGLE_ALLOC, 0, sg_kfree, |
3e302dbc MG |
246 | table->total_nents); |
247 | } | |
248 | EXPORT_SYMBOL(sg_free_append_table); | |
249 | ||
250 | ||
0db9299f JA |
251 | /** |
252 | * sg_free_table - Free a previously allocated sg table | |
253 | * @table: The mapped sg table header | |
254 | * | |
255 | **/ | |
256 | void sg_free_table(struct sg_table *table) | |
257 | { | |
6d529ea8 | 258 | __sg_free_table(table, SG_MAX_SINGLE_ALLOC, 0, sg_kfree, |
3e302dbc | 259 | table->orig_nents); |
0db9299f JA |
260 | } |
261 | EXPORT_SYMBOL(sg_free_table); | |
262 | ||
263 | /** | |
264 | * __sg_alloc_table - Allocate and initialize an sg table with given allocator | |
265 | * @table: The sg table header to use | |
266 | * @nents: Number of entries in sg list | |
7cedb1f1 | 267 | * @max_ents: The maximum number of entries the allocator returns per call |
4635873c ML |
268 | * @nents_first_chunk: Number of entries int the (preallocated) first |
269 | * scatterlist chunk, 0 means no such preallocated chunk provided by user | |
0db9299f JA |
270 | * @gfp_mask: GFP allocation mask |
271 | * @alloc_fn: Allocator to use | |
272 | * | |
7cedb1f1 JB |
273 | * Description: |
274 | * This function returns a @table @nents long. The allocator is | |
275 | * defined to return scatterlist chunks of maximum size @max_ents. | |
276 | * Thus if @nents is bigger than @max_ents, the scatterlists will be | |
277 | * chained in units of @max_ents. | |
278 | * | |
0db9299f JA |
279 | * Notes: |
280 | * If this function returns non-0 (eg failure), the caller must call | |
281 | * __sg_free_table() to cleanup any leftover allocations. | |
282 | * | |
283 | **/ | |
7cedb1f1 | 284 | int __sg_alloc_table(struct sg_table *table, unsigned int nents, |
c53c6d6a | 285 | unsigned int max_ents, struct scatterlist *first_chunk, |
4635873c ML |
286 | unsigned int nents_first_chunk, gfp_t gfp_mask, |
287 | sg_alloc_fn *alloc_fn) | |
0db9299f JA |
288 | { |
289 | struct scatterlist *sg, *prv; | |
290 | unsigned int left; | |
4635873c ML |
291 | unsigned curr_max_ents = nents_first_chunk ?: max_ents; |
292 | unsigned prv_max_ents; | |
0db9299f | 293 | |
27daabd9 DC |
294 | memset(table, 0, sizeof(*table)); |
295 | ||
296 | if (nents == 0) | |
297 | return -EINVAL; | |
7c703e54 | 298 | #ifdef CONFIG_ARCH_NO_SG_CHAIN |
6fd59a83 NB |
299 | if (WARN_ON_ONCE(nents > max_ents)) |
300 | return -EINVAL; | |
0db9299f JA |
301 | #endif |
302 | ||
0db9299f JA |
303 | left = nents; |
304 | prv = NULL; | |
305 | do { | |
306 | unsigned int sg_size, alloc_size = left; | |
307 | ||
4635873c ML |
308 | if (alloc_size > curr_max_ents) { |
309 | alloc_size = curr_max_ents; | |
0db9299f JA |
310 | sg_size = alloc_size - 1; |
311 | } else | |
312 | sg_size = alloc_size; | |
313 | ||
314 | left -= sg_size; | |
315 | ||
c53c6d6a CH |
316 | if (first_chunk) { |
317 | sg = first_chunk; | |
318 | first_chunk = NULL; | |
319 | } else { | |
320 | sg = alloc_fn(alloc_size, gfp_mask); | |
321 | } | |
edce6820 JC |
322 | if (unlikely(!sg)) { |
323 | /* | |
324 | * Adjust entry count to reflect that the last | |
325 | * entry of the previous table won't be used for | |
326 | * linkage. Without this, sg_kfree() may get | |
327 | * confused. | |
328 | */ | |
329 | if (prv) | |
330 | table->nents = ++table->orig_nents; | |
331 | ||
4e456fee | 332 | return -ENOMEM; |
edce6820 | 333 | } |
0db9299f JA |
334 | |
335 | sg_init_table(sg, alloc_size); | |
336 | table->nents = table->orig_nents += sg_size; | |
337 | ||
338 | /* | |
339 | * If this is the first mapping, assign the sg table header. | |
340 | * If this is not the first mapping, chain previous part. | |
341 | */ | |
342 | if (prv) | |
4635873c | 343 | sg_chain(prv, prv_max_ents, sg); |
0db9299f JA |
344 | else |
345 | table->sgl = sg; | |
346 | ||
347 | /* | |
348 | * If no more entries after this one, mark the end | |
349 | */ | |
350 | if (!left) | |
351 | sg_mark_end(&sg[sg_size - 1]); | |
352 | ||
0db9299f | 353 | prv = sg; |
4635873c ML |
354 | prv_max_ents = curr_max_ents; |
355 | curr_max_ents = max_ents; | |
0db9299f JA |
356 | } while (left); |
357 | ||
358 | return 0; | |
359 | } | |
360 | EXPORT_SYMBOL(__sg_alloc_table); | |
361 | ||
362 | /** | |
363 | * sg_alloc_table - Allocate and initialize an sg table | |
364 | * @table: The sg table header to use | |
365 | * @nents: Number of entries in sg list | |
366 | * @gfp_mask: GFP allocation mask | |
367 | * | |
368 | * Description: | |
369 | * Allocate and initialize an sg table. If @nents@ is larger than | |
370 | * SG_MAX_SINGLE_ALLOC a chained sg table will be setup. | |
371 | * | |
372 | **/ | |
373 | int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) | |
374 | { | |
375 | int ret; | |
376 | ||
7cedb1f1 | 377 | ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC, |
4635873c | 378 | NULL, 0, gfp_mask, sg_kmalloc); |
0db9299f | 379 | if (unlikely(ret)) |
3e302dbc | 380 | sg_free_table(table); |
0db9299f JA |
381 | return ret; |
382 | } | |
383 | EXPORT_SYMBOL(sg_alloc_table); | |
b1adaf65 | 384 | |
3e302dbc | 385 | static struct scatterlist *get_next_sg(struct sg_append_table *table, |
07da1223 MG |
386 | struct scatterlist *cur, |
387 | unsigned long needed_sges, | |
388 | gfp_t gfp_mask) | |
389 | { | |
390 | struct scatterlist *new_sg, *next_sg; | |
391 | unsigned int alloc_size; | |
392 | ||
393 | if (cur) { | |
394 | next_sg = sg_next(cur); | |
395 | /* Check if last entry should be keeped for chainning */ | |
396 | if (!sg_is_last(next_sg) || needed_sges == 1) | |
397 | return next_sg; | |
398 | } | |
399 | ||
400 | alloc_size = min_t(unsigned long, needed_sges, SG_MAX_SINGLE_ALLOC); | |
401 | new_sg = sg_kmalloc(alloc_size, gfp_mask); | |
402 | if (!new_sg) | |
403 | return ERR_PTR(-ENOMEM); | |
404 | sg_init_table(new_sg, alloc_size); | |
405 | if (cur) { | |
3e302dbc | 406 | table->total_nents += alloc_size - 1; |
07da1223 | 407 | __sg_chain(next_sg, new_sg); |
07da1223 | 408 | } else { |
3e302dbc MG |
409 | table->sgt.sgl = new_sg; |
410 | table->total_nents = alloc_size; | |
07da1223 MG |
411 | } |
412 | return new_sg; | |
413 | } | |
414 | ||
1567b49d LG |
415 | static bool pages_are_mergeable(struct page *a, struct page *b) |
416 | { | |
417 | if (page_to_pfn(a) != page_to_pfn(b) + 1) | |
418 | return false; | |
419 | if (!zone_device_pages_have_same_pgmap(a, b)) | |
420 | return false; | |
421 | return true; | |
422 | } | |
423 | ||
efc42bc9 | 424 | /** |
3e302dbc MG |
425 | * sg_alloc_append_table_from_pages - Allocate and initialize an append sg |
426 | * table from an array of pages | |
427 | * @sgt_append: The sg append table to use | |
428 | * @pages: Pointer to an array of page pointers | |
429 | * @n_pages: Number of pages in the pages array | |
89d8589c TU |
430 | * @offset: Offset from start of the first page to the start of a buffer |
431 | * @size: Number of valid bytes in the buffer (after offset) | |
9a40401c | 432 | * @max_segment: Maximum size of a scatterlist element in bytes |
07da1223 | 433 | * @left_pages: Left pages caller have to set after this call |
89d8589c | 434 | * @gfp_mask: GFP allocation mask |
efc42bc9 | 435 | * |
07da1223 | 436 | * Description: |
3e302dbc MG |
437 | * In the first call it allocate and initialize an sg table from a list of |
438 | * pages, else reuse the scatterlist from sgt_append. Contiguous ranges of | |
439 | * the pages are squashed into a single scatterlist entry up to the maximum | |
440 | * size specified in @max_segment. A user may provide an offset at a start | |
441 | * and a size of valid data in a buffer specified by the page array. The | |
442 | * returned sg table is released by sg_free_append_table | |
efc42bc9 TS |
443 | * |
444 | * Returns: | |
3e302dbc | 445 | * 0 on success, negative error on failure |
07da1223 MG |
446 | * |
447 | * Notes: | |
448 | * If this function returns non-0 (eg failure), the caller must call | |
3e302dbc MG |
449 | * sg_free_append_table() to cleanup any leftover allocations. |
450 | * | |
451 | * In the fist call, sgt_append must by initialized. | |
efc42bc9 | 452 | */ |
3e302dbc | 453 | int sg_alloc_append_table_from_pages(struct sg_append_table *sgt_append, |
07da1223 MG |
454 | struct page **pages, unsigned int n_pages, unsigned int offset, |
455 | unsigned long size, unsigned int max_segment, | |
3e302dbc | 456 | unsigned int left_pages, gfp_t gfp_mask) |
efc42bc9 | 457 | { |
07da1223 MG |
458 | unsigned int chunks, cur_page, seg_len, i, prv_len = 0; |
459 | unsigned int added_nents = 0; | |
3e302dbc | 460 | struct scatterlist *s = sgt_append->prv; |
1567b49d | 461 | struct page *last_pg; |
efc42bc9 | 462 | |
9a40401c JG |
463 | /* |
464 | * The algorithm below requires max_segment to be aligned to PAGE_SIZE | |
465 | * otherwise it can overshoot. | |
466 | */ | |
467 | max_segment = ALIGN_DOWN(max_segment, PAGE_SIZE); | |
468 | if (WARN_ON(max_segment < PAGE_SIZE)) | |
3e302dbc | 469 | return -EINVAL; |
07da1223 | 470 | |
3e302dbc MG |
471 | if (IS_ENABLED(CONFIG_ARCH_NO_SG_CHAIN) && sgt_append->prv) |
472 | return -EOPNOTSUPP; | |
07da1223 | 473 | |
3e302dbc | 474 | if (sgt_append->prv) { |
0f097f08 YH |
475 | unsigned long next_pfn = (page_to_phys(sg_page(sgt_append->prv)) + |
476 | sgt_append->prv->offset + sgt_append->prv->length) / PAGE_SIZE; | |
477 | ||
07da1223 | 478 | if (WARN_ON(offset)) |
3e302dbc | 479 | return -EINVAL; |
07da1223 MG |
480 | |
481 | /* Merge contiguous pages into the last SG */ | |
3e302dbc | 482 | prv_len = sgt_append->prv->length; |
0f097f08 YH |
483 | if (page_to_pfn(pages[0]) == next_pfn) { |
484 | last_pg = pfn_to_page(next_pfn - 1); | |
485 | while (n_pages && pages_are_mergeable(pages[0], last_pg)) { | |
486 | if (sgt_append->prv->length + PAGE_SIZE > max_segment) | |
487 | break; | |
488 | sgt_append->prv->length += PAGE_SIZE; | |
489 | last_pg = pages[0]; | |
490 | pages++; | |
491 | n_pages--; | |
492 | } | |
493 | if (!n_pages) | |
494 | goto out; | |
07da1223 | 495 | } |
07da1223 | 496 | } |
89d8589c | 497 | |
efc42bc9 TS |
498 | /* compute number of contiguous chunks */ |
499 | chunks = 1; | |
c125906b TU |
500 | seg_len = 0; |
501 | for (i = 1; i < n_pages; i++) { | |
502 | seg_len += PAGE_SIZE; | |
503 | if (seg_len >= max_segment || | |
1567b49d | 504 | !pages_are_mergeable(pages[i], pages[i - 1])) { |
c125906b TU |
505 | chunks++; |
506 | seg_len = 0; | |
507 | } | |
508 | } | |
efc42bc9 | 509 | |
efc42bc9 TS |
510 | /* merging chunks and putting them into the scatterlist */ |
511 | cur_page = 0; | |
07da1223 | 512 | for (i = 0; i < chunks; i++) { |
c125906b | 513 | unsigned int j, chunk_size; |
efc42bc9 TS |
514 | |
515 | /* look for the end of the current chunk */ | |
c125906b TU |
516 | seg_len = 0; |
517 | for (j = cur_page + 1; j < n_pages; j++) { | |
518 | seg_len += PAGE_SIZE; | |
519 | if (seg_len >= max_segment || | |
1567b49d | 520 | !pages_are_mergeable(pages[j], pages[j - 1])) |
efc42bc9 | 521 | break; |
c125906b | 522 | } |
efc42bc9 | 523 | |
07da1223 | 524 | /* Pass how many chunks might be left */ |
3e302dbc MG |
525 | s = get_next_sg(sgt_append, s, chunks - i + left_pages, |
526 | gfp_mask); | |
07da1223 MG |
527 | if (IS_ERR(s)) { |
528 | /* | |
529 | * Adjust entry length to be as before function was | |
530 | * called. | |
531 | */ | |
3e302dbc MG |
532 | if (sgt_append->prv) |
533 | sgt_append->prv->length = prv_len; | |
534 | return PTR_ERR(s); | |
07da1223 | 535 | } |
efc42bc9 | 536 | chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset; |
c125906b TU |
537 | sg_set_page(s, pages[cur_page], |
538 | min_t(unsigned long, size, chunk_size), offset); | |
07da1223 | 539 | added_nents++; |
efc42bc9 TS |
540 | size -= chunk_size; |
541 | offset = 0; | |
542 | cur_page = j; | |
543 | } | |
3e302dbc MG |
544 | sgt_append->sgt.nents += added_nents; |
545 | sgt_append->sgt.orig_nents = sgt_append->sgt.nents; | |
546 | sgt_append->prv = s; | |
07da1223 MG |
547 | out: |
548 | if (!left_pages) | |
549 | sg_mark_end(s); | |
3e302dbc | 550 | return 0; |
efc42bc9 | 551 | } |
90e7a6de | 552 | EXPORT_SYMBOL(sg_alloc_append_table_from_pages); |
89d8589c TU |
553 | |
554 | /** | |
90e7a6de MG |
555 | * sg_alloc_table_from_pages_segment - Allocate and initialize an sg table from |
556 | * an array of pages and given maximum | |
557 | * segment. | |
89d8589c TU |
558 | * @sgt: The sg table header to use |
559 | * @pages: Pointer to an array of page pointers | |
560 | * @n_pages: Number of pages in the pages array | |
561 | * @offset: Offset from start of the first page to the start of a buffer | |
562 | * @size: Number of valid bytes in the buffer (after offset) | |
90e7a6de | 563 | * @max_segment: Maximum size of a scatterlist element in bytes |
89d8589c TU |
564 | * @gfp_mask: GFP allocation mask |
565 | * | |
566 | * Description: | |
567 | * Allocate and initialize an sg table from a list of pages. Contiguous | |
90e7a6de MG |
568 | * ranges of the pages are squashed into a single scatterlist node up to the |
569 | * maximum size specified in @max_segment. A user may provide an offset at a | |
570 | * start and a size of valid data in a buffer specified by the page array. | |
89d8589c | 571 | * |
90e7a6de MG |
572 | * The returned sg table is released by sg_free_table. |
573 | * | |
574 | * Returns: | |
89d8589c TU |
575 | * 0 on success, negative error on failure |
576 | */ | |
90e7a6de MG |
577 | int sg_alloc_table_from_pages_segment(struct sg_table *sgt, struct page **pages, |
578 | unsigned int n_pages, unsigned int offset, | |
579 | unsigned long size, unsigned int max_segment, | |
580 | gfp_t gfp_mask) | |
89d8589c | 581 | { |
3e302dbc MG |
582 | struct sg_append_table append = {}; |
583 | int err; | |
584 | ||
585 | err = sg_alloc_append_table_from_pages(&append, pages, n_pages, offset, | |
586 | size, max_segment, 0, gfp_mask); | |
587 | if (err) { | |
588 | sg_free_append_table(&append); | |
589 | return err; | |
590 | } | |
591 | memcpy(sgt, &append.sgt, sizeof(*sgt)); | |
592 | WARN_ON(append.total_nents != sgt->orig_nents); | |
593 | return 0; | |
89d8589c | 594 | } |
90e7a6de | 595 | EXPORT_SYMBOL(sg_alloc_table_from_pages_segment); |
efc42bc9 | 596 | |
e80a0af4 BVA |
597 | #ifdef CONFIG_SGL_ALLOC |
598 | ||
599 | /** | |
600 | * sgl_alloc_order - allocate a scatterlist and its pages | |
601 | * @length: Length in bytes of the scatterlist. Must be at least one | |
602 | * @order: Second argument for alloc_pages() | |
603 | * @chainable: Whether or not to allocate an extra element in the scatterlist | |
604 | * for scatterlist chaining purposes | |
605 | * @gfp: Memory allocation flags | |
606 | * @nent_p: [out] Number of entries in the scatterlist that have pages | |
607 | * | |
608 | * Returns: A pointer to an initialized scatterlist or %NULL upon failure. | |
609 | */ | |
610 | struct scatterlist *sgl_alloc_order(unsigned long long length, | |
611 | unsigned int order, bool chainable, | |
612 | gfp_t gfp, unsigned int *nent_p) | |
613 | { | |
614 | struct scatterlist *sgl, *sg; | |
615 | struct page *page; | |
616 | unsigned int nent, nalloc; | |
617 | u32 elem_len; | |
618 | ||
619 | nent = round_up(length, PAGE_SIZE << order) >> (PAGE_SHIFT + order); | |
620 | /* Check for integer overflow */ | |
621 | if (length > (nent << (PAGE_SHIFT + order))) | |
622 | return NULL; | |
623 | nalloc = nent; | |
624 | if (chainable) { | |
625 | /* Check for integer overflow */ | |
626 | if (nalloc + 1 < nalloc) | |
627 | return NULL; | |
628 | nalloc++; | |
629 | } | |
630 | sgl = kmalloc_array(nalloc, sizeof(struct scatterlist), | |
6ed9b92e | 631 | gfp & ~GFP_DMA); |
e80a0af4 BVA |
632 | if (!sgl) |
633 | return NULL; | |
634 | ||
8c7a8d1c | 635 | sg_init_table(sgl, nalloc); |
e80a0af4 BVA |
636 | sg = sgl; |
637 | while (length) { | |
638 | elem_len = min_t(u64, length, PAGE_SIZE << order); | |
639 | page = alloc_pages(gfp, order); | |
640 | if (!page) { | |
b2a182a4 | 641 | sgl_free_order(sgl, order); |
e80a0af4 BVA |
642 | return NULL; |
643 | } | |
644 | ||
645 | sg_set_page(sg, page, elem_len, 0); | |
646 | length -= elem_len; | |
647 | sg = sg_next(sg); | |
648 | } | |
8c7a8d1c | 649 | WARN_ONCE(length, "length = %lld\n", length); |
e80a0af4 BVA |
650 | if (nent_p) |
651 | *nent_p = nent; | |
652 | return sgl; | |
653 | } | |
654 | EXPORT_SYMBOL(sgl_alloc_order); | |
655 | ||
656 | /** | |
657 | * sgl_alloc - allocate a scatterlist and its pages | |
658 | * @length: Length in bytes of the scatterlist | |
659 | * @gfp: Memory allocation flags | |
660 | * @nent_p: [out] Number of entries in the scatterlist | |
661 | * | |
662 | * Returns: A pointer to an initialized scatterlist or %NULL upon failure. | |
663 | */ | |
664 | struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp, | |
665 | unsigned int *nent_p) | |
666 | { | |
667 | return sgl_alloc_order(length, 0, false, gfp, nent_p); | |
668 | } | |
669 | EXPORT_SYMBOL(sgl_alloc); | |
670 | ||
671 | /** | |
8c7a8d1c | 672 | * sgl_free_n_order - free a scatterlist and its pages |
e80a0af4 | 673 | * @sgl: Scatterlist with one or more elements |
8c7a8d1c | 674 | * @nents: Maximum number of elements to free |
e80a0af4 | 675 | * @order: Second argument for __free_pages() |
8c7a8d1c BVA |
676 | * |
677 | * Notes: | |
678 | * - If several scatterlists have been chained and each chain element is | |
679 | * freed separately then it's essential to set nents correctly to avoid that a | |
680 | * page would get freed twice. | |
681 | * - All pages in a chained scatterlist can be freed at once by setting @nents | |
682 | * to a high number. | |
e80a0af4 | 683 | */ |
8c7a8d1c | 684 | void sgl_free_n_order(struct scatterlist *sgl, int nents, int order) |
e80a0af4 BVA |
685 | { |
686 | struct scatterlist *sg; | |
687 | struct page *page; | |
8c7a8d1c | 688 | int i; |
e80a0af4 | 689 | |
8c7a8d1c BVA |
690 | for_each_sg(sgl, sg, nents, i) { |
691 | if (!sg) | |
692 | break; | |
e80a0af4 BVA |
693 | page = sg_page(sg); |
694 | if (page) | |
695 | __free_pages(page, order); | |
696 | } | |
697 | kfree(sgl); | |
698 | } | |
8c7a8d1c BVA |
699 | EXPORT_SYMBOL(sgl_free_n_order); |
700 | ||
701 | /** | |
702 | * sgl_free_order - free a scatterlist and its pages | |
703 | * @sgl: Scatterlist with one or more elements | |
704 | * @order: Second argument for __free_pages() | |
705 | */ | |
706 | void sgl_free_order(struct scatterlist *sgl, int order) | |
707 | { | |
708 | sgl_free_n_order(sgl, INT_MAX, order); | |
709 | } | |
e80a0af4 BVA |
710 | EXPORT_SYMBOL(sgl_free_order); |
711 | ||
712 | /** | |
713 | * sgl_free - free a scatterlist and its pages | |
714 | * @sgl: Scatterlist with one or more elements | |
715 | */ | |
716 | void sgl_free(struct scatterlist *sgl) | |
717 | { | |
718 | sgl_free_order(sgl, 0); | |
719 | } | |
720 | EXPORT_SYMBOL(sgl_free); | |
721 | ||
722 | #endif /* CONFIG_SGL_ALLOC */ | |
723 | ||
a321e91b ID |
724 | void __sg_page_iter_start(struct sg_page_iter *piter, |
725 | struct scatterlist *sglist, unsigned int nents, | |
726 | unsigned long pgoffset) | |
727 | { | |
728 | piter->__pg_advance = 0; | |
729 | piter->__nents = nents; | |
730 | ||
a321e91b ID |
731 | piter->sg = sglist; |
732 | piter->sg_pgoffset = pgoffset; | |
733 | } | |
734 | EXPORT_SYMBOL(__sg_page_iter_start); | |
735 | ||
736 | static int sg_page_count(struct scatterlist *sg) | |
737 | { | |
738 | return PAGE_ALIGN(sg->offset + sg->length) >> PAGE_SHIFT; | |
739 | } | |
740 | ||
741 | bool __sg_page_iter_next(struct sg_page_iter *piter) | |
742 | { | |
743 | if (!piter->__nents || !piter->sg) | |
744 | return false; | |
745 | ||
746 | piter->sg_pgoffset += piter->__pg_advance; | |
747 | piter->__pg_advance = 1; | |
748 | ||
749 | while (piter->sg_pgoffset >= sg_page_count(piter->sg)) { | |
750 | piter->sg_pgoffset -= sg_page_count(piter->sg); | |
751 | piter->sg = sg_next(piter->sg); | |
752 | if (!--piter->__nents || !piter->sg) | |
753 | return false; | |
754 | } | |
a321e91b ID |
755 | |
756 | return true; | |
757 | } | |
758 | EXPORT_SYMBOL(__sg_page_iter_next); | |
759 | ||
d901b276 JG |
760 | static int sg_dma_page_count(struct scatterlist *sg) |
761 | { | |
762 | return PAGE_ALIGN(sg->offset + sg_dma_len(sg)) >> PAGE_SHIFT; | |
763 | } | |
764 | ||
765 | bool __sg_page_iter_dma_next(struct sg_dma_page_iter *dma_iter) | |
766 | { | |
767 | struct sg_page_iter *piter = &dma_iter->base; | |
768 | ||
769 | if (!piter->__nents || !piter->sg) | |
770 | return false; | |
771 | ||
772 | piter->sg_pgoffset += piter->__pg_advance; | |
773 | piter->__pg_advance = 1; | |
774 | ||
775 | while (piter->sg_pgoffset >= sg_dma_page_count(piter->sg)) { | |
776 | piter->sg_pgoffset -= sg_dma_page_count(piter->sg); | |
777 | piter->sg = sg_next(piter->sg); | |
778 | if (!--piter->__nents || !piter->sg) | |
779 | return false; | |
780 | } | |
781 | ||
782 | return true; | |
783 | } | |
784 | EXPORT_SYMBOL(__sg_page_iter_dma_next); | |
785 | ||
137d3edb TH |
786 | /** |
787 | * sg_miter_start - start mapping iteration over a sg list | |
788 | * @miter: sg mapping iter to be started | |
789 | * @sgl: sg list to iterate over | |
790 | * @nents: number of sg entries | |
791 | * | |
792 | * Description: | |
793 | * Starts mapping iterator @miter. | |
794 | * | |
795 | * Context: | |
796 | * Don't care. | |
797 | */ | |
798 | void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, | |
799 | unsigned int nents, unsigned int flags) | |
800 | { | |
801 | memset(miter, 0, sizeof(struct sg_mapping_iter)); | |
802 | ||
4225fc85 | 803 | __sg_page_iter_start(&miter->piter, sgl, nents, 0); |
6de7e356 | 804 | WARN_ON(!(flags & (SG_MITER_TO_SG | SG_MITER_FROM_SG))); |
137d3edb TH |
805 | miter->__flags = flags; |
806 | } | |
807 | EXPORT_SYMBOL(sg_miter_start); | |
808 | ||
11052004 AM |
809 | static bool sg_miter_get_next_page(struct sg_mapping_iter *miter) |
810 | { | |
811 | if (!miter->__remaining) { | |
812 | struct scatterlist *sg; | |
11052004 AM |
813 | |
814 | if (!__sg_page_iter_next(&miter->piter)) | |
815 | return false; | |
816 | ||
817 | sg = miter->piter.sg; | |
11052004 | 818 | |
aeb87246 CL |
819 | miter->__offset = miter->piter.sg_pgoffset ? 0 : sg->offset; |
820 | miter->piter.sg_pgoffset += miter->__offset >> PAGE_SHIFT; | |
821 | miter->__offset &= PAGE_SIZE - 1; | |
11052004 | 822 | miter->__remaining = sg->offset + sg->length - |
aeb87246 CL |
823 | (miter->piter.sg_pgoffset << PAGE_SHIFT) - |
824 | miter->__offset; | |
11052004 AM |
825 | miter->__remaining = min_t(unsigned long, miter->__remaining, |
826 | PAGE_SIZE - miter->__offset); | |
827 | } | |
828 | ||
829 | return true; | |
830 | } | |
831 | ||
df642cea AM |
832 | /** |
833 | * sg_miter_skip - reposition mapping iterator | |
834 | * @miter: sg mapping iter to be skipped | |
835 | * @offset: number of bytes to plus the current location | |
836 | * | |
837 | * Description: | |
838 | * Sets the offset of @miter to its current location plus @offset bytes. | |
839 | * If mapping iterator @miter has been proceeded by sg_miter_next(), this | |
840 | * stops @miter. | |
841 | * | |
842 | * Context: | |
723aca20 | 843 | * Don't care. |
df642cea AM |
844 | * |
845 | * Returns: | |
846 | * true if @miter contains the valid mapping. false if end of sg | |
847 | * list is reached. | |
848 | */ | |
0d6077f8 | 849 | bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset) |
df642cea AM |
850 | { |
851 | sg_miter_stop(miter); | |
852 | ||
853 | while (offset) { | |
854 | off_t consumed; | |
855 | ||
856 | if (!sg_miter_get_next_page(miter)) | |
857 | return false; | |
858 | ||
859 | consumed = min_t(off_t, offset, miter->__remaining); | |
860 | miter->__offset += consumed; | |
861 | miter->__remaining -= consumed; | |
862 | offset -= consumed; | |
863 | } | |
864 | ||
865 | return true; | |
866 | } | |
0d6077f8 | 867 | EXPORT_SYMBOL(sg_miter_skip); |
df642cea | 868 | |
137d3edb TH |
869 | /** |
870 | * sg_miter_next - proceed mapping iterator to the next mapping | |
871 | * @miter: sg mapping iter to proceed | |
872 | * | |
873 | * Description: | |
8290e2d2 TH |
874 | * Proceeds @miter to the next mapping. @miter should have been started |
875 | * using sg_miter_start(). On successful return, @miter->page, | |
876 | * @miter->addr and @miter->length point to the current mapping. | |
137d3edb TH |
877 | * |
878 | * Context: | |
723aca20 | 879 | * May sleep if !SG_MITER_ATOMIC. |
137d3edb TH |
880 | * |
881 | * Returns: | |
882 | * true if @miter contains the next mapping. false if end of sg | |
883 | * list is reached. | |
884 | */ | |
885 | bool sg_miter_next(struct sg_mapping_iter *miter) | |
886 | { | |
137d3edb TH |
887 | sg_miter_stop(miter); |
888 | ||
4225fc85 ID |
889 | /* |
890 | * Get to the next page if necessary. | |
891 | * __remaining, __offset is adjusted by sg_miter_stop | |
892 | */ | |
11052004 AM |
893 | if (!sg_miter_get_next_page(miter)) |
894 | return false; | |
137d3edb | 895 | |
2db76d7c | 896 | miter->page = sg_page_iter_page(&miter->piter); |
4225fc85 | 897 | miter->consumed = miter->length = miter->__remaining; |
137d3edb TH |
898 | |
899 | if (miter->__flags & SG_MITER_ATOMIC) | |
4225fc85 | 900 | miter->addr = kmap_atomic(miter->page) + miter->__offset; |
137d3edb | 901 | else |
4225fc85 | 902 | miter->addr = kmap(miter->page) + miter->__offset; |
137d3edb TH |
903 | |
904 | return true; | |
905 | } | |
906 | EXPORT_SYMBOL(sg_miter_next); | |
907 | ||
908 | /** | |
909 | * sg_miter_stop - stop mapping iteration | |
910 | * @miter: sg mapping iter to be stopped | |
911 | * | |
912 | * Description: | |
913 | * Stops mapping iterator @miter. @miter should have been started | |
4ba6a2b2 MY |
914 | * using sg_miter_start(). A stopped iteration can be resumed by |
915 | * calling sg_miter_next() on it. This is useful when resources (kmap) | |
916 | * need to be released during iteration. | |
137d3edb TH |
917 | * |
918 | * Context: | |
723aca20 | 919 | * Don't care otherwise. |
137d3edb TH |
920 | */ |
921 | void sg_miter_stop(struct sg_mapping_iter *miter) | |
922 | { | |
923 | WARN_ON(miter->consumed > miter->length); | |
924 | ||
925 | /* drop resources from the last iteration */ | |
926 | if (miter->addr) { | |
927 | miter->__offset += miter->consumed; | |
4225fc85 | 928 | miter->__remaining -= miter->consumed; |
137d3edb | 929 | |
0e84f5db CH |
930 | if (miter->__flags & SG_MITER_TO_SG) |
931 | flush_dcache_page(miter->page); | |
6de7e356 | 932 | |
137d3edb | 933 | if (miter->__flags & SG_MITER_ATOMIC) { |
723aca20 | 934 | WARN_ON_ONCE(!pagefault_disabled()); |
c3eede8e | 935 | kunmap_atomic(miter->addr); |
137d3edb | 936 | } else |
f652c521 | 937 | kunmap(miter->page); |
137d3edb TH |
938 | |
939 | miter->page = NULL; | |
940 | miter->addr = NULL; | |
941 | miter->length = 0; | |
942 | miter->consumed = 0; | |
943 | } | |
944 | } | |
945 | EXPORT_SYMBOL(sg_miter_stop); | |
946 | ||
b1adaf65 FT |
947 | /** |
948 | * sg_copy_buffer - Copy data between a linear buffer and an SG list | |
949 | * @sgl: The SG list | |
950 | * @nents: Number of SG entries | |
951 | * @buf: Where to copy from | |
952 | * @buflen: The number of bytes to copy | |
df642cea AM |
953 | * @skip: Number of bytes to skip before copying |
954 | * @to_buffer: transfer direction (true == from an sg list to a | |
6e853185 | 955 | * buffer, false == from a buffer to an sg list) |
b1adaf65 FT |
956 | * |
957 | * Returns the number of copied bytes. | |
958 | * | |
959 | **/ | |
386ecb12 DG |
960 | size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, |
961 | size_t buflen, off_t skip, bool to_buffer) | |
b1adaf65 | 962 | { |
137d3edb TH |
963 | unsigned int offset = 0; |
964 | struct sg_mapping_iter miter; | |
6de7e356 SAS |
965 | unsigned int sg_flags = SG_MITER_ATOMIC; |
966 | ||
967 | if (to_buffer) | |
968 | sg_flags |= SG_MITER_FROM_SG; | |
969 | else | |
970 | sg_flags |= SG_MITER_TO_SG; | |
137d3edb | 971 | |
6de7e356 | 972 | sg_miter_start(&miter, sgl, nents, sg_flags); |
137d3edb | 973 | |
df642cea | 974 | if (!sg_miter_skip(&miter, skip)) |
1f41be7d | 975 | return 0; |
df642cea | 976 | |
1d5210ef | 977 | while ((offset < buflen) && sg_miter_next(&miter)) { |
137d3edb TH |
978 | unsigned int len; |
979 | ||
980 | len = min(miter.length, buflen - offset); | |
981 | ||
982 | if (to_buffer) | |
983 | memcpy(buf + offset, miter.addr, len); | |
6de7e356 | 984 | else |
137d3edb | 985 | memcpy(miter.addr, buf + offset, len); |
b1adaf65 | 986 | |
137d3edb | 987 | offset += len; |
b1adaf65 FT |
988 | } |
989 | ||
137d3edb TH |
990 | sg_miter_stop(&miter); |
991 | ||
992 | return offset; | |
b1adaf65 | 993 | } |
386ecb12 | 994 | EXPORT_SYMBOL(sg_copy_buffer); |
b1adaf65 FT |
995 | |
996 | /** | |
997 | * sg_copy_from_buffer - Copy from a linear buffer to an SG list | |
998 | * @sgl: The SG list | |
999 | * @nents: Number of SG entries | |
1000 | * @buf: Where to copy from | |
1001 | * @buflen: The number of bytes to copy | |
1002 | * | |
1003 | * Returns the number of copied bytes. | |
1004 | * | |
1005 | **/ | |
1006 | size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, | |
2a1bf8f9 | 1007 | const void *buf, size_t buflen) |
b1adaf65 | 1008 | { |
2a1bf8f9 | 1009 | return sg_copy_buffer(sgl, nents, (void *)buf, buflen, 0, false); |
b1adaf65 FT |
1010 | } |
1011 | EXPORT_SYMBOL(sg_copy_from_buffer); | |
1012 | ||
1013 | /** | |
1014 | * sg_copy_to_buffer - Copy from an SG list to a linear buffer | |
1015 | * @sgl: The SG list | |
1016 | * @nents: Number of SG entries | |
1017 | * @buf: Where to copy to | |
1018 | * @buflen: The number of bytes to copy | |
1019 | * | |
1020 | * Returns the number of copied bytes. | |
1021 | * | |
1022 | **/ | |
1023 | size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, | |
1024 | void *buf, size_t buflen) | |
1025 | { | |
df642cea | 1026 | return sg_copy_buffer(sgl, nents, buf, buflen, 0, true); |
b1adaf65 FT |
1027 | } |
1028 | EXPORT_SYMBOL(sg_copy_to_buffer); | |
df642cea AM |
1029 | |
1030 | /** | |
1031 | * sg_pcopy_from_buffer - Copy from a linear buffer to an SG list | |
1032 | * @sgl: The SG list | |
1033 | * @nents: Number of SG entries | |
1034 | * @buf: Where to copy from | |
df642cea | 1035 | * @buflen: The number of bytes to copy |
4dc7daf8 | 1036 | * @skip: Number of bytes to skip before copying |
df642cea AM |
1037 | * |
1038 | * Returns the number of copied bytes. | |
1039 | * | |
1040 | **/ | |
1041 | size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, | |
2a1bf8f9 | 1042 | const void *buf, size_t buflen, off_t skip) |
df642cea | 1043 | { |
2a1bf8f9 | 1044 | return sg_copy_buffer(sgl, nents, (void *)buf, buflen, skip, false); |
df642cea AM |
1045 | } |
1046 | EXPORT_SYMBOL(sg_pcopy_from_buffer); | |
1047 | ||
1048 | /** | |
1049 | * sg_pcopy_to_buffer - Copy from an SG list to a linear buffer | |
1050 | * @sgl: The SG list | |
1051 | * @nents: Number of SG entries | |
1052 | * @buf: Where to copy to | |
df642cea | 1053 | * @buflen: The number of bytes to copy |
4dc7daf8 | 1054 | * @skip: Number of bytes to skip before copying |
df642cea AM |
1055 | * |
1056 | * Returns the number of copied bytes. | |
1057 | * | |
1058 | **/ | |
1059 | size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, | |
1060 | void *buf, size_t buflen, off_t skip) | |
1061 | { | |
1062 | return sg_copy_buffer(sgl, nents, buf, buflen, skip, true); | |
1063 | } | |
1064 | EXPORT_SYMBOL(sg_pcopy_to_buffer); | |
0945e569 JT |
1065 | |
1066 | /** | |
1067 | * sg_zero_buffer - Zero-out a part of a SG list | |
1068 | * @sgl: The SG list | |
1069 | * @nents: Number of SG entries | |
1070 | * @buflen: The number of bytes to zero out | |
1071 | * @skip: Number of bytes to skip before zeroing | |
1072 | * | |
1073 | * Returns the number of bytes zeroed. | |
1074 | **/ | |
1075 | size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, | |
1076 | size_t buflen, off_t skip) | |
1077 | { | |
1078 | unsigned int offset = 0; | |
1079 | struct sg_mapping_iter miter; | |
1080 | unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG; | |
1081 | ||
1082 | sg_miter_start(&miter, sgl, nents, sg_flags); | |
1083 | ||
1084 | if (!sg_miter_skip(&miter, skip)) | |
1085 | return false; | |
1086 | ||
1087 | while (offset < buflen && sg_miter_next(&miter)) { | |
1088 | unsigned int len; | |
1089 | ||
1090 | len = min(miter.length, buflen - offset); | |
1091 | memset(miter.addr, 0, len); | |
1092 | ||
1093 | offset += len; | |
1094 | } | |
1095 | ||
1096 | sg_miter_stop(&miter); | |
1097 | return offset; | |
1098 | } | |
1099 | EXPORT_SYMBOL(sg_zero_buffer); | |
f5f82cd1 DH |
1100 | |
1101 | /* | |
1102 | * Extract and pin a list of up to sg_max pages from UBUF- or IOVEC-class | |
1103 | * iterators, and add them to the scatterlist. | |
1104 | */ | |
1105 | static ssize_t extract_user_to_sg(struct iov_iter *iter, | |
1106 | ssize_t maxsize, | |
1107 | struct sg_table *sgtable, | |
1108 | unsigned int sg_max, | |
1109 | iov_iter_extraction_t extraction_flags) | |
1110 | { | |
1111 | struct scatterlist *sg = sgtable->sgl + sgtable->nents; | |
1112 | struct page **pages; | |
1113 | unsigned int npages; | |
1114 | ssize_t ret = 0, res; | |
1115 | size_t len, off; | |
1116 | ||
1117 | /* We decant the page list into the tail of the scatterlist */ | |
1118 | pages = (void *)sgtable->sgl + | |
1119 | array_size(sg_max, sizeof(struct scatterlist)); | |
1120 | pages -= sg_max; | |
1121 | ||
1122 | do { | |
1123 | res = iov_iter_extract_pages(iter, &pages, maxsize, sg_max, | |
1124 | extraction_flags, &off); | |
1125 | if (res < 0) | |
1126 | goto failed; | |
1127 | ||
1128 | len = res; | |
1129 | maxsize -= len; | |
1130 | ret += len; | |
1131 | npages = DIV_ROUND_UP(off + len, PAGE_SIZE); | |
1132 | sg_max -= npages; | |
1133 | ||
1134 | for (; npages > 0; npages--) { | |
1135 | struct page *page = *pages; | |
1136 | size_t seg = min_t(size_t, PAGE_SIZE - off, len); | |
1137 | ||
1138 | *pages++ = NULL; | |
1139 | sg_set_page(sg, page, seg, off); | |
1140 | sgtable->nents++; | |
1141 | sg++; | |
1142 | len -= seg; | |
1143 | off = 0; | |
1144 | } | |
1145 | } while (maxsize > 0 && sg_max > 0); | |
1146 | ||
1147 | return ret; | |
1148 | ||
1149 | failed: | |
1150 | while (sgtable->nents > sgtable->orig_nents) | |
f443fd5a | 1151 | unpin_user_page(sg_page(&sgtable->sgl[--sgtable->nents])); |
f5f82cd1 DH |
1152 | return res; |
1153 | } | |
1154 | ||
1155 | /* | |
1156 | * Extract up to sg_max pages from a BVEC-type iterator and add them to the | |
1157 | * scatterlist. The pages are not pinned. | |
1158 | */ | |
1159 | static ssize_t extract_bvec_to_sg(struct iov_iter *iter, | |
1160 | ssize_t maxsize, | |
1161 | struct sg_table *sgtable, | |
1162 | unsigned int sg_max, | |
1163 | iov_iter_extraction_t extraction_flags) | |
1164 | { | |
1165 | const struct bio_vec *bv = iter->bvec; | |
1166 | struct scatterlist *sg = sgtable->sgl + sgtable->nents; | |
1167 | unsigned long start = iter->iov_offset; | |
1168 | unsigned int i; | |
1169 | ssize_t ret = 0; | |
1170 | ||
1171 | for (i = 0; i < iter->nr_segs; i++) { | |
1172 | size_t off, len; | |
1173 | ||
1174 | len = bv[i].bv_len; | |
1175 | if (start >= len) { | |
1176 | start -= len; | |
1177 | continue; | |
1178 | } | |
1179 | ||
1180 | len = min_t(size_t, maxsize, len - start); | |
1181 | off = bv[i].bv_offset + start; | |
1182 | ||
1183 | sg_set_page(sg, bv[i].bv_page, len, off); | |
1184 | sgtable->nents++; | |
1185 | sg++; | |
1186 | sg_max--; | |
1187 | ||
1188 | ret += len; | |
1189 | maxsize -= len; | |
1190 | if (maxsize <= 0 || sg_max == 0) | |
1191 | break; | |
1192 | start = 0; | |
1193 | } | |
1194 | ||
1195 | if (ret > 0) | |
1196 | iov_iter_advance(iter, ret); | |
1197 | return ret; | |
1198 | } | |
1199 | ||
1200 | /* | |
1201 | * Extract up to sg_max pages from a KVEC-type iterator and add them to the | |
1202 | * scatterlist. This can deal with vmalloc'd buffers as well as kmalloc'd or | |
1203 | * static buffers. The pages are not pinned. | |
1204 | */ | |
1205 | static ssize_t extract_kvec_to_sg(struct iov_iter *iter, | |
1206 | ssize_t maxsize, | |
1207 | struct sg_table *sgtable, | |
1208 | unsigned int sg_max, | |
1209 | iov_iter_extraction_t extraction_flags) | |
1210 | { | |
1211 | const struct kvec *kv = iter->kvec; | |
1212 | struct scatterlist *sg = sgtable->sgl + sgtable->nents; | |
1213 | unsigned long start = iter->iov_offset; | |
1214 | unsigned int i; | |
1215 | ssize_t ret = 0; | |
1216 | ||
1217 | for (i = 0; i < iter->nr_segs; i++) { | |
1218 | struct page *page; | |
1219 | unsigned long kaddr; | |
1220 | size_t off, len, seg; | |
1221 | ||
1222 | len = kv[i].iov_len; | |
1223 | if (start >= len) { | |
1224 | start -= len; | |
1225 | continue; | |
1226 | } | |
1227 | ||
1228 | kaddr = (unsigned long)kv[i].iov_base + start; | |
1229 | off = kaddr & ~PAGE_MASK; | |
1230 | len = min_t(size_t, maxsize, len - start); | |
1231 | kaddr &= PAGE_MASK; | |
1232 | ||
1233 | maxsize -= len; | |
1234 | ret += len; | |
1235 | do { | |
1236 | seg = min_t(size_t, len, PAGE_SIZE - off); | |
1237 | if (is_vmalloc_or_module_addr((void *)kaddr)) | |
1238 | page = vmalloc_to_page((void *)kaddr); | |
1239 | else | |
7b82e904 | 1240 | page = virt_to_page((void *)kaddr); |
f5f82cd1 DH |
1241 | |
1242 | sg_set_page(sg, page, len, off); | |
1243 | sgtable->nents++; | |
1244 | sg++; | |
1245 | sg_max--; | |
1246 | ||
1247 | len -= seg; | |
1248 | kaddr += PAGE_SIZE; | |
1249 | off = 0; | |
1250 | } while (len > 0 && sg_max > 0); | |
1251 | ||
1252 | if (maxsize <= 0 || sg_max == 0) | |
1253 | break; | |
1254 | start = 0; | |
1255 | } | |
1256 | ||
1257 | if (ret > 0) | |
1258 | iov_iter_advance(iter, ret); | |
1259 | return ret; | |
1260 | } | |
1261 | ||
1262 | /* | |
1263 | * Extract up to sg_max folios from an XARRAY-type iterator and add them to | |
1264 | * the scatterlist. The pages are not pinned. | |
1265 | */ | |
1266 | static ssize_t extract_xarray_to_sg(struct iov_iter *iter, | |
1267 | ssize_t maxsize, | |
1268 | struct sg_table *sgtable, | |
1269 | unsigned int sg_max, | |
1270 | iov_iter_extraction_t extraction_flags) | |
1271 | { | |
1272 | struct scatterlist *sg = sgtable->sgl + sgtable->nents; | |
1273 | struct xarray *xa = iter->xarray; | |
1274 | struct folio *folio; | |
1275 | loff_t start = iter->xarray_start + iter->iov_offset; | |
1276 | pgoff_t index = start / PAGE_SIZE; | |
1277 | ssize_t ret = 0; | |
1278 | size_t offset, len; | |
1279 | XA_STATE(xas, xa, index); | |
1280 | ||
1281 | rcu_read_lock(); | |
1282 | ||
1283 | xas_for_each(&xas, folio, ULONG_MAX) { | |
1284 | if (xas_retry(&xas, folio)) | |
1285 | continue; | |
1286 | if (WARN_ON(xa_is_value(folio))) | |
1287 | break; | |
1288 | if (WARN_ON(folio_test_hugetlb(folio))) | |
1289 | break; | |
1290 | ||
1291 | offset = offset_in_folio(folio, start); | |
1292 | len = min_t(size_t, maxsize, folio_size(folio) - offset); | |
1293 | ||
1294 | sg_set_page(sg, folio_page(folio, 0), len, offset); | |
1295 | sgtable->nents++; | |
1296 | sg++; | |
1297 | sg_max--; | |
1298 | ||
1299 | maxsize -= len; | |
1300 | ret += len; | |
1301 | if (maxsize <= 0 || sg_max == 0) | |
1302 | break; | |
1303 | } | |
1304 | ||
1305 | rcu_read_unlock(); | |
1306 | if (ret > 0) | |
1307 | iov_iter_advance(iter, ret); | |
1308 | return ret; | |
1309 | } | |
1310 | ||
1311 | /** | |
1312 | * extract_iter_to_sg - Extract pages from an iterator and add to an sglist | |
1313 | * @iter: The iterator to extract from | |
1314 | * @maxsize: The amount of iterator to copy | |
1315 | * @sgtable: The scatterlist table to fill in | |
1316 | * @sg_max: Maximum number of elements in @sgtable that may be filled | |
1317 | * @extraction_flags: Flags to qualify the request | |
1318 | * | |
1319 | * Extract the page fragments from the given amount of the source iterator and | |
1320 | * add them to a scatterlist that refers to all of those bits, to a maximum | |
1321 | * addition of @sg_max elements. | |
1322 | * | |
1323 | * The pages referred to by UBUF- and IOVEC-type iterators are extracted and | |
1324 | * pinned; BVEC-, KVEC- and XARRAY-type are extracted but aren't pinned; PIPE- | |
1325 | * and DISCARD-type are not supported. | |
1326 | * | |
1327 | * No end mark is placed on the scatterlist; that's left to the caller. | |
1328 | * | |
1329 | * @extraction_flags can have ITER_ALLOW_P2PDMA set to request peer-to-peer DMA | |
1330 | * be allowed on the pages extracted. | |
1331 | * | |
1332 | * If successful, @sgtable->nents is updated to include the number of elements | |
1333 | * added and the number of bytes added is returned. @sgtable->orig_nents is | |
1334 | * left unaltered. | |
1335 | * | |
1336 | * The iov_iter_extract_mode() function should be used to query how cleanup | |
1337 | * should be performed. | |
1338 | */ | |
1339 | ssize_t extract_iter_to_sg(struct iov_iter *iter, size_t maxsize, | |
1340 | struct sg_table *sgtable, unsigned int sg_max, | |
1341 | iov_iter_extraction_t extraction_flags) | |
1342 | { | |
1343 | if (maxsize == 0) | |
1344 | return 0; | |
1345 | ||
1346 | switch (iov_iter_type(iter)) { | |
1347 | case ITER_UBUF: | |
1348 | case ITER_IOVEC: | |
1349 | return extract_user_to_sg(iter, maxsize, sgtable, sg_max, | |
1350 | extraction_flags); | |
1351 | case ITER_BVEC: | |
1352 | return extract_bvec_to_sg(iter, maxsize, sgtable, sg_max, | |
1353 | extraction_flags); | |
1354 | case ITER_KVEC: | |
1355 | return extract_kvec_to_sg(iter, maxsize, sgtable, sg_max, | |
1356 | extraction_flags); | |
1357 | case ITER_XARRAY: | |
1358 | return extract_xarray_to_sg(iter, maxsize, sgtable, sg_max, | |
1359 | extraction_flags); | |
1360 | default: | |
1361 | pr_err("%s(%u) unsupported\n", __func__, iov_iter_type(iter)); | |
1362 | WARN_ON_ONCE(1); | |
1363 | return -EIO; | |
1364 | } | |
1365 | } | |
1366 | EXPORT_SYMBOL_GPL(extract_iter_to_sg); |