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1 | /* | |
2 | * Functions related to generic helpers functions | |
3 | */ | |
4 | #include <linux/kernel.h> | |
5 | #include <linux/module.h> | |
6 | #include <linux/bio.h> | |
7 | #include <linux/blkdev.h> | |
8 | #include <linux/scatterlist.h> | |
9 | ||
10 | #include "blk.h" | |
11 | ||
12 | static struct bio *next_bio(struct bio *bio, unsigned int nr_pages, | |
13 | gfp_t gfp) | |
14 | { | |
15 | struct bio *new = bio_alloc(gfp, nr_pages); | |
16 | ||
17 | if (bio) { | |
18 | bio_chain(bio, new); | |
19 | submit_bio(bio); | |
20 | } | |
21 | ||
22 | return new; | |
23 | } | |
24 | ||
25 | int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, | |
26 | sector_t nr_sects, gfp_t gfp_mask, int flags, | |
27 | struct bio **biop) | |
28 | { | |
29 | struct request_queue *q = bdev_get_queue(bdev); | |
30 | struct bio *bio = *biop; | |
31 | unsigned int granularity; | |
32 | unsigned int op; | |
33 | int alignment; | |
34 | sector_t bs_mask; | |
35 | ||
36 | if (!q) | |
37 | return -ENXIO; | |
38 | ||
39 | if (flags & BLKDEV_DISCARD_SECURE) { | |
40 | if (!blk_queue_secure_erase(q)) | |
41 | return -EOPNOTSUPP; | |
42 | op = REQ_OP_SECURE_ERASE; | |
43 | } else { | |
44 | if (!blk_queue_discard(q)) | |
45 | return -EOPNOTSUPP; | |
46 | op = REQ_OP_DISCARD; | |
47 | } | |
48 | ||
49 | bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; | |
50 | if ((sector | nr_sects) & bs_mask) | |
51 | return -EINVAL; | |
52 | ||
53 | /* Zero-sector (unknown) and one-sector granularities are the same. */ | |
54 | granularity = max(q->limits.discard_granularity >> 9, 1U); | |
55 | alignment = (bdev_discard_alignment(bdev) >> 9) % granularity; | |
56 | ||
57 | while (nr_sects) { | |
58 | unsigned int req_sects; | |
59 | sector_t end_sect, tmp; | |
60 | ||
61 | /* Make sure bi_size doesn't overflow */ | |
62 | req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9); | |
63 | ||
64 | /** | |
65 | * If splitting a request, and the next starting sector would be | |
66 | * misaligned, stop the discard at the previous aligned sector. | |
67 | */ | |
68 | end_sect = sector + req_sects; | |
69 | tmp = end_sect; | |
70 | if (req_sects < nr_sects && | |
71 | sector_div(tmp, granularity) != alignment) { | |
72 | end_sect = end_sect - alignment; | |
73 | sector_div(end_sect, granularity); | |
74 | end_sect = end_sect * granularity + alignment; | |
75 | req_sects = end_sect - sector; | |
76 | } | |
77 | ||
78 | bio = next_bio(bio, 0, gfp_mask); | |
79 | bio->bi_iter.bi_sector = sector; | |
80 | bio->bi_bdev = bdev; | |
81 | bio_set_op_attrs(bio, op, 0); | |
82 | ||
83 | bio->bi_iter.bi_size = req_sects << 9; | |
84 | nr_sects -= req_sects; | |
85 | sector = end_sect; | |
86 | ||
87 | /* | |
88 | * We can loop for a long time in here, if someone does | |
89 | * full device discards (like mkfs). Be nice and allow | |
90 | * us to schedule out to avoid softlocking if preempt | |
91 | * is disabled. | |
92 | */ | |
93 | cond_resched(); | |
94 | } | |
95 | ||
96 | *biop = bio; | |
97 | return 0; | |
98 | } | |
99 | EXPORT_SYMBOL(__blkdev_issue_discard); | |
100 | ||
101 | /** | |
102 | * blkdev_issue_discard - queue a discard | |
103 | * @bdev: blockdev to issue discard for | |
104 | * @sector: start sector | |
105 | * @nr_sects: number of sectors to discard | |
106 | * @gfp_mask: memory allocation flags (for bio_alloc) | |
107 | * @flags: BLKDEV_DISCARD_* flags to control behaviour | |
108 | * | |
109 | * Description: | |
110 | * Issue a discard request for the sectors in question. | |
111 | */ | |
112 | int blkdev_issue_discard(struct block_device *bdev, sector_t sector, | |
113 | sector_t nr_sects, gfp_t gfp_mask, unsigned long flags) | |
114 | { | |
115 | struct bio *bio = NULL; | |
116 | struct blk_plug plug; | |
117 | int ret; | |
118 | ||
119 | blk_start_plug(&plug); | |
120 | ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags, | |
121 | &bio); | |
122 | if (!ret && bio) { | |
123 | ret = submit_bio_wait(bio); | |
124 | if (ret == -EOPNOTSUPP) | |
125 | ret = 0; | |
126 | bio_put(bio); | |
127 | } | |
128 | blk_finish_plug(&plug); | |
129 | ||
130 | return ret; | |
131 | } | |
132 | EXPORT_SYMBOL(blkdev_issue_discard); | |
133 | ||
134 | /** | |
135 | * __blkdev_issue_write_same - generate number of bios with same page | |
136 | * @bdev: target blockdev | |
137 | * @sector: start sector | |
138 | * @nr_sects: number of sectors to write | |
139 | * @gfp_mask: memory allocation flags (for bio_alloc) | |
140 | * @page: page containing data to write | |
141 | * @biop: pointer to anchor bio | |
142 | * | |
143 | * Description: | |
144 | * Generate and issue number of bios(REQ_OP_WRITE_SAME) with same page. | |
145 | */ | |
146 | static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector, | |
147 | sector_t nr_sects, gfp_t gfp_mask, struct page *page, | |
148 | struct bio **biop) | |
149 | { | |
150 | struct request_queue *q = bdev_get_queue(bdev); | |
151 | unsigned int max_write_same_sectors; | |
152 | struct bio *bio = *biop; | |
153 | sector_t bs_mask; | |
154 | ||
155 | if (!q) | |
156 | return -ENXIO; | |
157 | ||
158 | bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; | |
159 | if ((sector | nr_sects) & bs_mask) | |
160 | return -EINVAL; | |
161 | ||
162 | if (!bdev_write_same(bdev)) | |
163 | return -EOPNOTSUPP; | |
164 | ||
165 | /* Ensure that max_write_same_sectors doesn't overflow bi_size */ | |
166 | max_write_same_sectors = UINT_MAX >> 9; | |
167 | ||
168 | while (nr_sects) { | |
169 | bio = next_bio(bio, 1, gfp_mask); | |
170 | bio->bi_iter.bi_sector = sector; | |
171 | bio->bi_bdev = bdev; | |
172 | bio->bi_vcnt = 1; | |
173 | bio->bi_io_vec->bv_page = page; | |
174 | bio->bi_io_vec->bv_offset = 0; | |
175 | bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev); | |
176 | bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0); | |
177 | ||
178 | if (nr_sects > max_write_same_sectors) { | |
179 | bio->bi_iter.bi_size = max_write_same_sectors << 9; | |
180 | nr_sects -= max_write_same_sectors; | |
181 | sector += max_write_same_sectors; | |
182 | } else { | |
183 | bio->bi_iter.bi_size = nr_sects << 9; | |
184 | nr_sects = 0; | |
185 | } | |
186 | cond_resched(); | |
187 | } | |
188 | ||
189 | *biop = bio; | |
190 | return 0; | |
191 | } | |
192 | ||
193 | /** | |
194 | * blkdev_issue_write_same - queue a write same operation | |
195 | * @bdev: target blockdev | |
196 | * @sector: start sector | |
197 | * @nr_sects: number of sectors to write | |
198 | * @gfp_mask: memory allocation flags (for bio_alloc) | |
199 | * @page: page containing data | |
200 | * | |
201 | * Description: | |
202 | * Issue a write same request for the sectors in question. | |
203 | */ | |
204 | int blkdev_issue_write_same(struct block_device *bdev, sector_t sector, | |
205 | sector_t nr_sects, gfp_t gfp_mask, | |
206 | struct page *page) | |
207 | { | |
208 | struct bio *bio = NULL; | |
209 | struct blk_plug plug; | |
210 | int ret; | |
211 | ||
212 | blk_start_plug(&plug); | |
213 | ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, page, | |
214 | &bio); | |
215 | if (ret == 0 && bio) { | |
216 | ret = submit_bio_wait(bio); | |
217 | bio_put(bio); | |
218 | } | |
219 | blk_finish_plug(&plug); | |
220 | return ret; | |
221 | } | |
222 | EXPORT_SYMBOL(blkdev_issue_write_same); | |
223 | ||
224 | static int __blkdev_issue_write_zeroes(struct block_device *bdev, | |
225 | sector_t sector, sector_t nr_sects, gfp_t gfp_mask, | |
226 | struct bio **biop, unsigned flags) | |
227 | { | |
228 | struct bio *bio = *biop; | |
229 | unsigned int max_write_zeroes_sectors; | |
230 | struct request_queue *q = bdev_get_queue(bdev); | |
231 | ||
232 | if (!q) | |
233 | return -ENXIO; | |
234 | ||
235 | /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */ | |
236 | max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev); | |
237 | ||
238 | if (max_write_zeroes_sectors == 0) | |
239 | return -EOPNOTSUPP; | |
240 | ||
241 | while (nr_sects) { | |
242 | bio = next_bio(bio, 0, gfp_mask); | |
243 | bio->bi_iter.bi_sector = sector; | |
244 | bio->bi_bdev = bdev; | |
245 | bio->bi_opf = REQ_OP_WRITE_ZEROES; | |
246 | if (flags & BLKDEV_ZERO_NOUNMAP) | |
247 | bio->bi_opf |= REQ_NOUNMAP; | |
248 | ||
249 | if (nr_sects > max_write_zeroes_sectors) { | |
250 | bio->bi_iter.bi_size = max_write_zeroes_sectors << 9; | |
251 | nr_sects -= max_write_zeroes_sectors; | |
252 | sector += max_write_zeroes_sectors; | |
253 | } else { | |
254 | bio->bi_iter.bi_size = nr_sects << 9; | |
255 | nr_sects = 0; | |
256 | } | |
257 | cond_resched(); | |
258 | } | |
259 | ||
260 | *biop = bio; | |
261 | return 0; | |
262 | } | |
263 | ||
264 | /* | |
265 | * Convert a number of 512B sectors to a number of pages. | |
266 | * The result is limited to a number of pages that can fit into a BIO. | |
267 | * Also make sure that the result is always at least 1 (page) for the cases | |
268 | * where nr_sects is lower than the number of sectors in a page. | |
269 | */ | |
270 | static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects) | |
271 | { | |
272 | sector_t bytes = (nr_sects << 9) + PAGE_SIZE - 1; | |
273 | ||
274 | return min(bytes >> PAGE_SHIFT, (sector_t)BIO_MAX_PAGES); | |
275 | } | |
276 | ||
277 | static int __blkdev_issue_zero_pages(struct block_device *bdev, | |
278 | sector_t sector, sector_t nr_sects, gfp_t gfp_mask, | |
279 | struct bio **biop) | |
280 | { | |
281 | struct request_queue *q = bdev_get_queue(bdev); | |
282 | struct bio *bio = *biop; | |
283 | int bi_size = 0; | |
284 | unsigned int sz; | |
285 | ||
286 | if (!q) | |
287 | return -ENXIO; | |
288 | ||
289 | while (nr_sects != 0) { | |
290 | bio = next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects), | |
291 | gfp_mask); | |
292 | bio->bi_iter.bi_sector = sector; | |
293 | bio->bi_bdev = bdev; | |
294 | bio_set_op_attrs(bio, REQ_OP_WRITE, 0); | |
295 | ||
296 | while (nr_sects != 0) { | |
297 | sz = min((sector_t) PAGE_SIZE, nr_sects << 9); | |
298 | bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0); | |
299 | nr_sects -= bi_size >> 9; | |
300 | sector += bi_size >> 9; | |
301 | if (bi_size < sz) | |
302 | break; | |
303 | } | |
304 | cond_resched(); | |
305 | } | |
306 | ||
307 | *biop = bio; | |
308 | return 0; | |
309 | } | |
310 | ||
311 | /** | |
312 | * __blkdev_issue_zeroout - generate number of zero filed write bios | |
313 | * @bdev: blockdev to issue | |
314 | * @sector: start sector | |
315 | * @nr_sects: number of sectors to write | |
316 | * @gfp_mask: memory allocation flags (for bio_alloc) | |
317 | * @biop: pointer to anchor bio | |
318 | * @flags: controls detailed behavior | |
319 | * | |
320 | * Description: | |
321 | * Zero-fill a block range, either using hardware offload or by explicitly | |
322 | * writing zeroes to the device. | |
323 | * | |
324 | * If a device is using logical block provisioning, the underlying space will | |
325 | * not be released if %flags contains BLKDEV_ZERO_NOUNMAP. | |
326 | * | |
327 | * If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return | |
328 | * -EOPNOTSUPP if no explicit hardware offload for zeroing is provided. | |
329 | */ | |
330 | int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, | |
331 | sector_t nr_sects, gfp_t gfp_mask, struct bio **biop, | |
332 | unsigned flags) | |
333 | { | |
334 | int ret; | |
335 | sector_t bs_mask; | |
336 | ||
337 | bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; | |
338 | if ((sector | nr_sects) & bs_mask) | |
339 | return -EINVAL; | |
340 | ||
341 | ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask, | |
342 | biop, flags); | |
343 | if (ret != -EOPNOTSUPP || (flags & BLKDEV_ZERO_NOFALLBACK)) | |
344 | return ret; | |
345 | ||
346 | return __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask, | |
347 | biop); | |
348 | } | |
349 | EXPORT_SYMBOL(__blkdev_issue_zeroout); | |
350 | ||
351 | /** | |
352 | * blkdev_issue_zeroout - zero-fill a block range | |
353 | * @bdev: blockdev to write | |
354 | * @sector: start sector | |
355 | * @nr_sects: number of sectors to write | |
356 | * @gfp_mask: memory allocation flags (for bio_alloc) | |
357 | * @flags: controls detailed behavior | |
358 | * | |
359 | * Description: | |
360 | * Zero-fill a block range, either using hardware offload or by explicitly | |
361 | * writing zeroes to the device. See __blkdev_issue_zeroout() for the | |
362 | * valid values for %flags. | |
363 | */ | |
364 | int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, | |
365 | sector_t nr_sects, gfp_t gfp_mask, unsigned flags) | |
366 | { | |
367 | int ret = 0; | |
368 | sector_t bs_mask; | |
369 | struct bio *bio; | |
370 | struct blk_plug plug; | |
371 | bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev); | |
372 | ||
373 | bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; | |
374 | if ((sector | nr_sects) & bs_mask) | |
375 | return -EINVAL; | |
376 | ||
377 | retry: | |
378 | bio = NULL; | |
379 | blk_start_plug(&plug); | |
380 | if (try_write_zeroes) { | |
381 | ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, | |
382 | gfp_mask, &bio, flags); | |
383 | } else if (!(flags & BLKDEV_ZERO_NOFALLBACK)) { | |
384 | ret = __blkdev_issue_zero_pages(bdev, sector, nr_sects, | |
385 | gfp_mask, &bio); | |
386 | } else { | |
387 | /* No zeroing offload support */ | |
388 | ret = -EOPNOTSUPP; | |
389 | } | |
390 | if (ret == 0 && bio) { | |
391 | ret = submit_bio_wait(bio); | |
392 | bio_put(bio); | |
393 | } | |
394 | blk_finish_plug(&plug); | |
395 | if (ret && try_write_zeroes) { | |
396 | if (!(flags & BLKDEV_ZERO_NOFALLBACK)) { | |
397 | try_write_zeroes = false; | |
398 | goto retry; | |
399 | } | |
400 | if (!bdev_write_zeroes_sectors(bdev)) { | |
401 | /* | |
402 | * Zeroing offload support was indicated, but the | |
403 | * device reported ILLEGAL REQUEST (for some devices | |
404 | * there is no non-destructive way to verify whether | |
405 | * WRITE ZEROES is actually supported). | |
406 | */ | |
407 | ret = -EOPNOTSUPP; | |
408 | } | |
409 | } | |
410 | ||
411 | return ret; | |
412 | } | |
413 | EXPORT_SYMBOL(blkdev_issue_zeroout); |