1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Functions related to generic helpers functions
4 */
5 #include <linux/kernel.h>
6 #include <linux/module.h>
7 #include <linux/bio.h>
8 #include <linux/blkdev.h>
9 #include <linux/scatterlist.h>
10
11 #include "blk.h"
12
blk_next_bio(struct bio * bio,unsigned int nr_pages,gfp_t gfp)13 struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, 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 EXPORT_SYMBOL_GPL(blk_next_bio);
25
__blkdev_issue_discard(struct block_device * bdev,sector_t sector,sector_t nr_sects,gfp_t gfp_mask,int flags,struct bio ** biop)26 int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
27 sector_t nr_sects, gfp_t gfp_mask, int flags,
28 struct bio **biop)
29 {
30 struct request_queue *q = bdev_get_queue(bdev);
31 struct bio *bio = *biop;
32 unsigned int op;
33 sector_t bs_mask, part_offset = 0;
34
35 if (!q)
36 return -ENXIO;
37
38 if (bdev_read_only(bdev))
39 return -EPERM;
40
41 if (flags & BLKDEV_DISCARD_SECURE) {
42 if (!blk_queue_secure_erase(q))
43 return -EOPNOTSUPP;
44 op = REQ_OP_SECURE_ERASE;
45 } else {
46 if (!blk_queue_discard(q))
47 return -EOPNOTSUPP;
48 op = REQ_OP_DISCARD;
49 }
50
51 /* In case the discard granularity isn't set by buggy device driver */
52 if (WARN_ON_ONCE(!q->limits.discard_granularity)) {
53 char dev_name[BDEVNAME_SIZE];
54
55 bdevname(bdev, dev_name);
56 pr_err_ratelimited("%s: Error: discard_granularity is 0.\n", dev_name);
57 return -EOPNOTSUPP;
58 }
59
60 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
61 if ((sector | nr_sects) & bs_mask)
62 return -EINVAL;
63
64 if (!nr_sects)
65 return -EINVAL;
66
67 /* In case the discard request is in a partition */
68 if (bdev_is_partition(bdev))
69 part_offset = bdev->bd_start_sect;
70
71 while (nr_sects) {
72 sector_t granularity_aligned_lba, req_sects;
73 sector_t sector_mapped = sector + part_offset;
74
75 granularity_aligned_lba = round_up(sector_mapped,
76 q->limits.discard_granularity >> SECTOR_SHIFT);
77
78 /*
79 * Check whether the discard bio starts at a discard_granularity
80 * aligned LBA,
81 * - If no: set (granularity_aligned_lba - sector_mapped) to
82 * bi_size of the first split bio, then the second bio will
83 * start at a discard_granularity aligned LBA on the device.
84 * - If yes: use bio_aligned_discard_max_sectors() as the max
85 * possible bi_size of the first split bio. Then when this bio
86 * is split in device drive, the split ones are very probably
87 * to be aligned to discard_granularity of the device's queue.
88 */
89 if (granularity_aligned_lba == sector_mapped)
90 req_sects = min_t(sector_t, nr_sects,
91 bio_aligned_discard_max_sectors(q));
92 else
93 req_sects = min_t(sector_t, nr_sects,
94 granularity_aligned_lba - sector_mapped);
95
96 WARN_ON_ONCE((req_sects << 9) > UINT_MAX);
97
98 bio = blk_next_bio(bio, 0, gfp_mask);
99 bio->bi_iter.bi_sector = sector;
100 bio_set_dev(bio, bdev);
101 bio_set_op_attrs(bio, op, 0);
102
103 bio->bi_iter.bi_size = req_sects << 9;
104 sector += req_sects;
105 nr_sects -= req_sects;
106
107 /*
108 * We can loop for a long time in here, if someone does
109 * full device discards (like mkfs). Be nice and allow
110 * us to schedule out to avoid softlocking if preempt
111 * is disabled.
112 */
113 cond_resched();
114 }
115
116 *biop = bio;
117 return 0;
118 }
119 EXPORT_SYMBOL(__blkdev_issue_discard);
120
121 /**
122 * blkdev_issue_discard - queue a discard
123 * @bdev: blockdev to issue discard for
124 * @sector: start sector
125 * @nr_sects: number of sectors to discard
126 * @gfp_mask: memory allocation flags (for bio_alloc)
127 * @flags: BLKDEV_DISCARD_* flags to control behaviour
128 *
129 * Description:
130 * Issue a discard request for the sectors in question.
131 */
blkdev_issue_discard(struct block_device * bdev,sector_t sector,sector_t nr_sects,gfp_t gfp_mask,unsigned long flags)132 int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
133 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
134 {
135 struct bio *bio = NULL;
136 struct blk_plug plug;
137 int ret;
138
139 blk_start_plug(&plug);
140 ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags,
141 &bio);
142 if (!ret && bio) {
143 ret = submit_bio_wait(bio);
144 if (ret == -EOPNOTSUPP)
145 ret = 0;
146 bio_put(bio);
147 }
148 blk_finish_plug(&plug);
149
150 return ret;
151 }
152 EXPORT_SYMBOL(blkdev_issue_discard);
153
154 /**
155 * __blkdev_issue_write_same - generate number of bios with same page
156 * @bdev: target blockdev
157 * @sector: start sector
158 * @nr_sects: number of sectors to write
159 * @gfp_mask: memory allocation flags (for bio_alloc)
160 * @page: page containing data to write
161 * @biop: pointer to anchor bio
162 *
163 * Description:
164 * Generate and issue number of bios(REQ_OP_WRITE_SAME) with same page.
165 */
__blkdev_issue_write_same(struct block_device * bdev,sector_t sector,sector_t nr_sects,gfp_t gfp_mask,struct page * page,struct bio ** biop)166 static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
167 sector_t nr_sects, gfp_t gfp_mask, struct page *page,
168 struct bio **biop)
169 {
170 struct request_queue *q = bdev_get_queue(bdev);
171 unsigned int max_write_same_sectors;
172 struct bio *bio = *biop;
173 sector_t bs_mask;
174
175 if (!q)
176 return -ENXIO;
177
178 if (bdev_read_only(bdev))
179 return -EPERM;
180
181 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
182 if ((sector | nr_sects) & bs_mask)
183 return -EINVAL;
184
185 if (!bdev_write_same(bdev))
186 return -EOPNOTSUPP;
187
188 /* Ensure that max_write_same_sectors doesn't overflow bi_size */
189 max_write_same_sectors = bio_allowed_max_sectors(q);
190
191 while (nr_sects) {
192 bio = blk_next_bio(bio, 1, gfp_mask);
193 bio->bi_iter.bi_sector = sector;
194 bio_set_dev(bio, bdev);
195 bio->bi_vcnt = 1;
196 bio->bi_io_vec->bv_page = page;
197 bio->bi_io_vec->bv_offset = 0;
198 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
199 bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0);
200
201 if (nr_sects > max_write_same_sectors) {
202 bio->bi_iter.bi_size = max_write_same_sectors << 9;
203 nr_sects -= max_write_same_sectors;
204 sector += max_write_same_sectors;
205 } else {
206 bio->bi_iter.bi_size = nr_sects << 9;
207 nr_sects = 0;
208 }
209 cond_resched();
210 }
211
212 *biop = bio;
213 return 0;
214 }
215
216 /**
217 * blkdev_issue_write_same - queue a write same operation
218 * @bdev: target blockdev
219 * @sector: start sector
220 * @nr_sects: number of sectors to write
221 * @gfp_mask: memory allocation flags (for bio_alloc)
222 * @page: page containing data
223 *
224 * Description:
225 * Issue a write same request for the sectors in question.
226 */
blkdev_issue_write_same(struct block_device * bdev,sector_t sector,sector_t nr_sects,gfp_t gfp_mask,struct page * page)227 int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
228 sector_t nr_sects, gfp_t gfp_mask,
229 struct page *page)
230 {
231 struct bio *bio = NULL;
232 struct blk_plug plug;
233 int ret;
234
235 blk_start_plug(&plug);
236 ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, page,
237 &bio);
238 if (ret == 0 && bio) {
239 ret = submit_bio_wait(bio);
240 bio_put(bio);
241 }
242 blk_finish_plug(&plug);
243 return ret;
244 }
245 EXPORT_SYMBOL(blkdev_issue_write_same);
246
__blkdev_issue_write_zeroes(struct block_device * bdev,sector_t sector,sector_t nr_sects,gfp_t gfp_mask,struct bio ** biop,unsigned flags)247 static int __blkdev_issue_write_zeroes(struct block_device *bdev,
248 sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
249 struct bio **biop, unsigned flags)
250 {
251 struct bio *bio = *biop;
252 unsigned int max_write_zeroes_sectors;
253 struct request_queue *q = bdev_get_queue(bdev);
254
255 if (!q)
256 return -ENXIO;
257
258 if (bdev_read_only(bdev))
259 return -EPERM;
260
261 /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */
262 max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev);
263
264 if (max_write_zeroes_sectors == 0)
265 return -EOPNOTSUPP;
266
267 while (nr_sects) {
268 bio = blk_next_bio(bio, 0, gfp_mask);
269 bio->bi_iter.bi_sector = sector;
270 bio_set_dev(bio, bdev);
271 bio->bi_opf = REQ_OP_WRITE_ZEROES;
272 if (flags & BLKDEV_ZERO_NOUNMAP)
273 bio->bi_opf |= REQ_NOUNMAP;
274
275 if (nr_sects > max_write_zeroes_sectors) {
276 bio->bi_iter.bi_size = max_write_zeroes_sectors << 9;
277 nr_sects -= max_write_zeroes_sectors;
278 sector += max_write_zeroes_sectors;
279 } else {
280 bio->bi_iter.bi_size = nr_sects << 9;
281 nr_sects = 0;
282 }
283 cond_resched();
284 }
285
286 *biop = bio;
287 return 0;
288 }
289
290 /*
291 * Convert a number of 512B sectors to a number of pages.
292 * The result is limited to a number of pages that can fit into a BIO.
293 * Also make sure that the result is always at least 1 (page) for the cases
294 * where nr_sects is lower than the number of sectors in a page.
295 */
__blkdev_sectors_to_bio_pages(sector_t nr_sects)296 static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects)
297 {
298 sector_t pages = DIV_ROUND_UP_SECTOR_T(nr_sects, PAGE_SIZE / 512);
299
300 return min(pages, (sector_t)BIO_MAX_VECS);
301 }
302
__blkdev_issue_zero_pages(struct block_device * bdev,sector_t sector,sector_t nr_sects,gfp_t gfp_mask,struct bio ** biop)303 static int __blkdev_issue_zero_pages(struct block_device *bdev,
304 sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
305 struct bio **biop)
306 {
307 struct request_queue *q = bdev_get_queue(bdev);
308 struct bio *bio = *biop;
309 int bi_size = 0;
310 unsigned int sz;
311
312 if (!q)
313 return -ENXIO;
314
315 if (bdev_read_only(bdev))
316 return -EPERM;
317
318 while (nr_sects != 0) {
319 bio = blk_next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
320 gfp_mask);
321 bio->bi_iter.bi_sector = sector;
322 bio_set_dev(bio, bdev);
323 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
324
325 while (nr_sects != 0) {
326 sz = min((sector_t) PAGE_SIZE, nr_sects << 9);
327 bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0);
328 nr_sects -= bi_size >> 9;
329 sector += bi_size >> 9;
330 if (bi_size < sz)
331 break;
332 }
333 cond_resched();
334 }
335
336 *biop = bio;
337 return 0;
338 }
339
340 /**
341 * __blkdev_issue_zeroout - generate number of zero filed write bios
342 * @bdev: blockdev to issue
343 * @sector: start sector
344 * @nr_sects: number of sectors to write
345 * @gfp_mask: memory allocation flags (for bio_alloc)
346 * @biop: pointer to anchor bio
347 * @flags: controls detailed behavior
348 *
349 * Description:
350 * Zero-fill a block range, either using hardware offload or by explicitly
351 * writing zeroes to the device.
352 *
353 * If a device is using logical block provisioning, the underlying space will
354 * not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
355 *
356 * If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return
357 * -EOPNOTSUPP if no explicit hardware offload for zeroing is provided.
358 */
__blkdev_issue_zeroout(struct block_device * bdev,sector_t sector,sector_t nr_sects,gfp_t gfp_mask,struct bio ** biop,unsigned flags)359 int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
360 sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
361 unsigned flags)
362 {
363 int ret;
364 sector_t bs_mask;
365
366 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
367 if ((sector | nr_sects) & bs_mask)
368 return -EINVAL;
369
370 ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask,
371 biop, flags);
372 if (ret != -EOPNOTSUPP || (flags & BLKDEV_ZERO_NOFALLBACK))
373 return ret;
374
375 return __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
376 biop);
377 }
378 EXPORT_SYMBOL(__blkdev_issue_zeroout);
379
380 /**
381 * blkdev_issue_zeroout - zero-fill a block range
382 * @bdev: blockdev to write
383 * @sector: start sector
384 * @nr_sects: number of sectors to write
385 * @gfp_mask: memory allocation flags (for bio_alloc)
386 * @flags: controls detailed behavior
387 *
388 * Description:
389 * Zero-fill a block range, either using hardware offload or by explicitly
390 * writing zeroes to the device. See __blkdev_issue_zeroout() for the
391 * valid values for %flags.
392 */
blkdev_issue_zeroout(struct block_device * bdev,sector_t sector,sector_t nr_sects,gfp_t gfp_mask,unsigned flags)393 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
394 sector_t nr_sects, gfp_t gfp_mask, unsigned flags)
395 {
396 int ret = 0;
397 sector_t bs_mask;
398 struct bio *bio;
399 struct blk_plug plug;
400 bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev);
401
402 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
403 if ((sector | nr_sects) & bs_mask)
404 return -EINVAL;
405
406 retry:
407 bio = NULL;
408 blk_start_plug(&plug);
409 if (try_write_zeroes) {
410 ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects,
411 gfp_mask, &bio, flags);
412 } else if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
413 ret = __blkdev_issue_zero_pages(bdev, sector, nr_sects,
414 gfp_mask, &bio);
415 } else {
416 /* No zeroing offload support */
417 ret = -EOPNOTSUPP;
418 }
419 if (ret == 0 && bio) {
420 ret = submit_bio_wait(bio);
421 bio_put(bio);
422 }
423 blk_finish_plug(&plug);
424 if (ret && try_write_zeroes) {
425 if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
426 try_write_zeroes = false;
427 goto retry;
428 }
429 if (!bdev_write_zeroes_sectors(bdev)) {
430 /*
431 * Zeroing offload support was indicated, but the
432 * device reported ILLEGAL REQUEST (for some devices
433 * there is no non-destructive way to verify whether
434 * WRITE ZEROES is actually supported).
435 */
436 ret = -EOPNOTSUPP;
437 }
438 }
439
440 return ret;
441 }
442 EXPORT_SYMBOL(blkdev_issue_zeroout);
443
