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