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