Loading...
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
12struct bio_batch {
13 atomic_t done;
14 unsigned long flags;
15 struct completion *wait;
16};
17
18static void bio_batch_end_io(struct bio *bio, int err)
19{
20 struct bio_batch *bb = bio->bi_private;
21
22 if (err && (err != -EOPNOTSUPP))
23 clear_bit(BIO_UPTODATE, &bb->flags);
24 if (atomic_dec_and_test(&bb->done))
25 complete(bb->wait);
26 bio_put(bio);
27}
28
29/**
30 * blkdev_issue_discard - queue a discard
31 * @bdev: blockdev to issue discard for
32 * @sector: start sector
33 * @nr_sects: number of sectors to discard
34 * @gfp_mask: memory allocation flags (for bio_alloc)
35 * @flags: BLKDEV_IFL_* flags to control behaviour
36 *
37 * Description:
38 * Issue a discard request for the sectors in question.
39 */
40int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
41 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
42{
43 DECLARE_COMPLETION_ONSTACK(wait);
44 struct request_queue *q = bdev_get_queue(bdev);
45 int type = REQ_WRITE | REQ_DISCARD;
46 unsigned int max_discard_sectors;
47 struct bio_batch bb;
48 struct bio *bio;
49 int ret = 0;
50
51 if (!q)
52 return -ENXIO;
53
54 if (!blk_queue_discard(q))
55 return -EOPNOTSUPP;
56
57 /*
58 * Ensure that max_discard_sectors is of the proper
59 * granularity
60 */
61 max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
62 if (unlikely(!max_discard_sectors)) {
63 /* Avoid infinite loop below. Being cautious never hurts. */
64 return -EOPNOTSUPP;
65 } else if (q->limits.discard_granularity) {
66 unsigned int disc_sects = q->limits.discard_granularity >> 9;
67
68 max_discard_sectors &= ~(disc_sects - 1);
69 }
70
71 if (flags & BLKDEV_DISCARD_SECURE) {
72 if (!blk_queue_secdiscard(q))
73 return -EOPNOTSUPP;
74 type |= REQ_SECURE;
75 }
76
77 atomic_set(&bb.done, 1);
78 bb.flags = 1 << BIO_UPTODATE;
79 bb.wait = &wait;
80
81 while (nr_sects) {
82 bio = bio_alloc(gfp_mask, 1);
83 if (!bio) {
84 ret = -ENOMEM;
85 break;
86 }
87
88 bio->bi_sector = sector;
89 bio->bi_end_io = bio_batch_end_io;
90 bio->bi_bdev = bdev;
91 bio->bi_private = &bb;
92
93 if (nr_sects > max_discard_sectors) {
94 bio->bi_size = max_discard_sectors << 9;
95 nr_sects -= max_discard_sectors;
96 sector += max_discard_sectors;
97 } else {
98 bio->bi_size = nr_sects << 9;
99 nr_sects = 0;
100 }
101
102 atomic_inc(&bb.done);
103 submit_bio(type, bio);
104 }
105
106 /* Wait for bios in-flight */
107 if (!atomic_dec_and_test(&bb.done))
108 wait_for_completion(&wait);
109
110 if (!test_bit(BIO_UPTODATE, &bb.flags))
111 ret = -EIO;
112
113 return ret;
114}
115EXPORT_SYMBOL(blkdev_issue_discard);
116
117/**
118 * blkdev_issue_zeroout - generate number of zero filed write bios
119 * @bdev: blockdev to issue
120 * @sector: start sector
121 * @nr_sects: number of sectors to write
122 * @gfp_mask: memory allocation flags (for bio_alloc)
123 *
124 * Description:
125 * Generate and issue number of bios with zerofiled pages.
126 */
127
128int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
129 sector_t nr_sects, gfp_t gfp_mask)
130{
131 int ret;
132 struct bio *bio;
133 struct bio_batch bb;
134 unsigned int sz;
135 DECLARE_COMPLETION_ONSTACK(wait);
136
137 atomic_set(&bb.done, 1);
138 bb.flags = 1 << BIO_UPTODATE;
139 bb.wait = &wait;
140
141 ret = 0;
142 while (nr_sects != 0) {
143 bio = bio_alloc(gfp_mask,
144 min(nr_sects, (sector_t)BIO_MAX_PAGES));
145 if (!bio) {
146 ret = -ENOMEM;
147 break;
148 }
149
150 bio->bi_sector = sector;
151 bio->bi_bdev = bdev;
152 bio->bi_end_io = bio_batch_end_io;
153 bio->bi_private = &bb;
154
155 while (nr_sects != 0) {
156 sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
157 ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
158 nr_sects -= ret >> 9;
159 sector += ret >> 9;
160 if (ret < (sz << 9))
161 break;
162 }
163 ret = 0;
164 atomic_inc(&bb.done);
165 submit_bio(WRITE, bio);
166 }
167
168 /* Wait for bios in-flight */
169 if (!atomic_dec_and_test(&bb.done))
170 wait_for_completion(&wait);
171
172 if (!test_bit(BIO_UPTODATE, &bb.flags))
173 /* One of bios in the batch was completed with error.*/
174 ret = -EIO;
175
176 return ret;
177}
178EXPORT_SYMBOL(blkdev_issue_zeroout);
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
12static 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
25int __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 (flags & BLKDEV_DISCARD_ZERO)
41 return -EOPNOTSUPP;
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 if ((flags & BLKDEV_DISCARD_ZERO) &&
49 !q->limits.discard_zeroes_data)
50 return -EOPNOTSUPP;
51 op = REQ_OP_DISCARD;
52 }
53
54 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
55 if ((sector | nr_sects) & bs_mask)
56 return -EINVAL;
57
58 /* Zero-sector (unknown) and one-sector granularities are the same. */
59 granularity = max(q->limits.discard_granularity >> 9, 1U);
60 alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
61
62 while (nr_sects) {
63 unsigned int req_sects;
64 sector_t end_sect, tmp;
65
66 /* Make sure bi_size doesn't overflow */
67 req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9);
68
69 /**
70 * If splitting a request, and the next starting sector would be
71 * misaligned, stop the discard at the previous aligned sector.
72 */
73 end_sect = sector + req_sects;
74 tmp = end_sect;
75 if (req_sects < nr_sects &&
76 sector_div(tmp, granularity) != alignment) {
77 end_sect = end_sect - alignment;
78 sector_div(end_sect, granularity);
79 end_sect = end_sect * granularity + alignment;
80 req_sects = end_sect - sector;
81 }
82
83 bio = next_bio(bio, 0, gfp_mask);
84 bio->bi_iter.bi_sector = sector;
85 bio->bi_bdev = bdev;
86 bio_set_op_attrs(bio, op, 0);
87
88 bio->bi_iter.bi_size = req_sects << 9;
89 nr_sects -= req_sects;
90 sector = end_sect;
91
92 /*
93 * We can loop for a long time in here, if someone does
94 * full device discards (like mkfs). Be nice and allow
95 * us to schedule out to avoid softlocking if preempt
96 * is disabled.
97 */
98 cond_resched();
99 }
100
101 *biop = bio;
102 return 0;
103}
104EXPORT_SYMBOL(__blkdev_issue_discard);
105
106/**
107 * blkdev_issue_discard - queue a discard
108 * @bdev: blockdev to issue discard for
109 * @sector: start sector
110 * @nr_sects: number of sectors to discard
111 * @gfp_mask: memory allocation flags (for bio_alloc)
112 * @flags: BLKDEV_IFL_* flags to control behaviour
113 *
114 * Description:
115 * Issue a discard request for the sectors in question.
116 */
117int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
118 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
119{
120 struct bio *bio = NULL;
121 struct blk_plug plug;
122 int ret;
123
124 blk_start_plug(&plug);
125 ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags,
126 &bio);
127 if (!ret && bio) {
128 ret = submit_bio_wait(bio);
129 if (ret == -EOPNOTSUPP && !(flags & BLKDEV_DISCARD_ZERO))
130 ret = 0;
131 bio_put(bio);
132 }
133 blk_finish_plug(&plug);
134
135 return ret;
136}
137EXPORT_SYMBOL(blkdev_issue_discard);
138
139/**
140 * __blkdev_issue_write_same - generate number of bios with same page
141 * @bdev: target blockdev
142 * @sector: start sector
143 * @nr_sects: number of sectors to write
144 * @gfp_mask: memory allocation flags (for bio_alloc)
145 * @page: page containing data to write
146 * @biop: pointer to anchor bio
147 *
148 * Description:
149 * Generate and issue number of bios(REQ_OP_WRITE_SAME) with same page.
150 */
151static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
152 sector_t nr_sects, gfp_t gfp_mask, struct page *page,
153 struct bio **biop)
154{
155 struct request_queue *q = bdev_get_queue(bdev);
156 unsigned int max_write_same_sectors;
157 struct bio *bio = *biop;
158 sector_t bs_mask;
159
160 if (!q)
161 return -ENXIO;
162
163 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
164 if ((sector | nr_sects) & bs_mask)
165 return -EINVAL;
166
167 if (!bdev_write_same(bdev))
168 return -EOPNOTSUPP;
169
170 /* Ensure that max_write_same_sectors doesn't overflow bi_size */
171 max_write_same_sectors = UINT_MAX >> 9;
172
173 while (nr_sects) {
174 bio = next_bio(bio, 1, gfp_mask);
175 bio->bi_iter.bi_sector = sector;
176 bio->bi_bdev = bdev;
177 bio->bi_vcnt = 1;
178 bio->bi_io_vec->bv_page = page;
179 bio->bi_io_vec->bv_offset = 0;
180 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
181 bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0);
182
183 if (nr_sects > max_write_same_sectors) {
184 bio->bi_iter.bi_size = max_write_same_sectors << 9;
185 nr_sects -= max_write_same_sectors;
186 sector += max_write_same_sectors;
187 } else {
188 bio->bi_iter.bi_size = nr_sects << 9;
189 nr_sects = 0;
190 }
191 cond_resched();
192 }
193
194 *biop = bio;
195 return 0;
196}
197
198/**
199 * blkdev_issue_write_same - queue a write same operation
200 * @bdev: target blockdev
201 * @sector: start sector
202 * @nr_sects: number of sectors to write
203 * @gfp_mask: memory allocation flags (for bio_alloc)
204 * @page: page containing data
205 *
206 * Description:
207 * Issue a write same request for the sectors in question.
208 */
209int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
210 sector_t nr_sects, gfp_t gfp_mask,
211 struct page *page)
212{
213 struct bio *bio = NULL;
214 struct blk_plug plug;
215 int ret;
216
217 blk_start_plug(&plug);
218 ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, page,
219 &bio);
220 if (ret == 0 && bio) {
221 ret = submit_bio_wait(bio);
222 bio_put(bio);
223 }
224 blk_finish_plug(&plug);
225 return ret;
226}
227EXPORT_SYMBOL(blkdev_issue_write_same);
228
229/**
230 * __blkdev_issue_write_zeroes - generate number of bios with WRITE ZEROES
231 * @bdev: blockdev to issue
232 * @sector: start sector
233 * @nr_sects: number of sectors to write
234 * @gfp_mask: memory allocation flags (for bio_alloc)
235 * @biop: pointer to anchor bio
236 *
237 * Description:
238 * Generate and issue number of bios(REQ_OP_WRITE_ZEROES) with zerofiled pages.
239 */
240static int __blkdev_issue_write_zeroes(struct block_device *bdev,
241 sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
242 struct bio **biop)
243{
244 struct bio *bio = *biop;
245 unsigned int max_write_zeroes_sectors;
246 struct request_queue *q = bdev_get_queue(bdev);
247
248 if (!q)
249 return -ENXIO;
250
251 /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */
252 max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev);
253
254 if (max_write_zeroes_sectors == 0)
255 return -EOPNOTSUPP;
256
257 while (nr_sects) {
258 bio = next_bio(bio, 0, gfp_mask);
259 bio->bi_iter.bi_sector = sector;
260 bio->bi_bdev = bdev;
261 bio_set_op_attrs(bio, REQ_OP_WRITE_ZEROES, 0);
262
263 if (nr_sects > max_write_zeroes_sectors) {
264 bio->bi_iter.bi_size = max_write_zeroes_sectors << 9;
265 nr_sects -= max_write_zeroes_sectors;
266 sector += max_write_zeroes_sectors;
267 } else {
268 bio->bi_iter.bi_size = nr_sects << 9;
269 nr_sects = 0;
270 }
271 cond_resched();
272 }
273
274 *biop = bio;
275 return 0;
276}
277
278/**
279 * __blkdev_issue_zeroout - generate number of zero filed write bios
280 * @bdev: blockdev to issue
281 * @sector: start sector
282 * @nr_sects: number of sectors to write
283 * @gfp_mask: memory allocation flags (for bio_alloc)
284 * @biop: pointer to anchor bio
285 * @discard: discard flag
286 *
287 * Description:
288 * Generate and issue number of bios with zerofiled pages.
289 */
290int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
291 sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
292 bool discard)
293{
294 int ret;
295 int bi_size = 0;
296 struct bio *bio = *biop;
297 unsigned int sz;
298 sector_t bs_mask;
299
300 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
301 if ((sector | nr_sects) & bs_mask)
302 return -EINVAL;
303
304 ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask,
305 biop);
306 if (ret == 0 || (ret && ret != -EOPNOTSUPP))
307 goto out;
308
309 ret = 0;
310 while (nr_sects != 0) {
311 bio = next_bio(bio, min(nr_sects, (sector_t)BIO_MAX_PAGES),
312 gfp_mask);
313 bio->bi_iter.bi_sector = sector;
314 bio->bi_bdev = bdev;
315 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
316
317 while (nr_sects != 0) {
318 sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
319 bi_size = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
320 nr_sects -= bi_size >> 9;
321 sector += bi_size >> 9;
322 if (bi_size < (sz << 9))
323 break;
324 }
325 cond_resched();
326 }
327
328 *biop = bio;
329out:
330 return ret;
331}
332EXPORT_SYMBOL(__blkdev_issue_zeroout);
333
334/**
335 * blkdev_issue_zeroout - zero-fill a block range
336 * @bdev: blockdev to write
337 * @sector: start sector
338 * @nr_sects: number of sectors to write
339 * @gfp_mask: memory allocation flags (for bio_alloc)
340 * @discard: whether to discard the block range
341 *
342 * Description:
343 * Zero-fill a block range. If the discard flag is set and the block
344 * device guarantees that subsequent READ operations to the block range
345 * in question will return zeroes, the blocks will be discarded. Should
346 * the discard request fail, if the discard flag is not set, or if
347 * discard_zeroes_data is not supported, this function will resort to
348 * zeroing the blocks manually, thus provisioning (allocating,
349 * anchoring) them. If the block device supports WRITE ZEROES or WRITE SAME
350 * command(s), blkdev_issue_zeroout() will use it to optimize the process of
351 * clearing the block range. Otherwise the zeroing will be performed
352 * using regular WRITE calls.
353 */
354int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
355 sector_t nr_sects, gfp_t gfp_mask, bool discard)
356{
357 int ret;
358 struct bio *bio = NULL;
359 struct blk_plug plug;
360
361 if (discard) {
362 if (!blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask,
363 BLKDEV_DISCARD_ZERO))
364 return 0;
365 }
366
367 if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
368 ZERO_PAGE(0)))
369 return 0;
370
371 blk_start_plug(&plug);
372 ret = __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask,
373 &bio, discard);
374 if (ret == 0 && bio) {
375 ret = submit_bio_wait(bio);
376 bio_put(bio);
377 }
378 blk_finish_plug(&plug);
379
380 return ret;
381}
382EXPORT_SYMBOL(blkdev_issue_zeroout);