Stefan Schmidt says:
[linux-2.6-microblaze.git] / block / blk-lib.c
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
13 int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
14                 sector_t nr_sects, gfp_t gfp_mask, int flags,
15                 struct bio **biop)
16 {
17         struct request_queue *q = bdev_get_queue(bdev);
18         struct bio *bio = *biop;
19         unsigned int op;
20         sector_t bs_mask, part_offset = 0;
21
22         if (bdev_read_only(bdev))
23                 return -EPERM;
24
25         if (flags & BLKDEV_DISCARD_SECURE) {
26                 if (!blk_queue_secure_erase(q))
27                         return -EOPNOTSUPP;
28                 op = REQ_OP_SECURE_ERASE;
29         } else {
30                 if (!blk_queue_discard(q))
31                         return -EOPNOTSUPP;
32                 op = REQ_OP_DISCARD;
33         }
34
35         /* In case the discard granularity isn't set by buggy device driver */
36         if (WARN_ON_ONCE(!q->limits.discard_granularity)) {
37                 char dev_name[BDEVNAME_SIZE];
38
39                 bdevname(bdev, dev_name);
40                 pr_err_ratelimited("%s: Error: discard_granularity is 0.\n", dev_name);
41                 return -EOPNOTSUPP;
42         }
43
44         bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
45         if ((sector | nr_sects) & bs_mask)
46                 return -EINVAL;
47
48         if (!nr_sects)
49                 return -EINVAL;
50
51         /* In case the discard request is in a partition */
52         if (bdev_is_partition(bdev))
53                 part_offset = bdev->bd_start_sect;
54
55         while (nr_sects) {
56                 sector_t granularity_aligned_lba, req_sects;
57                 sector_t sector_mapped = sector + part_offset;
58
59                 granularity_aligned_lba = round_up(sector_mapped,
60                                 q->limits.discard_granularity >> SECTOR_SHIFT);
61
62                 /*
63                  * Check whether the discard bio starts at a discard_granularity
64                  * aligned LBA,
65                  * - If no: set (granularity_aligned_lba - sector_mapped) to
66                  *   bi_size of the first split bio, then the second bio will
67                  *   start at a discard_granularity aligned LBA on the device.
68                  * - If yes: use bio_aligned_discard_max_sectors() as the max
69                  *   possible bi_size of the first split bio. Then when this bio
70                  *   is split in device drive, the split ones are very probably
71                  *   to be aligned to discard_granularity of the device's queue.
72                  */
73                 if (granularity_aligned_lba == sector_mapped)
74                         req_sects = min_t(sector_t, nr_sects,
75                                           bio_aligned_discard_max_sectors(q));
76                 else
77                         req_sects = min_t(sector_t, nr_sects,
78                                           granularity_aligned_lba - sector_mapped);
79
80                 WARN_ON_ONCE((req_sects << 9) > UINT_MAX);
81
82                 bio = blk_next_bio(bio, bdev, 0, op, gfp_mask);
83                 bio->bi_iter.bi_sector = sector;
84                 bio->bi_iter.bi_size = req_sects << 9;
85                 sector += req_sects;
86                 nr_sects -= req_sects;
87
88                 /*
89                  * We can loop for a long time in here, if someone does
90                  * full device discards (like mkfs). Be nice and allow
91                  * us to schedule out to avoid softlocking if preempt
92                  * is disabled.
93                  */
94                 cond_resched();
95         }
96
97         *biop = bio;
98         return 0;
99 }
100 EXPORT_SYMBOL(__blkdev_issue_discard);
101
102 /**
103  * blkdev_issue_discard - queue a discard
104  * @bdev:       blockdev to issue discard for
105  * @sector:     start sector
106  * @nr_sects:   number of sectors to discard
107  * @gfp_mask:   memory allocation flags (for bio_alloc)
108  * @flags:      BLKDEV_DISCARD_* flags to control behaviour
109  *
110  * Description:
111  *    Issue a discard request for the sectors in question.
112  */
113 int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
114                 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
115 {
116         struct bio *bio = NULL;
117         struct blk_plug plug;
118         int ret;
119
120         blk_start_plug(&plug);
121         ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags,
122                         &bio);
123         if (!ret && bio) {
124                 ret = submit_bio_wait(bio);
125                 if (ret == -EOPNOTSUPP)
126                         ret = 0;
127                 bio_put(bio);
128         }
129         blk_finish_plug(&plug);
130
131         return ret;
132 }
133 EXPORT_SYMBOL(blkdev_issue_discard);
134
135 static int __blkdev_issue_write_zeroes(struct block_device *bdev,
136                 sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
137                 struct bio **biop, unsigned flags)
138 {
139         struct bio *bio = *biop;
140         unsigned int max_write_zeroes_sectors;
141
142         if (bdev_read_only(bdev))
143                 return -EPERM;
144
145         /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */
146         max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev);
147
148         if (max_write_zeroes_sectors == 0)
149                 return -EOPNOTSUPP;
150
151         while (nr_sects) {
152                 bio = blk_next_bio(bio, bdev, 0, REQ_OP_WRITE_ZEROES, gfp_mask);
153                 bio->bi_iter.bi_sector = sector;
154                 if (flags & BLKDEV_ZERO_NOUNMAP)
155                         bio->bi_opf |= REQ_NOUNMAP;
156
157                 if (nr_sects > max_write_zeroes_sectors) {
158                         bio->bi_iter.bi_size = max_write_zeroes_sectors << 9;
159                         nr_sects -= max_write_zeroes_sectors;
160                         sector += max_write_zeroes_sectors;
161                 } else {
162                         bio->bi_iter.bi_size = nr_sects << 9;
163                         nr_sects = 0;
164                 }
165                 cond_resched();
166         }
167
168         *biop = bio;
169         return 0;
170 }
171
172 /*
173  * Convert a number of 512B sectors to a number of pages.
174  * The result is limited to a number of pages that can fit into a BIO.
175  * Also make sure that the result is always at least 1 (page) for the cases
176  * where nr_sects is lower than the number of sectors in a page.
177  */
178 static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects)
179 {
180         sector_t pages = DIV_ROUND_UP_SECTOR_T(nr_sects, PAGE_SIZE / 512);
181
182         return min(pages, (sector_t)BIO_MAX_VECS);
183 }
184
185 static int __blkdev_issue_zero_pages(struct block_device *bdev,
186                 sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
187                 struct bio **biop)
188 {
189         struct bio *bio = *biop;
190         int bi_size = 0;
191         unsigned int sz;
192
193         if (bdev_read_only(bdev))
194                 return -EPERM;
195
196         while (nr_sects != 0) {
197                 bio = blk_next_bio(bio, bdev, __blkdev_sectors_to_bio_pages(nr_sects),
198                                    REQ_OP_WRITE, gfp_mask);
199                 bio->bi_iter.bi_sector = sector;
200
201                 while (nr_sects != 0) {
202                         sz = min((sector_t) PAGE_SIZE, nr_sects << 9);
203                         bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0);
204                         nr_sects -= bi_size >> 9;
205                         sector += bi_size >> 9;
206                         if (bi_size < sz)
207                                 break;
208                 }
209                 cond_resched();
210         }
211
212         *biop = bio;
213         return 0;
214 }
215
216 /**
217  * __blkdev_issue_zeroout - generate number of zero filed write bios
218  * @bdev:       blockdev to issue
219  * @sector:     start sector
220  * @nr_sects:   number of sectors to write
221  * @gfp_mask:   memory allocation flags (for bio_alloc)
222  * @biop:       pointer to anchor bio
223  * @flags:      controls detailed behavior
224  *
225  * Description:
226  *  Zero-fill a block range, either using hardware offload or by explicitly
227  *  writing zeroes to the device.
228  *
229  *  If a device is using logical block provisioning, the underlying space will
230  *  not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
231  *
232  *  If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return
233  *  -EOPNOTSUPP if no explicit hardware offload for zeroing is provided.
234  */
235 int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
236                 sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
237                 unsigned flags)
238 {
239         int ret;
240         sector_t bs_mask;
241
242         bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
243         if ((sector | nr_sects) & bs_mask)
244                 return -EINVAL;
245
246         ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask,
247                         biop, flags);
248         if (ret != -EOPNOTSUPP || (flags & BLKDEV_ZERO_NOFALLBACK))
249                 return ret;
250
251         return __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
252                                          biop);
253 }
254 EXPORT_SYMBOL(__blkdev_issue_zeroout);
255
256 /**
257  * blkdev_issue_zeroout - zero-fill a block range
258  * @bdev:       blockdev to write
259  * @sector:     start sector
260  * @nr_sects:   number of sectors to write
261  * @gfp_mask:   memory allocation flags (for bio_alloc)
262  * @flags:      controls detailed behavior
263  *
264  * Description:
265  *  Zero-fill a block range, either using hardware offload or by explicitly
266  *  writing zeroes to the device.  See __blkdev_issue_zeroout() for the
267  *  valid values for %flags.
268  */
269 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
270                 sector_t nr_sects, gfp_t gfp_mask, unsigned flags)
271 {
272         int ret = 0;
273         sector_t bs_mask;
274         struct bio *bio;
275         struct blk_plug plug;
276         bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev);
277
278         bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
279         if ((sector | nr_sects) & bs_mask)
280                 return -EINVAL;
281
282 retry:
283         bio = NULL;
284         blk_start_plug(&plug);
285         if (try_write_zeroes) {
286                 ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects,
287                                                   gfp_mask, &bio, flags);
288         } else if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
289                 ret = __blkdev_issue_zero_pages(bdev, sector, nr_sects,
290                                                 gfp_mask, &bio);
291         } else {
292                 /* No zeroing offload support */
293                 ret = -EOPNOTSUPP;
294         }
295         if (ret == 0 && bio) {
296                 ret = submit_bio_wait(bio);
297                 bio_put(bio);
298         }
299         blk_finish_plug(&plug);
300         if (ret && try_write_zeroes) {
301                 if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
302                         try_write_zeroes = false;
303                         goto retry;
304                 }
305                 if (!bdev_write_zeroes_sectors(bdev)) {
306                         /*
307                          * Zeroing offload support was indicated, but the
308                          * device reported ILLEGAL REQUEST (for some devices
309                          * there is no non-destructive way to verify whether
310                          * WRITE ZEROES is actually supported).
311                          */
312                         ret = -EOPNOTSUPP;
313                 }
314         }
315
316         return ret;
317 }
318 EXPORT_SYMBOL(blkdev_issue_zeroout);