Merge tag 'metag-for-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jhoga...
[linux-2.6-block.git] / block / blk-lib.c
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
12 static 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
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 granularity;
32         enum req_op 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, 1, 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 }
104 EXPORT_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  */
117 int 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 }
137 EXPORT_SYMBOL(blkdev_issue_discard);
138
139 /**
140  * blkdev_issue_write_same - queue a write same operation
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  *
147  * Description:
148  *    Issue a write same request for the sectors in question.
149  */
150 int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
151                             sector_t nr_sects, gfp_t gfp_mask,
152                             struct page *page)
153 {
154         struct request_queue *q = bdev_get_queue(bdev);
155         unsigned int max_write_same_sectors;
156         struct bio *bio = NULL;
157         int ret = 0;
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         /* Ensure that max_write_same_sectors doesn't overflow bi_size */
168         max_write_same_sectors = UINT_MAX >> 9;
169
170         while (nr_sects) {
171                 bio = next_bio(bio, 1, gfp_mask);
172                 bio->bi_iter.bi_sector = sector;
173                 bio->bi_bdev = bdev;
174                 bio->bi_vcnt = 1;
175                 bio->bi_io_vec->bv_page = page;
176                 bio->bi_io_vec->bv_offset = 0;
177                 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
178                 bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0);
179
180                 if (nr_sects > max_write_same_sectors) {
181                         bio->bi_iter.bi_size = max_write_same_sectors << 9;
182                         nr_sects -= max_write_same_sectors;
183                         sector += max_write_same_sectors;
184                 } else {
185                         bio->bi_iter.bi_size = nr_sects << 9;
186                         nr_sects = 0;
187                 }
188         }
189
190         if (bio) {
191                 ret = submit_bio_wait(bio);
192                 bio_put(bio);
193         }
194         return ret;
195 }
196 EXPORT_SYMBOL(blkdev_issue_write_same);
197
198 /**
199  * blkdev_issue_zeroout - generate number of zero filed write bios
200  * @bdev:       blockdev to issue
201  * @sector:     start sector
202  * @nr_sects:   number of sectors to write
203  * @gfp_mask:   memory allocation flags (for bio_alloc)
204  *
205  * Description:
206  *  Generate and issue number of bios with zerofiled pages.
207  */
208
209 static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
210                                   sector_t nr_sects, gfp_t gfp_mask)
211 {
212         int ret;
213         struct bio *bio = NULL;
214         unsigned int sz;
215         sector_t bs_mask;
216
217         bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
218         if ((sector | nr_sects) & bs_mask)
219                 return -EINVAL;
220
221         while (nr_sects != 0) {
222                 bio = next_bio(bio, min(nr_sects, (sector_t)BIO_MAX_PAGES),
223                                 gfp_mask);
224                 bio->bi_iter.bi_sector = sector;
225                 bio->bi_bdev   = bdev;
226                 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
227
228                 while (nr_sects != 0) {
229                         sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
230                         ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
231                         nr_sects -= ret >> 9;
232                         sector += ret >> 9;
233                         if (ret < (sz << 9))
234                                 break;
235                 }
236         }
237
238         if (bio) {
239                 ret = submit_bio_wait(bio);
240                 bio_put(bio);
241                 return ret;
242         }
243         return 0;
244 }
245
246 /**
247  * blkdev_issue_zeroout - zero-fill a block range
248  * @bdev:       blockdev to write
249  * @sector:     start sector
250  * @nr_sects:   number of sectors to write
251  * @gfp_mask:   memory allocation flags (for bio_alloc)
252  * @discard:    whether to discard the block range
253  *
254  * Description:
255  *  Zero-fill a block range.  If the discard flag is set and the block
256  *  device guarantees that subsequent READ operations to the block range
257  *  in question will return zeroes, the blocks will be discarded. Should
258  *  the discard request fail, if the discard flag is not set, or if
259  *  discard_zeroes_data is not supported, this function will resort to
260  *  zeroing the blocks manually, thus provisioning (allocating,
261  *  anchoring) them. If the block device supports the WRITE SAME command
262  *  blkdev_issue_zeroout() will use it to optimize the process of
263  *  clearing the block range. Otherwise the zeroing will be performed
264  *  using regular WRITE calls.
265  */
266
267 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
268                          sector_t nr_sects, gfp_t gfp_mask, bool discard)
269 {
270         if (discard) {
271                 if (!blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask,
272                                 BLKDEV_DISCARD_ZERO))
273                         return 0;
274         }
275
276         if (bdev_write_same(bdev) &&
277             blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
278                                     ZERO_PAGE(0)) == 0)
279                 return 0;
280
281         return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
282 }
283 EXPORT_SYMBOL(blkdev_issue_zeroout);