Merge remote-tracking branch 'lsk/v3.10/topic/arm64-fpsimd' into linux-linaro-lsk
[firefly-linux-kernel-4.4.55.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 struct bio_batch {
13         atomic_t                done;
14         unsigned long           flags;
15         struct completion       *wait;
16 };
17
18 static 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  */
40 int 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         sector_t max_discard_sectors;
47         sector_t granularity, alignment;
48         struct bio_batch bb;
49         struct bio *bio;
50         int ret = 0;
51         struct blk_plug plug;
52
53         if (!q)
54                 return -ENXIO;
55
56         if (!blk_queue_discard(q))
57                 return -EOPNOTSUPP;
58
59         /* Zero-sector (unknown) and one-sector granularities are the same.  */
60         granularity = max(q->limits.discard_granularity >> 9, 1U);
61         alignment = bdev_discard_alignment(bdev) >> 9;
62         alignment = sector_div(alignment, granularity);
63
64         /*
65          * Ensure that max_discard_sectors is of the proper
66          * granularity, so that requests stay aligned after a split.
67          */
68         max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
69         sector_div(max_discard_sectors, granularity);
70         max_discard_sectors *= granularity;
71         if (unlikely(!max_discard_sectors)) {
72                 /* Avoid infinite loop below. Being cautious never hurts. */
73                 return -EOPNOTSUPP;
74         }
75
76         if (flags & BLKDEV_DISCARD_SECURE) {
77                 if (!blk_queue_secdiscard(q))
78                         return -EOPNOTSUPP;
79                 type |= REQ_SECURE;
80         }
81
82         atomic_set(&bb.done, 1);
83         bb.flags = 1 << BIO_UPTODATE;
84         bb.wait = &wait;
85
86         blk_start_plug(&plug);
87         while (nr_sects) {
88                 unsigned int req_sects;
89                 sector_t end_sect, tmp;
90
91                 bio = bio_alloc(gfp_mask, 1);
92                 if (!bio) {
93                         ret = -ENOMEM;
94                         break;
95                 }
96
97                 req_sects = min_t(sector_t, nr_sects, max_discard_sectors);
98
99                 /*
100                  * If splitting a request, and the next starting sector would be
101                  * misaligned, stop the discard at the previous aligned sector.
102                  */
103                 end_sect = sector + req_sects;
104                 tmp = end_sect;
105                 if (req_sects < nr_sects &&
106                     sector_div(tmp, granularity) != alignment) {
107                         end_sect = end_sect - alignment;
108                         sector_div(end_sect, granularity);
109                         end_sect = end_sect * granularity + alignment;
110                         req_sects = end_sect - sector;
111                 }
112
113                 bio->bi_sector = sector;
114                 bio->bi_end_io = bio_batch_end_io;
115                 bio->bi_bdev = bdev;
116                 bio->bi_private = &bb;
117
118                 bio->bi_size = req_sects << 9;
119                 nr_sects -= req_sects;
120                 sector = end_sect;
121
122                 atomic_inc(&bb.done);
123                 submit_bio(type, bio);
124
125                 /*
126                  * We can loop for a long time in here, if someone does
127                  * full device discards (like mkfs). Be nice and allow
128                  * us to schedule out to avoid softlocking if preempt
129                  * is disabled.
130                  */
131                 cond_resched();
132         }
133         blk_finish_plug(&plug);
134
135         /* Wait for bios in-flight */
136         if (!atomic_dec_and_test(&bb.done))
137                 wait_for_completion_io(&wait);
138
139         if (!test_bit(BIO_UPTODATE, &bb.flags))
140                 ret = -EIO;
141
142         return ret;
143 }
144 EXPORT_SYMBOL(blkdev_issue_discard);
145
146 /**
147  * blkdev_issue_write_same - queue a write same operation
148  * @bdev:       target blockdev
149  * @sector:     start sector
150  * @nr_sects:   number of sectors to write
151  * @gfp_mask:   memory allocation flags (for bio_alloc)
152  * @page:       page containing data to write
153  *
154  * Description:
155  *    Issue a write same request for the sectors in question.
156  */
157 int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
158                             sector_t nr_sects, gfp_t gfp_mask,
159                             struct page *page)
160 {
161         DECLARE_COMPLETION_ONSTACK(wait);
162         struct request_queue *q = bdev_get_queue(bdev);
163         unsigned int max_write_same_sectors;
164         struct bio_batch bb;
165         struct bio *bio;
166         int ret = 0;
167
168         if (!q)
169                 return -ENXIO;
170
171         max_write_same_sectors = q->limits.max_write_same_sectors;
172
173         if (max_write_same_sectors == 0)
174                 return -EOPNOTSUPP;
175
176         atomic_set(&bb.done, 1);
177         bb.flags = 1 << BIO_UPTODATE;
178         bb.wait = &wait;
179
180         while (nr_sects) {
181                 bio = bio_alloc(gfp_mask, 1);
182                 if (!bio) {
183                         ret = -ENOMEM;
184                         break;
185                 }
186
187                 bio->bi_sector = sector;
188                 bio->bi_end_io = bio_batch_end_io;
189                 bio->bi_bdev = bdev;
190                 bio->bi_private = &bb;
191                 bio->bi_vcnt = 1;
192                 bio->bi_io_vec->bv_page = page;
193                 bio->bi_io_vec->bv_offset = 0;
194                 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
195
196                 if (nr_sects > max_write_same_sectors) {
197                         bio->bi_size = max_write_same_sectors << 9;
198                         nr_sects -= max_write_same_sectors;
199                         sector += max_write_same_sectors;
200                 } else {
201                         bio->bi_size = nr_sects << 9;
202                         nr_sects = 0;
203                 }
204
205                 atomic_inc(&bb.done);
206                 submit_bio(REQ_WRITE | REQ_WRITE_SAME, bio);
207         }
208
209         /* Wait for bios in-flight */
210         if (!atomic_dec_and_test(&bb.done))
211                 wait_for_completion_io(&wait);
212
213         if (!test_bit(BIO_UPTODATE, &bb.flags))
214                 ret = -ENOTSUPP;
215
216         return ret;
217 }
218 EXPORT_SYMBOL(blkdev_issue_write_same);
219
220 /**
221  * blkdev_issue_zeroout - generate number of zero filed write bios
222  * @bdev:       blockdev to issue
223  * @sector:     start sector
224  * @nr_sects:   number of sectors to write
225  * @gfp_mask:   memory allocation flags (for bio_alloc)
226  *
227  * Description:
228  *  Generate and issue number of bios with zerofiled pages.
229  */
230
231 int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
232                         sector_t nr_sects, gfp_t gfp_mask)
233 {
234         int ret;
235         struct bio *bio;
236         struct bio_batch bb;
237         unsigned int sz;
238         DECLARE_COMPLETION_ONSTACK(wait);
239
240         atomic_set(&bb.done, 1);
241         bb.flags = 1 << BIO_UPTODATE;
242         bb.wait = &wait;
243
244         ret = 0;
245         while (nr_sects != 0) {
246                 bio = bio_alloc(gfp_mask,
247                                 min(nr_sects, (sector_t)BIO_MAX_PAGES));
248                 if (!bio) {
249                         ret = -ENOMEM;
250                         break;
251                 }
252
253                 bio->bi_sector = sector;
254                 bio->bi_bdev   = bdev;
255                 bio->bi_end_io = bio_batch_end_io;
256                 bio->bi_private = &bb;
257
258                 while (nr_sects != 0) {
259                         sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
260                         ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
261                         nr_sects -= ret >> 9;
262                         sector += ret >> 9;
263                         if (ret < (sz << 9))
264                                 break;
265                 }
266                 ret = 0;
267                 atomic_inc(&bb.done);
268                 submit_bio(WRITE, bio);
269         }
270
271         /* Wait for bios in-flight */
272         if (!atomic_dec_and_test(&bb.done))
273                 wait_for_completion_io(&wait);
274
275         if (!test_bit(BIO_UPTODATE, &bb.flags))
276                 /* One of bios in the batch was completed with error.*/
277                 ret = -EIO;
278
279         return ret;
280 }
281
282 /**
283  * blkdev_issue_zeroout - zero-fill a block range
284  * @bdev:       blockdev to write
285  * @sector:     start sector
286  * @nr_sects:   number of sectors to write
287  * @gfp_mask:   memory allocation flags (for bio_alloc)
288  *
289  * Description:
290  *  Generate and issue number of bios with zerofiled pages.
291  */
292
293 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
294                          sector_t nr_sects, gfp_t gfp_mask)
295 {
296         if (bdev_write_same(bdev)) {
297                 unsigned char bdn[BDEVNAME_SIZE];
298
299                 if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
300                                              ZERO_PAGE(0)))
301                         return 0;
302
303                 bdevname(bdev, bdn);
304                 pr_err("%s: WRITE SAME failed. Manually zeroing.\n", bdn);
305         }
306
307         return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
308 }
309 EXPORT_SYMBOL(blkdev_issue_zeroout);