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