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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 | 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 | blk_finish_plug(&plug); | |
126 | ||
127 | /* Wait for bios in-flight */ | |
128 | if (!atomic_dec_and_test(&bb.done)) | |
129 | wait_for_completion_io(&wait); | |
130 | ||
131 | if (!test_bit(BIO_UPTODATE, &bb.flags)) | |
132 | ret = -EIO; | |
133 | ||
134 | return ret; | |
135 | } | |
136 | EXPORT_SYMBOL(blkdev_issue_discard); | |
137 | ||
138 | /** | |
139 | * blkdev_issue_write_same - queue a write same operation | |
140 | * @bdev: target blockdev | |
141 | * @sector: start sector | |
142 | * @nr_sects: number of sectors to write | |
143 | * @gfp_mask: memory allocation flags (for bio_alloc) | |
144 | * @page: page containing data to write | |
145 | * | |
146 | * Description: | |
147 | * Issue a write same request for the sectors in question. | |
148 | */ | |
149 | int blkdev_issue_write_same(struct block_device *bdev, sector_t sector, | |
150 | sector_t nr_sects, gfp_t gfp_mask, | |
151 | struct page *page) | |
152 | { | |
153 | DECLARE_COMPLETION_ONSTACK(wait); | |
154 | struct request_queue *q = bdev_get_queue(bdev); | |
155 | unsigned int max_write_same_sectors; | |
156 | struct bio_batch bb; | |
157 | struct bio *bio; | |
158 | int ret = 0; | |
159 | ||
160 | if (!q) | |
161 | return -ENXIO; | |
162 | ||
163 | max_write_same_sectors = q->limits.max_write_same_sectors; | |
164 | ||
165 | if (max_write_same_sectors == 0) | |
166 | return -EOPNOTSUPP; | |
167 | ||
168 | atomic_set(&bb.done, 1); | |
169 | bb.flags = 1 << BIO_UPTODATE; | |
170 | bb.wait = &wait; | |
171 | ||
172 | while (nr_sects) { | |
173 | bio = bio_alloc(gfp_mask, 1); | |
174 | if (!bio) { | |
175 | ret = -ENOMEM; | |
176 | break; | |
177 | } | |
178 | ||
179 | bio->bi_sector = sector; | |
180 | bio->bi_end_io = bio_batch_end_io; | |
181 | bio->bi_bdev = bdev; | |
182 | bio->bi_private = &bb; | |
183 | bio->bi_vcnt = 1; | |
184 | bio->bi_io_vec->bv_page = page; | |
185 | bio->bi_io_vec->bv_offset = 0; | |
186 | bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev); | |
187 | ||
188 | if (nr_sects > max_write_same_sectors) { | |
189 | bio->bi_size = max_write_same_sectors << 9; | |
190 | nr_sects -= max_write_same_sectors; | |
191 | sector += max_write_same_sectors; | |
192 | } else { | |
193 | bio->bi_size = nr_sects << 9; | |
194 | nr_sects = 0; | |
195 | } | |
196 | ||
197 | atomic_inc(&bb.done); | |
198 | submit_bio(REQ_WRITE | REQ_WRITE_SAME, bio); | |
199 | } | |
200 | ||
201 | /* Wait for bios in-flight */ | |
202 | if (!atomic_dec_and_test(&bb.done)) | |
203 | wait_for_completion_io(&wait); | |
204 | ||
205 | if (!test_bit(BIO_UPTODATE, &bb.flags)) | |
206 | ret = -ENOTSUPP; | |
207 | ||
208 | return ret; | |
209 | } | |
210 | EXPORT_SYMBOL(blkdev_issue_write_same); | |
211 | ||
212 | /** | |
213 | * blkdev_issue_zeroout - generate number of zero filed write bios | |
214 | * @bdev: blockdev to issue | |
215 | * @sector: start sector | |
216 | * @nr_sects: number of sectors to write | |
217 | * @gfp_mask: memory allocation flags (for bio_alloc) | |
218 | * | |
219 | * Description: | |
220 | * Generate and issue number of bios with zerofiled pages. | |
221 | */ | |
222 | ||
223 | int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, | |
224 | sector_t nr_sects, gfp_t gfp_mask) | |
225 | { | |
226 | int ret; | |
227 | struct bio *bio; | |
228 | struct bio_batch bb; | |
229 | unsigned int sz; | |
230 | DECLARE_COMPLETION_ONSTACK(wait); | |
231 | ||
232 | atomic_set(&bb.done, 1); | |
233 | bb.flags = 1 << BIO_UPTODATE; | |
234 | bb.wait = &wait; | |
235 | ||
236 | ret = 0; | |
237 | while (nr_sects != 0) { | |
238 | bio = bio_alloc(gfp_mask, | |
239 | min(nr_sects, (sector_t)BIO_MAX_PAGES)); | |
240 | if (!bio) { | |
241 | ret = -ENOMEM; | |
242 | break; | |
243 | } | |
244 | ||
245 | bio->bi_sector = sector; | |
246 | bio->bi_bdev = bdev; | |
247 | bio->bi_end_io = bio_batch_end_io; | |
248 | bio->bi_private = &bb; | |
249 | ||
250 | while (nr_sects != 0) { | |
251 | sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects); | |
252 | ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0); | |
253 | nr_sects -= ret >> 9; | |
254 | sector += ret >> 9; | |
255 | if (ret < (sz << 9)) | |
256 | break; | |
257 | } | |
258 | ret = 0; | |
259 | atomic_inc(&bb.done); | |
260 | submit_bio(WRITE, bio); | |
261 | } | |
262 | ||
263 | /* Wait for bios in-flight */ | |
264 | if (!atomic_dec_and_test(&bb.done)) | |
265 | wait_for_completion_io(&wait); | |
266 | ||
267 | if (!test_bit(BIO_UPTODATE, &bb.flags)) | |
268 | /* One of bios in the batch was completed with error.*/ | |
269 | ret = -EIO; | |
270 | ||
271 | return ret; | |
272 | } | |
273 | ||
274 | /** | |
275 | * blkdev_issue_zeroout - zero-fill a block range | |
276 | * @bdev: blockdev to write | |
277 | * @sector: start sector | |
278 | * @nr_sects: number of sectors to write | |
279 | * @gfp_mask: memory allocation flags (for bio_alloc) | |
280 | * | |
281 | * Description: | |
282 | * Generate and issue number of bios with zerofiled pages. | |
283 | */ | |
284 | ||
285 | int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, | |
286 | sector_t nr_sects, gfp_t gfp_mask) | |
287 | { | |
288 | if (bdev_write_same(bdev)) { | |
289 | unsigned char bdn[BDEVNAME_SIZE]; | |
290 | ||
291 | if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, | |
292 | ZERO_PAGE(0))) | |
293 | return 0; | |
294 | ||
295 | bdevname(bdev, bdn); | |
296 | pr_err("%s: WRITE SAME failed. Manually zeroing.\n", bdn); | |
297 | } | |
298 | ||
299 | return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask); | |
300 | } | |
301 | EXPORT_SYMBOL(blkdev_issue_zeroout); |