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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; |
47 | unsigned int granularity, alignment, mask; |
48 | struct bio_batch bb; |
49 | struct bio *bio; |
50 | int ret = 0; |
51 | |
52 | if (!q) |
53 | return -ENXIO; |
54 | |
55 | if (!blk_queue_discard(q)) |
56 | return -EOPNOTSUPP; |
57 | |
58 | /* Zero-sector (unknown) and one-sector granularities are the same. */ |
59 | granularity = max(q->limits.discard_granularity >> 9, 1U); |
60 | mask = granularity - 1; |
61 | alignment = (bdev_discard_alignment(bdev) >> 9) & mask; |
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 = round_down(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 | while (nr_sects) { |
85 | unsigned int req_sects; |
86 | sector_t end_sect; |
87 | |
88 | bio = bio_alloc(gfp_mask, 1); |
89 | if (!bio) { |
90 | ret = -ENOMEM; |
91 | break; |
92 | } |
93 | |
94 | req_sects = min_t(sector_t, nr_sects, max_discard_sectors); |
95 | |
96 | /* |
97 | * If splitting a request, and the next starting sector would be |
98 | * misaligned, stop the discard at the previous aligned sector. |
99 | */ |
100 | end_sect = sector + req_sects; |
101 | if (req_sects < nr_sects && (end_sect & mask) != alignment) { |
102 | end_sect = |
103 | round_down(end_sect - alignment, granularity) |
104 | + alignment; |
105 | req_sects = end_sect - sector; |
106 | } |
107 | |
108 | bio->bi_sector = sector; |
109 | bio->bi_end_io = bio_batch_end_io; |
110 | bio->bi_bdev = bdev; |
111 | bio->bi_private = &bb; |
112 | |
113 | bio->bi_size = req_sects << 9; |
114 | nr_sects -= req_sects; |
115 | sector = end_sect; |
116 | |
117 | atomic_inc(&bb.done); |
118 | submit_bio(type, bio); |
119 | } |
120 | |
121 | /* Wait for bios in-flight */ |
122 | if (!atomic_dec_and_test(&bb.done)) |
123 | wait_for_completion(&wait); |
124 | |
125 | if (!test_bit(BIO_UPTODATE, &bb.flags)) |
126 | ret = -EIO; |
127 | |
128 | return ret; |
129 | } |
130 | EXPORT_SYMBOL(blkdev_issue_discard); |
131 | |
132 | /** |
133 | * blkdev_issue_zeroout - generate number of zero filed write bios |
134 | * @bdev: blockdev to issue |
135 | * @sector: start sector |
136 | * @nr_sects: number of sectors to write |
137 | * @gfp_mask: memory allocation flags (for bio_alloc) |
138 | * |
139 | * Description: |
140 | * Generate and issue number of bios with zerofiled pages. |
141 | */ |
142 | |
143 | int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, |
144 | sector_t nr_sects, gfp_t gfp_mask) |
145 | { |
146 | int ret; |
147 | struct bio *bio; |
148 | struct bio_batch bb; |
149 | unsigned int sz; |
150 | DECLARE_COMPLETION_ONSTACK(wait); |
151 | |
152 | atomic_set(&bb.done, 1); |
153 | bb.flags = 1 << BIO_UPTODATE; |
154 | bb.wait = &wait; |
155 | |
156 | ret = 0; |
157 | while (nr_sects != 0) { |
158 | bio = bio_alloc(gfp_mask, |
159 | min(nr_sects, (sector_t)BIO_MAX_PAGES)); |
160 | if (!bio) { |
161 | ret = -ENOMEM; |
162 | break; |
163 | } |
164 | |
165 | bio->bi_sector = sector; |
166 | bio->bi_bdev = bdev; |
167 | bio->bi_end_io = bio_batch_end_io; |
168 | bio->bi_private = &bb; |
169 | |
170 | while (nr_sects != 0) { |
171 | sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects); |
172 | ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0); |
173 | nr_sects -= ret >> 9; |
174 | sector += ret >> 9; |
175 | if (ret < (sz << 9)) |
176 | break; |
177 | } |
178 | ret = 0; |
179 | atomic_inc(&bb.done); |
180 | submit_bio(WRITE, bio); |
181 | } |
182 | |
183 | /* Wait for bios in-flight */ |
184 | if (!atomic_dec_and_test(&bb.done)) |
185 | wait_for_completion(&wait); |
186 | |
187 | if (!test_bit(BIO_UPTODATE, &bb.flags)) |
188 | /* One of bios in the batch was completed with error.*/ |
189 | ret = -EIO; |
190 | |
191 | return ret; |
192 | } |
193 | EXPORT_SYMBOL(blkdev_issue_zeroout); |
194 |
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