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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 | struct bio_batch bb; |
48 | struct bio *bio; |
49 | int ret = 0; |
50 | |
51 | if (!q) |
52 | return -ENXIO; |
53 | |
54 | if (!blk_queue_discard(q)) |
55 | return -EOPNOTSUPP; |
56 | |
57 | /* |
58 | * Ensure that max_discard_sectors is of the proper |
59 | * granularity |
60 | */ |
61 | max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9); |
62 | if (unlikely(!max_discard_sectors)) { |
63 | /* Avoid infinite loop below. Being cautious never hurts. */ |
64 | return -EOPNOTSUPP; |
65 | } else if (q->limits.discard_granularity) { |
66 | unsigned int disc_sects = q->limits.discard_granularity >> 9; |
67 | |
68 | max_discard_sectors &= ~(disc_sects - 1); |
69 | } |
70 | |
71 | if (flags & BLKDEV_DISCARD_SECURE) { |
72 | if (!blk_queue_secdiscard(q)) |
73 | return -EOPNOTSUPP; |
74 | type |= REQ_SECURE; |
75 | } |
76 | |
77 | atomic_set(&bb.done, 1); |
78 | bb.flags = 1 << BIO_UPTODATE; |
79 | bb.wait = &wait; |
80 | |
81 | while (nr_sects) { |
82 | bio = bio_alloc(gfp_mask, 1); |
83 | if (!bio) { |
84 | ret = -ENOMEM; |
85 | break; |
86 | } |
87 | |
88 | bio->bi_sector = sector; |
89 | bio->bi_end_io = bio_batch_end_io; |
90 | bio->bi_bdev = bdev; |
91 | bio->bi_private = &bb; |
92 | |
93 | if (nr_sects > max_discard_sectors) { |
94 | bio->bi_size = max_discard_sectors << 9; |
95 | nr_sects -= max_discard_sectors; |
96 | sector += max_discard_sectors; |
97 | } else { |
98 | bio->bi_size = nr_sects << 9; |
99 | nr_sects = 0; |
100 | } |
101 | |
102 | atomic_inc(&bb.done); |
103 | submit_bio(type, bio); |
104 | } |
105 | |
106 | /* Wait for bios in-flight */ |
107 | if (!atomic_dec_and_test(&bb.done)) |
108 | wait_for_completion(&wait); |
109 | |
110 | if (!test_bit(BIO_UPTODATE, &bb.flags)) |
111 | ret = -EIO; |
112 | |
113 | return ret; |
114 | } |
115 | EXPORT_SYMBOL(blkdev_issue_discard); |
116 | |
117 | /** |
118 | * blkdev_issue_zeroout - generate number of zero filed write bios |
119 | * @bdev: blockdev to issue |
120 | * @sector: start sector |
121 | * @nr_sects: number of sectors to write |
122 | * @gfp_mask: memory allocation flags (for bio_alloc) |
123 | * |
124 | * Description: |
125 | * Generate and issue number of bios with zerofiled pages. |
126 | */ |
127 | |
128 | int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, |
129 | sector_t nr_sects, gfp_t gfp_mask) |
130 | { |
131 | int ret; |
132 | struct bio *bio; |
133 | struct bio_batch bb; |
134 | unsigned int sz; |
135 | DECLARE_COMPLETION_ONSTACK(wait); |
136 | |
137 | atomic_set(&bb.done, 1); |
138 | bb.flags = 1 << BIO_UPTODATE; |
139 | bb.wait = &wait; |
140 | |
141 | ret = 0; |
142 | while (nr_sects != 0) { |
143 | bio = bio_alloc(gfp_mask, |
144 | min(nr_sects, (sector_t)BIO_MAX_PAGES)); |
145 | if (!bio) { |
146 | ret = -ENOMEM; |
147 | break; |
148 | } |
149 | |
150 | bio->bi_sector = sector; |
151 | bio->bi_bdev = bdev; |
152 | bio->bi_end_io = bio_batch_end_io; |
153 | bio->bi_private = &bb; |
154 | |
155 | while (nr_sects != 0) { |
156 | sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects); |
157 | ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0); |
158 | nr_sects -= ret >> 9; |
159 | sector += ret >> 9; |
160 | if (ret < (sz << 9)) |
161 | break; |
162 | } |
163 | ret = 0; |
164 | atomic_inc(&bb.done); |
165 | submit_bio(WRITE, bio); |
166 | } |
167 | |
168 | /* Wait for bios in-flight */ |
169 | if (!atomic_dec_and_test(&bb.done)) |
170 | wait_for_completion(&wait); |
171 | |
172 | if (!test_bit(BIO_UPTODATE, &bb.flags)) |
173 | /* One of bios in the batch was completed with error.*/ |
174 | ret = -EIO; |
175 | |
176 | return ret; |
177 | } |
178 | EXPORT_SYMBOL(blkdev_issue_zeroout); |
179 |
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od-2011-09-04
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