Commit | Line | Data |
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f31e7e40 DM |
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 | static void blkdev_discard_end_io(struct bio *bio, int err) | |
13 | { | |
14 | if (err) { | |
15 | if (err == -EOPNOTSUPP) | |
16 | set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); | |
17 | clear_bit(BIO_UPTODATE, &bio->bi_flags); | |
18 | } | |
19 | ||
20 | if (bio->bi_private) | |
21 | complete(bio->bi_private); | |
22 | __free_page(bio_page(bio)); | |
23 | ||
24 | bio_put(bio); | |
25 | } | |
26 | ||
27 | /** | |
28 | * blkdev_issue_discard - queue a discard | |
29 | * @bdev: blockdev to issue discard for | |
30 | * @sector: start sector | |
31 | * @nr_sects: number of sectors to discard | |
32 | * @gfp_mask: memory allocation flags (for bio_alloc) | |
33 | * @flags: BLKDEV_IFL_* flags to control behaviour | |
34 | * | |
35 | * Description: | |
36 | * Issue a discard request for the sectors in question. | |
37 | */ | |
38 | int blkdev_issue_discard(struct block_device *bdev, sector_t sector, | |
39 | sector_t nr_sects, gfp_t gfp_mask, unsigned long flags) | |
40 | { | |
41 | DECLARE_COMPLETION_ONSTACK(wait); | |
42 | struct request_queue *q = bdev_get_queue(bdev); | |
43 | int type = flags & BLKDEV_IFL_BARRIER ? | |
44 | DISCARD_BARRIER : DISCARD_NOBARRIER; | |
45 | struct bio *bio; | |
46 | struct page *page; | |
47 | int ret = 0; | |
48 | ||
49 | if (!q) | |
50 | return -ENXIO; | |
51 | ||
52 | if (!blk_queue_discard(q)) | |
53 | return -EOPNOTSUPP; | |
54 | ||
55 | while (nr_sects && !ret) { | |
56 | unsigned int sector_size = q->limits.logical_block_size; | |
57 | unsigned int max_discard_sectors = | |
58 | min(q->limits.max_discard_sectors, UINT_MAX >> 9); | |
59 | ||
60 | bio = bio_alloc(gfp_mask, 1); | |
61 | if (!bio) | |
62 | goto out; | |
63 | bio->bi_sector = sector; | |
64 | bio->bi_end_io = blkdev_discard_end_io; | |
65 | bio->bi_bdev = bdev; | |
66 | if (flags & BLKDEV_IFL_WAIT) | |
67 | bio->bi_private = &wait; | |
68 | ||
69 | /* | |
70 | * Add a zeroed one-sector payload as that's what | |
71 | * our current implementations need. If we'll ever need | |
72 | * more the interface will need revisiting. | |
73 | */ | |
74 | page = alloc_page(gfp_mask | __GFP_ZERO); | |
75 | if (!page) | |
76 | goto out_free_bio; | |
77 | if (bio_add_pc_page(q, bio, page, sector_size, 0) < sector_size) | |
78 | goto out_free_page; | |
79 | ||
80 | /* | |
81 | * And override the bio size - the way discard works we | |
82 | * touch many more blocks on disk than the actual payload | |
83 | * length. | |
84 | */ | |
85 | if (nr_sects > max_discard_sectors) { | |
86 | bio->bi_size = max_discard_sectors << 9; | |
87 | nr_sects -= max_discard_sectors; | |
88 | sector += max_discard_sectors; | |
89 | } else { | |
90 | bio->bi_size = nr_sects << 9; | |
91 | nr_sects = 0; | |
92 | } | |
93 | ||
94 | bio_get(bio); | |
95 | submit_bio(type, bio); | |
96 | ||
97 | if (flags & BLKDEV_IFL_WAIT) | |
98 | wait_for_completion(&wait); | |
99 | ||
100 | if (bio_flagged(bio, BIO_EOPNOTSUPP)) | |
101 | ret = -EOPNOTSUPP; | |
102 | else if (!bio_flagged(bio, BIO_UPTODATE)) | |
103 | ret = -EIO; | |
104 | bio_put(bio); | |
105 | } | |
106 | return ret; | |
107 | out_free_page: | |
108 | __free_page(page); | |
109 | out_free_bio: | |
110 | bio_put(bio); | |
111 | out: | |
112 | return -ENOMEM; | |
113 | } | |
114 | EXPORT_SYMBOL(blkdev_issue_discard); |