| 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); |