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 (q->limits.discard_granularity) { 63 unsigned int disc_sects = q->limits.discard_granularity >> 9; 64 65 max_discard_sectors &= ~(disc_sects - 1); 66 } 67 68 if (flags & BLKDEV_DISCARD_SECURE) { 69 if (!blk_queue_secdiscard(q)) 70 return -EOPNOTSUPP; 71 type |= REQ_SECURE; 72 } 73 74 atomic_set(&bb.done, 1); 75 bb.flags = 1 << BIO_UPTODATE; 76 bb.wait = &wait; 77 78 while (nr_sects) { 79 bio = bio_alloc(gfp_mask, 1); 80 if (!bio) { 81 ret = -ENOMEM; 82 break; 83 } 84 85 bio->bi_sector = sector; 86 bio->bi_end_io = bio_batch_end_io; 87 bio->bi_bdev = bdev; 88 bio->bi_private = &bb; 89 90 if (nr_sects > max_discard_sectors) { 91 bio->bi_size = max_discard_sectors << 9; 92 nr_sects -= max_discard_sectors; 93 sector += max_discard_sectors; 94 } else { 95 bio->bi_size = nr_sects << 9; 96 nr_sects = 0; 97 } 98 99 atomic_inc(&bb.done); 100 submit_bio(type, bio); 101 } 102 103 /* Wait for bios in-flight */ 104 if (!atomic_dec_and_test(&bb.done)) 105 wait_for_completion(&wait); 106 107 if (!test_bit(BIO_UPTODATE, &bb.flags)) 108 ret = -EIO; 109 110 return ret; 111 } 112 EXPORT_SYMBOL(blkdev_issue_discard); 113 114 /** 115 * blkdev_issue_zeroout - generate number of zero filed write bios 116 * @bdev: blockdev to issue 117 * @sector: start sector 118 * @nr_sects: number of sectors to write 119 * @gfp_mask: memory allocation flags (for bio_alloc) 120 * 121 * Description: 122 * Generate and issue number of bios with zerofiled pages. 123 */ 124 125 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, 126 sector_t nr_sects, gfp_t gfp_mask) 127 { 128 int ret; 129 struct bio *bio; 130 struct bio_batch bb; 131 unsigned int sz; 132 DECLARE_COMPLETION_ONSTACK(wait); 133 134 atomic_set(&bb.done, 1); 135 bb.flags = 1 << BIO_UPTODATE; 136 bb.wait = &wait; 137 138 ret = 0; 139 while (nr_sects != 0) { 140 bio = bio_alloc(gfp_mask, 141 min(nr_sects, (sector_t)BIO_MAX_PAGES)); 142 if (!bio) { 143 ret = -ENOMEM; 144 break; 145 } 146 147 bio->bi_sector = sector; 148 bio->bi_bdev = bdev; 149 bio->bi_end_io = bio_batch_end_io; 150 bio->bi_private = &bb; 151 152 while (nr_sects != 0) { 153 sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects); 154 ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0); 155 nr_sects -= ret >> 9; 156 sector += ret >> 9; 157 if (ret < (sz << 9)) 158 break; 159 } 160 ret = 0; 161 atomic_inc(&bb.done); 162 submit_bio(WRITE, bio); 163 } 164 165 /* Wait for bios in-flight */ 166 if (!atomic_dec_and_test(&bb.done)) 167 wait_for_completion(&wait); 168 169 if (!test_bit(BIO_UPTODATE, &bb.flags)) 170 /* One of bios in the batch was completed with error.*/ 171 ret = -EIO; 172 173 return ret; 174 } 175 EXPORT_SYMBOL(blkdev_issue_zeroout); 176