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