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 struct bio *next_bio(struct bio *bio, unsigned int nr_pages, 13 gfp_t gfp) 14 { 15 struct bio *new = bio_alloc(gfp, nr_pages); 16 17 if (bio) { 18 bio_chain(bio, new); 19 submit_bio(bio); 20 } 21 22 return new; 23 } 24 25 int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, 26 sector_t nr_sects, gfp_t gfp_mask, int flags, 27 struct bio **biop) 28 { 29 struct request_queue *q = bdev_get_queue(bdev); 30 struct bio *bio = *biop; 31 unsigned int granularity; 32 enum req_op op; 33 int alignment; 34 sector_t bs_mask; 35 36 if (!q) 37 return -ENXIO; 38 39 if (flags & BLKDEV_DISCARD_SECURE) { 40 if (flags & BLKDEV_DISCARD_ZERO) 41 return -EOPNOTSUPP; 42 if (!blk_queue_secure_erase(q)) 43 return -EOPNOTSUPP; 44 op = REQ_OP_SECURE_ERASE; 45 } else { 46 if (!blk_queue_discard(q)) 47 return -EOPNOTSUPP; 48 if ((flags & BLKDEV_DISCARD_ZERO) && 49 !q->limits.discard_zeroes_data) 50 return -EOPNOTSUPP; 51 op = REQ_OP_DISCARD; 52 } 53 54 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; 55 if ((sector | nr_sects) & bs_mask) 56 return -EINVAL; 57 58 /* Zero-sector (unknown) and one-sector granularities are the same. */ 59 granularity = max(q->limits.discard_granularity >> 9, 1U); 60 alignment = (bdev_discard_alignment(bdev) >> 9) % granularity; 61 62 while (nr_sects) { 63 unsigned int req_sects; 64 sector_t end_sect, tmp; 65 66 /* Make sure bi_size doesn't overflow */ 67 req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9); 68 69 /** 70 * If splitting a request, and the next starting sector would be 71 * misaligned, stop the discard at the previous aligned sector. 72 */ 73 end_sect = sector + req_sects; 74 tmp = end_sect; 75 if (req_sects < nr_sects && 76 sector_div(tmp, granularity) != alignment) { 77 end_sect = end_sect - alignment; 78 sector_div(end_sect, granularity); 79 end_sect = end_sect * granularity + alignment; 80 req_sects = end_sect - sector; 81 } 82 83 bio = next_bio(bio, 1, gfp_mask); 84 bio->bi_iter.bi_sector = sector; 85 bio->bi_bdev = bdev; 86 bio_set_op_attrs(bio, op, 0); 87 88 bio->bi_iter.bi_size = req_sects << 9; 89 nr_sects -= req_sects; 90 sector = end_sect; 91 92 /* 93 * We can loop for a long time in here, if someone does 94 * full device discards (like mkfs). Be nice and allow 95 * us to schedule out to avoid softlocking if preempt 96 * is disabled. 97 */ 98 cond_resched(); 99 } 100 101 *biop = bio; 102 return 0; 103 } 104 EXPORT_SYMBOL(__blkdev_issue_discard); 105 106 /** 107 * blkdev_issue_discard - queue a discard 108 * @bdev: blockdev to issue discard for 109 * @sector: start sector 110 * @nr_sects: number of sectors to discard 111 * @gfp_mask: memory allocation flags (for bio_alloc) 112 * @flags: BLKDEV_IFL_* flags to control behaviour 113 * 114 * Description: 115 * Issue a discard request for the sectors in question. 116 */ 117 int blkdev_issue_discard(struct block_device *bdev, sector_t sector, 118 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags) 119 { 120 struct bio *bio = NULL; 121 struct blk_plug plug; 122 int ret; 123 124 blk_start_plug(&plug); 125 ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags, 126 &bio); 127 if (!ret && bio) { 128 ret = submit_bio_wait(bio); 129 if (ret == -EOPNOTSUPP && !(flags & BLKDEV_DISCARD_ZERO)) 130 ret = 0; 131 bio_put(bio); 132 } 133 blk_finish_plug(&plug); 134 135 return ret; 136 } 137 EXPORT_SYMBOL(blkdev_issue_discard); 138 139 /** 140 * blkdev_issue_write_same - queue a write same operation 141 * @bdev: target blockdev 142 * @sector: start sector 143 * @nr_sects: number of sectors to write 144 * @gfp_mask: memory allocation flags (for bio_alloc) 145 * @page: page containing data to write 146 * 147 * Description: 148 * Issue a write same request for the sectors in question. 149 */ 150 int blkdev_issue_write_same(struct block_device *bdev, sector_t sector, 151 sector_t nr_sects, gfp_t gfp_mask, 152 struct page *page) 153 { 154 struct request_queue *q = bdev_get_queue(bdev); 155 unsigned int max_write_same_sectors; 156 struct bio *bio = NULL; 157 int ret = 0; 158 sector_t bs_mask; 159 160 if (!q) 161 return -ENXIO; 162 163 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; 164 if ((sector | nr_sects) & bs_mask) 165 return -EINVAL; 166 167 /* Ensure that max_write_same_sectors doesn't overflow bi_size */ 168 max_write_same_sectors = UINT_MAX >> 9; 169 170 while (nr_sects) { 171 bio = next_bio(bio, 1, gfp_mask); 172 bio->bi_iter.bi_sector = sector; 173 bio->bi_bdev = bdev; 174 bio->bi_vcnt = 1; 175 bio->bi_io_vec->bv_page = page; 176 bio->bi_io_vec->bv_offset = 0; 177 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev); 178 bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0); 179 180 if (nr_sects > max_write_same_sectors) { 181 bio->bi_iter.bi_size = max_write_same_sectors << 9; 182 nr_sects -= max_write_same_sectors; 183 sector += max_write_same_sectors; 184 } else { 185 bio->bi_iter.bi_size = nr_sects << 9; 186 nr_sects = 0; 187 } 188 } 189 190 if (bio) { 191 ret = submit_bio_wait(bio); 192 bio_put(bio); 193 } 194 return ret; 195 } 196 EXPORT_SYMBOL(blkdev_issue_write_same); 197 198 /** 199 * blkdev_issue_zeroout - generate number of zero filed write bios 200 * @bdev: blockdev to issue 201 * @sector: start sector 202 * @nr_sects: number of sectors to write 203 * @gfp_mask: memory allocation flags (for bio_alloc) 204 * 205 * Description: 206 * Generate and issue number of bios with zerofiled pages. 207 */ 208 209 static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, 210 sector_t nr_sects, gfp_t gfp_mask) 211 { 212 int ret; 213 struct bio *bio = NULL; 214 unsigned int sz; 215 sector_t bs_mask; 216 217 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; 218 if ((sector | nr_sects) & bs_mask) 219 return -EINVAL; 220 221 while (nr_sects != 0) { 222 bio = next_bio(bio, min(nr_sects, (sector_t)BIO_MAX_PAGES), 223 gfp_mask); 224 bio->bi_iter.bi_sector = sector; 225 bio->bi_bdev = bdev; 226 bio_set_op_attrs(bio, REQ_OP_WRITE, 0); 227 228 while (nr_sects != 0) { 229 sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects); 230 ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0); 231 nr_sects -= ret >> 9; 232 sector += ret >> 9; 233 if (ret < (sz << 9)) 234 break; 235 } 236 } 237 238 if (bio) { 239 ret = submit_bio_wait(bio); 240 bio_put(bio); 241 return ret; 242 } 243 return 0; 244 } 245 246 /** 247 * blkdev_issue_zeroout - zero-fill a block range 248 * @bdev: blockdev to write 249 * @sector: start sector 250 * @nr_sects: number of sectors to write 251 * @gfp_mask: memory allocation flags (for bio_alloc) 252 * @discard: whether to discard the block range 253 * 254 * Description: 255 * Zero-fill a block range. If the discard flag is set and the block 256 * device guarantees that subsequent READ operations to the block range 257 * in question will return zeroes, the blocks will be discarded. Should 258 * the discard request fail, if the discard flag is not set, or if 259 * discard_zeroes_data is not supported, this function will resort to 260 * zeroing the blocks manually, thus provisioning (allocating, 261 * anchoring) them. If the block device supports the WRITE SAME command 262 * blkdev_issue_zeroout() will use it to optimize the process of 263 * clearing the block range. Otherwise the zeroing will be performed 264 * using regular WRITE calls. 265 */ 266 267 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, 268 sector_t nr_sects, gfp_t gfp_mask, bool discard) 269 { 270 if (discard) { 271 if (!blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, 272 BLKDEV_DISCARD_ZERO)) 273 return 0; 274 } 275 276 if (bdev_write_same(bdev) && 277 blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, 278 ZERO_PAGE(0)) == 0) 279 return 0; 280 281 return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask); 282 } 283 EXPORT_SYMBOL(blkdev_issue_zeroout); 284