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 unsigned int 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, 0, 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 - generate number of bios with same page 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 * @biop: pointer to anchor bio 147 * 148 * Description: 149 * Generate and issue number of bios(REQ_OP_WRITE_SAME) with same page. 150 */ 151 static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector, 152 sector_t nr_sects, gfp_t gfp_mask, struct page *page, 153 struct bio **biop) 154 { 155 struct request_queue *q = bdev_get_queue(bdev); 156 unsigned int max_write_same_sectors; 157 struct bio *bio = *biop; 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 if (!bdev_write_same(bdev)) 168 return -EOPNOTSUPP; 169 170 /* Ensure that max_write_same_sectors doesn't overflow bi_size */ 171 max_write_same_sectors = UINT_MAX >> 9; 172 173 while (nr_sects) { 174 bio = next_bio(bio, 1, gfp_mask); 175 bio->bi_iter.bi_sector = sector; 176 bio->bi_bdev = bdev; 177 bio->bi_vcnt = 1; 178 bio->bi_io_vec->bv_page = page; 179 bio->bi_io_vec->bv_offset = 0; 180 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev); 181 bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0); 182 183 if (nr_sects > max_write_same_sectors) { 184 bio->bi_iter.bi_size = max_write_same_sectors << 9; 185 nr_sects -= max_write_same_sectors; 186 sector += max_write_same_sectors; 187 } else { 188 bio->bi_iter.bi_size = nr_sects << 9; 189 nr_sects = 0; 190 } 191 cond_resched(); 192 } 193 194 *biop = bio; 195 return 0; 196 } 197 198 /** 199 * blkdev_issue_write_same - queue a write same operation 200 * @bdev: target blockdev 201 * @sector: start sector 202 * @nr_sects: number of sectors to write 203 * @gfp_mask: memory allocation flags (for bio_alloc) 204 * @page: page containing data 205 * 206 * Description: 207 * Issue a write same request for the sectors in question. 208 */ 209 int blkdev_issue_write_same(struct block_device *bdev, sector_t sector, 210 sector_t nr_sects, gfp_t gfp_mask, 211 struct page *page) 212 { 213 struct bio *bio = NULL; 214 struct blk_plug plug; 215 int ret; 216 217 blk_start_plug(&plug); 218 ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, page, 219 &bio); 220 if (ret == 0 && bio) { 221 ret = submit_bio_wait(bio); 222 bio_put(bio); 223 } 224 blk_finish_plug(&plug); 225 return ret; 226 } 227 EXPORT_SYMBOL(blkdev_issue_write_same); 228 229 /** 230 * __blkdev_issue_write_zeroes - generate number of bios with WRITE ZEROES 231 * @bdev: blockdev to issue 232 * @sector: start sector 233 * @nr_sects: number of sectors to write 234 * @gfp_mask: memory allocation flags (for bio_alloc) 235 * @biop: pointer to anchor bio 236 * 237 * Description: 238 * Generate and issue number of bios(REQ_OP_WRITE_ZEROES) with zerofiled pages. 239 */ 240 static int __blkdev_issue_write_zeroes(struct block_device *bdev, 241 sector_t sector, sector_t nr_sects, gfp_t gfp_mask, 242 struct bio **biop) 243 { 244 struct bio *bio = *biop; 245 unsigned int max_write_zeroes_sectors; 246 struct request_queue *q = bdev_get_queue(bdev); 247 248 if (!q) 249 return -ENXIO; 250 251 /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */ 252 max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev); 253 254 if (max_write_zeroes_sectors == 0) 255 return -EOPNOTSUPP; 256 257 while (nr_sects) { 258 bio = next_bio(bio, 0, gfp_mask); 259 bio->bi_iter.bi_sector = sector; 260 bio->bi_bdev = bdev; 261 bio_set_op_attrs(bio, REQ_OP_WRITE_ZEROES, 0); 262 263 if (nr_sects > max_write_zeroes_sectors) { 264 bio->bi_iter.bi_size = max_write_zeroes_sectors << 9; 265 nr_sects -= max_write_zeroes_sectors; 266 sector += max_write_zeroes_sectors; 267 } else { 268 bio->bi_iter.bi_size = nr_sects << 9; 269 nr_sects = 0; 270 } 271 cond_resched(); 272 } 273 274 *biop = bio; 275 return 0; 276 } 277 278 /** 279 * __blkdev_issue_zeroout - generate number of zero filed write bios 280 * @bdev: blockdev to issue 281 * @sector: start sector 282 * @nr_sects: number of sectors to write 283 * @gfp_mask: memory allocation flags (for bio_alloc) 284 * @biop: pointer to anchor bio 285 * @discard: discard flag 286 * 287 * Description: 288 * Generate and issue number of bios with zerofiled pages. 289 */ 290 int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, 291 sector_t nr_sects, gfp_t gfp_mask, struct bio **biop, 292 bool discard) 293 { 294 int ret; 295 int bi_size = 0; 296 struct bio *bio = *biop; 297 unsigned int sz; 298 sector_t bs_mask; 299 300 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; 301 if ((sector | nr_sects) & bs_mask) 302 return -EINVAL; 303 304 ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask, 305 biop); 306 if (ret == 0 || (ret && ret != -EOPNOTSUPP)) 307 goto out; 308 309 ret = 0; 310 while (nr_sects != 0) { 311 bio = next_bio(bio, min(nr_sects, (sector_t)BIO_MAX_PAGES), 312 gfp_mask); 313 bio->bi_iter.bi_sector = sector; 314 bio->bi_bdev = bdev; 315 bio_set_op_attrs(bio, REQ_OP_WRITE, 0); 316 317 while (nr_sects != 0) { 318 sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects); 319 bi_size = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0); 320 nr_sects -= bi_size >> 9; 321 sector += bi_size >> 9; 322 if (bi_size < (sz << 9)) 323 break; 324 } 325 cond_resched(); 326 } 327 328 *biop = bio; 329 out: 330 return ret; 331 } 332 EXPORT_SYMBOL(__blkdev_issue_zeroout); 333 334 /** 335 * blkdev_issue_zeroout - zero-fill a block range 336 * @bdev: blockdev to write 337 * @sector: start sector 338 * @nr_sects: number of sectors to write 339 * @gfp_mask: memory allocation flags (for bio_alloc) 340 * @discard: whether to discard the block range 341 * 342 * Description: 343 * Zero-fill a block range. If the discard flag is set and the block 344 * device guarantees that subsequent READ operations to the block range 345 * in question will return zeroes, the blocks will be discarded. Should 346 * the discard request fail, if the discard flag is not set, or if 347 * discard_zeroes_data is not supported, this function will resort to 348 * zeroing the blocks manually, thus provisioning (allocating, 349 * anchoring) them. If the block device supports WRITE ZEROES or WRITE SAME 350 * command(s), blkdev_issue_zeroout() will use it to optimize the process of 351 * clearing the block range. Otherwise the zeroing will be performed 352 * using regular WRITE calls. 353 */ 354 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, 355 sector_t nr_sects, gfp_t gfp_mask, bool discard) 356 { 357 int ret; 358 struct bio *bio = NULL; 359 struct blk_plug plug; 360 361 if (discard) { 362 if (!blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, 363 BLKDEV_DISCARD_ZERO)) 364 return 0; 365 } 366 367 if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, 368 ZERO_PAGE(0))) 369 return 0; 370 371 blk_start_plug(&plug); 372 ret = __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask, 373 &bio, discard); 374 if (ret == 0 && bio) { 375 ret = submit_bio_wait(bio); 376 bio_put(bio); 377 } 378 blk_finish_plug(&plug); 379 380 return ret; 381 } 382 EXPORT_SYMBOL(blkdev_issue_zeroout); 383