1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Functions related to generic helpers functions 4 */ 5 #include <linux/kernel.h> 6 #include <linux/module.h> 7 #include <linux/bio.h> 8 #include <linux/blkdev.h> 9 #include <linux/scatterlist.h> 10 11 #include "blk.h" 12 13 static struct bio *next_bio(struct bio *bio, unsigned int nr_pages, 14 gfp_t gfp) 15 { 16 struct bio *new = bio_alloc(gfp, nr_pages); 17 18 if (bio) { 19 bio_chain(bio, new); 20 submit_bio(bio); 21 } 22 23 return new; 24 } 25 26 int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, 27 sector_t nr_sects, gfp_t gfp_mask, int flags, 28 struct bio **biop) 29 { 30 struct request_queue *q = bdev_get_queue(bdev); 31 struct bio *bio = *biop; 32 unsigned int granularity; 33 unsigned int op; 34 int alignment; 35 sector_t bs_mask; 36 37 if (!q) 38 return -ENXIO; 39 40 if (bdev_read_only(bdev)) 41 return -EPERM; 42 43 if (flags & BLKDEV_DISCARD_SECURE) { 44 if (!blk_queue_secure_erase(q)) 45 return -EOPNOTSUPP; 46 op = REQ_OP_SECURE_ERASE; 47 } else { 48 if (!blk_queue_discard(q)) 49 return -EOPNOTSUPP; 50 op = REQ_OP_DISCARD; 51 } 52 53 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; 54 if ((sector | nr_sects) & bs_mask) 55 return -EINVAL; 56 57 /* Zero-sector (unknown) and one-sector granularities are the same. */ 58 granularity = max(q->limits.discard_granularity >> 9, 1U); 59 alignment = (bdev_discard_alignment(bdev) >> 9) % granularity; 60 61 while (nr_sects) { 62 unsigned int req_sects; 63 sector_t end_sect, tmp; 64 65 /* Make sure bi_size doesn't overflow */ 66 req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9); 67 68 /** 69 * If splitting a request, and the next starting sector would be 70 * misaligned, stop the discard at the previous aligned sector. 71 */ 72 end_sect = sector + req_sects; 73 tmp = end_sect; 74 if (req_sects < nr_sects && 75 sector_div(tmp, granularity) != alignment) { 76 end_sect = end_sect - alignment; 77 sector_div(end_sect, granularity); 78 end_sect = end_sect * granularity + alignment; 79 req_sects = end_sect - sector; 80 } 81 82 bio = next_bio(bio, 0, gfp_mask); 83 bio->bi_iter.bi_sector = sector; 84 bio_set_dev(bio, bdev); 85 bio_set_op_attrs(bio, op, 0); 86 87 bio->bi_iter.bi_size = req_sects << 9; 88 nr_sects -= req_sects; 89 sector = end_sect; 90 91 /* 92 * We can loop for a long time in here, if someone does 93 * full device discards (like mkfs). Be nice and allow 94 * us to schedule out to avoid softlocking if preempt 95 * is disabled. 96 */ 97 cond_resched(); 98 } 99 100 *biop = bio; 101 return 0; 102 } 103 EXPORT_SYMBOL(__blkdev_issue_discard); 104 105 /** 106 * blkdev_issue_discard - queue a discard 107 * @bdev: blockdev to issue discard for 108 * @sector: start sector 109 * @nr_sects: number of sectors to discard 110 * @gfp_mask: memory allocation flags (for bio_alloc) 111 * @flags: BLKDEV_DISCARD_* flags to control behaviour 112 * 113 * Description: 114 * Issue a discard request for the sectors in question. 115 */ 116 int blkdev_issue_discard(struct block_device *bdev, sector_t sector, 117 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags) 118 { 119 struct bio *bio = NULL; 120 struct blk_plug plug; 121 int ret; 122 123 blk_start_plug(&plug); 124 ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags, 125 &bio); 126 if (!ret && bio) { 127 ret = submit_bio_wait(bio); 128 if (ret == -EOPNOTSUPP) 129 ret = 0; 130 bio_put(bio); 131 } 132 blk_finish_plug(&plug); 133 134 return ret; 135 } 136 EXPORT_SYMBOL(blkdev_issue_discard); 137 138 /** 139 * __blkdev_issue_write_same - generate number of bios with same page 140 * @bdev: target blockdev 141 * @sector: start sector 142 * @nr_sects: number of sectors to write 143 * @gfp_mask: memory allocation flags (for bio_alloc) 144 * @page: page containing data to write 145 * @biop: pointer to anchor bio 146 * 147 * Description: 148 * Generate and issue number of bios(REQ_OP_WRITE_SAME) with same page. 149 */ 150 static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector, 151 sector_t nr_sects, gfp_t gfp_mask, struct page *page, 152 struct bio **biop) 153 { 154 struct request_queue *q = bdev_get_queue(bdev); 155 unsigned int max_write_same_sectors; 156 struct bio *bio = *biop; 157 sector_t bs_mask; 158 159 if (!q) 160 return -ENXIO; 161 162 if (bdev_read_only(bdev)) 163 return -EPERM; 164 165 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; 166 if ((sector | nr_sects) & bs_mask) 167 return -EINVAL; 168 169 if (!bdev_write_same(bdev)) 170 return -EOPNOTSUPP; 171 172 /* Ensure that max_write_same_sectors doesn't overflow bi_size */ 173 max_write_same_sectors = UINT_MAX >> 9; 174 175 while (nr_sects) { 176 bio = next_bio(bio, 1, gfp_mask); 177 bio->bi_iter.bi_sector = sector; 178 bio_set_dev(bio, bdev); 179 bio->bi_vcnt = 1; 180 bio->bi_io_vec->bv_page = page; 181 bio->bi_io_vec->bv_offset = 0; 182 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev); 183 bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0); 184 185 if (nr_sects > max_write_same_sectors) { 186 bio->bi_iter.bi_size = max_write_same_sectors << 9; 187 nr_sects -= max_write_same_sectors; 188 sector += max_write_same_sectors; 189 } else { 190 bio->bi_iter.bi_size = nr_sects << 9; 191 nr_sects = 0; 192 } 193 cond_resched(); 194 } 195 196 *biop = bio; 197 return 0; 198 } 199 200 /** 201 * blkdev_issue_write_same - queue a write same operation 202 * @bdev: target blockdev 203 * @sector: start sector 204 * @nr_sects: number of sectors to write 205 * @gfp_mask: memory allocation flags (for bio_alloc) 206 * @page: page containing data 207 * 208 * Description: 209 * Issue a write same request for the sectors in question. 210 */ 211 int blkdev_issue_write_same(struct block_device *bdev, sector_t sector, 212 sector_t nr_sects, gfp_t gfp_mask, 213 struct page *page) 214 { 215 struct bio *bio = NULL; 216 struct blk_plug plug; 217 int ret; 218 219 blk_start_plug(&plug); 220 ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, page, 221 &bio); 222 if (ret == 0 && bio) { 223 ret = submit_bio_wait(bio); 224 bio_put(bio); 225 } 226 blk_finish_plug(&plug); 227 return ret; 228 } 229 EXPORT_SYMBOL(blkdev_issue_write_same); 230 231 static int __blkdev_issue_write_zeroes(struct block_device *bdev, 232 sector_t sector, sector_t nr_sects, gfp_t gfp_mask, 233 struct bio **biop, unsigned flags) 234 { 235 struct bio *bio = *biop; 236 unsigned int max_write_zeroes_sectors; 237 struct request_queue *q = bdev_get_queue(bdev); 238 239 if (!q) 240 return -ENXIO; 241 242 if (bdev_read_only(bdev)) 243 return -EPERM; 244 245 /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */ 246 max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev); 247 248 if (max_write_zeroes_sectors == 0) 249 return -EOPNOTSUPP; 250 251 while (nr_sects) { 252 bio = next_bio(bio, 0, gfp_mask); 253 bio->bi_iter.bi_sector = sector; 254 bio_set_dev(bio, bdev); 255 bio->bi_opf = REQ_OP_WRITE_ZEROES; 256 if (flags & BLKDEV_ZERO_NOUNMAP) 257 bio->bi_opf |= REQ_NOUNMAP; 258 259 if (nr_sects > max_write_zeroes_sectors) { 260 bio->bi_iter.bi_size = max_write_zeroes_sectors << 9; 261 nr_sects -= max_write_zeroes_sectors; 262 sector += max_write_zeroes_sectors; 263 } else { 264 bio->bi_iter.bi_size = nr_sects << 9; 265 nr_sects = 0; 266 } 267 cond_resched(); 268 } 269 270 *biop = bio; 271 return 0; 272 } 273 274 /* 275 * Convert a number of 512B sectors to a number of pages. 276 * The result is limited to a number of pages that can fit into a BIO. 277 * Also make sure that the result is always at least 1 (page) for the cases 278 * where nr_sects is lower than the number of sectors in a page. 279 */ 280 static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects) 281 { 282 sector_t pages = DIV_ROUND_UP_SECTOR_T(nr_sects, PAGE_SIZE / 512); 283 284 return min(pages, (sector_t)BIO_MAX_PAGES); 285 } 286 287 static int __blkdev_issue_zero_pages(struct block_device *bdev, 288 sector_t sector, sector_t nr_sects, gfp_t gfp_mask, 289 struct bio **biop) 290 { 291 struct request_queue *q = bdev_get_queue(bdev); 292 struct bio *bio = *biop; 293 int bi_size = 0; 294 unsigned int sz; 295 296 if (!q) 297 return -ENXIO; 298 299 if (bdev_read_only(bdev)) 300 return -EPERM; 301 302 while (nr_sects != 0) { 303 bio = next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects), 304 gfp_mask); 305 bio->bi_iter.bi_sector = sector; 306 bio_set_dev(bio, bdev); 307 bio_set_op_attrs(bio, REQ_OP_WRITE, 0); 308 309 while (nr_sects != 0) { 310 sz = min((sector_t) PAGE_SIZE, nr_sects << 9); 311 bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0); 312 nr_sects -= bi_size >> 9; 313 sector += bi_size >> 9; 314 if (bi_size < sz) 315 break; 316 } 317 cond_resched(); 318 } 319 320 *biop = bio; 321 return 0; 322 } 323 324 /** 325 * __blkdev_issue_zeroout - generate number of zero filed write bios 326 * @bdev: blockdev to issue 327 * @sector: start sector 328 * @nr_sects: number of sectors to write 329 * @gfp_mask: memory allocation flags (for bio_alloc) 330 * @biop: pointer to anchor bio 331 * @flags: controls detailed behavior 332 * 333 * Description: 334 * Zero-fill a block range, either using hardware offload or by explicitly 335 * writing zeroes to the device. 336 * 337 * If a device is using logical block provisioning, the underlying space will 338 * not be released if %flags contains BLKDEV_ZERO_NOUNMAP. 339 * 340 * If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return 341 * -EOPNOTSUPP if no explicit hardware offload for zeroing is provided. 342 */ 343 int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, 344 sector_t nr_sects, gfp_t gfp_mask, struct bio **biop, 345 unsigned flags) 346 { 347 int ret; 348 sector_t bs_mask; 349 350 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; 351 if ((sector | nr_sects) & bs_mask) 352 return -EINVAL; 353 354 ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask, 355 biop, flags); 356 if (ret != -EOPNOTSUPP || (flags & BLKDEV_ZERO_NOFALLBACK)) 357 return ret; 358 359 return __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask, 360 biop); 361 } 362 EXPORT_SYMBOL(__blkdev_issue_zeroout); 363 364 /** 365 * blkdev_issue_zeroout - zero-fill a block range 366 * @bdev: blockdev to write 367 * @sector: start sector 368 * @nr_sects: number of sectors to write 369 * @gfp_mask: memory allocation flags (for bio_alloc) 370 * @flags: controls detailed behavior 371 * 372 * Description: 373 * Zero-fill a block range, either using hardware offload or by explicitly 374 * writing zeroes to the device. See __blkdev_issue_zeroout() for the 375 * valid values for %flags. 376 */ 377 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, 378 sector_t nr_sects, gfp_t gfp_mask, unsigned flags) 379 { 380 int ret = 0; 381 sector_t bs_mask; 382 struct bio *bio; 383 struct blk_plug plug; 384 bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev); 385 386 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; 387 if ((sector | nr_sects) & bs_mask) 388 return -EINVAL; 389 390 retry: 391 bio = NULL; 392 blk_start_plug(&plug); 393 if (try_write_zeroes) { 394 ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, 395 gfp_mask, &bio, flags); 396 } else if (!(flags & BLKDEV_ZERO_NOFALLBACK)) { 397 ret = __blkdev_issue_zero_pages(bdev, sector, nr_sects, 398 gfp_mask, &bio); 399 } else { 400 /* No zeroing offload support */ 401 ret = -EOPNOTSUPP; 402 } 403 if (ret == 0 && bio) { 404 ret = submit_bio_wait(bio); 405 bio_put(bio); 406 } 407 blk_finish_plug(&plug); 408 if (ret && try_write_zeroes) { 409 if (!(flags & BLKDEV_ZERO_NOFALLBACK)) { 410 try_write_zeroes = false; 411 goto retry; 412 } 413 if (!bdev_write_zeroes_sectors(bdev)) { 414 /* 415 * Zeroing offload support was indicated, but the 416 * device reported ILLEGAL REQUEST (for some devices 417 * there is no non-destructive way to verify whether 418 * WRITE ZEROES is actually supported). 419 */ 420 ret = -EOPNOTSUPP; 421 } 422 } 423 424 return ret; 425 } 426 EXPORT_SYMBOL(blkdev_issue_zeroout); 427