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 (!blk_queue_secure_erase(q)) 41 return -EOPNOTSUPP; 42 op = REQ_OP_SECURE_ERASE; 43 } else { 44 if (!blk_queue_discard(q)) 45 return -EOPNOTSUPP; 46 op = REQ_OP_DISCARD; 47 } 48 49 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; 50 if ((sector | nr_sects) & bs_mask) 51 return -EINVAL; 52 53 /* Zero-sector (unknown) and one-sector granularities are the same. */ 54 granularity = max(q->limits.discard_granularity >> 9, 1U); 55 alignment = (bdev_discard_alignment(bdev) >> 9) % granularity; 56 57 while (nr_sects) { 58 unsigned int req_sects; 59 sector_t end_sect, tmp; 60 61 /* Make sure bi_size doesn't overflow */ 62 req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9); 63 64 /** 65 * If splitting a request, and the next starting sector would be 66 * misaligned, stop the discard at the previous aligned sector. 67 */ 68 end_sect = sector + req_sects; 69 tmp = end_sect; 70 if (req_sects < nr_sects && 71 sector_div(tmp, granularity) != alignment) { 72 end_sect = end_sect - alignment; 73 sector_div(end_sect, granularity); 74 end_sect = end_sect * granularity + alignment; 75 req_sects = end_sect - sector; 76 } 77 78 bio = next_bio(bio, 0, gfp_mask); 79 bio->bi_iter.bi_sector = sector; 80 bio->bi_bdev = bdev; 81 bio_set_op_attrs(bio, op, 0); 82 83 bio->bi_iter.bi_size = req_sects << 9; 84 nr_sects -= req_sects; 85 sector = end_sect; 86 87 /* 88 * We can loop for a long time in here, if someone does 89 * full device discards (like mkfs). Be nice and allow 90 * us to schedule out to avoid softlocking if preempt 91 * is disabled. 92 */ 93 cond_resched(); 94 } 95 96 *biop = bio; 97 return 0; 98 } 99 EXPORT_SYMBOL(__blkdev_issue_discard); 100 101 /** 102 * blkdev_issue_discard - queue a discard 103 * @bdev: blockdev to issue discard for 104 * @sector: start sector 105 * @nr_sects: number of sectors to discard 106 * @gfp_mask: memory allocation flags (for bio_alloc) 107 * @flags: BLKDEV_DISCARD_* flags to control behaviour 108 * 109 * Description: 110 * Issue a discard request for the sectors in question. 111 */ 112 int blkdev_issue_discard(struct block_device *bdev, sector_t sector, 113 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags) 114 { 115 struct bio *bio = NULL; 116 struct blk_plug plug; 117 int ret; 118 119 blk_start_plug(&plug); 120 ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags, 121 &bio); 122 if (!ret && bio) { 123 ret = submit_bio_wait(bio); 124 if (ret == -EOPNOTSUPP) 125 ret = 0; 126 bio_put(bio); 127 } 128 blk_finish_plug(&plug); 129 130 return ret; 131 } 132 EXPORT_SYMBOL(blkdev_issue_discard); 133 134 /** 135 * __blkdev_issue_write_same - generate number of bios with same page 136 * @bdev: target blockdev 137 * @sector: start sector 138 * @nr_sects: number of sectors to write 139 * @gfp_mask: memory allocation flags (for bio_alloc) 140 * @page: page containing data to write 141 * @biop: pointer to anchor bio 142 * 143 * Description: 144 * Generate and issue number of bios(REQ_OP_WRITE_SAME) with same page. 145 */ 146 static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector, 147 sector_t nr_sects, gfp_t gfp_mask, struct page *page, 148 struct bio **biop) 149 { 150 struct request_queue *q = bdev_get_queue(bdev); 151 unsigned int max_write_same_sectors; 152 struct bio *bio = *biop; 153 sector_t bs_mask; 154 155 if (!q) 156 return -ENXIO; 157 158 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; 159 if ((sector | nr_sects) & bs_mask) 160 return -EINVAL; 161 162 if (!bdev_write_same(bdev)) 163 return -EOPNOTSUPP; 164 165 /* Ensure that max_write_same_sectors doesn't overflow bi_size */ 166 max_write_same_sectors = UINT_MAX >> 9; 167 168 while (nr_sects) { 169 bio = next_bio(bio, 1, gfp_mask); 170 bio->bi_iter.bi_sector = sector; 171 bio->bi_bdev = bdev; 172 bio->bi_vcnt = 1; 173 bio->bi_io_vec->bv_page = page; 174 bio->bi_io_vec->bv_offset = 0; 175 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev); 176 bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0); 177 178 if (nr_sects > max_write_same_sectors) { 179 bio->bi_iter.bi_size = max_write_same_sectors << 9; 180 nr_sects -= max_write_same_sectors; 181 sector += max_write_same_sectors; 182 } else { 183 bio->bi_iter.bi_size = nr_sects << 9; 184 nr_sects = 0; 185 } 186 cond_resched(); 187 } 188 189 *biop = bio; 190 return 0; 191 } 192 193 /** 194 * blkdev_issue_write_same - queue a write same operation 195 * @bdev: target blockdev 196 * @sector: start sector 197 * @nr_sects: number of sectors to write 198 * @gfp_mask: memory allocation flags (for bio_alloc) 199 * @page: page containing data 200 * 201 * Description: 202 * Issue a write same request for the sectors in question. 203 */ 204 int blkdev_issue_write_same(struct block_device *bdev, sector_t sector, 205 sector_t nr_sects, gfp_t gfp_mask, 206 struct page *page) 207 { 208 struct bio *bio = NULL; 209 struct blk_plug plug; 210 int ret; 211 212 blk_start_plug(&plug); 213 ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, page, 214 &bio); 215 if (ret == 0 && bio) { 216 ret = submit_bio_wait(bio); 217 bio_put(bio); 218 } 219 blk_finish_plug(&plug); 220 return ret; 221 } 222 EXPORT_SYMBOL(blkdev_issue_write_same); 223 224 static int __blkdev_issue_write_zeroes(struct block_device *bdev, 225 sector_t sector, sector_t nr_sects, gfp_t gfp_mask, 226 struct bio **biop, unsigned flags) 227 { 228 struct bio *bio = *biop; 229 unsigned int max_write_zeroes_sectors; 230 struct request_queue *q = bdev_get_queue(bdev); 231 232 if (!q) 233 return -ENXIO; 234 235 /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */ 236 max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev); 237 238 if (max_write_zeroes_sectors == 0) 239 return -EOPNOTSUPP; 240 241 while (nr_sects) { 242 bio = next_bio(bio, 0, gfp_mask); 243 bio->bi_iter.bi_sector = sector; 244 bio->bi_bdev = bdev; 245 bio->bi_opf = REQ_OP_WRITE_ZEROES; 246 if (flags & BLKDEV_ZERO_NOUNMAP) 247 bio->bi_opf |= REQ_NOUNMAP; 248 249 if (nr_sects > max_write_zeroes_sectors) { 250 bio->bi_iter.bi_size = max_write_zeroes_sectors << 9; 251 nr_sects -= max_write_zeroes_sectors; 252 sector += max_write_zeroes_sectors; 253 } else { 254 bio->bi_iter.bi_size = nr_sects << 9; 255 nr_sects = 0; 256 } 257 cond_resched(); 258 } 259 260 *biop = bio; 261 return 0; 262 } 263 264 /** 265 * __blkdev_issue_zeroout - generate number of zero filed write bios 266 * @bdev: blockdev to issue 267 * @sector: start sector 268 * @nr_sects: number of sectors to write 269 * @gfp_mask: memory allocation flags (for bio_alloc) 270 * @biop: pointer to anchor bio 271 * @flags: controls detailed behavior 272 * 273 * Description: 274 * Zero-fill a block range, either using hardware offload or by explicitly 275 * writing zeroes to the device. 276 * 277 * Note that this function may fail with -EOPNOTSUPP if the driver signals 278 * zeroing offload support, but the device fails to process the command (for 279 * some devices there is no non-destructive way to verify whether this 280 * operation is actually supported). In this case the caller should call 281 * retry the call to blkdev_issue_zeroout() and the fallback path will be used. 282 * 283 * If a device is using logical block provisioning, the underlying space will 284 * not be released if %flags contains BLKDEV_ZERO_NOUNMAP. 285 * 286 * If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return 287 * -EOPNOTSUPP if no explicit hardware offload for zeroing is provided. 288 */ 289 int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, 290 sector_t nr_sects, gfp_t gfp_mask, struct bio **biop, 291 unsigned flags) 292 { 293 int ret; 294 int bi_size = 0; 295 struct bio *bio = *biop; 296 unsigned int sz; 297 sector_t bs_mask; 298 299 bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; 300 if ((sector | nr_sects) & bs_mask) 301 return -EINVAL; 302 303 ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask, 304 biop, flags); 305 if (ret != -EOPNOTSUPP || (flags & BLKDEV_ZERO_NOFALLBACK)) 306 goto out; 307 308 ret = 0; 309 while (nr_sects != 0) { 310 bio = next_bio(bio, min(nr_sects, (sector_t)BIO_MAX_PAGES), 311 gfp_mask); 312 bio->bi_iter.bi_sector = sector; 313 bio->bi_bdev = bdev; 314 bio_set_op_attrs(bio, REQ_OP_WRITE, 0); 315 316 while (nr_sects != 0) { 317 sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects); 318 bi_size = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0); 319 nr_sects -= bi_size >> 9; 320 sector += bi_size >> 9; 321 if (bi_size < (sz << 9)) 322 break; 323 } 324 cond_resched(); 325 } 326 327 *biop = bio; 328 out: 329 return ret; 330 } 331 EXPORT_SYMBOL(__blkdev_issue_zeroout); 332 333 /** 334 * blkdev_issue_zeroout - zero-fill a block range 335 * @bdev: blockdev to write 336 * @sector: start sector 337 * @nr_sects: number of sectors to write 338 * @gfp_mask: memory allocation flags (for bio_alloc) 339 * @flags: controls detailed behavior 340 * 341 * Description: 342 * Zero-fill a block range, either using hardware offload or by explicitly 343 * writing zeroes to the device. See __blkdev_issue_zeroout() for the 344 * valid values for %flags. 345 */ 346 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, 347 sector_t nr_sects, gfp_t gfp_mask, unsigned flags) 348 { 349 int ret; 350 struct bio *bio = NULL; 351 struct blk_plug plug; 352 353 blk_start_plug(&plug); 354 ret = __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask, 355 &bio, flags); 356 if (ret == 0 && bio) { 357 ret = submit_bio_wait(bio); 358 bio_put(bio); 359 } 360 blk_finish_plug(&plug); 361 362 return ret; 363 } 364 EXPORT_SYMBOL(blkdev_issue_zeroout); 365