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, granularity; 47 int alignment; 48 struct bio_batch bb; 49 struct bio *bio; 50 int ret = 0; 51 struct blk_plug plug; 52 53 if (!q) 54 return -ENXIO; 55 56 if (!blk_queue_discard(q)) 57 return -EOPNOTSUPP; 58 59 /* Zero-sector (unknown) and one-sector granularities are the same. */ 60 granularity = max(q->limits.discard_granularity >> 9, 1U); 61 alignment = (bdev_discard_alignment(bdev) >> 9) % granularity; 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 -= 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 blk_start_plug(&plug); 85 while (nr_sects) { 86 unsigned int req_sects; 87 sector_t end_sect, tmp; 88 89 bio = bio_alloc(gfp_mask, 1); 90 if (!bio) { 91 ret = -ENOMEM; 92 break; 93 } 94 95 req_sects = min_t(sector_t, nr_sects, max_discard_sectors); 96 97 /* 98 * If splitting a request, and the next starting sector would be 99 * misaligned, stop the discard at the previous aligned sector. 100 */ 101 end_sect = sector + req_sects; 102 tmp = end_sect; 103 if (req_sects < nr_sects && 104 sector_div(tmp, granularity) != alignment) { 105 end_sect = end_sect - alignment; 106 sector_div(end_sect, granularity); 107 end_sect = end_sect * granularity + alignment; 108 req_sects = end_sect - sector; 109 } 110 111 bio->bi_sector = sector; 112 bio->bi_end_io = bio_batch_end_io; 113 bio->bi_bdev = bdev; 114 bio->bi_private = &bb; 115 116 bio->bi_size = req_sects << 9; 117 nr_sects -= req_sects; 118 sector = end_sect; 119 120 atomic_inc(&bb.done); 121 submit_bio(type, bio); 122 } 123 blk_finish_plug(&plug); 124 125 /* Wait for bios in-flight */ 126 if (!atomic_dec_and_test(&bb.done)) 127 wait_for_completion_io(&wait); 128 129 if (!test_bit(BIO_UPTODATE, &bb.flags)) 130 ret = -EIO; 131 132 return ret; 133 } 134 EXPORT_SYMBOL(blkdev_issue_discard); 135 136 /** 137 * blkdev_issue_write_same - queue a write same operation 138 * @bdev: target blockdev 139 * @sector: start sector 140 * @nr_sects: number of sectors to write 141 * @gfp_mask: memory allocation flags (for bio_alloc) 142 * @page: page containing data to write 143 * 144 * Description: 145 * Issue a write same request for the sectors in question. 146 */ 147 int blkdev_issue_write_same(struct block_device *bdev, sector_t sector, 148 sector_t nr_sects, gfp_t gfp_mask, 149 struct page *page) 150 { 151 DECLARE_COMPLETION_ONSTACK(wait); 152 struct request_queue *q = bdev_get_queue(bdev); 153 unsigned int max_write_same_sectors; 154 struct bio_batch bb; 155 struct bio *bio; 156 int ret = 0; 157 158 if (!q) 159 return -ENXIO; 160 161 max_write_same_sectors = q->limits.max_write_same_sectors; 162 163 if (max_write_same_sectors == 0) 164 return -EOPNOTSUPP; 165 166 atomic_set(&bb.done, 1); 167 bb.flags = 1 << BIO_UPTODATE; 168 bb.wait = &wait; 169 170 while (nr_sects) { 171 bio = bio_alloc(gfp_mask, 1); 172 if (!bio) { 173 ret = -ENOMEM; 174 break; 175 } 176 177 bio->bi_sector = sector; 178 bio->bi_end_io = bio_batch_end_io; 179 bio->bi_bdev = bdev; 180 bio->bi_private = &bb; 181 bio->bi_vcnt = 1; 182 bio->bi_io_vec->bv_page = page; 183 bio->bi_io_vec->bv_offset = 0; 184 bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev); 185 186 if (nr_sects > max_write_same_sectors) { 187 bio->bi_size = max_write_same_sectors << 9; 188 nr_sects -= max_write_same_sectors; 189 sector += max_write_same_sectors; 190 } else { 191 bio->bi_size = nr_sects << 9; 192 nr_sects = 0; 193 } 194 195 atomic_inc(&bb.done); 196 submit_bio(REQ_WRITE | REQ_WRITE_SAME, bio); 197 } 198 199 /* Wait for bios in-flight */ 200 if (!atomic_dec_and_test(&bb.done)) 201 wait_for_completion_io(&wait); 202 203 if (!test_bit(BIO_UPTODATE, &bb.flags)) 204 ret = -ENOTSUPP; 205 206 return ret; 207 } 208 EXPORT_SYMBOL(blkdev_issue_write_same); 209 210 /** 211 * blkdev_issue_zeroout - generate number of zero filed write bios 212 * @bdev: blockdev to issue 213 * @sector: start sector 214 * @nr_sects: number of sectors to write 215 * @gfp_mask: memory allocation flags (for bio_alloc) 216 * 217 * Description: 218 * Generate and issue number of bios with zerofiled pages. 219 */ 220 221 int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, 222 sector_t nr_sects, gfp_t gfp_mask) 223 { 224 int ret; 225 struct bio *bio; 226 struct bio_batch bb; 227 unsigned int sz; 228 DECLARE_COMPLETION_ONSTACK(wait); 229 230 atomic_set(&bb.done, 1); 231 bb.flags = 1 << BIO_UPTODATE; 232 bb.wait = &wait; 233 234 ret = 0; 235 while (nr_sects != 0) { 236 bio = bio_alloc(gfp_mask, 237 min(nr_sects, (sector_t)BIO_MAX_PAGES)); 238 if (!bio) { 239 ret = -ENOMEM; 240 break; 241 } 242 243 bio->bi_sector = sector; 244 bio->bi_bdev = bdev; 245 bio->bi_end_io = bio_batch_end_io; 246 bio->bi_private = &bb; 247 248 while (nr_sects != 0) { 249 sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects); 250 ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0); 251 nr_sects -= ret >> 9; 252 sector += ret >> 9; 253 if (ret < (sz << 9)) 254 break; 255 } 256 ret = 0; 257 atomic_inc(&bb.done); 258 submit_bio(WRITE, bio); 259 } 260 261 /* Wait for bios in-flight */ 262 if (!atomic_dec_and_test(&bb.done)) 263 wait_for_completion_io(&wait); 264 265 if (!test_bit(BIO_UPTODATE, &bb.flags)) 266 /* One of bios in the batch was completed with error.*/ 267 ret = -EIO; 268 269 return ret; 270 } 271 272 /** 273 * blkdev_issue_zeroout - zero-fill a block range 274 * @bdev: blockdev to write 275 * @sector: start sector 276 * @nr_sects: number of sectors to write 277 * @gfp_mask: memory allocation flags (for bio_alloc) 278 * 279 * Description: 280 * Generate and issue number of bios with zerofiled pages. 281 */ 282 283 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, 284 sector_t nr_sects, gfp_t gfp_mask) 285 { 286 if (bdev_write_same(bdev)) { 287 unsigned char bdn[BDEVNAME_SIZE]; 288 289 if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, 290 ZERO_PAGE(0))) 291 return 0; 292 293 bdevname(bdev, bdn); 294 pr_err("%s: WRITE SAME failed. Manually zeroing.\n", bdn); 295 } 296 297 return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask); 298 } 299 EXPORT_SYMBOL(blkdev_issue_zeroout); 300