1 /* 2 * blk-integrity.c - Block layer data integrity extensions 3 * 4 * Copyright (C) 2007, 2008 Oracle Corporation 5 * Written by: Martin K. Petersen <martin.petersen@oracle.com> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License version 9 * 2 as published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, but 12 * WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; see the file COPYING. If not, write to 18 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, 19 * USA. 20 * 21 */ 22 23 #include <linux/blkdev.h> 24 #include <linux/mempool.h> 25 #include <linux/bio.h> 26 #include <linux/scatterlist.h> 27 #include <linux/slab.h> 28 29 #include "blk.h" 30 31 static struct kmem_cache *integrity_cachep; 32 33 static const char *bi_unsupported_name = "unsupported"; 34 35 /** 36 * blk_rq_count_integrity_sg - Count number of integrity scatterlist elements 37 * @q: request queue 38 * @bio: bio with integrity metadata attached 39 * 40 * Description: Returns the number of elements required in a 41 * scatterlist corresponding to the integrity metadata in a bio. 42 */ 43 int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio) 44 { 45 struct bio_vec *iv, *ivprv = NULL; 46 unsigned int segments = 0; 47 unsigned int seg_size = 0; 48 unsigned int i = 0; 49 50 bio_for_each_integrity_vec(iv, bio, i) { 51 52 if (ivprv) { 53 if (!BIOVEC_PHYS_MERGEABLE(ivprv, iv)) 54 goto new_segment; 55 56 if (!BIOVEC_SEG_BOUNDARY(q, ivprv, iv)) 57 goto new_segment; 58 59 if (seg_size + iv->bv_len > queue_max_segment_size(q)) 60 goto new_segment; 61 62 seg_size += iv->bv_len; 63 } else { 64 new_segment: 65 segments++; 66 seg_size = iv->bv_len; 67 } 68 69 ivprv = iv; 70 } 71 72 return segments; 73 } 74 EXPORT_SYMBOL(blk_rq_count_integrity_sg); 75 76 /** 77 * blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist 78 * @q: request queue 79 * @bio: bio with integrity metadata attached 80 * @sglist: target scatterlist 81 * 82 * Description: Map the integrity vectors in request into a 83 * scatterlist. The scatterlist must be big enough to hold all 84 * elements. I.e. sized using blk_rq_count_integrity_sg(). 85 */ 86 int blk_rq_map_integrity_sg(struct request_queue *q, struct bio *bio, 87 struct scatterlist *sglist) 88 { 89 struct bio_vec *iv, *ivprv = NULL; 90 struct scatterlist *sg = NULL; 91 unsigned int segments = 0; 92 unsigned int i = 0; 93 94 bio_for_each_integrity_vec(iv, bio, i) { 95 96 if (ivprv) { 97 if (!BIOVEC_PHYS_MERGEABLE(ivprv, iv)) 98 goto new_segment; 99 100 if (!BIOVEC_SEG_BOUNDARY(q, ivprv, iv)) 101 goto new_segment; 102 103 if (sg->length + iv->bv_len > queue_max_segment_size(q)) 104 goto new_segment; 105 106 sg->length += iv->bv_len; 107 } else { 108 new_segment: 109 if (!sg) 110 sg = sglist; 111 else { 112 sg->page_link &= ~0x02; 113 sg = sg_next(sg); 114 } 115 116 sg_set_page(sg, iv->bv_page, iv->bv_len, iv->bv_offset); 117 segments++; 118 } 119 120 ivprv = iv; 121 } 122 123 if (sg) 124 sg_mark_end(sg); 125 126 return segments; 127 } 128 EXPORT_SYMBOL(blk_rq_map_integrity_sg); 129 130 /** 131 * blk_integrity_compare - Compare integrity profile of two disks 132 * @gd1: Disk to compare 133 * @gd2: Disk to compare 134 * 135 * Description: Meta-devices like DM and MD need to verify that all 136 * sub-devices use the same integrity format before advertising to 137 * upper layers that they can send/receive integrity metadata. This 138 * function can be used to check whether two gendisk devices have 139 * compatible integrity formats. 140 */ 141 int blk_integrity_compare(struct gendisk *gd1, struct gendisk *gd2) 142 { 143 struct blk_integrity *b1 = gd1->integrity; 144 struct blk_integrity *b2 = gd2->integrity; 145 146 if (!b1 && !b2) 147 return 0; 148 149 if (!b1 || !b2) 150 return -1; 151 152 if (b1->sector_size != b2->sector_size) { 153 printk(KERN_ERR "%s: %s/%s sector sz %u != %u\n", __func__, 154 gd1->disk_name, gd2->disk_name, 155 b1->sector_size, b2->sector_size); 156 return -1; 157 } 158 159 if (b1->tuple_size != b2->tuple_size) { 160 printk(KERN_ERR "%s: %s/%s tuple sz %u != %u\n", __func__, 161 gd1->disk_name, gd2->disk_name, 162 b1->tuple_size, b2->tuple_size); 163 return -1; 164 } 165 166 if (b1->tag_size && b2->tag_size && (b1->tag_size != b2->tag_size)) { 167 printk(KERN_ERR "%s: %s/%s tag sz %u != %u\n", __func__, 168 gd1->disk_name, gd2->disk_name, 169 b1->tag_size, b2->tag_size); 170 return -1; 171 } 172 173 if (strcmp(b1->name, b2->name)) { 174 printk(KERN_ERR "%s: %s/%s type %s != %s\n", __func__, 175 gd1->disk_name, gd2->disk_name, 176 b1->name, b2->name); 177 return -1; 178 } 179 180 return 0; 181 } 182 EXPORT_SYMBOL(blk_integrity_compare); 183 184 int blk_integrity_merge_rq(struct request_queue *q, struct request *req, 185 struct request *next) 186 { 187 if (blk_integrity_rq(req) != blk_integrity_rq(next)) 188 return -1; 189 190 if (req->nr_integrity_segments + next->nr_integrity_segments > 191 q->limits.max_integrity_segments) 192 return -1; 193 194 return 0; 195 } 196 EXPORT_SYMBOL(blk_integrity_merge_rq); 197 198 int blk_integrity_merge_bio(struct request_queue *q, struct request *req, 199 struct bio *bio) 200 { 201 int nr_integrity_segs; 202 struct bio *next = bio->bi_next; 203 204 bio->bi_next = NULL; 205 nr_integrity_segs = blk_rq_count_integrity_sg(q, bio); 206 bio->bi_next = next; 207 208 if (req->nr_integrity_segments + nr_integrity_segs > 209 q->limits.max_integrity_segments) 210 return -1; 211 212 req->nr_integrity_segments += nr_integrity_segs; 213 214 return 0; 215 } 216 EXPORT_SYMBOL(blk_integrity_merge_bio); 217 218 struct integrity_sysfs_entry { 219 struct attribute attr; 220 ssize_t (*show)(struct blk_integrity *, char *); 221 ssize_t (*store)(struct blk_integrity *, const char *, size_t); 222 }; 223 224 static ssize_t integrity_attr_show(struct kobject *kobj, struct attribute *attr, 225 char *page) 226 { 227 struct blk_integrity *bi = 228 container_of(kobj, struct blk_integrity, kobj); 229 struct integrity_sysfs_entry *entry = 230 container_of(attr, struct integrity_sysfs_entry, attr); 231 232 return entry->show(bi, page); 233 } 234 235 static ssize_t integrity_attr_store(struct kobject *kobj, 236 struct attribute *attr, const char *page, 237 size_t count) 238 { 239 struct blk_integrity *bi = 240 container_of(kobj, struct blk_integrity, kobj); 241 struct integrity_sysfs_entry *entry = 242 container_of(attr, struct integrity_sysfs_entry, attr); 243 ssize_t ret = 0; 244 245 if (entry->store) 246 ret = entry->store(bi, page, count); 247 248 return ret; 249 } 250 251 static ssize_t integrity_format_show(struct blk_integrity *bi, char *page) 252 { 253 if (bi != NULL && bi->name != NULL) 254 return sprintf(page, "%s\n", bi->name); 255 else 256 return sprintf(page, "none\n"); 257 } 258 259 static ssize_t integrity_tag_size_show(struct blk_integrity *bi, char *page) 260 { 261 if (bi != NULL) 262 return sprintf(page, "%u\n", bi->tag_size); 263 else 264 return sprintf(page, "0\n"); 265 } 266 267 static ssize_t integrity_read_store(struct blk_integrity *bi, 268 const char *page, size_t count) 269 { 270 char *p = (char *) page; 271 unsigned long val = simple_strtoul(p, &p, 10); 272 273 if (val) 274 bi->flags |= INTEGRITY_FLAG_READ; 275 else 276 bi->flags &= ~INTEGRITY_FLAG_READ; 277 278 return count; 279 } 280 281 static ssize_t integrity_read_show(struct blk_integrity *bi, char *page) 282 { 283 return sprintf(page, "%d\n", (bi->flags & INTEGRITY_FLAG_READ) != 0); 284 } 285 286 static ssize_t integrity_write_store(struct blk_integrity *bi, 287 const char *page, size_t count) 288 { 289 char *p = (char *) page; 290 unsigned long val = simple_strtoul(p, &p, 10); 291 292 if (val) 293 bi->flags |= INTEGRITY_FLAG_WRITE; 294 else 295 bi->flags &= ~INTEGRITY_FLAG_WRITE; 296 297 return count; 298 } 299 300 static ssize_t integrity_write_show(struct blk_integrity *bi, char *page) 301 { 302 return sprintf(page, "%d\n", (bi->flags & INTEGRITY_FLAG_WRITE) != 0); 303 } 304 305 static struct integrity_sysfs_entry integrity_format_entry = { 306 .attr = { .name = "format", .mode = S_IRUGO }, 307 .show = integrity_format_show, 308 }; 309 310 static struct integrity_sysfs_entry integrity_tag_size_entry = { 311 .attr = { .name = "tag_size", .mode = S_IRUGO }, 312 .show = integrity_tag_size_show, 313 }; 314 315 static struct integrity_sysfs_entry integrity_read_entry = { 316 .attr = { .name = "read_verify", .mode = S_IRUGO | S_IWUSR }, 317 .show = integrity_read_show, 318 .store = integrity_read_store, 319 }; 320 321 static struct integrity_sysfs_entry integrity_write_entry = { 322 .attr = { .name = "write_generate", .mode = S_IRUGO | S_IWUSR }, 323 .show = integrity_write_show, 324 .store = integrity_write_store, 325 }; 326 327 static struct attribute *integrity_attrs[] = { 328 &integrity_format_entry.attr, 329 &integrity_tag_size_entry.attr, 330 &integrity_read_entry.attr, 331 &integrity_write_entry.attr, 332 NULL, 333 }; 334 335 static const struct sysfs_ops integrity_ops = { 336 .show = &integrity_attr_show, 337 .store = &integrity_attr_store, 338 }; 339 340 static int __init blk_dev_integrity_init(void) 341 { 342 integrity_cachep = kmem_cache_create("blkdev_integrity", 343 sizeof(struct blk_integrity), 344 0, SLAB_PANIC, NULL); 345 return 0; 346 } 347 subsys_initcall(blk_dev_integrity_init); 348 349 static void blk_integrity_release(struct kobject *kobj) 350 { 351 struct blk_integrity *bi = 352 container_of(kobj, struct blk_integrity, kobj); 353 354 kmem_cache_free(integrity_cachep, bi); 355 } 356 357 static struct kobj_type integrity_ktype = { 358 .default_attrs = integrity_attrs, 359 .sysfs_ops = &integrity_ops, 360 .release = blk_integrity_release, 361 }; 362 363 bool blk_integrity_is_initialized(struct gendisk *disk) 364 { 365 struct blk_integrity *bi = blk_get_integrity(disk); 366 367 return (bi && bi->name && strcmp(bi->name, bi_unsupported_name) != 0); 368 } 369 EXPORT_SYMBOL(blk_integrity_is_initialized); 370 371 /** 372 * blk_integrity_register - Register a gendisk as being integrity-capable 373 * @disk: struct gendisk pointer to make integrity-aware 374 * @template: optional integrity profile to register 375 * 376 * Description: When a device needs to advertise itself as being able 377 * to send/receive integrity metadata it must use this function to 378 * register the capability with the block layer. The template is a 379 * blk_integrity struct with values appropriate for the underlying 380 * hardware. If template is NULL the new profile is allocated but 381 * not filled out. See Documentation/block/data-integrity.txt. 382 */ 383 int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template) 384 { 385 struct blk_integrity *bi; 386 387 BUG_ON(disk == NULL); 388 389 if (disk->integrity == NULL) { 390 bi = kmem_cache_alloc(integrity_cachep, 391 GFP_KERNEL | __GFP_ZERO); 392 if (!bi) 393 return -1; 394 395 if (kobject_init_and_add(&bi->kobj, &integrity_ktype, 396 &disk_to_dev(disk)->kobj, 397 "%s", "integrity")) { 398 kmem_cache_free(integrity_cachep, bi); 399 return -1; 400 } 401 402 kobject_uevent(&bi->kobj, KOBJ_ADD); 403 404 bi->flags |= INTEGRITY_FLAG_READ | INTEGRITY_FLAG_WRITE; 405 bi->sector_size = queue_logical_block_size(disk->queue); 406 disk->integrity = bi; 407 } else 408 bi = disk->integrity; 409 410 /* Use the provided profile as template */ 411 if (template != NULL) { 412 bi->name = template->name; 413 bi->generate_fn = template->generate_fn; 414 bi->verify_fn = template->verify_fn; 415 bi->tuple_size = template->tuple_size; 416 bi->set_tag_fn = template->set_tag_fn; 417 bi->get_tag_fn = template->get_tag_fn; 418 bi->tag_size = template->tag_size; 419 } else 420 bi->name = bi_unsupported_name; 421 422 return 0; 423 } 424 EXPORT_SYMBOL(blk_integrity_register); 425 426 /** 427 * blk_integrity_unregister - Remove block integrity profile 428 * @disk: disk whose integrity profile to deallocate 429 * 430 * Description: This function frees all memory used by the block 431 * integrity profile. To be called at device teardown. 432 */ 433 void blk_integrity_unregister(struct gendisk *disk) 434 { 435 struct blk_integrity *bi; 436 437 if (!disk || !disk->integrity) 438 return; 439 440 bi = disk->integrity; 441 442 kobject_uevent(&bi->kobj, KOBJ_REMOVE); 443 kobject_del(&bi->kobj); 444 kobject_put(&bi->kobj); 445 disk->integrity = NULL; 446 } 447 EXPORT_SYMBOL(blk_integrity_unregister); 448