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/export.h> 28 #include <linux/slab.h> 29 30 #include "blk.h" 31 32 static struct kmem_cache *integrity_cachep; 33 34 static const char *bi_unsupported_name = "unsupported"; 35 36 /** 37 * blk_rq_count_integrity_sg - Count number of integrity scatterlist elements 38 * @q: request queue 39 * @bio: bio with integrity metadata attached 40 * 41 * Description: Returns the number of elements required in a 42 * scatterlist corresponding to the integrity metadata in a bio. 43 */ 44 int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio) 45 { 46 struct bio_vec *iv, *ivprv = NULL; 47 unsigned int segments = 0; 48 unsigned int seg_size = 0; 49 unsigned int i = 0; 50 51 bio_for_each_integrity_vec(iv, bio, i) { 52 53 if (ivprv) { 54 if (!BIOVEC_PHYS_MERGEABLE(ivprv, iv)) 55 goto new_segment; 56 57 if (!BIOVEC_SEG_BOUNDARY(q, ivprv, iv)) 58 goto new_segment; 59 60 if (seg_size + iv->bv_len > queue_max_segment_size(q)) 61 goto new_segment; 62 63 seg_size += iv->bv_len; 64 } else { 65 new_segment: 66 segments++; 67 seg_size = iv->bv_len; 68 } 69 70 ivprv = iv; 71 } 72 73 return segments; 74 } 75 EXPORT_SYMBOL(blk_rq_count_integrity_sg); 76 77 /** 78 * blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist 79 * @q: request queue 80 * @bio: bio with integrity metadata attached 81 * @sglist: target scatterlist 82 * 83 * Description: Map the integrity vectors in request into a 84 * scatterlist. The scatterlist must be big enough to hold all 85 * elements. I.e. sized using blk_rq_count_integrity_sg(). 86 */ 87 int blk_rq_map_integrity_sg(struct request_queue *q, struct bio *bio, 88 struct scatterlist *sglist) 89 { 90 struct bio_vec *iv, *ivprv = NULL; 91 struct scatterlist *sg = NULL; 92 unsigned int segments = 0; 93 unsigned int i = 0; 94 95 bio_for_each_integrity_vec(iv, bio, i) { 96 97 if (ivprv) { 98 if (!BIOVEC_PHYS_MERGEABLE(ivprv, iv)) 99 goto new_segment; 100 101 if (!BIOVEC_SEG_BOUNDARY(q, ivprv, iv)) 102 goto new_segment; 103 104 if (sg->length + iv->bv_len > queue_max_segment_size(q)) 105 goto new_segment; 106 107 sg->length += iv->bv_len; 108 } else { 109 new_segment: 110 if (!sg) 111 sg = sglist; 112 else { 113 sg->page_link &= ~0x02; 114 sg = sg_next(sg); 115 } 116 117 sg_set_page(sg, iv->bv_page, iv->bv_len, iv->bv_offset); 118 segments++; 119 } 120 121 ivprv = iv; 122 } 123 124 if (sg) 125 sg_mark_end(sg); 126 127 return segments; 128 } 129 EXPORT_SYMBOL(blk_rq_map_integrity_sg); 130 131 /** 132 * blk_integrity_compare - Compare integrity profile of two disks 133 * @gd1: Disk to compare 134 * @gd2: Disk to compare 135 * 136 * Description: Meta-devices like DM and MD need to verify that all 137 * sub-devices use the same integrity format before advertising to 138 * upper layers that they can send/receive integrity metadata. This 139 * function can be used to check whether two gendisk devices have 140 * compatible integrity formats. 141 */ 142 int blk_integrity_compare(struct gendisk *gd1, struct gendisk *gd2) 143 { 144 struct blk_integrity *b1 = gd1->integrity; 145 struct blk_integrity *b2 = gd2->integrity; 146 147 if (!b1 && !b2) 148 return 0; 149 150 if (!b1 || !b2) 151 return -1; 152 153 if (b1->sector_size != b2->sector_size) { 154 printk(KERN_ERR "%s: %s/%s sector sz %u != %u\n", __func__, 155 gd1->disk_name, gd2->disk_name, 156 b1->sector_size, b2->sector_size); 157 return -1; 158 } 159 160 if (b1->tuple_size != b2->tuple_size) { 161 printk(KERN_ERR "%s: %s/%s tuple sz %u != %u\n", __func__, 162 gd1->disk_name, gd2->disk_name, 163 b1->tuple_size, b2->tuple_size); 164 return -1; 165 } 166 167 if (b1->tag_size && b2->tag_size && (b1->tag_size != b2->tag_size)) { 168 printk(KERN_ERR "%s: %s/%s tag sz %u != %u\n", __func__, 169 gd1->disk_name, gd2->disk_name, 170 b1->tag_size, b2->tag_size); 171 return -1; 172 } 173 174 if (strcmp(b1->name, b2->name)) { 175 printk(KERN_ERR "%s: %s/%s type %s != %s\n", __func__, 176 gd1->disk_name, gd2->disk_name, 177 b1->name, b2->name); 178 return -1; 179 } 180 181 return 0; 182 } 183 EXPORT_SYMBOL(blk_integrity_compare); 184 185 int blk_integrity_merge_rq(struct request_queue *q, struct request *req, 186 struct request *next) 187 { 188 if (blk_integrity_rq(req) != blk_integrity_rq(next)) 189 return -1; 190 191 if (req->nr_integrity_segments + next->nr_integrity_segments > 192 q->limits.max_integrity_segments) 193 return -1; 194 195 return 0; 196 } 197 EXPORT_SYMBOL(blk_integrity_merge_rq); 198 199 int blk_integrity_merge_bio(struct request_queue *q, struct request *req, 200 struct bio *bio) 201 { 202 int nr_integrity_segs; 203 struct bio *next = bio->bi_next; 204 205 bio->bi_next = NULL; 206 nr_integrity_segs = blk_rq_count_integrity_sg(q, bio); 207 bio->bi_next = next; 208 209 if (req->nr_integrity_segments + nr_integrity_segs > 210 q->limits.max_integrity_segments) 211 return -1; 212 213 req->nr_integrity_segments += nr_integrity_segs; 214 215 return 0; 216 } 217 EXPORT_SYMBOL(blk_integrity_merge_bio); 218 219 struct integrity_sysfs_entry { 220 struct attribute attr; 221 ssize_t (*show)(struct blk_integrity *, char *); 222 ssize_t (*store)(struct blk_integrity *, const char *, size_t); 223 }; 224 225 static ssize_t integrity_attr_show(struct kobject *kobj, struct attribute *attr, 226 char *page) 227 { 228 struct blk_integrity *bi = 229 container_of(kobj, struct blk_integrity, kobj); 230 struct integrity_sysfs_entry *entry = 231 container_of(attr, struct integrity_sysfs_entry, attr); 232 233 return entry->show(bi, page); 234 } 235 236 static ssize_t integrity_attr_store(struct kobject *kobj, 237 struct attribute *attr, const char *page, 238 size_t count) 239 { 240 struct blk_integrity *bi = 241 container_of(kobj, struct blk_integrity, kobj); 242 struct integrity_sysfs_entry *entry = 243 container_of(attr, struct integrity_sysfs_entry, attr); 244 ssize_t ret = 0; 245 246 if (entry->store) 247 ret = entry->store(bi, page, count); 248 249 return ret; 250 } 251 252 static ssize_t integrity_format_show(struct blk_integrity *bi, char *page) 253 { 254 if (bi != NULL && bi->name != NULL) 255 return sprintf(page, "%s\n", bi->name); 256 else 257 return sprintf(page, "none\n"); 258 } 259 260 static ssize_t integrity_tag_size_show(struct blk_integrity *bi, char *page) 261 { 262 if (bi != NULL) 263 return sprintf(page, "%u\n", bi->tag_size); 264 else 265 return sprintf(page, "0\n"); 266 } 267 268 static ssize_t integrity_read_store(struct blk_integrity *bi, 269 const char *page, size_t count) 270 { 271 char *p = (char *) page; 272 unsigned long val = simple_strtoul(p, &p, 10); 273 274 if (val) 275 bi->flags |= INTEGRITY_FLAG_READ; 276 else 277 bi->flags &= ~INTEGRITY_FLAG_READ; 278 279 return count; 280 } 281 282 static ssize_t integrity_read_show(struct blk_integrity *bi, char *page) 283 { 284 return sprintf(page, "%d\n", (bi->flags & INTEGRITY_FLAG_READ) != 0); 285 } 286 287 static ssize_t integrity_write_store(struct blk_integrity *bi, 288 const char *page, size_t count) 289 { 290 char *p = (char *) page; 291 unsigned long val = simple_strtoul(p, &p, 10); 292 293 if (val) 294 bi->flags |= INTEGRITY_FLAG_WRITE; 295 else 296 bi->flags &= ~INTEGRITY_FLAG_WRITE; 297 298 return count; 299 } 300 301 static ssize_t integrity_write_show(struct blk_integrity *bi, char *page) 302 { 303 return sprintf(page, "%d\n", (bi->flags & INTEGRITY_FLAG_WRITE) != 0); 304 } 305 306 static struct integrity_sysfs_entry integrity_format_entry = { 307 .attr = { .name = "format", .mode = S_IRUGO }, 308 .show = integrity_format_show, 309 }; 310 311 static struct integrity_sysfs_entry integrity_tag_size_entry = { 312 .attr = { .name = "tag_size", .mode = S_IRUGO }, 313 .show = integrity_tag_size_show, 314 }; 315 316 static struct integrity_sysfs_entry integrity_read_entry = { 317 .attr = { .name = "read_verify", .mode = S_IRUGO | S_IWUSR }, 318 .show = integrity_read_show, 319 .store = integrity_read_store, 320 }; 321 322 static struct integrity_sysfs_entry integrity_write_entry = { 323 .attr = { .name = "write_generate", .mode = S_IRUGO | S_IWUSR }, 324 .show = integrity_write_show, 325 .store = integrity_write_store, 326 }; 327 328 static struct attribute *integrity_attrs[] = { 329 &integrity_format_entry.attr, 330 &integrity_tag_size_entry.attr, 331 &integrity_read_entry.attr, 332 &integrity_write_entry.attr, 333 NULL, 334 }; 335 336 static const struct sysfs_ops integrity_ops = { 337 .show = &integrity_attr_show, 338 .store = &integrity_attr_store, 339 }; 340 341 static int __init blk_dev_integrity_init(void) 342 { 343 integrity_cachep = kmem_cache_create("blkdev_integrity", 344 sizeof(struct blk_integrity), 345 0, SLAB_PANIC, NULL); 346 return 0; 347 } 348 subsys_initcall(blk_dev_integrity_init); 349 350 static void blk_integrity_release(struct kobject *kobj) 351 { 352 struct blk_integrity *bi = 353 container_of(kobj, struct blk_integrity, kobj); 354 355 kmem_cache_free(integrity_cachep, bi); 356 } 357 358 static struct kobj_type integrity_ktype = { 359 .default_attrs = integrity_attrs, 360 .sysfs_ops = &integrity_ops, 361 .release = blk_integrity_release, 362 }; 363 364 bool blk_integrity_is_initialized(struct gendisk *disk) 365 { 366 struct blk_integrity *bi = blk_get_integrity(disk); 367 368 return (bi && bi->name && strcmp(bi->name, bi_unsupported_name) != 0); 369 } 370 EXPORT_SYMBOL(blk_integrity_is_initialized); 371 372 /** 373 * blk_integrity_register - Register a gendisk as being integrity-capable 374 * @disk: struct gendisk pointer to make integrity-aware 375 * @template: optional integrity profile to register 376 * 377 * Description: When a device needs to advertise itself as being able 378 * to send/receive integrity metadata it must use this function to 379 * register the capability with the block layer. The template is a 380 * blk_integrity struct with values appropriate for the underlying 381 * hardware. If template is NULL the new profile is allocated but 382 * not filled out. See Documentation/block/data-integrity.txt. 383 */ 384 int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template) 385 { 386 struct blk_integrity *bi; 387 388 BUG_ON(disk == NULL); 389 390 if (disk->integrity == NULL) { 391 bi = kmem_cache_alloc(integrity_cachep, 392 GFP_KERNEL | __GFP_ZERO); 393 if (!bi) 394 return -1; 395 396 if (kobject_init_and_add(&bi->kobj, &integrity_ktype, 397 &disk_to_dev(disk)->kobj, 398 "%s", "integrity")) { 399 kmem_cache_free(integrity_cachep, bi); 400 return -1; 401 } 402 403 kobject_uevent(&bi->kobj, KOBJ_ADD); 404 405 bi->flags |= INTEGRITY_FLAG_READ | INTEGRITY_FLAG_WRITE; 406 bi->sector_size = queue_logical_block_size(disk->queue); 407 disk->integrity = bi; 408 } else 409 bi = disk->integrity; 410 411 /* Use the provided profile as template */ 412 if (template != NULL) { 413 bi->name = template->name; 414 bi->generate_fn = template->generate_fn; 415 bi->verify_fn = template->verify_fn; 416 bi->tuple_size = template->tuple_size; 417 bi->set_tag_fn = template->set_tag_fn; 418 bi->get_tag_fn = template->get_tag_fn; 419 bi->tag_size = template->tag_size; 420 } else 421 bi->name = bi_unsupported_name; 422 423 return 0; 424 } 425 EXPORT_SYMBOL(blk_integrity_register); 426 427 /** 428 * blk_integrity_unregister - Remove block integrity profile 429 * @disk: disk whose integrity profile to deallocate 430 * 431 * Description: This function frees all memory used by the block 432 * integrity profile. To be called at device teardown. 433 */ 434 void blk_integrity_unregister(struct gendisk *disk) 435 { 436 struct blk_integrity *bi; 437 438 if (!disk || !disk->integrity) 439 return; 440 441 bi = disk->integrity; 442 443 kobject_uevent(&bi->kobj, KOBJ_REMOVE); 444 kobject_del(&bi->kobj); 445 kobject_put(&bi->kobj); 446 disk->integrity = NULL; 447 } 448 EXPORT_SYMBOL(blk_integrity_unregister); 449