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