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