1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * gendisk handling 4 * 5 * Portions Copyright (C) 2020 Christoph Hellwig 6 */ 7 8 #include <linux/module.h> 9 #include <linux/ctype.h> 10 #include <linux/fs.h> 11 #include <linux/genhd.h> 12 #include <linux/kdev_t.h> 13 #include <linux/kernel.h> 14 #include <linux/blkdev.h> 15 #include <linux/backing-dev.h> 16 #include <linux/init.h> 17 #include <linux/spinlock.h> 18 #include <linux/proc_fs.h> 19 #include <linux/seq_file.h> 20 #include <linux/slab.h> 21 #include <linux/kmod.h> 22 #include <linux/mutex.h> 23 #include <linux/idr.h> 24 #include <linux/log2.h> 25 #include <linux/pm_runtime.h> 26 #include <linux/badblocks.h> 27 28 #include "blk.h" 29 #include "blk-rq-qos.h" 30 31 static struct kobject *block_depr; 32 33 /* 34 * Unique, monotonically increasing sequential number associated with block 35 * devices instances (i.e. incremented each time a device is attached). 36 * Associating uevents with block devices in userspace is difficult and racy: 37 * the uevent netlink socket is lossy, and on slow and overloaded systems has 38 * a very high latency. 39 * Block devices do not have exclusive owners in userspace, any process can set 40 * one up (e.g. loop devices). Moreover, device names can be reused (e.g. loop0 41 * can be reused again and again). 42 * A userspace process setting up a block device and watching for its events 43 * cannot thus reliably tell whether an event relates to the device it just set 44 * up or another earlier instance with the same name. 45 * This sequential number allows userspace processes to solve this problem, and 46 * uniquely associate an uevent to the lifetime to a device. 47 */ 48 static atomic64_t diskseq; 49 50 /* for extended dynamic devt allocation, currently only one major is used */ 51 #define NR_EXT_DEVT (1 << MINORBITS) 52 static DEFINE_IDA(ext_devt_ida); 53 54 void set_capacity(struct gendisk *disk, sector_t sectors) 55 { 56 struct block_device *bdev = disk->part0; 57 58 spin_lock(&bdev->bd_size_lock); 59 i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT); 60 spin_unlock(&bdev->bd_size_lock); 61 } 62 EXPORT_SYMBOL(set_capacity); 63 64 /* 65 * Set disk capacity and notify if the size is not currently zero and will not 66 * be set to zero. Returns true if a uevent was sent, otherwise false. 67 */ 68 bool set_capacity_and_notify(struct gendisk *disk, sector_t size) 69 { 70 sector_t capacity = get_capacity(disk); 71 char *envp[] = { "RESIZE=1", NULL }; 72 73 set_capacity(disk, size); 74 75 /* 76 * Only print a message and send a uevent if the gendisk is user visible 77 * and alive. This avoids spamming the log and udev when setting the 78 * initial capacity during probing. 79 */ 80 if (size == capacity || 81 !disk_live(disk) || 82 (disk->flags & GENHD_FL_HIDDEN)) 83 return false; 84 85 pr_info("%s: detected capacity change from %lld to %lld\n", 86 disk->disk_name, capacity, size); 87 88 /* 89 * Historically we did not send a uevent for changes to/from an empty 90 * device. 91 */ 92 if (!capacity || !size) 93 return false; 94 kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp); 95 return true; 96 } 97 EXPORT_SYMBOL_GPL(set_capacity_and_notify); 98 99 /* 100 * Format the device name of the indicated block device into the supplied buffer 101 * and return a pointer to that same buffer for convenience. 102 * 103 * Note: do not use this in new code, use the %pg specifier to sprintf and 104 * printk insted. 105 */ 106 const char *bdevname(struct block_device *bdev, char *buf) 107 { 108 struct gendisk *hd = bdev->bd_disk; 109 int partno = bdev->bd_partno; 110 111 if (!partno) 112 snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name); 113 else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1])) 114 snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno); 115 else 116 snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno); 117 118 return buf; 119 } 120 EXPORT_SYMBOL(bdevname); 121 122 static void part_stat_read_all(struct block_device *part, 123 struct disk_stats *stat) 124 { 125 int cpu; 126 127 memset(stat, 0, sizeof(struct disk_stats)); 128 for_each_possible_cpu(cpu) { 129 struct disk_stats *ptr = per_cpu_ptr(part->bd_stats, cpu); 130 int group; 131 132 for (group = 0; group < NR_STAT_GROUPS; group++) { 133 stat->nsecs[group] += ptr->nsecs[group]; 134 stat->sectors[group] += ptr->sectors[group]; 135 stat->ios[group] += ptr->ios[group]; 136 stat->merges[group] += ptr->merges[group]; 137 } 138 139 stat->io_ticks += ptr->io_ticks; 140 } 141 } 142 143 static unsigned int part_in_flight(struct block_device *part) 144 { 145 unsigned int inflight = 0; 146 int cpu; 147 148 for_each_possible_cpu(cpu) { 149 inflight += part_stat_local_read_cpu(part, in_flight[0], cpu) + 150 part_stat_local_read_cpu(part, in_flight[1], cpu); 151 } 152 if ((int)inflight < 0) 153 inflight = 0; 154 155 return inflight; 156 } 157 158 static void part_in_flight_rw(struct block_device *part, 159 unsigned int inflight[2]) 160 { 161 int cpu; 162 163 inflight[0] = 0; 164 inflight[1] = 0; 165 for_each_possible_cpu(cpu) { 166 inflight[0] += part_stat_local_read_cpu(part, in_flight[0], cpu); 167 inflight[1] += part_stat_local_read_cpu(part, in_flight[1], cpu); 168 } 169 if ((int)inflight[0] < 0) 170 inflight[0] = 0; 171 if ((int)inflight[1] < 0) 172 inflight[1] = 0; 173 } 174 175 /* 176 * Can be deleted altogether. Later. 177 * 178 */ 179 #define BLKDEV_MAJOR_HASH_SIZE 255 180 static struct blk_major_name { 181 struct blk_major_name *next; 182 int major; 183 char name[16]; 184 void (*probe)(dev_t devt); 185 } *major_names[BLKDEV_MAJOR_HASH_SIZE]; 186 static DEFINE_MUTEX(major_names_lock); 187 static DEFINE_SPINLOCK(major_names_spinlock); 188 189 /* index in the above - for now: assume no multimajor ranges */ 190 static inline int major_to_index(unsigned major) 191 { 192 return major % BLKDEV_MAJOR_HASH_SIZE; 193 } 194 195 #ifdef CONFIG_PROC_FS 196 void blkdev_show(struct seq_file *seqf, off_t offset) 197 { 198 struct blk_major_name *dp; 199 200 spin_lock(&major_names_spinlock); 201 for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next) 202 if (dp->major == offset) 203 seq_printf(seqf, "%3d %s\n", dp->major, dp->name); 204 spin_unlock(&major_names_spinlock); 205 } 206 #endif /* CONFIG_PROC_FS */ 207 208 /** 209 * __register_blkdev - register a new block device 210 * 211 * @major: the requested major device number [1..BLKDEV_MAJOR_MAX-1]. If 212 * @major = 0, try to allocate any unused major number. 213 * @name: the name of the new block device as a zero terminated string 214 * @probe: allback that is called on access to any minor number of @major 215 * 216 * The @name must be unique within the system. 217 * 218 * The return value depends on the @major input parameter: 219 * 220 * - if a major device number was requested in range [1..BLKDEV_MAJOR_MAX-1] 221 * then the function returns zero on success, or a negative error code 222 * - if any unused major number was requested with @major = 0 parameter 223 * then the return value is the allocated major number in range 224 * [1..BLKDEV_MAJOR_MAX-1] or a negative error code otherwise 225 * 226 * See Documentation/admin-guide/devices.txt for the list of allocated 227 * major numbers. 228 * 229 * Use register_blkdev instead for any new code. 230 */ 231 int __register_blkdev(unsigned int major, const char *name, 232 void (*probe)(dev_t devt)) 233 { 234 struct blk_major_name **n, *p; 235 int index, ret = 0; 236 237 mutex_lock(&major_names_lock); 238 239 /* temporary */ 240 if (major == 0) { 241 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) { 242 if (major_names[index] == NULL) 243 break; 244 } 245 246 if (index == 0) { 247 printk("%s: failed to get major for %s\n", 248 __func__, name); 249 ret = -EBUSY; 250 goto out; 251 } 252 major = index; 253 ret = major; 254 } 255 256 if (major >= BLKDEV_MAJOR_MAX) { 257 pr_err("%s: major requested (%u) is greater than the maximum (%u) for %s\n", 258 __func__, major, BLKDEV_MAJOR_MAX-1, name); 259 260 ret = -EINVAL; 261 goto out; 262 } 263 264 p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL); 265 if (p == NULL) { 266 ret = -ENOMEM; 267 goto out; 268 } 269 270 p->major = major; 271 p->probe = probe; 272 strlcpy(p->name, name, sizeof(p->name)); 273 p->next = NULL; 274 index = major_to_index(major); 275 276 spin_lock(&major_names_spinlock); 277 for (n = &major_names[index]; *n; n = &(*n)->next) { 278 if ((*n)->major == major) 279 break; 280 } 281 if (!*n) 282 *n = p; 283 else 284 ret = -EBUSY; 285 spin_unlock(&major_names_spinlock); 286 287 if (ret < 0) { 288 printk("register_blkdev: cannot get major %u for %s\n", 289 major, name); 290 kfree(p); 291 } 292 out: 293 mutex_unlock(&major_names_lock); 294 return ret; 295 } 296 EXPORT_SYMBOL(__register_blkdev); 297 298 void unregister_blkdev(unsigned int major, const char *name) 299 { 300 struct blk_major_name **n; 301 struct blk_major_name *p = NULL; 302 int index = major_to_index(major); 303 304 mutex_lock(&major_names_lock); 305 spin_lock(&major_names_spinlock); 306 for (n = &major_names[index]; *n; n = &(*n)->next) 307 if ((*n)->major == major) 308 break; 309 if (!*n || strcmp((*n)->name, name)) { 310 WARN_ON(1); 311 } else { 312 p = *n; 313 *n = p->next; 314 } 315 spin_unlock(&major_names_spinlock); 316 mutex_unlock(&major_names_lock); 317 kfree(p); 318 } 319 320 EXPORT_SYMBOL(unregister_blkdev); 321 322 int blk_alloc_ext_minor(void) 323 { 324 int idx; 325 326 idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT, GFP_KERNEL); 327 if (idx == -ENOSPC) 328 return -EBUSY; 329 return idx; 330 } 331 332 void blk_free_ext_minor(unsigned int minor) 333 { 334 ida_free(&ext_devt_ida, minor); 335 } 336 337 static char *bdevt_str(dev_t devt, char *buf) 338 { 339 if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) { 340 char tbuf[BDEVT_SIZE]; 341 snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt)); 342 snprintf(buf, BDEVT_SIZE, "%-9s", tbuf); 343 } else 344 snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt)); 345 346 return buf; 347 } 348 349 void disk_uevent(struct gendisk *disk, enum kobject_action action) 350 { 351 struct block_device *part; 352 unsigned long idx; 353 354 rcu_read_lock(); 355 xa_for_each(&disk->part_tbl, idx, part) { 356 if (bdev_is_partition(part) && !bdev_nr_sectors(part)) 357 continue; 358 if (!kobject_get_unless_zero(&part->bd_device.kobj)) 359 continue; 360 361 rcu_read_unlock(); 362 kobject_uevent(bdev_kobj(part), action); 363 put_device(&part->bd_device); 364 rcu_read_lock(); 365 } 366 rcu_read_unlock(); 367 } 368 EXPORT_SYMBOL_GPL(disk_uevent); 369 370 static void disk_scan_partitions(struct gendisk *disk) 371 { 372 struct block_device *bdev; 373 374 if (!get_capacity(disk) || !disk_part_scan_enabled(disk)) 375 return; 376 377 set_bit(GD_NEED_PART_SCAN, &disk->state); 378 bdev = blkdev_get_by_dev(disk_devt(disk), FMODE_READ, NULL); 379 if (!IS_ERR(bdev)) 380 blkdev_put(bdev, FMODE_READ); 381 } 382 383 /** 384 * device_add_disk - add disk information to kernel list 385 * @parent: parent device for the disk 386 * @disk: per-device partitioning information 387 * @groups: Additional per-device sysfs groups 388 * 389 * This function registers the partitioning information in @disk 390 * with the kernel. 391 */ 392 int device_add_disk(struct device *parent, struct gendisk *disk, 393 const struct attribute_group **groups) 394 395 { 396 struct device *ddev = disk_to_dev(disk); 397 int ret; 398 399 /* 400 * The disk queue should now be all set with enough information about 401 * the device for the elevator code to pick an adequate default 402 * elevator if one is needed, that is, for devices requesting queue 403 * registration. 404 */ 405 elevator_init_mq(disk->queue); 406 407 /* 408 * If the driver provides an explicit major number it also must provide 409 * the number of minors numbers supported, and those will be used to 410 * setup the gendisk. 411 * Otherwise just allocate the device numbers for both the whole device 412 * and all partitions from the extended dev_t space. 413 */ 414 if (disk->major) { 415 if (WARN_ON(!disk->minors)) 416 return -EINVAL; 417 418 if (disk->minors > DISK_MAX_PARTS) { 419 pr_err("block: can't allocate more than %d partitions\n", 420 DISK_MAX_PARTS); 421 disk->minors = DISK_MAX_PARTS; 422 } 423 } else { 424 if (WARN_ON(disk->minors)) 425 return -EINVAL; 426 427 ret = blk_alloc_ext_minor(); 428 if (ret < 0) 429 return ret; 430 disk->major = BLOCK_EXT_MAJOR; 431 disk->first_minor = ret; 432 disk->flags |= GENHD_FL_EXT_DEVT; 433 } 434 435 ret = disk_alloc_events(disk); 436 if (ret) 437 goto out_free_ext_minor; 438 439 /* delay uevents, until we scanned partition table */ 440 dev_set_uevent_suppress(ddev, 1); 441 442 ddev->parent = parent; 443 ddev->groups = groups; 444 dev_set_name(ddev, "%s", disk->disk_name); 445 if (!(disk->flags & GENHD_FL_HIDDEN)) 446 ddev->devt = MKDEV(disk->major, disk->first_minor); 447 ret = device_add(ddev); 448 if (ret) 449 goto out_disk_release_events; 450 if (!sysfs_deprecated) { 451 ret = sysfs_create_link(block_depr, &ddev->kobj, 452 kobject_name(&ddev->kobj)); 453 if (ret) 454 goto out_device_del; 455 } 456 457 /* 458 * avoid probable deadlock caused by allocating memory with 459 * GFP_KERNEL in runtime_resume callback of its all ancestor 460 * devices 461 */ 462 pm_runtime_set_memalloc_noio(ddev, true); 463 464 ret = blk_integrity_add(disk); 465 if (ret) 466 goto out_del_block_link; 467 468 disk->part0->bd_holder_dir = 469 kobject_create_and_add("holders", &ddev->kobj); 470 if (!disk->part0->bd_holder_dir) 471 goto out_del_integrity; 472 disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj); 473 if (!disk->slave_dir) 474 goto out_put_holder_dir; 475 476 ret = bd_register_pending_holders(disk); 477 if (ret < 0) 478 goto out_put_slave_dir; 479 480 ret = blk_register_queue(disk); 481 if (ret) 482 goto out_put_slave_dir; 483 484 if (disk->flags & GENHD_FL_HIDDEN) { 485 /* 486 * Don't let hidden disks show up in /proc/partitions, 487 * and don't bother scanning for partitions either. 488 */ 489 disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO; 490 disk->flags |= GENHD_FL_NO_PART_SCAN; 491 } else { 492 ret = bdi_register(disk->bdi, "%u:%u", 493 disk->major, disk->first_minor); 494 if (ret) 495 goto out_unregister_queue; 496 bdi_set_owner(disk->bdi, ddev); 497 ret = sysfs_create_link(&ddev->kobj, 498 &disk->bdi->dev->kobj, "bdi"); 499 if (ret) 500 goto out_unregister_bdi; 501 502 bdev_add(disk->part0, ddev->devt); 503 disk_scan_partitions(disk); 504 505 /* 506 * Announce the disk and partitions after all partitions are 507 * created. (for hidden disks uevents remain suppressed forever) 508 */ 509 dev_set_uevent_suppress(ddev, 0); 510 disk_uevent(disk, KOBJ_ADD); 511 } 512 513 disk_update_readahead(disk); 514 disk_add_events(disk); 515 return 0; 516 517 out_unregister_bdi: 518 if (!(disk->flags & GENHD_FL_HIDDEN)) 519 bdi_unregister(disk->bdi); 520 out_unregister_queue: 521 blk_unregister_queue(disk); 522 out_put_slave_dir: 523 kobject_put(disk->slave_dir); 524 out_put_holder_dir: 525 kobject_put(disk->part0->bd_holder_dir); 526 out_del_integrity: 527 blk_integrity_del(disk); 528 out_del_block_link: 529 if (!sysfs_deprecated) 530 sysfs_remove_link(block_depr, dev_name(ddev)); 531 out_device_del: 532 device_del(ddev); 533 out_disk_release_events: 534 disk_release_events(disk); 535 out_free_ext_minor: 536 if (disk->major == BLOCK_EXT_MAJOR) 537 blk_free_ext_minor(disk->first_minor); 538 return WARN_ON_ONCE(ret); /* keep until all callers handle errors */ 539 } 540 EXPORT_SYMBOL(device_add_disk); 541 542 /** 543 * del_gendisk - remove the gendisk 544 * @disk: the struct gendisk to remove 545 * 546 * Removes the gendisk and all its associated resources. This deletes the 547 * partitions associated with the gendisk, and unregisters the associated 548 * request_queue. 549 * 550 * This is the counter to the respective __device_add_disk() call. 551 * 552 * The final removal of the struct gendisk happens when its refcount reaches 0 553 * with put_disk(), which should be called after del_gendisk(), if 554 * __device_add_disk() was used. 555 * 556 * Drivers exist which depend on the release of the gendisk to be synchronous, 557 * it should not be deferred. 558 * 559 * Context: can sleep 560 */ 561 void del_gendisk(struct gendisk *disk) 562 { 563 struct request_queue *q = disk->queue; 564 565 might_sleep(); 566 567 if (WARN_ON_ONCE(!disk_live(disk) && !(disk->flags & GENHD_FL_HIDDEN))) 568 return; 569 570 blk_integrity_del(disk); 571 disk_del_events(disk); 572 573 mutex_lock(&disk->open_mutex); 574 remove_inode_hash(disk->part0->bd_inode); 575 blk_drop_partitions(disk); 576 mutex_unlock(&disk->open_mutex); 577 578 fsync_bdev(disk->part0); 579 __invalidate_device(disk->part0, true); 580 581 /* 582 * Fail any new I/O. 583 */ 584 set_bit(GD_DEAD, &disk->state); 585 set_capacity(disk, 0); 586 587 /* 588 * Prevent new I/O from crossing bio_queue_enter(). 589 */ 590 blk_queue_start_drain(q); 591 blk_mq_freeze_queue_wait(q); 592 593 rq_qos_exit(q); 594 blk_sync_queue(q); 595 blk_flush_integrity(); 596 /* 597 * Allow using passthrough request again after the queue is torn down. 598 */ 599 blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q); 600 __blk_mq_unfreeze_queue(q, true); 601 602 if (!(disk->flags & GENHD_FL_HIDDEN)) { 603 sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi"); 604 605 /* 606 * Unregister bdi before releasing device numbers (as they can 607 * get reused and we'd get clashes in sysfs). 608 */ 609 bdi_unregister(disk->bdi); 610 } 611 612 blk_unregister_queue(disk); 613 614 kobject_put(disk->part0->bd_holder_dir); 615 kobject_put(disk->slave_dir); 616 617 part_stat_set_all(disk->part0, 0); 618 disk->part0->bd_stamp = 0; 619 if (!sysfs_deprecated) 620 sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk))); 621 pm_runtime_set_memalloc_noio(disk_to_dev(disk), false); 622 device_del(disk_to_dev(disk)); 623 } 624 EXPORT_SYMBOL(del_gendisk); 625 626 /* sysfs access to bad-blocks list. */ 627 static ssize_t disk_badblocks_show(struct device *dev, 628 struct device_attribute *attr, 629 char *page) 630 { 631 struct gendisk *disk = dev_to_disk(dev); 632 633 if (!disk->bb) 634 return sprintf(page, "\n"); 635 636 return badblocks_show(disk->bb, page, 0); 637 } 638 639 static ssize_t disk_badblocks_store(struct device *dev, 640 struct device_attribute *attr, 641 const char *page, size_t len) 642 { 643 struct gendisk *disk = dev_to_disk(dev); 644 645 if (!disk->bb) 646 return -ENXIO; 647 648 return badblocks_store(disk->bb, page, len, 0); 649 } 650 651 void blk_request_module(dev_t devt) 652 { 653 unsigned int major = MAJOR(devt); 654 struct blk_major_name **n; 655 656 mutex_lock(&major_names_lock); 657 for (n = &major_names[major_to_index(major)]; *n; n = &(*n)->next) { 658 if ((*n)->major == major && (*n)->probe) { 659 (*n)->probe(devt); 660 mutex_unlock(&major_names_lock); 661 return; 662 } 663 } 664 mutex_unlock(&major_names_lock); 665 666 if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0) 667 /* Make old-style 2.4 aliases work */ 668 request_module("block-major-%d", MAJOR(devt)); 669 } 670 671 /* 672 * print a full list of all partitions - intended for places where the root 673 * filesystem can't be mounted and thus to give the victim some idea of what 674 * went wrong 675 */ 676 void __init printk_all_partitions(void) 677 { 678 struct class_dev_iter iter; 679 struct device *dev; 680 681 class_dev_iter_init(&iter, &block_class, NULL, &disk_type); 682 while ((dev = class_dev_iter_next(&iter))) { 683 struct gendisk *disk = dev_to_disk(dev); 684 struct block_device *part; 685 char devt_buf[BDEVT_SIZE]; 686 unsigned long idx; 687 688 /* 689 * Don't show empty devices or things that have been 690 * suppressed 691 */ 692 if (get_capacity(disk) == 0 || 693 (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)) 694 continue; 695 696 /* 697 * Note, unlike /proc/partitions, I am showing the numbers in 698 * hex - the same format as the root= option takes. 699 */ 700 rcu_read_lock(); 701 xa_for_each(&disk->part_tbl, idx, part) { 702 if (!bdev_nr_sectors(part)) 703 continue; 704 printk("%s%s %10llu %pg %s", 705 bdev_is_partition(part) ? " " : "", 706 bdevt_str(part->bd_dev, devt_buf), 707 bdev_nr_sectors(part) >> 1, part, 708 part->bd_meta_info ? 709 part->bd_meta_info->uuid : ""); 710 if (bdev_is_partition(part)) 711 printk("\n"); 712 else if (dev->parent && dev->parent->driver) 713 printk(" driver: %s\n", 714 dev->parent->driver->name); 715 else 716 printk(" (driver?)\n"); 717 } 718 rcu_read_unlock(); 719 } 720 class_dev_iter_exit(&iter); 721 } 722 723 #ifdef CONFIG_PROC_FS 724 /* iterator */ 725 static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos) 726 { 727 loff_t skip = *pos; 728 struct class_dev_iter *iter; 729 struct device *dev; 730 731 iter = kmalloc(sizeof(*iter), GFP_KERNEL); 732 if (!iter) 733 return ERR_PTR(-ENOMEM); 734 735 seqf->private = iter; 736 class_dev_iter_init(iter, &block_class, NULL, &disk_type); 737 do { 738 dev = class_dev_iter_next(iter); 739 if (!dev) 740 return NULL; 741 } while (skip--); 742 743 return dev_to_disk(dev); 744 } 745 746 static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos) 747 { 748 struct device *dev; 749 750 (*pos)++; 751 dev = class_dev_iter_next(seqf->private); 752 if (dev) 753 return dev_to_disk(dev); 754 755 return NULL; 756 } 757 758 static void disk_seqf_stop(struct seq_file *seqf, void *v) 759 { 760 struct class_dev_iter *iter = seqf->private; 761 762 /* stop is called even after start failed :-( */ 763 if (iter) { 764 class_dev_iter_exit(iter); 765 kfree(iter); 766 seqf->private = NULL; 767 } 768 } 769 770 static void *show_partition_start(struct seq_file *seqf, loff_t *pos) 771 { 772 void *p; 773 774 p = disk_seqf_start(seqf, pos); 775 if (!IS_ERR_OR_NULL(p) && !*pos) 776 seq_puts(seqf, "major minor #blocks name\n\n"); 777 return p; 778 } 779 780 static int show_partition(struct seq_file *seqf, void *v) 781 { 782 struct gendisk *sgp = v; 783 struct block_device *part; 784 unsigned long idx; 785 786 /* Don't show non-partitionable removeable devices or empty devices */ 787 if (!get_capacity(sgp) || (!disk_max_parts(sgp) && 788 (sgp->flags & GENHD_FL_REMOVABLE))) 789 return 0; 790 if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO) 791 return 0; 792 793 rcu_read_lock(); 794 xa_for_each(&sgp->part_tbl, idx, part) { 795 if (!bdev_nr_sectors(part)) 796 continue; 797 seq_printf(seqf, "%4d %7d %10llu %pg\n", 798 MAJOR(part->bd_dev), MINOR(part->bd_dev), 799 bdev_nr_sectors(part) >> 1, part); 800 } 801 rcu_read_unlock(); 802 return 0; 803 } 804 805 static const struct seq_operations partitions_op = { 806 .start = show_partition_start, 807 .next = disk_seqf_next, 808 .stop = disk_seqf_stop, 809 .show = show_partition 810 }; 811 #endif 812 813 static int __init genhd_device_init(void) 814 { 815 int error; 816 817 block_class.dev_kobj = sysfs_dev_block_kobj; 818 error = class_register(&block_class); 819 if (unlikely(error)) 820 return error; 821 blk_dev_init(); 822 823 register_blkdev(BLOCK_EXT_MAJOR, "blkext"); 824 825 /* create top-level block dir */ 826 if (!sysfs_deprecated) 827 block_depr = kobject_create_and_add("block", NULL); 828 return 0; 829 } 830 831 subsys_initcall(genhd_device_init); 832 833 static ssize_t disk_range_show(struct device *dev, 834 struct device_attribute *attr, char *buf) 835 { 836 struct gendisk *disk = dev_to_disk(dev); 837 838 return sprintf(buf, "%d\n", disk->minors); 839 } 840 841 static ssize_t disk_ext_range_show(struct device *dev, 842 struct device_attribute *attr, char *buf) 843 { 844 struct gendisk *disk = dev_to_disk(dev); 845 846 return sprintf(buf, "%d\n", disk_max_parts(disk)); 847 } 848 849 static ssize_t disk_removable_show(struct device *dev, 850 struct device_attribute *attr, char *buf) 851 { 852 struct gendisk *disk = dev_to_disk(dev); 853 854 return sprintf(buf, "%d\n", 855 (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0)); 856 } 857 858 static ssize_t disk_hidden_show(struct device *dev, 859 struct device_attribute *attr, char *buf) 860 { 861 struct gendisk *disk = dev_to_disk(dev); 862 863 return sprintf(buf, "%d\n", 864 (disk->flags & GENHD_FL_HIDDEN ? 1 : 0)); 865 } 866 867 static ssize_t disk_ro_show(struct device *dev, 868 struct device_attribute *attr, char *buf) 869 { 870 struct gendisk *disk = dev_to_disk(dev); 871 872 return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0); 873 } 874 875 ssize_t part_size_show(struct device *dev, 876 struct device_attribute *attr, char *buf) 877 { 878 return sprintf(buf, "%llu\n", bdev_nr_sectors(dev_to_bdev(dev))); 879 } 880 881 ssize_t part_stat_show(struct device *dev, 882 struct device_attribute *attr, char *buf) 883 { 884 struct block_device *bdev = dev_to_bdev(dev); 885 struct request_queue *q = bdev->bd_disk->queue; 886 struct disk_stats stat; 887 unsigned int inflight; 888 889 part_stat_read_all(bdev, &stat); 890 if (queue_is_mq(q)) 891 inflight = blk_mq_in_flight(q, bdev); 892 else 893 inflight = part_in_flight(bdev); 894 895 return sprintf(buf, 896 "%8lu %8lu %8llu %8u " 897 "%8lu %8lu %8llu %8u " 898 "%8u %8u %8u " 899 "%8lu %8lu %8llu %8u " 900 "%8lu %8u" 901 "\n", 902 stat.ios[STAT_READ], 903 stat.merges[STAT_READ], 904 (unsigned long long)stat.sectors[STAT_READ], 905 (unsigned int)div_u64(stat.nsecs[STAT_READ], NSEC_PER_MSEC), 906 stat.ios[STAT_WRITE], 907 stat.merges[STAT_WRITE], 908 (unsigned long long)stat.sectors[STAT_WRITE], 909 (unsigned int)div_u64(stat.nsecs[STAT_WRITE], NSEC_PER_MSEC), 910 inflight, 911 jiffies_to_msecs(stat.io_ticks), 912 (unsigned int)div_u64(stat.nsecs[STAT_READ] + 913 stat.nsecs[STAT_WRITE] + 914 stat.nsecs[STAT_DISCARD] + 915 stat.nsecs[STAT_FLUSH], 916 NSEC_PER_MSEC), 917 stat.ios[STAT_DISCARD], 918 stat.merges[STAT_DISCARD], 919 (unsigned long long)stat.sectors[STAT_DISCARD], 920 (unsigned int)div_u64(stat.nsecs[STAT_DISCARD], NSEC_PER_MSEC), 921 stat.ios[STAT_FLUSH], 922 (unsigned int)div_u64(stat.nsecs[STAT_FLUSH], NSEC_PER_MSEC)); 923 } 924 925 ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr, 926 char *buf) 927 { 928 struct block_device *bdev = dev_to_bdev(dev); 929 struct request_queue *q = bdev->bd_disk->queue; 930 unsigned int inflight[2]; 931 932 if (queue_is_mq(q)) 933 blk_mq_in_flight_rw(q, bdev, inflight); 934 else 935 part_in_flight_rw(bdev, inflight); 936 937 return sprintf(buf, "%8u %8u\n", inflight[0], inflight[1]); 938 } 939 940 static ssize_t disk_capability_show(struct device *dev, 941 struct device_attribute *attr, char *buf) 942 { 943 struct gendisk *disk = dev_to_disk(dev); 944 945 return sprintf(buf, "%x\n", disk->flags); 946 } 947 948 static ssize_t disk_alignment_offset_show(struct device *dev, 949 struct device_attribute *attr, 950 char *buf) 951 { 952 struct gendisk *disk = dev_to_disk(dev); 953 954 return sprintf(buf, "%d\n", queue_alignment_offset(disk->queue)); 955 } 956 957 static ssize_t disk_discard_alignment_show(struct device *dev, 958 struct device_attribute *attr, 959 char *buf) 960 { 961 struct gendisk *disk = dev_to_disk(dev); 962 963 return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue)); 964 } 965 966 static ssize_t diskseq_show(struct device *dev, 967 struct device_attribute *attr, char *buf) 968 { 969 struct gendisk *disk = dev_to_disk(dev); 970 971 return sprintf(buf, "%llu\n", disk->diskseq); 972 } 973 974 static DEVICE_ATTR(range, 0444, disk_range_show, NULL); 975 static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL); 976 static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL); 977 static DEVICE_ATTR(hidden, 0444, disk_hidden_show, NULL); 978 static DEVICE_ATTR(ro, 0444, disk_ro_show, NULL); 979 static DEVICE_ATTR(size, 0444, part_size_show, NULL); 980 static DEVICE_ATTR(alignment_offset, 0444, disk_alignment_offset_show, NULL); 981 static DEVICE_ATTR(discard_alignment, 0444, disk_discard_alignment_show, NULL); 982 static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL); 983 static DEVICE_ATTR(stat, 0444, part_stat_show, NULL); 984 static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL); 985 static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store); 986 static DEVICE_ATTR(diskseq, 0444, diskseq_show, NULL); 987 988 #ifdef CONFIG_FAIL_MAKE_REQUEST 989 ssize_t part_fail_show(struct device *dev, 990 struct device_attribute *attr, char *buf) 991 { 992 return sprintf(buf, "%d\n", dev_to_bdev(dev)->bd_make_it_fail); 993 } 994 995 ssize_t part_fail_store(struct device *dev, 996 struct device_attribute *attr, 997 const char *buf, size_t count) 998 { 999 int i; 1000 1001 if (count > 0 && sscanf(buf, "%d", &i) > 0) 1002 dev_to_bdev(dev)->bd_make_it_fail = i; 1003 1004 return count; 1005 } 1006 1007 static struct device_attribute dev_attr_fail = 1008 __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store); 1009 #endif /* CONFIG_FAIL_MAKE_REQUEST */ 1010 1011 #ifdef CONFIG_FAIL_IO_TIMEOUT 1012 static struct device_attribute dev_attr_fail_timeout = 1013 __ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store); 1014 #endif 1015 1016 static struct attribute *disk_attrs[] = { 1017 &dev_attr_range.attr, 1018 &dev_attr_ext_range.attr, 1019 &dev_attr_removable.attr, 1020 &dev_attr_hidden.attr, 1021 &dev_attr_ro.attr, 1022 &dev_attr_size.attr, 1023 &dev_attr_alignment_offset.attr, 1024 &dev_attr_discard_alignment.attr, 1025 &dev_attr_capability.attr, 1026 &dev_attr_stat.attr, 1027 &dev_attr_inflight.attr, 1028 &dev_attr_badblocks.attr, 1029 &dev_attr_events.attr, 1030 &dev_attr_events_async.attr, 1031 &dev_attr_events_poll_msecs.attr, 1032 &dev_attr_diskseq.attr, 1033 #ifdef CONFIG_FAIL_MAKE_REQUEST 1034 &dev_attr_fail.attr, 1035 #endif 1036 #ifdef CONFIG_FAIL_IO_TIMEOUT 1037 &dev_attr_fail_timeout.attr, 1038 #endif 1039 NULL 1040 }; 1041 1042 static umode_t disk_visible(struct kobject *kobj, struct attribute *a, int n) 1043 { 1044 struct device *dev = container_of(kobj, typeof(*dev), kobj); 1045 struct gendisk *disk = dev_to_disk(dev); 1046 1047 if (a == &dev_attr_badblocks.attr && !disk->bb) 1048 return 0; 1049 return a->mode; 1050 } 1051 1052 static struct attribute_group disk_attr_group = { 1053 .attrs = disk_attrs, 1054 .is_visible = disk_visible, 1055 }; 1056 1057 static const struct attribute_group *disk_attr_groups[] = { 1058 &disk_attr_group, 1059 NULL 1060 }; 1061 1062 /** 1063 * disk_release - releases all allocated resources of the gendisk 1064 * @dev: the device representing this disk 1065 * 1066 * This function releases all allocated resources of the gendisk. 1067 * 1068 * Drivers which used __device_add_disk() have a gendisk with a request_queue 1069 * assigned. Since the request_queue sits on top of the gendisk for these 1070 * drivers we also call blk_put_queue() for them, and we expect the 1071 * request_queue refcount to reach 0 at this point, and so the request_queue 1072 * will also be freed prior to the disk. 1073 * 1074 * Context: can sleep 1075 */ 1076 static void disk_release(struct device *dev) 1077 { 1078 struct gendisk *disk = dev_to_disk(dev); 1079 1080 might_sleep(); 1081 WARN_ON_ONCE(disk_live(disk)); 1082 1083 disk_release_events(disk); 1084 kfree(disk->random); 1085 xa_destroy(&disk->part_tbl); 1086 disk->queue->disk = NULL; 1087 blk_put_queue(disk->queue); 1088 iput(disk->part0->bd_inode); /* frees the disk */ 1089 } 1090 1091 static int block_uevent(struct device *dev, struct kobj_uevent_env *env) 1092 { 1093 struct gendisk *disk = dev_to_disk(dev); 1094 1095 return add_uevent_var(env, "DISKSEQ=%llu", disk->diskseq); 1096 } 1097 1098 struct class block_class = { 1099 .name = "block", 1100 .dev_uevent = block_uevent, 1101 }; 1102 1103 static char *block_devnode(struct device *dev, umode_t *mode, 1104 kuid_t *uid, kgid_t *gid) 1105 { 1106 struct gendisk *disk = dev_to_disk(dev); 1107 1108 if (disk->fops->devnode) 1109 return disk->fops->devnode(disk, mode); 1110 return NULL; 1111 } 1112 1113 const struct device_type disk_type = { 1114 .name = "disk", 1115 .groups = disk_attr_groups, 1116 .release = disk_release, 1117 .devnode = block_devnode, 1118 }; 1119 1120 #ifdef CONFIG_PROC_FS 1121 /* 1122 * aggregate disk stat collector. Uses the same stats that the sysfs 1123 * entries do, above, but makes them available through one seq_file. 1124 * 1125 * The output looks suspiciously like /proc/partitions with a bunch of 1126 * extra fields. 1127 */ 1128 static int diskstats_show(struct seq_file *seqf, void *v) 1129 { 1130 struct gendisk *gp = v; 1131 struct block_device *hd; 1132 unsigned int inflight; 1133 struct disk_stats stat; 1134 unsigned long idx; 1135 1136 /* 1137 if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next) 1138 seq_puts(seqf, "major minor name" 1139 " rio rmerge rsect ruse wio wmerge " 1140 "wsect wuse running use aveq" 1141 "\n\n"); 1142 */ 1143 1144 rcu_read_lock(); 1145 xa_for_each(&gp->part_tbl, idx, hd) { 1146 if (bdev_is_partition(hd) && !bdev_nr_sectors(hd)) 1147 continue; 1148 part_stat_read_all(hd, &stat); 1149 if (queue_is_mq(gp->queue)) 1150 inflight = blk_mq_in_flight(gp->queue, hd); 1151 else 1152 inflight = part_in_flight(hd); 1153 1154 seq_printf(seqf, "%4d %7d %pg " 1155 "%lu %lu %lu %u " 1156 "%lu %lu %lu %u " 1157 "%u %u %u " 1158 "%lu %lu %lu %u " 1159 "%lu %u" 1160 "\n", 1161 MAJOR(hd->bd_dev), MINOR(hd->bd_dev), hd, 1162 stat.ios[STAT_READ], 1163 stat.merges[STAT_READ], 1164 stat.sectors[STAT_READ], 1165 (unsigned int)div_u64(stat.nsecs[STAT_READ], 1166 NSEC_PER_MSEC), 1167 stat.ios[STAT_WRITE], 1168 stat.merges[STAT_WRITE], 1169 stat.sectors[STAT_WRITE], 1170 (unsigned int)div_u64(stat.nsecs[STAT_WRITE], 1171 NSEC_PER_MSEC), 1172 inflight, 1173 jiffies_to_msecs(stat.io_ticks), 1174 (unsigned int)div_u64(stat.nsecs[STAT_READ] + 1175 stat.nsecs[STAT_WRITE] + 1176 stat.nsecs[STAT_DISCARD] + 1177 stat.nsecs[STAT_FLUSH], 1178 NSEC_PER_MSEC), 1179 stat.ios[STAT_DISCARD], 1180 stat.merges[STAT_DISCARD], 1181 stat.sectors[STAT_DISCARD], 1182 (unsigned int)div_u64(stat.nsecs[STAT_DISCARD], 1183 NSEC_PER_MSEC), 1184 stat.ios[STAT_FLUSH], 1185 (unsigned int)div_u64(stat.nsecs[STAT_FLUSH], 1186 NSEC_PER_MSEC) 1187 ); 1188 } 1189 rcu_read_unlock(); 1190 1191 return 0; 1192 } 1193 1194 static const struct seq_operations diskstats_op = { 1195 .start = disk_seqf_start, 1196 .next = disk_seqf_next, 1197 .stop = disk_seqf_stop, 1198 .show = diskstats_show 1199 }; 1200 1201 static int __init proc_genhd_init(void) 1202 { 1203 proc_create_seq("diskstats", 0, NULL, &diskstats_op); 1204 proc_create_seq("partitions", 0, NULL, &partitions_op); 1205 return 0; 1206 } 1207 module_init(proc_genhd_init); 1208 #endif /* CONFIG_PROC_FS */ 1209 1210 dev_t part_devt(struct gendisk *disk, u8 partno) 1211 { 1212 struct block_device *part; 1213 dev_t devt = 0; 1214 1215 rcu_read_lock(); 1216 part = xa_load(&disk->part_tbl, partno); 1217 if (part) 1218 devt = part->bd_dev; 1219 rcu_read_unlock(); 1220 1221 return devt; 1222 } 1223 1224 dev_t blk_lookup_devt(const char *name, int partno) 1225 { 1226 dev_t devt = MKDEV(0, 0); 1227 struct class_dev_iter iter; 1228 struct device *dev; 1229 1230 class_dev_iter_init(&iter, &block_class, NULL, &disk_type); 1231 while ((dev = class_dev_iter_next(&iter))) { 1232 struct gendisk *disk = dev_to_disk(dev); 1233 1234 if (strcmp(dev_name(dev), name)) 1235 continue; 1236 1237 if (partno < disk->minors) { 1238 /* We need to return the right devno, even 1239 * if the partition doesn't exist yet. 1240 */ 1241 devt = MKDEV(MAJOR(dev->devt), 1242 MINOR(dev->devt) + partno); 1243 } else { 1244 devt = part_devt(disk, partno); 1245 if (devt) 1246 break; 1247 } 1248 } 1249 class_dev_iter_exit(&iter); 1250 return devt; 1251 } 1252 1253 struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id, 1254 struct lock_class_key *lkclass) 1255 { 1256 struct gendisk *disk; 1257 1258 if (!blk_get_queue(q)) 1259 return NULL; 1260 1261 disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id); 1262 if (!disk) 1263 goto out_put_queue; 1264 1265 disk->bdi = bdi_alloc(node_id); 1266 if (!disk->bdi) 1267 goto out_free_disk; 1268 1269 disk->part0 = bdev_alloc(disk, 0); 1270 if (!disk->part0) 1271 goto out_free_bdi; 1272 1273 disk->node_id = node_id; 1274 mutex_init(&disk->open_mutex); 1275 xa_init(&disk->part_tbl); 1276 if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL)) 1277 goto out_destroy_part_tbl; 1278 1279 rand_initialize_disk(disk); 1280 disk_to_dev(disk)->class = &block_class; 1281 disk_to_dev(disk)->type = &disk_type; 1282 device_initialize(disk_to_dev(disk)); 1283 inc_diskseq(disk); 1284 disk->queue = q; 1285 q->disk = disk; 1286 lockdep_init_map(&disk->lockdep_map, "(bio completion)", lkclass, 0); 1287 #ifdef CONFIG_BLOCK_HOLDER_DEPRECATED 1288 INIT_LIST_HEAD(&disk->slave_bdevs); 1289 #endif 1290 return disk; 1291 1292 out_destroy_part_tbl: 1293 xa_destroy(&disk->part_tbl); 1294 disk->part0->bd_disk = NULL; 1295 iput(disk->part0->bd_inode); 1296 out_free_bdi: 1297 bdi_put(disk->bdi); 1298 out_free_disk: 1299 kfree(disk); 1300 out_put_queue: 1301 blk_put_queue(q); 1302 return NULL; 1303 } 1304 EXPORT_SYMBOL(__alloc_disk_node); 1305 1306 struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass) 1307 { 1308 struct request_queue *q; 1309 struct gendisk *disk; 1310 1311 q = blk_alloc_queue(node); 1312 if (!q) 1313 return NULL; 1314 1315 disk = __alloc_disk_node(q, node, lkclass); 1316 if (!disk) { 1317 blk_cleanup_queue(q); 1318 return NULL; 1319 } 1320 return disk; 1321 } 1322 EXPORT_SYMBOL(__blk_alloc_disk); 1323 1324 /** 1325 * put_disk - decrements the gendisk refcount 1326 * @disk: the struct gendisk to decrement the refcount for 1327 * 1328 * This decrements the refcount for the struct gendisk. When this reaches 0 1329 * we'll have disk_release() called. 1330 * 1331 * Context: Any context, but the last reference must not be dropped from 1332 * atomic context. 1333 */ 1334 void put_disk(struct gendisk *disk) 1335 { 1336 if (disk) 1337 put_device(disk_to_dev(disk)); 1338 } 1339 EXPORT_SYMBOL(put_disk); 1340 1341 /** 1342 * blk_cleanup_disk - shutdown a gendisk allocated by blk_alloc_disk 1343 * @disk: gendisk to shutdown 1344 * 1345 * Mark the queue hanging off @disk DYING, drain all pending requests, then mark 1346 * the queue DEAD, destroy and put it and the gendisk structure. 1347 * 1348 * Context: can sleep 1349 */ 1350 void blk_cleanup_disk(struct gendisk *disk) 1351 { 1352 blk_cleanup_queue(disk->queue); 1353 put_disk(disk); 1354 } 1355 EXPORT_SYMBOL(blk_cleanup_disk); 1356 1357 static void set_disk_ro_uevent(struct gendisk *gd, int ro) 1358 { 1359 char event[] = "DISK_RO=1"; 1360 char *envp[] = { event, NULL }; 1361 1362 if (!ro) 1363 event[8] = '0'; 1364 kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp); 1365 } 1366 1367 /** 1368 * set_disk_ro - set a gendisk read-only 1369 * @disk: gendisk to operate on 1370 * @read_only: %true to set the disk read-only, %false set the disk read/write 1371 * 1372 * This function is used to indicate whether a given disk device should have its 1373 * read-only flag set. set_disk_ro() is typically used by device drivers to 1374 * indicate whether the underlying physical device is write-protected. 1375 */ 1376 void set_disk_ro(struct gendisk *disk, bool read_only) 1377 { 1378 if (read_only) { 1379 if (test_and_set_bit(GD_READ_ONLY, &disk->state)) 1380 return; 1381 } else { 1382 if (!test_and_clear_bit(GD_READ_ONLY, &disk->state)) 1383 return; 1384 } 1385 set_disk_ro_uevent(disk, read_only); 1386 } 1387 EXPORT_SYMBOL(set_disk_ro); 1388 1389 int bdev_read_only(struct block_device *bdev) 1390 { 1391 return bdev->bd_read_only || get_disk_ro(bdev->bd_disk); 1392 } 1393 EXPORT_SYMBOL(bdev_read_only); 1394 1395 void inc_diskseq(struct gendisk *disk) 1396 { 1397 disk->diskseq = atomic64_inc_return(&diskseq); 1398 } 1399