1 /* 2 * gendisk handling 3 */ 4 5 #include <linux/module.h> 6 #include <linux/fs.h> 7 #include <linux/genhd.h> 8 #include <linux/kdev_t.h> 9 #include <linux/kernel.h> 10 #include <linux/blkdev.h> 11 #include <linux/backing-dev.h> 12 #include <linux/init.h> 13 #include <linux/spinlock.h> 14 #include <linux/proc_fs.h> 15 #include <linux/seq_file.h> 16 #include <linux/slab.h> 17 #include <linux/kmod.h> 18 #include <linux/kobj_map.h> 19 #include <linux/mutex.h> 20 #include <linux/idr.h> 21 #include <linux/log2.h> 22 #include <linux/pm_runtime.h> 23 #include <linux/badblocks.h> 24 25 #include "blk.h" 26 27 static DEFINE_MUTEX(block_class_lock); 28 struct kobject *block_depr; 29 30 /* for extended dynamic devt allocation, currently only one major is used */ 31 #define NR_EXT_DEVT (1 << MINORBITS) 32 33 /* For extended devt allocation. ext_devt_lock prevents look up 34 * results from going away underneath its user. 35 */ 36 static DEFINE_SPINLOCK(ext_devt_lock); 37 static DEFINE_IDR(ext_devt_idr); 38 39 static struct device_type disk_type; 40 41 static void disk_check_events(struct disk_events *ev, 42 unsigned int *clearing_ptr); 43 static void disk_alloc_events(struct gendisk *disk); 44 static void disk_add_events(struct gendisk *disk); 45 static void disk_del_events(struct gendisk *disk); 46 static void disk_release_events(struct gendisk *disk); 47 48 /** 49 * disk_get_part - get partition 50 * @disk: disk to look partition from 51 * @partno: partition number 52 * 53 * Look for partition @partno from @disk. If found, increment 54 * reference count and return it. 55 * 56 * CONTEXT: 57 * Don't care. 58 * 59 * RETURNS: 60 * Pointer to the found partition on success, NULL if not found. 61 */ 62 struct hd_struct *disk_get_part(struct gendisk *disk, int partno) 63 { 64 struct hd_struct *part = NULL; 65 struct disk_part_tbl *ptbl; 66 67 if (unlikely(partno < 0)) 68 return NULL; 69 70 rcu_read_lock(); 71 72 ptbl = rcu_dereference(disk->part_tbl); 73 if (likely(partno < ptbl->len)) { 74 part = rcu_dereference(ptbl->part[partno]); 75 if (part) 76 get_device(part_to_dev(part)); 77 } 78 79 rcu_read_unlock(); 80 81 return part; 82 } 83 EXPORT_SYMBOL_GPL(disk_get_part); 84 85 /** 86 * disk_part_iter_init - initialize partition iterator 87 * @piter: iterator to initialize 88 * @disk: disk to iterate over 89 * @flags: DISK_PITER_* flags 90 * 91 * Initialize @piter so that it iterates over partitions of @disk. 92 * 93 * CONTEXT: 94 * Don't care. 95 */ 96 void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk, 97 unsigned int flags) 98 { 99 struct disk_part_tbl *ptbl; 100 101 rcu_read_lock(); 102 ptbl = rcu_dereference(disk->part_tbl); 103 104 piter->disk = disk; 105 piter->part = NULL; 106 107 if (flags & DISK_PITER_REVERSE) 108 piter->idx = ptbl->len - 1; 109 else if (flags & (DISK_PITER_INCL_PART0 | DISK_PITER_INCL_EMPTY_PART0)) 110 piter->idx = 0; 111 else 112 piter->idx = 1; 113 114 piter->flags = flags; 115 116 rcu_read_unlock(); 117 } 118 EXPORT_SYMBOL_GPL(disk_part_iter_init); 119 120 /** 121 * disk_part_iter_next - proceed iterator to the next partition and return it 122 * @piter: iterator of interest 123 * 124 * Proceed @piter to the next partition and return it. 125 * 126 * CONTEXT: 127 * Don't care. 128 */ 129 struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter) 130 { 131 struct disk_part_tbl *ptbl; 132 int inc, end; 133 134 /* put the last partition */ 135 disk_put_part(piter->part); 136 piter->part = NULL; 137 138 /* get part_tbl */ 139 rcu_read_lock(); 140 ptbl = rcu_dereference(piter->disk->part_tbl); 141 142 /* determine iteration parameters */ 143 if (piter->flags & DISK_PITER_REVERSE) { 144 inc = -1; 145 if (piter->flags & (DISK_PITER_INCL_PART0 | 146 DISK_PITER_INCL_EMPTY_PART0)) 147 end = -1; 148 else 149 end = 0; 150 } else { 151 inc = 1; 152 end = ptbl->len; 153 } 154 155 /* iterate to the next partition */ 156 for (; piter->idx != end; piter->idx += inc) { 157 struct hd_struct *part; 158 159 part = rcu_dereference(ptbl->part[piter->idx]); 160 if (!part) 161 continue; 162 if (!part_nr_sects_read(part) && 163 !(piter->flags & DISK_PITER_INCL_EMPTY) && 164 !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 && 165 piter->idx == 0)) 166 continue; 167 168 get_device(part_to_dev(part)); 169 piter->part = part; 170 piter->idx += inc; 171 break; 172 } 173 174 rcu_read_unlock(); 175 176 return piter->part; 177 } 178 EXPORT_SYMBOL_GPL(disk_part_iter_next); 179 180 /** 181 * disk_part_iter_exit - finish up partition iteration 182 * @piter: iter of interest 183 * 184 * Called when iteration is over. Cleans up @piter. 185 * 186 * CONTEXT: 187 * Don't care. 188 */ 189 void disk_part_iter_exit(struct disk_part_iter *piter) 190 { 191 disk_put_part(piter->part); 192 piter->part = NULL; 193 } 194 EXPORT_SYMBOL_GPL(disk_part_iter_exit); 195 196 static inline int sector_in_part(struct hd_struct *part, sector_t sector) 197 { 198 return part->start_sect <= sector && 199 sector < part->start_sect + part_nr_sects_read(part); 200 } 201 202 /** 203 * disk_map_sector_rcu - map sector to partition 204 * @disk: gendisk of interest 205 * @sector: sector to map 206 * 207 * Find out which partition @sector maps to on @disk. This is 208 * primarily used for stats accounting. 209 * 210 * CONTEXT: 211 * RCU read locked. The returned partition pointer is valid only 212 * while preemption is disabled. 213 * 214 * RETURNS: 215 * Found partition on success, part0 is returned if no partition matches 216 */ 217 struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector) 218 { 219 struct disk_part_tbl *ptbl; 220 struct hd_struct *part; 221 int i; 222 223 ptbl = rcu_dereference(disk->part_tbl); 224 225 part = rcu_dereference(ptbl->last_lookup); 226 if (part && sector_in_part(part, sector)) 227 return part; 228 229 for (i = 1; i < ptbl->len; i++) { 230 part = rcu_dereference(ptbl->part[i]); 231 232 if (part && sector_in_part(part, sector)) { 233 rcu_assign_pointer(ptbl->last_lookup, part); 234 return part; 235 } 236 } 237 return &disk->part0; 238 } 239 EXPORT_SYMBOL_GPL(disk_map_sector_rcu); 240 241 /* 242 * Can be deleted altogether. Later. 243 * 244 */ 245 static struct blk_major_name { 246 struct blk_major_name *next; 247 int major; 248 char name[16]; 249 } *major_names[BLKDEV_MAJOR_HASH_SIZE]; 250 251 /* index in the above - for now: assume no multimajor ranges */ 252 static inline int major_to_index(unsigned major) 253 { 254 return major % BLKDEV_MAJOR_HASH_SIZE; 255 } 256 257 #ifdef CONFIG_PROC_FS 258 void blkdev_show(struct seq_file *seqf, off_t offset) 259 { 260 struct blk_major_name *dp; 261 262 if (offset < BLKDEV_MAJOR_HASH_SIZE) { 263 mutex_lock(&block_class_lock); 264 for (dp = major_names[offset]; dp; dp = dp->next) 265 seq_printf(seqf, "%3d %s\n", dp->major, dp->name); 266 mutex_unlock(&block_class_lock); 267 } 268 } 269 #endif /* CONFIG_PROC_FS */ 270 271 /** 272 * register_blkdev - register a new block device 273 * 274 * @major: the requested major device number [1..255]. If @major=0, try to 275 * allocate any unused major number. 276 * @name: the name of the new block device as a zero terminated string 277 * 278 * The @name must be unique within the system. 279 * 280 * The return value depends on the @major input parameter. 281 * - if a major device number was requested in range [1..255] then the 282 * function returns zero on success, or a negative error code 283 * - if any unused major number was requested with @major=0 parameter 284 * then the return value is the allocated major number in range 285 * [1..255] or a negative error code otherwise 286 */ 287 int register_blkdev(unsigned int major, const char *name) 288 { 289 struct blk_major_name **n, *p; 290 int index, ret = 0; 291 292 mutex_lock(&block_class_lock); 293 294 /* temporary */ 295 if (major == 0) { 296 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) { 297 if (major_names[index] == NULL) 298 break; 299 } 300 301 if (index == 0) { 302 printk("register_blkdev: failed to get major for %s\n", 303 name); 304 ret = -EBUSY; 305 goto out; 306 } 307 major = index; 308 ret = major; 309 } 310 311 p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL); 312 if (p == NULL) { 313 ret = -ENOMEM; 314 goto out; 315 } 316 317 p->major = major; 318 strlcpy(p->name, name, sizeof(p->name)); 319 p->next = NULL; 320 index = major_to_index(major); 321 322 for (n = &major_names[index]; *n; n = &(*n)->next) { 323 if ((*n)->major == major) 324 break; 325 } 326 if (!*n) 327 *n = p; 328 else 329 ret = -EBUSY; 330 331 if (ret < 0) { 332 printk("register_blkdev: cannot get major %d for %s\n", 333 major, name); 334 kfree(p); 335 } 336 out: 337 mutex_unlock(&block_class_lock); 338 return ret; 339 } 340 341 EXPORT_SYMBOL(register_blkdev); 342 343 void unregister_blkdev(unsigned int major, const char *name) 344 { 345 struct blk_major_name **n; 346 struct blk_major_name *p = NULL; 347 int index = major_to_index(major); 348 349 mutex_lock(&block_class_lock); 350 for (n = &major_names[index]; *n; n = &(*n)->next) 351 if ((*n)->major == major) 352 break; 353 if (!*n || strcmp((*n)->name, name)) { 354 WARN_ON(1); 355 } else { 356 p = *n; 357 *n = p->next; 358 } 359 mutex_unlock(&block_class_lock); 360 kfree(p); 361 } 362 363 EXPORT_SYMBOL(unregister_blkdev); 364 365 static struct kobj_map *bdev_map; 366 367 /** 368 * blk_mangle_minor - scatter minor numbers apart 369 * @minor: minor number to mangle 370 * 371 * Scatter consecutively allocated @minor number apart if MANGLE_DEVT 372 * is enabled. Mangling twice gives the original value. 373 * 374 * RETURNS: 375 * Mangled value. 376 * 377 * CONTEXT: 378 * Don't care. 379 */ 380 static int blk_mangle_minor(int minor) 381 { 382 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT 383 int i; 384 385 for (i = 0; i < MINORBITS / 2; i++) { 386 int low = minor & (1 << i); 387 int high = minor & (1 << (MINORBITS - 1 - i)); 388 int distance = MINORBITS - 1 - 2 * i; 389 390 minor ^= low | high; /* clear both bits */ 391 low <<= distance; /* swap the positions */ 392 high >>= distance; 393 minor |= low | high; /* and set */ 394 } 395 #endif 396 return minor; 397 } 398 399 /** 400 * blk_alloc_devt - allocate a dev_t for a partition 401 * @part: partition to allocate dev_t for 402 * @devt: out parameter for resulting dev_t 403 * 404 * Allocate a dev_t for block device. 405 * 406 * RETURNS: 407 * 0 on success, allocated dev_t is returned in *@devt. -errno on 408 * failure. 409 * 410 * CONTEXT: 411 * Might sleep. 412 */ 413 int blk_alloc_devt(struct hd_struct *part, dev_t *devt) 414 { 415 struct gendisk *disk = part_to_disk(part); 416 int idx; 417 418 /* in consecutive minor range? */ 419 if (part->partno < disk->minors) { 420 *devt = MKDEV(disk->major, disk->first_minor + part->partno); 421 return 0; 422 } 423 424 /* allocate ext devt */ 425 idr_preload(GFP_KERNEL); 426 427 spin_lock_bh(&ext_devt_lock); 428 idx = idr_alloc(&ext_devt_idr, part, 0, NR_EXT_DEVT, GFP_NOWAIT); 429 spin_unlock_bh(&ext_devt_lock); 430 431 idr_preload_end(); 432 if (idx < 0) 433 return idx == -ENOSPC ? -EBUSY : idx; 434 435 *devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx)); 436 return 0; 437 } 438 439 /** 440 * blk_free_devt - free a dev_t 441 * @devt: dev_t to free 442 * 443 * Free @devt which was allocated using blk_alloc_devt(). 444 * 445 * CONTEXT: 446 * Might sleep. 447 */ 448 void blk_free_devt(dev_t devt) 449 { 450 if (devt == MKDEV(0, 0)) 451 return; 452 453 if (MAJOR(devt) == BLOCK_EXT_MAJOR) { 454 spin_lock_bh(&ext_devt_lock); 455 idr_remove(&ext_devt_idr, blk_mangle_minor(MINOR(devt))); 456 spin_unlock_bh(&ext_devt_lock); 457 } 458 } 459 460 static char *bdevt_str(dev_t devt, char *buf) 461 { 462 if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) { 463 char tbuf[BDEVT_SIZE]; 464 snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt)); 465 snprintf(buf, BDEVT_SIZE, "%-9s", tbuf); 466 } else 467 snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt)); 468 469 return buf; 470 } 471 472 /* 473 * Register device numbers dev..(dev+range-1) 474 * range must be nonzero 475 * The hash chain is sorted on range, so that subranges can override. 476 */ 477 void blk_register_region(dev_t devt, unsigned long range, struct module *module, 478 struct kobject *(*probe)(dev_t, int *, void *), 479 int (*lock)(dev_t, void *), void *data) 480 { 481 kobj_map(bdev_map, devt, range, module, probe, lock, data); 482 } 483 484 EXPORT_SYMBOL(blk_register_region); 485 486 void blk_unregister_region(dev_t devt, unsigned long range) 487 { 488 kobj_unmap(bdev_map, devt, range); 489 } 490 491 EXPORT_SYMBOL(blk_unregister_region); 492 493 static struct kobject *exact_match(dev_t devt, int *partno, void *data) 494 { 495 struct gendisk *p = data; 496 497 return &disk_to_dev(p)->kobj; 498 } 499 500 static int exact_lock(dev_t devt, void *data) 501 { 502 struct gendisk *p = data; 503 504 if (!get_disk(p)) 505 return -1; 506 return 0; 507 } 508 509 static void register_disk(struct device *parent, struct gendisk *disk) 510 { 511 struct device *ddev = disk_to_dev(disk); 512 struct block_device *bdev; 513 struct disk_part_iter piter; 514 struct hd_struct *part; 515 int err; 516 517 ddev->parent = parent; 518 519 dev_set_name(ddev, "%s", disk->disk_name); 520 521 /* delay uevents, until we scanned partition table */ 522 dev_set_uevent_suppress(ddev, 1); 523 524 if (device_add(ddev)) 525 return; 526 if (!sysfs_deprecated) { 527 err = sysfs_create_link(block_depr, &ddev->kobj, 528 kobject_name(&ddev->kobj)); 529 if (err) { 530 device_del(ddev); 531 return; 532 } 533 } 534 535 /* 536 * avoid probable deadlock caused by allocating memory with 537 * GFP_KERNEL in runtime_resume callback of its all ancestor 538 * devices 539 */ 540 pm_runtime_set_memalloc_noio(ddev, true); 541 542 disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj); 543 disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj); 544 545 /* No minors to use for partitions */ 546 if (!disk_part_scan_enabled(disk)) 547 goto exit; 548 549 /* No such device (e.g., media were just removed) */ 550 if (!get_capacity(disk)) 551 goto exit; 552 553 bdev = bdget_disk(disk, 0); 554 if (!bdev) 555 goto exit; 556 557 bdev->bd_invalidated = 1; 558 err = blkdev_get(bdev, FMODE_READ, NULL); 559 if (err < 0) 560 goto exit; 561 blkdev_put(bdev, FMODE_READ); 562 563 exit: 564 /* announce disk after possible partitions are created */ 565 dev_set_uevent_suppress(ddev, 0); 566 kobject_uevent(&ddev->kobj, KOBJ_ADD); 567 568 /* announce possible partitions */ 569 disk_part_iter_init(&piter, disk, 0); 570 while ((part = disk_part_iter_next(&piter))) 571 kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD); 572 disk_part_iter_exit(&piter); 573 } 574 575 void put_disk_devt(struct disk_devt *disk_devt) 576 { 577 if (disk_devt && atomic_dec_and_test(&disk_devt->count)) 578 disk_devt->release(disk_devt); 579 } 580 EXPORT_SYMBOL(put_disk_devt); 581 582 void get_disk_devt(struct disk_devt *disk_devt) 583 { 584 if (disk_devt) 585 atomic_inc(&disk_devt->count); 586 } 587 EXPORT_SYMBOL(get_disk_devt); 588 589 /** 590 * device_add_disk - add partitioning information to kernel list 591 * @parent: parent device for the disk 592 * @disk: per-device partitioning information 593 * 594 * This function registers the partitioning information in @disk 595 * with the kernel. 596 * 597 * FIXME: error handling 598 */ 599 void device_add_disk(struct device *parent, struct gendisk *disk) 600 { 601 struct backing_dev_info *bdi; 602 dev_t devt; 603 int retval; 604 605 /* minors == 0 indicates to use ext devt from part0 and should 606 * be accompanied with EXT_DEVT flag. Make sure all 607 * parameters make sense. 608 */ 609 WARN_ON(disk->minors && !(disk->major || disk->first_minor)); 610 WARN_ON(!disk->minors && !(disk->flags & GENHD_FL_EXT_DEVT)); 611 612 disk->flags |= GENHD_FL_UP; 613 614 retval = blk_alloc_devt(&disk->part0, &devt); 615 if (retval) { 616 WARN_ON(1); 617 return; 618 } 619 disk_to_dev(disk)->devt = devt; 620 621 /* ->major and ->first_minor aren't supposed to be 622 * dereferenced from here on, but set them just in case. 623 */ 624 disk->major = MAJOR(devt); 625 disk->first_minor = MINOR(devt); 626 627 disk_alloc_events(disk); 628 629 /* 630 * Take a reference on the devt and assign it to queue since it 631 * must not be reallocated while the bdi is registered 632 */ 633 disk->queue->disk_devt = disk->disk_devt; 634 get_disk_devt(disk->disk_devt); 635 636 /* Register BDI before referencing it from bdev */ 637 bdi = disk->queue->backing_dev_info; 638 bdi_register_owner(bdi, disk_to_dev(disk)); 639 640 blk_register_region(disk_devt(disk), disk->minors, NULL, 641 exact_match, exact_lock, disk); 642 register_disk(parent, disk); 643 blk_register_queue(disk); 644 645 /* 646 * Take an extra ref on queue which will be put on disk_release() 647 * so that it sticks around as long as @disk is there. 648 */ 649 WARN_ON_ONCE(!blk_get_queue(disk->queue)); 650 651 retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj, 652 "bdi"); 653 WARN_ON(retval); 654 655 disk_add_events(disk); 656 blk_integrity_add(disk); 657 } 658 EXPORT_SYMBOL(device_add_disk); 659 660 void del_gendisk(struct gendisk *disk) 661 { 662 struct disk_part_iter piter; 663 struct hd_struct *part; 664 665 blk_integrity_del(disk); 666 disk_del_events(disk); 667 668 /* invalidate stuff */ 669 disk_part_iter_init(&piter, disk, 670 DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE); 671 while ((part = disk_part_iter_next(&piter))) { 672 invalidate_partition(disk, part->partno); 673 bdev_unhash_inode(part_devt(part)); 674 delete_partition(disk, part->partno); 675 } 676 disk_part_iter_exit(&piter); 677 678 invalidate_partition(disk, 0); 679 bdev_unhash_inode(disk_devt(disk)); 680 set_capacity(disk, 0); 681 disk->flags &= ~GENHD_FL_UP; 682 683 sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi"); 684 blk_unregister_queue(disk); 685 blk_unregister_region(disk_devt(disk), disk->minors); 686 687 part_stat_set_all(&disk->part0, 0); 688 disk->part0.stamp = 0; 689 690 kobject_put(disk->part0.holder_dir); 691 kobject_put(disk->slave_dir); 692 if (!sysfs_deprecated) 693 sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk))); 694 pm_runtime_set_memalloc_noio(disk_to_dev(disk), false); 695 device_del(disk_to_dev(disk)); 696 } 697 EXPORT_SYMBOL(del_gendisk); 698 699 /* sysfs access to bad-blocks list. */ 700 static ssize_t disk_badblocks_show(struct device *dev, 701 struct device_attribute *attr, 702 char *page) 703 { 704 struct gendisk *disk = dev_to_disk(dev); 705 706 if (!disk->bb) 707 return sprintf(page, "\n"); 708 709 return badblocks_show(disk->bb, page, 0); 710 } 711 712 static ssize_t disk_badblocks_store(struct device *dev, 713 struct device_attribute *attr, 714 const char *page, size_t len) 715 { 716 struct gendisk *disk = dev_to_disk(dev); 717 718 if (!disk->bb) 719 return -ENXIO; 720 721 return badblocks_store(disk->bb, page, len, 0); 722 } 723 724 /** 725 * get_gendisk - get partitioning information for a given device 726 * @devt: device to get partitioning information for 727 * @partno: returned partition index 728 * 729 * This function gets the structure containing partitioning 730 * information for the given device @devt. 731 */ 732 struct gendisk *get_gendisk(dev_t devt, int *partno) 733 { 734 struct gendisk *disk = NULL; 735 736 if (MAJOR(devt) != BLOCK_EXT_MAJOR) { 737 struct kobject *kobj; 738 739 kobj = kobj_lookup(bdev_map, devt, partno); 740 if (kobj) 741 disk = dev_to_disk(kobj_to_dev(kobj)); 742 } else { 743 struct hd_struct *part; 744 745 spin_lock_bh(&ext_devt_lock); 746 part = idr_find(&ext_devt_idr, blk_mangle_minor(MINOR(devt))); 747 if (part && get_disk(part_to_disk(part))) { 748 *partno = part->partno; 749 disk = part_to_disk(part); 750 } 751 spin_unlock_bh(&ext_devt_lock); 752 } 753 754 return disk; 755 } 756 EXPORT_SYMBOL(get_gendisk); 757 758 /** 759 * bdget_disk - do bdget() by gendisk and partition number 760 * @disk: gendisk of interest 761 * @partno: partition number 762 * 763 * Find partition @partno from @disk, do bdget() on it. 764 * 765 * CONTEXT: 766 * Don't care. 767 * 768 * RETURNS: 769 * Resulting block_device on success, NULL on failure. 770 */ 771 struct block_device *bdget_disk(struct gendisk *disk, int partno) 772 { 773 struct hd_struct *part; 774 struct block_device *bdev = NULL; 775 776 part = disk_get_part(disk, partno); 777 if (part) 778 bdev = bdget(part_devt(part)); 779 disk_put_part(part); 780 781 return bdev; 782 } 783 EXPORT_SYMBOL(bdget_disk); 784 785 /* 786 * print a full list of all partitions - intended for places where the root 787 * filesystem can't be mounted and thus to give the victim some idea of what 788 * went wrong 789 */ 790 void __init printk_all_partitions(void) 791 { 792 struct class_dev_iter iter; 793 struct device *dev; 794 795 class_dev_iter_init(&iter, &block_class, NULL, &disk_type); 796 while ((dev = class_dev_iter_next(&iter))) { 797 struct gendisk *disk = dev_to_disk(dev); 798 struct disk_part_iter piter; 799 struct hd_struct *part; 800 char name_buf[BDEVNAME_SIZE]; 801 char devt_buf[BDEVT_SIZE]; 802 803 /* 804 * Don't show empty devices or things that have been 805 * suppressed 806 */ 807 if (get_capacity(disk) == 0 || 808 (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)) 809 continue; 810 811 /* 812 * Note, unlike /proc/partitions, I am showing the 813 * numbers in hex - the same format as the root= 814 * option takes. 815 */ 816 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0); 817 while ((part = disk_part_iter_next(&piter))) { 818 bool is_part0 = part == &disk->part0; 819 820 printk("%s%s %10llu %s %s", is_part0 ? "" : " ", 821 bdevt_str(part_devt(part), devt_buf), 822 (unsigned long long)part_nr_sects_read(part) >> 1 823 , disk_name(disk, part->partno, name_buf), 824 part->info ? part->info->uuid : ""); 825 if (is_part0) { 826 if (dev->parent && dev->parent->driver) 827 printk(" driver: %s\n", 828 dev->parent->driver->name); 829 else 830 printk(" (driver?)\n"); 831 } else 832 printk("\n"); 833 } 834 disk_part_iter_exit(&piter); 835 } 836 class_dev_iter_exit(&iter); 837 } 838 839 #ifdef CONFIG_PROC_FS 840 /* iterator */ 841 static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos) 842 { 843 loff_t skip = *pos; 844 struct class_dev_iter *iter; 845 struct device *dev; 846 847 iter = kmalloc(sizeof(*iter), GFP_KERNEL); 848 if (!iter) 849 return ERR_PTR(-ENOMEM); 850 851 seqf->private = iter; 852 class_dev_iter_init(iter, &block_class, NULL, &disk_type); 853 do { 854 dev = class_dev_iter_next(iter); 855 if (!dev) 856 return NULL; 857 } while (skip--); 858 859 return dev_to_disk(dev); 860 } 861 862 static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos) 863 { 864 struct device *dev; 865 866 (*pos)++; 867 dev = class_dev_iter_next(seqf->private); 868 if (dev) 869 return dev_to_disk(dev); 870 871 return NULL; 872 } 873 874 static void disk_seqf_stop(struct seq_file *seqf, void *v) 875 { 876 struct class_dev_iter *iter = seqf->private; 877 878 /* stop is called even after start failed :-( */ 879 if (iter) { 880 class_dev_iter_exit(iter); 881 kfree(iter); 882 seqf->private = NULL; 883 } 884 } 885 886 static void *show_partition_start(struct seq_file *seqf, loff_t *pos) 887 { 888 void *p; 889 890 p = disk_seqf_start(seqf, pos); 891 if (!IS_ERR_OR_NULL(p) && !*pos) 892 seq_puts(seqf, "major minor #blocks name\n\n"); 893 return p; 894 } 895 896 static int show_partition(struct seq_file *seqf, void *v) 897 { 898 struct gendisk *sgp = v; 899 struct disk_part_iter piter; 900 struct hd_struct *part; 901 char buf[BDEVNAME_SIZE]; 902 903 /* Don't show non-partitionable removeable devices or empty devices */ 904 if (!get_capacity(sgp) || (!disk_max_parts(sgp) && 905 (sgp->flags & GENHD_FL_REMOVABLE))) 906 return 0; 907 if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO) 908 return 0; 909 910 /* show the full disk and all non-0 size partitions of it */ 911 disk_part_iter_init(&piter, sgp, DISK_PITER_INCL_PART0); 912 while ((part = disk_part_iter_next(&piter))) 913 seq_printf(seqf, "%4d %7d %10llu %s\n", 914 MAJOR(part_devt(part)), MINOR(part_devt(part)), 915 (unsigned long long)part_nr_sects_read(part) >> 1, 916 disk_name(sgp, part->partno, buf)); 917 disk_part_iter_exit(&piter); 918 919 return 0; 920 } 921 922 static const struct seq_operations partitions_op = { 923 .start = show_partition_start, 924 .next = disk_seqf_next, 925 .stop = disk_seqf_stop, 926 .show = show_partition 927 }; 928 929 static int partitions_open(struct inode *inode, struct file *file) 930 { 931 return seq_open(file, &partitions_op); 932 } 933 934 static const struct file_operations proc_partitions_operations = { 935 .open = partitions_open, 936 .read = seq_read, 937 .llseek = seq_lseek, 938 .release = seq_release, 939 }; 940 #endif 941 942 943 static struct kobject *base_probe(dev_t devt, int *partno, void *data) 944 { 945 if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0) 946 /* Make old-style 2.4 aliases work */ 947 request_module("block-major-%d", MAJOR(devt)); 948 return NULL; 949 } 950 951 static int __init genhd_device_init(void) 952 { 953 int error; 954 955 block_class.dev_kobj = sysfs_dev_block_kobj; 956 error = class_register(&block_class); 957 if (unlikely(error)) 958 return error; 959 bdev_map = kobj_map_init(base_probe, &block_class_lock); 960 blk_dev_init(); 961 962 register_blkdev(BLOCK_EXT_MAJOR, "blkext"); 963 964 /* create top-level block dir */ 965 if (!sysfs_deprecated) 966 block_depr = kobject_create_and_add("block", NULL); 967 return 0; 968 } 969 970 subsys_initcall(genhd_device_init); 971 972 static ssize_t disk_range_show(struct device *dev, 973 struct device_attribute *attr, char *buf) 974 { 975 struct gendisk *disk = dev_to_disk(dev); 976 977 return sprintf(buf, "%d\n", disk->minors); 978 } 979 980 static ssize_t disk_ext_range_show(struct device *dev, 981 struct device_attribute *attr, char *buf) 982 { 983 struct gendisk *disk = dev_to_disk(dev); 984 985 return sprintf(buf, "%d\n", disk_max_parts(disk)); 986 } 987 988 static ssize_t disk_removable_show(struct device *dev, 989 struct device_attribute *attr, char *buf) 990 { 991 struct gendisk *disk = dev_to_disk(dev); 992 993 return sprintf(buf, "%d\n", 994 (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0)); 995 } 996 997 static ssize_t disk_ro_show(struct device *dev, 998 struct device_attribute *attr, char *buf) 999 { 1000 struct gendisk *disk = dev_to_disk(dev); 1001 1002 return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0); 1003 } 1004 1005 static ssize_t disk_capability_show(struct device *dev, 1006 struct device_attribute *attr, char *buf) 1007 { 1008 struct gendisk *disk = dev_to_disk(dev); 1009 1010 return sprintf(buf, "%x\n", disk->flags); 1011 } 1012 1013 static ssize_t disk_alignment_offset_show(struct device *dev, 1014 struct device_attribute *attr, 1015 char *buf) 1016 { 1017 struct gendisk *disk = dev_to_disk(dev); 1018 1019 return sprintf(buf, "%d\n", queue_alignment_offset(disk->queue)); 1020 } 1021 1022 static ssize_t disk_discard_alignment_show(struct device *dev, 1023 struct device_attribute *attr, 1024 char *buf) 1025 { 1026 struct gendisk *disk = dev_to_disk(dev); 1027 1028 return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue)); 1029 } 1030 1031 static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL); 1032 static DEVICE_ATTR(ext_range, S_IRUGO, disk_ext_range_show, NULL); 1033 static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL); 1034 static DEVICE_ATTR(ro, S_IRUGO, disk_ro_show, NULL); 1035 static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL); 1036 static DEVICE_ATTR(alignment_offset, S_IRUGO, disk_alignment_offset_show, NULL); 1037 static DEVICE_ATTR(discard_alignment, S_IRUGO, disk_discard_alignment_show, 1038 NULL); 1039 static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL); 1040 static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL); 1041 static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL); 1042 static DEVICE_ATTR(badblocks, S_IRUGO | S_IWUSR, disk_badblocks_show, 1043 disk_badblocks_store); 1044 #ifdef CONFIG_FAIL_MAKE_REQUEST 1045 static struct device_attribute dev_attr_fail = 1046 __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store); 1047 #endif 1048 #ifdef CONFIG_FAIL_IO_TIMEOUT 1049 static struct device_attribute dev_attr_fail_timeout = 1050 __ATTR(io-timeout-fail, S_IRUGO|S_IWUSR, part_timeout_show, 1051 part_timeout_store); 1052 #endif 1053 1054 static struct attribute *disk_attrs[] = { 1055 &dev_attr_range.attr, 1056 &dev_attr_ext_range.attr, 1057 &dev_attr_removable.attr, 1058 &dev_attr_ro.attr, 1059 &dev_attr_size.attr, 1060 &dev_attr_alignment_offset.attr, 1061 &dev_attr_discard_alignment.attr, 1062 &dev_attr_capability.attr, 1063 &dev_attr_stat.attr, 1064 &dev_attr_inflight.attr, 1065 &dev_attr_badblocks.attr, 1066 #ifdef CONFIG_FAIL_MAKE_REQUEST 1067 &dev_attr_fail.attr, 1068 #endif 1069 #ifdef CONFIG_FAIL_IO_TIMEOUT 1070 &dev_attr_fail_timeout.attr, 1071 #endif 1072 NULL 1073 }; 1074 1075 static struct attribute_group disk_attr_group = { 1076 .attrs = disk_attrs, 1077 }; 1078 1079 static const struct attribute_group *disk_attr_groups[] = { 1080 &disk_attr_group, 1081 NULL 1082 }; 1083 1084 /** 1085 * disk_replace_part_tbl - replace disk->part_tbl in RCU-safe way 1086 * @disk: disk to replace part_tbl for 1087 * @new_ptbl: new part_tbl to install 1088 * 1089 * Replace disk->part_tbl with @new_ptbl in RCU-safe way. The 1090 * original ptbl is freed using RCU callback. 1091 * 1092 * LOCKING: 1093 * Matching bd_mutx locked. 1094 */ 1095 static void disk_replace_part_tbl(struct gendisk *disk, 1096 struct disk_part_tbl *new_ptbl) 1097 { 1098 struct disk_part_tbl *old_ptbl = disk->part_tbl; 1099 1100 rcu_assign_pointer(disk->part_tbl, new_ptbl); 1101 1102 if (old_ptbl) { 1103 rcu_assign_pointer(old_ptbl->last_lookup, NULL); 1104 kfree_rcu(old_ptbl, rcu_head); 1105 } 1106 } 1107 1108 /** 1109 * disk_expand_part_tbl - expand disk->part_tbl 1110 * @disk: disk to expand part_tbl for 1111 * @partno: expand such that this partno can fit in 1112 * 1113 * Expand disk->part_tbl such that @partno can fit in. disk->part_tbl 1114 * uses RCU to allow unlocked dereferencing for stats and other stuff. 1115 * 1116 * LOCKING: 1117 * Matching bd_mutex locked, might sleep. 1118 * 1119 * RETURNS: 1120 * 0 on success, -errno on failure. 1121 */ 1122 int disk_expand_part_tbl(struct gendisk *disk, int partno) 1123 { 1124 struct disk_part_tbl *old_ptbl = disk->part_tbl; 1125 struct disk_part_tbl *new_ptbl; 1126 int len = old_ptbl ? old_ptbl->len : 0; 1127 int i, target; 1128 size_t size; 1129 1130 /* 1131 * check for int overflow, since we can get here from blkpg_ioctl() 1132 * with a user passed 'partno'. 1133 */ 1134 target = partno + 1; 1135 if (target < 0) 1136 return -EINVAL; 1137 1138 /* disk_max_parts() is zero during initialization, ignore if so */ 1139 if (disk_max_parts(disk) && target > disk_max_parts(disk)) 1140 return -EINVAL; 1141 1142 if (target <= len) 1143 return 0; 1144 1145 size = sizeof(*new_ptbl) + target * sizeof(new_ptbl->part[0]); 1146 new_ptbl = kzalloc_node(size, GFP_KERNEL, disk->node_id); 1147 if (!new_ptbl) 1148 return -ENOMEM; 1149 1150 new_ptbl->len = target; 1151 1152 for (i = 0; i < len; i++) 1153 rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]); 1154 1155 disk_replace_part_tbl(disk, new_ptbl); 1156 return 0; 1157 } 1158 1159 static void disk_release(struct device *dev) 1160 { 1161 struct gendisk *disk = dev_to_disk(dev); 1162 1163 blk_free_devt(dev->devt); 1164 disk_release_events(disk); 1165 kfree(disk->random); 1166 disk_replace_part_tbl(disk, NULL); 1167 hd_free_part(&disk->part0); 1168 if (disk->queue) 1169 blk_put_queue(disk->queue); 1170 kfree(disk); 1171 } 1172 struct class block_class = { 1173 .name = "block", 1174 }; 1175 1176 static char *block_devnode(struct device *dev, umode_t *mode, 1177 kuid_t *uid, kgid_t *gid) 1178 { 1179 struct gendisk *disk = dev_to_disk(dev); 1180 1181 if (disk->devnode) 1182 return disk->devnode(disk, mode); 1183 return NULL; 1184 } 1185 1186 static struct device_type disk_type = { 1187 .name = "disk", 1188 .groups = disk_attr_groups, 1189 .release = disk_release, 1190 .devnode = block_devnode, 1191 }; 1192 1193 #ifdef CONFIG_PROC_FS 1194 /* 1195 * aggregate disk stat collector. Uses the same stats that the sysfs 1196 * entries do, above, but makes them available through one seq_file. 1197 * 1198 * The output looks suspiciously like /proc/partitions with a bunch of 1199 * extra fields. 1200 */ 1201 static int diskstats_show(struct seq_file *seqf, void *v) 1202 { 1203 struct gendisk *gp = v; 1204 struct disk_part_iter piter; 1205 struct hd_struct *hd; 1206 char buf[BDEVNAME_SIZE]; 1207 int cpu; 1208 1209 /* 1210 if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next) 1211 seq_puts(seqf, "major minor name" 1212 " rio rmerge rsect ruse wio wmerge " 1213 "wsect wuse running use aveq" 1214 "\n\n"); 1215 */ 1216 1217 disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0); 1218 while ((hd = disk_part_iter_next(&piter))) { 1219 cpu = part_stat_lock(); 1220 part_round_stats(cpu, hd); 1221 part_stat_unlock(); 1222 seq_printf(seqf, "%4d %7d %s %lu %lu %lu " 1223 "%u %lu %lu %lu %u %u %u %u\n", 1224 MAJOR(part_devt(hd)), MINOR(part_devt(hd)), 1225 disk_name(gp, hd->partno, buf), 1226 part_stat_read(hd, ios[READ]), 1227 part_stat_read(hd, merges[READ]), 1228 part_stat_read(hd, sectors[READ]), 1229 jiffies_to_msecs(part_stat_read(hd, ticks[READ])), 1230 part_stat_read(hd, ios[WRITE]), 1231 part_stat_read(hd, merges[WRITE]), 1232 part_stat_read(hd, sectors[WRITE]), 1233 jiffies_to_msecs(part_stat_read(hd, ticks[WRITE])), 1234 part_in_flight(hd), 1235 jiffies_to_msecs(part_stat_read(hd, io_ticks)), 1236 jiffies_to_msecs(part_stat_read(hd, time_in_queue)) 1237 ); 1238 } 1239 disk_part_iter_exit(&piter); 1240 1241 return 0; 1242 } 1243 1244 static const struct seq_operations diskstats_op = { 1245 .start = disk_seqf_start, 1246 .next = disk_seqf_next, 1247 .stop = disk_seqf_stop, 1248 .show = diskstats_show 1249 }; 1250 1251 static int diskstats_open(struct inode *inode, struct file *file) 1252 { 1253 return seq_open(file, &diskstats_op); 1254 } 1255 1256 static const struct file_operations proc_diskstats_operations = { 1257 .open = diskstats_open, 1258 .read = seq_read, 1259 .llseek = seq_lseek, 1260 .release = seq_release, 1261 }; 1262 1263 static int __init proc_genhd_init(void) 1264 { 1265 proc_create("diskstats", 0, NULL, &proc_diskstats_operations); 1266 proc_create("partitions", 0, NULL, &proc_partitions_operations); 1267 return 0; 1268 } 1269 module_init(proc_genhd_init); 1270 #endif /* CONFIG_PROC_FS */ 1271 1272 dev_t blk_lookup_devt(const char *name, int partno) 1273 { 1274 dev_t devt = MKDEV(0, 0); 1275 struct class_dev_iter iter; 1276 struct device *dev; 1277 1278 class_dev_iter_init(&iter, &block_class, NULL, &disk_type); 1279 while ((dev = class_dev_iter_next(&iter))) { 1280 struct gendisk *disk = dev_to_disk(dev); 1281 struct hd_struct *part; 1282 1283 if (strcmp(dev_name(dev), name)) 1284 continue; 1285 1286 if (partno < disk->minors) { 1287 /* We need to return the right devno, even 1288 * if the partition doesn't exist yet. 1289 */ 1290 devt = MKDEV(MAJOR(dev->devt), 1291 MINOR(dev->devt) + partno); 1292 break; 1293 } 1294 part = disk_get_part(disk, partno); 1295 if (part) { 1296 devt = part_devt(part); 1297 disk_put_part(part); 1298 break; 1299 } 1300 disk_put_part(part); 1301 } 1302 class_dev_iter_exit(&iter); 1303 return devt; 1304 } 1305 EXPORT_SYMBOL(blk_lookup_devt); 1306 1307 struct gendisk *alloc_disk(int minors) 1308 { 1309 return alloc_disk_node(minors, NUMA_NO_NODE); 1310 } 1311 EXPORT_SYMBOL(alloc_disk); 1312 1313 struct gendisk *alloc_disk_node(int minors, int node_id) 1314 { 1315 struct gendisk *disk; 1316 1317 disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id); 1318 if (disk) { 1319 if (!init_part_stats(&disk->part0)) { 1320 kfree(disk); 1321 return NULL; 1322 } 1323 disk->node_id = node_id; 1324 if (disk_expand_part_tbl(disk, 0)) { 1325 free_part_stats(&disk->part0); 1326 kfree(disk); 1327 return NULL; 1328 } 1329 disk->part_tbl->part[0] = &disk->part0; 1330 1331 /* 1332 * set_capacity() and get_capacity() currently don't use 1333 * seqcounter to read/update the part0->nr_sects. Still init 1334 * the counter as we can read the sectors in IO submission 1335 * patch using seqence counters. 1336 * 1337 * TODO: Ideally set_capacity() and get_capacity() should be 1338 * converted to make use of bd_mutex and sequence counters. 1339 */ 1340 seqcount_init(&disk->part0.nr_sects_seq); 1341 if (hd_ref_init(&disk->part0)) { 1342 hd_free_part(&disk->part0); 1343 kfree(disk); 1344 return NULL; 1345 } 1346 1347 disk->minors = minors; 1348 rand_initialize_disk(disk); 1349 disk_to_dev(disk)->class = &block_class; 1350 disk_to_dev(disk)->type = &disk_type; 1351 device_initialize(disk_to_dev(disk)); 1352 } 1353 return disk; 1354 } 1355 EXPORT_SYMBOL(alloc_disk_node); 1356 1357 struct kobject *get_disk(struct gendisk *disk) 1358 { 1359 struct module *owner; 1360 struct kobject *kobj; 1361 1362 if (!disk->fops) 1363 return NULL; 1364 owner = disk->fops->owner; 1365 if (owner && !try_module_get(owner)) 1366 return NULL; 1367 kobj = kobject_get(&disk_to_dev(disk)->kobj); 1368 if (kobj == NULL) { 1369 module_put(owner); 1370 return NULL; 1371 } 1372 return kobj; 1373 1374 } 1375 1376 EXPORT_SYMBOL(get_disk); 1377 1378 void put_disk(struct gendisk *disk) 1379 { 1380 if (disk) 1381 kobject_put(&disk_to_dev(disk)->kobj); 1382 } 1383 1384 EXPORT_SYMBOL(put_disk); 1385 1386 static void set_disk_ro_uevent(struct gendisk *gd, int ro) 1387 { 1388 char event[] = "DISK_RO=1"; 1389 char *envp[] = { event, NULL }; 1390 1391 if (!ro) 1392 event[8] = '0'; 1393 kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp); 1394 } 1395 1396 void set_device_ro(struct block_device *bdev, int flag) 1397 { 1398 bdev->bd_part->policy = flag; 1399 } 1400 1401 EXPORT_SYMBOL(set_device_ro); 1402 1403 void set_disk_ro(struct gendisk *disk, int flag) 1404 { 1405 struct disk_part_iter piter; 1406 struct hd_struct *part; 1407 1408 if (disk->part0.policy != flag) { 1409 set_disk_ro_uevent(disk, flag); 1410 disk->part0.policy = flag; 1411 } 1412 1413 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY); 1414 while ((part = disk_part_iter_next(&piter))) 1415 part->policy = flag; 1416 disk_part_iter_exit(&piter); 1417 } 1418 1419 EXPORT_SYMBOL(set_disk_ro); 1420 1421 int bdev_read_only(struct block_device *bdev) 1422 { 1423 if (!bdev) 1424 return 0; 1425 return bdev->bd_part->policy; 1426 } 1427 1428 EXPORT_SYMBOL(bdev_read_only); 1429 1430 int invalidate_partition(struct gendisk *disk, int partno) 1431 { 1432 int res = 0; 1433 struct block_device *bdev = bdget_disk(disk, partno); 1434 if (bdev) { 1435 fsync_bdev(bdev); 1436 res = __invalidate_device(bdev, true); 1437 bdput(bdev); 1438 } 1439 return res; 1440 } 1441 1442 EXPORT_SYMBOL(invalidate_partition); 1443 1444 /* 1445 * Disk events - monitor disk events like media change and eject request. 1446 */ 1447 struct disk_events { 1448 struct list_head node; /* all disk_event's */ 1449 struct gendisk *disk; /* the associated disk */ 1450 spinlock_t lock; 1451 1452 struct mutex block_mutex; /* protects blocking */ 1453 int block; /* event blocking depth */ 1454 unsigned int pending; /* events already sent out */ 1455 unsigned int clearing; /* events being cleared */ 1456 1457 long poll_msecs; /* interval, -1 for default */ 1458 struct delayed_work dwork; 1459 }; 1460 1461 static const char *disk_events_strs[] = { 1462 [ilog2(DISK_EVENT_MEDIA_CHANGE)] = "media_change", 1463 [ilog2(DISK_EVENT_EJECT_REQUEST)] = "eject_request", 1464 }; 1465 1466 static char *disk_uevents[] = { 1467 [ilog2(DISK_EVENT_MEDIA_CHANGE)] = "DISK_MEDIA_CHANGE=1", 1468 [ilog2(DISK_EVENT_EJECT_REQUEST)] = "DISK_EJECT_REQUEST=1", 1469 }; 1470 1471 /* list of all disk_events */ 1472 static DEFINE_MUTEX(disk_events_mutex); 1473 static LIST_HEAD(disk_events); 1474 1475 /* disable in-kernel polling by default */ 1476 static unsigned long disk_events_dfl_poll_msecs; 1477 1478 static unsigned long disk_events_poll_jiffies(struct gendisk *disk) 1479 { 1480 struct disk_events *ev = disk->ev; 1481 long intv_msecs = 0; 1482 1483 /* 1484 * If device-specific poll interval is set, always use it. If 1485 * the default is being used, poll iff there are events which 1486 * can't be monitored asynchronously. 1487 */ 1488 if (ev->poll_msecs >= 0) 1489 intv_msecs = ev->poll_msecs; 1490 else if (disk->events & ~disk->async_events) 1491 intv_msecs = disk_events_dfl_poll_msecs; 1492 1493 return msecs_to_jiffies(intv_msecs); 1494 } 1495 1496 /** 1497 * disk_block_events - block and flush disk event checking 1498 * @disk: disk to block events for 1499 * 1500 * On return from this function, it is guaranteed that event checking 1501 * isn't in progress and won't happen until unblocked by 1502 * disk_unblock_events(). Events blocking is counted and the actual 1503 * unblocking happens after the matching number of unblocks are done. 1504 * 1505 * Note that this intentionally does not block event checking from 1506 * disk_clear_events(). 1507 * 1508 * CONTEXT: 1509 * Might sleep. 1510 */ 1511 void disk_block_events(struct gendisk *disk) 1512 { 1513 struct disk_events *ev = disk->ev; 1514 unsigned long flags; 1515 bool cancel; 1516 1517 if (!ev) 1518 return; 1519 1520 /* 1521 * Outer mutex ensures that the first blocker completes canceling 1522 * the event work before further blockers are allowed to finish. 1523 */ 1524 mutex_lock(&ev->block_mutex); 1525 1526 spin_lock_irqsave(&ev->lock, flags); 1527 cancel = !ev->block++; 1528 spin_unlock_irqrestore(&ev->lock, flags); 1529 1530 if (cancel) 1531 cancel_delayed_work_sync(&disk->ev->dwork); 1532 1533 mutex_unlock(&ev->block_mutex); 1534 } 1535 1536 static void __disk_unblock_events(struct gendisk *disk, bool check_now) 1537 { 1538 struct disk_events *ev = disk->ev; 1539 unsigned long intv; 1540 unsigned long flags; 1541 1542 spin_lock_irqsave(&ev->lock, flags); 1543 1544 if (WARN_ON_ONCE(ev->block <= 0)) 1545 goto out_unlock; 1546 1547 if (--ev->block) 1548 goto out_unlock; 1549 1550 intv = disk_events_poll_jiffies(disk); 1551 if (check_now) 1552 queue_delayed_work(system_freezable_power_efficient_wq, 1553 &ev->dwork, 0); 1554 else if (intv) 1555 queue_delayed_work(system_freezable_power_efficient_wq, 1556 &ev->dwork, intv); 1557 out_unlock: 1558 spin_unlock_irqrestore(&ev->lock, flags); 1559 } 1560 1561 /** 1562 * disk_unblock_events - unblock disk event checking 1563 * @disk: disk to unblock events for 1564 * 1565 * Undo disk_block_events(). When the block count reaches zero, it 1566 * starts events polling if configured. 1567 * 1568 * CONTEXT: 1569 * Don't care. Safe to call from irq context. 1570 */ 1571 void disk_unblock_events(struct gendisk *disk) 1572 { 1573 if (disk->ev) 1574 __disk_unblock_events(disk, false); 1575 } 1576 1577 /** 1578 * disk_flush_events - schedule immediate event checking and flushing 1579 * @disk: disk to check and flush events for 1580 * @mask: events to flush 1581 * 1582 * Schedule immediate event checking on @disk if not blocked. Events in 1583 * @mask are scheduled to be cleared from the driver. Note that this 1584 * doesn't clear the events from @disk->ev. 1585 * 1586 * CONTEXT: 1587 * If @mask is non-zero must be called with bdev->bd_mutex held. 1588 */ 1589 void disk_flush_events(struct gendisk *disk, unsigned int mask) 1590 { 1591 struct disk_events *ev = disk->ev; 1592 1593 if (!ev) 1594 return; 1595 1596 spin_lock_irq(&ev->lock); 1597 ev->clearing |= mask; 1598 if (!ev->block) 1599 mod_delayed_work(system_freezable_power_efficient_wq, 1600 &ev->dwork, 0); 1601 spin_unlock_irq(&ev->lock); 1602 } 1603 1604 /** 1605 * disk_clear_events - synchronously check, clear and return pending events 1606 * @disk: disk to fetch and clear events from 1607 * @mask: mask of events to be fetched and cleared 1608 * 1609 * Disk events are synchronously checked and pending events in @mask 1610 * are cleared and returned. This ignores the block count. 1611 * 1612 * CONTEXT: 1613 * Might sleep. 1614 */ 1615 unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask) 1616 { 1617 const struct block_device_operations *bdops = disk->fops; 1618 struct disk_events *ev = disk->ev; 1619 unsigned int pending; 1620 unsigned int clearing = mask; 1621 1622 if (!ev) { 1623 /* for drivers still using the old ->media_changed method */ 1624 if ((mask & DISK_EVENT_MEDIA_CHANGE) && 1625 bdops->media_changed && bdops->media_changed(disk)) 1626 return DISK_EVENT_MEDIA_CHANGE; 1627 return 0; 1628 } 1629 1630 disk_block_events(disk); 1631 1632 /* 1633 * store the union of mask and ev->clearing on the stack so that the 1634 * race with disk_flush_events does not cause ambiguity (ev->clearing 1635 * can still be modified even if events are blocked). 1636 */ 1637 spin_lock_irq(&ev->lock); 1638 clearing |= ev->clearing; 1639 ev->clearing = 0; 1640 spin_unlock_irq(&ev->lock); 1641 1642 disk_check_events(ev, &clearing); 1643 /* 1644 * if ev->clearing is not 0, the disk_flush_events got called in the 1645 * middle of this function, so we want to run the workfn without delay. 1646 */ 1647 __disk_unblock_events(disk, ev->clearing ? true : false); 1648 1649 /* then, fetch and clear pending events */ 1650 spin_lock_irq(&ev->lock); 1651 pending = ev->pending & mask; 1652 ev->pending &= ~mask; 1653 spin_unlock_irq(&ev->lock); 1654 WARN_ON_ONCE(clearing & mask); 1655 1656 return pending; 1657 } 1658 1659 /* 1660 * Separate this part out so that a different pointer for clearing_ptr can be 1661 * passed in for disk_clear_events. 1662 */ 1663 static void disk_events_workfn(struct work_struct *work) 1664 { 1665 struct delayed_work *dwork = to_delayed_work(work); 1666 struct disk_events *ev = container_of(dwork, struct disk_events, dwork); 1667 1668 disk_check_events(ev, &ev->clearing); 1669 } 1670 1671 static void disk_check_events(struct disk_events *ev, 1672 unsigned int *clearing_ptr) 1673 { 1674 struct gendisk *disk = ev->disk; 1675 char *envp[ARRAY_SIZE(disk_uevents) + 1] = { }; 1676 unsigned int clearing = *clearing_ptr; 1677 unsigned int events; 1678 unsigned long intv; 1679 int nr_events = 0, i; 1680 1681 /* check events */ 1682 events = disk->fops->check_events(disk, clearing); 1683 1684 /* accumulate pending events and schedule next poll if necessary */ 1685 spin_lock_irq(&ev->lock); 1686 1687 events &= ~ev->pending; 1688 ev->pending |= events; 1689 *clearing_ptr &= ~clearing; 1690 1691 intv = disk_events_poll_jiffies(disk); 1692 if (!ev->block && intv) 1693 queue_delayed_work(system_freezable_power_efficient_wq, 1694 &ev->dwork, intv); 1695 1696 spin_unlock_irq(&ev->lock); 1697 1698 /* 1699 * Tell userland about new events. Only the events listed in 1700 * @disk->events are reported. Unlisted events are processed the 1701 * same internally but never get reported to userland. 1702 */ 1703 for (i = 0; i < ARRAY_SIZE(disk_uevents); i++) 1704 if (events & disk->events & (1 << i)) 1705 envp[nr_events++] = disk_uevents[i]; 1706 1707 if (nr_events) 1708 kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp); 1709 } 1710 1711 /* 1712 * A disk events enabled device has the following sysfs nodes under 1713 * its /sys/block/X/ directory. 1714 * 1715 * events : list of all supported events 1716 * events_async : list of events which can be detected w/o polling 1717 * events_poll_msecs : polling interval, 0: disable, -1: system default 1718 */ 1719 static ssize_t __disk_events_show(unsigned int events, char *buf) 1720 { 1721 const char *delim = ""; 1722 ssize_t pos = 0; 1723 int i; 1724 1725 for (i = 0; i < ARRAY_SIZE(disk_events_strs); i++) 1726 if (events & (1 << i)) { 1727 pos += sprintf(buf + pos, "%s%s", 1728 delim, disk_events_strs[i]); 1729 delim = " "; 1730 } 1731 if (pos) 1732 pos += sprintf(buf + pos, "\n"); 1733 return pos; 1734 } 1735 1736 static ssize_t disk_events_show(struct device *dev, 1737 struct device_attribute *attr, char *buf) 1738 { 1739 struct gendisk *disk = dev_to_disk(dev); 1740 1741 return __disk_events_show(disk->events, buf); 1742 } 1743 1744 static ssize_t disk_events_async_show(struct device *dev, 1745 struct device_attribute *attr, char *buf) 1746 { 1747 struct gendisk *disk = dev_to_disk(dev); 1748 1749 return __disk_events_show(disk->async_events, buf); 1750 } 1751 1752 static ssize_t disk_events_poll_msecs_show(struct device *dev, 1753 struct device_attribute *attr, 1754 char *buf) 1755 { 1756 struct gendisk *disk = dev_to_disk(dev); 1757 1758 return sprintf(buf, "%ld\n", disk->ev->poll_msecs); 1759 } 1760 1761 static ssize_t disk_events_poll_msecs_store(struct device *dev, 1762 struct device_attribute *attr, 1763 const char *buf, size_t count) 1764 { 1765 struct gendisk *disk = dev_to_disk(dev); 1766 long intv; 1767 1768 if (!count || !sscanf(buf, "%ld", &intv)) 1769 return -EINVAL; 1770 1771 if (intv < 0 && intv != -1) 1772 return -EINVAL; 1773 1774 disk_block_events(disk); 1775 disk->ev->poll_msecs = intv; 1776 __disk_unblock_events(disk, true); 1777 1778 return count; 1779 } 1780 1781 static const DEVICE_ATTR(events, S_IRUGO, disk_events_show, NULL); 1782 static const DEVICE_ATTR(events_async, S_IRUGO, disk_events_async_show, NULL); 1783 static const DEVICE_ATTR(events_poll_msecs, S_IRUGO|S_IWUSR, 1784 disk_events_poll_msecs_show, 1785 disk_events_poll_msecs_store); 1786 1787 static const struct attribute *disk_events_attrs[] = { 1788 &dev_attr_events.attr, 1789 &dev_attr_events_async.attr, 1790 &dev_attr_events_poll_msecs.attr, 1791 NULL, 1792 }; 1793 1794 /* 1795 * The default polling interval can be specified by the kernel 1796 * parameter block.events_dfl_poll_msecs which defaults to 0 1797 * (disable). This can also be modified runtime by writing to 1798 * /sys/module/block/events_dfl_poll_msecs. 1799 */ 1800 static int disk_events_set_dfl_poll_msecs(const char *val, 1801 const struct kernel_param *kp) 1802 { 1803 struct disk_events *ev; 1804 int ret; 1805 1806 ret = param_set_ulong(val, kp); 1807 if (ret < 0) 1808 return ret; 1809 1810 mutex_lock(&disk_events_mutex); 1811 1812 list_for_each_entry(ev, &disk_events, node) 1813 disk_flush_events(ev->disk, 0); 1814 1815 mutex_unlock(&disk_events_mutex); 1816 1817 return 0; 1818 } 1819 1820 static const struct kernel_param_ops disk_events_dfl_poll_msecs_param_ops = { 1821 .set = disk_events_set_dfl_poll_msecs, 1822 .get = param_get_ulong, 1823 }; 1824 1825 #undef MODULE_PARAM_PREFIX 1826 #define MODULE_PARAM_PREFIX "block." 1827 1828 module_param_cb(events_dfl_poll_msecs, &disk_events_dfl_poll_msecs_param_ops, 1829 &disk_events_dfl_poll_msecs, 0644); 1830 1831 /* 1832 * disk_{alloc|add|del|release}_events - initialize and destroy disk_events. 1833 */ 1834 static void disk_alloc_events(struct gendisk *disk) 1835 { 1836 struct disk_events *ev; 1837 1838 if (!disk->fops->check_events) 1839 return; 1840 1841 ev = kzalloc(sizeof(*ev), GFP_KERNEL); 1842 if (!ev) { 1843 pr_warn("%s: failed to initialize events\n", disk->disk_name); 1844 return; 1845 } 1846 1847 INIT_LIST_HEAD(&ev->node); 1848 ev->disk = disk; 1849 spin_lock_init(&ev->lock); 1850 mutex_init(&ev->block_mutex); 1851 ev->block = 1; 1852 ev->poll_msecs = -1; 1853 INIT_DELAYED_WORK(&ev->dwork, disk_events_workfn); 1854 1855 disk->ev = ev; 1856 } 1857 1858 static void disk_add_events(struct gendisk *disk) 1859 { 1860 if (!disk->ev) 1861 return; 1862 1863 /* FIXME: error handling */ 1864 if (sysfs_create_files(&disk_to_dev(disk)->kobj, disk_events_attrs) < 0) 1865 pr_warn("%s: failed to create sysfs files for events\n", 1866 disk->disk_name); 1867 1868 mutex_lock(&disk_events_mutex); 1869 list_add_tail(&disk->ev->node, &disk_events); 1870 mutex_unlock(&disk_events_mutex); 1871 1872 /* 1873 * Block count is initialized to 1 and the following initial 1874 * unblock kicks it into action. 1875 */ 1876 __disk_unblock_events(disk, true); 1877 } 1878 1879 static void disk_del_events(struct gendisk *disk) 1880 { 1881 if (!disk->ev) 1882 return; 1883 1884 disk_block_events(disk); 1885 1886 mutex_lock(&disk_events_mutex); 1887 list_del_init(&disk->ev->node); 1888 mutex_unlock(&disk_events_mutex); 1889 1890 sysfs_remove_files(&disk_to_dev(disk)->kobj, disk_events_attrs); 1891 } 1892 1893 static void disk_release_events(struct gendisk *disk) 1894 { 1895 /* the block count should be 1 from disk_del_events() */ 1896 WARN_ON_ONCE(disk->ev && disk->ev->block != 1); 1897 kfree(disk->ev); 1898 } 1899