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