drivers/block/genhd.c

   1 /*
   2  *  gendisk handling
   3  */
   4
   5 #include <linux/config.h>
   6 #include <linux/module.h>
   7 #include <linux/fs.h>
   8 #include <linux/genhd.h>
   9 #include <linux/kernel.h>
  10 #include <linux/blkdev.h>
  11 #include <linux/init.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/slab.h>
  15 #include <linux/kmod.h>
  16 #include <linux/kobj_map.h>
  17 #include <linux/buffer_head.h>
  18
  19 #define MAX_PROBE_HASH 255      /* random */
  20
  21 static struct subsystem block_subsys;
  22
  23 static DECLARE_MUTEX(block_subsys_sem);
  24
  25 /*
  26  * Can be deleted altogether. Later.
  27  *
  28  */
  29 static struct blk_major_name {
  30         struct blk_major_name *next;
  31         int major;
  32         char name[16];
  33 } *major_names[MAX_PROBE_HASH];
  34
  35 /* index in the above - for now: assume no multimajor ranges */
  36 static inline int major_to_index(int major)
  37 {
  38         return major % MAX_PROBE_HASH;
  39 }
  40
  41 #ifdef CONFIG_PROC_FS
  42 /* get block device names in somewhat random order */
  43 int get_blkdev_list(char *p)
  44 {
  45         struct blk_major_name *n;
  46         int i, len;
  47
  48         len = sprintf(p, "\nBlock devices:\n");
  49
  50         down(&block_subsys_sem);
  51         for (i = 0; i < ARRAY_SIZE(major_names); i++) {
  52                 for (n = major_names[i]; n; n = n->next)
  53                         len += sprintf(p+len, "%3d %s\n",
  54                                        n->major, n->name);
  55         }
  56         up(&block_subsys_sem);
  57
  58         return len;
  59 }
  60 #endif
  61
  62 int register_blkdev(unsigned int major, const char *name)
  63 {
  64         struct blk_major_name **n, *p;
  65         int index, ret = 0;
  66
  67         down(&block_subsys_sem);
  68
  69         /* temporary */
  70         if (major == 0) {
  71                 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
  72                         if (major_names[index] == NULL)
  73                                 break;
  74                 }
  75
  76                 if (index == 0) {
  77                         printk("register_blkdev: failed to get major for %s\n",
  78                                name);
  79                         ret = -EBUSY;
  80                         goto out;
  81                 }
  82                 major = index;
  83                 ret = major;
  84         }
  85
  86         p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
  87         if (p == NULL) {
  88                 ret = -ENOMEM;
  89                 goto out;
  90         }
  91
  92         p->major = major;
  93         strlcpy(p->name, name, sizeof(p->name));
  94         p->next = NULL;
  95         index = major_to_index(major);
  96
  97         for (n = &major_names[index]; *n; n = &(*n)->next) {
  98                 if ((*n)->major == major)
  99                         break;
 100         }
 101         if (!*n)
 102                 *n = p;
 103         else
 104                 ret = -EBUSY;
 105
 106         if (ret < 0) {
 107                 printk("register_blkdev: cannot get major %d for %s\n",
 108                        major, name);
 109                 kfree(p);
 110         }
 111 out:
 112         up(&block_subsys_sem);
 113         return ret;
 114 }
 115
 116 EXPORT_SYMBOL(register_blkdev);
 117
 118 /* todo: make void - error printk here */
 119 int unregister_blkdev(unsigned int major, const char *name)
 120 {
 121         struct blk_major_name **n;
 122         struct blk_major_name *p = NULL;
 123         int index = major_to_index(major);
 124         int ret = 0;
 125
 126         down(&block_subsys_sem);
 127         for (n = &major_names[index]; *n; n = &(*n)->next)
 128                 if ((*n)->major == major)
 129                         break;
 130         if (!*n || strcmp((*n)->name, name))
 131                 ret = -EINVAL;
 132         else {
 133                 p = *n;
 134                 *n = p->next;
 135         }
 136         up(&block_subsys_sem);
 137         kfree(p);
 138
 139         return ret;
 140 }
 141
 142 EXPORT_SYMBOL(unregister_blkdev);
 143
 144 static struct kobj_map *bdev_map;
 145
 146 /*
 147  * Register device numbers dev..(dev+range-1)
 148  * range must be nonzero
 149  * The hash chain is sorted on range, so that subranges can override.
 150  */
 151 void blk_register_region(dev_t dev, unsigned long range, struct module *module,
 152                          struct kobject *(*probe)(dev_t, int *, void *),
 153                          int (*lock)(dev_t, void *), void *data)
 154 {
 155         kobj_map(bdev_map, dev, range, module, probe, lock, data);
 156 }
 157
 158 EXPORT_SYMBOL(blk_register_region);
 159
 160 void blk_unregister_region(dev_t dev, unsigned long range)
 161 {
 162         kobj_unmap(bdev_map, dev, range);
 163 }
 164
 165 EXPORT_SYMBOL(blk_unregister_region);
 166
 167 static struct kobject *exact_match(dev_t dev, int *part, void *data)
 168 {
 169         struct gendisk *p = data;
 170         return &p->kobj;
 171 }
 172
 173 static int exact_lock(dev_t dev, void *data)
 174 {
 175         struct gendisk *p = data;
 176
 177         if (!get_disk(p))
 178                 return -1;
 179         return 0;
 180 }
 181
 182 /**
 183  * add_disk - add partitioning information to kernel list
 184  * @disk: per-device partitioning information
 185  *
 186  * This function registers the partitioning information in @disk
 187  * with the kernel.
 188  */
 189 void add_disk(struct gendisk *disk)
 190 {
 191         disk->flags |= GENHD_FL_UP;
 192         blk_register_region(MKDEV(disk->major, disk->first_minor),
 193                             disk->minors, NULL, exact_match, exact_lock, disk);
 194         register_disk(disk);
 195         blk_register_queue(disk);
 196 }
 197
 198 EXPORT_SYMBOL(add_disk);
 199 EXPORT_SYMBOL(del_gendisk);     /* in partitions/check.c */
 200
 201 void unlink_gendisk(struct gendisk *disk)
 202 {
 203         blk_unregister_queue(disk);
 204         blk_unregister_region(MKDEV(disk->major, disk->first_minor),
 205                               disk->minors);
 206 }
 207
 208 #define to_disk(obj) container_of(obj,struct gendisk,kobj)
 209
 210 /**
 211  * get_gendisk - get partitioning information for a given device
 212  * @dev: device to get partitioning information for
 213  *
 214  * This function gets the structure containing partitioning
 215  * information for the given device @dev.
 216  */
 217 struct gendisk *get_gendisk(dev_t dev, int *part)
 218 {
 219         struct kobject *kobj = kobj_lookup(bdev_map, dev, part);
 220         return  kobj ? to_disk(kobj) : NULL;
 221 }
 222
 223 #ifdef CONFIG_PROC_FS
 224 /* iterator */
 225 static void *part_start(struct seq_file *part, loff_t *pos)
 226 {
 227         struct list_head *p;
 228         loff_t l = *pos;
 229
 230         down(&block_subsys_sem);
 231         list_for_each(p, &block_subsys.kset.list)
 232                 if (!l--)
 233                         return list_entry(p, struct gendisk, kobj.entry);
 234         return NULL;
 235 }
 236
 237 static void *part_next(struct seq_file *part, void *v, loff_t *pos)
 238 {
 239         struct list_head *p = ((struct gendisk *)v)->kobj.entry.next;
 240         ++*pos;
 241         return p==&block_subsys.kset.list ? NULL :
 242                 list_entry(p, struct gendisk, kobj.entry);
 243 }
 244
 245 static void part_stop(struct seq_file *part, void *v)
 246 {
 247         up(&block_subsys_sem);
 248 }
 249
 250 static int show_partition(struct seq_file *part, void *v)
 251 {
 252         struct gendisk *sgp = v;
 253         int n;
 254         char buf[BDEVNAME_SIZE];
 255
 256         if (&sgp->kobj.entry == block_subsys.kset.list.next)
 257                 seq_puts(part, "major minor  #blocks  name\n\n");
 258
 259         /* Don't show non-partitionable removeable devices or empty devices */
 260         if (!get_capacity(sgp) ||
 261                         (sgp->minors == 1 && (sgp->flags & GENHD_FL_REMOVABLE)))
 262                 return 0;
 263         if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
 264                 return 0;
 265
 266         /* show the full disk and all non-0 size partitions of it */
 267         seq_printf(part, "%4d  %4d %10llu %s\n",
 268                 sgp->major, sgp->first_minor,
 269                 (unsigned long long)get_capacity(sgp) >> 1,
 270                 disk_name(sgp, 0, buf));
 271         for (n = 0; n < sgp->minors - 1; n++) {
 272                 if (!sgp->part[n])
 273                         continue;
 274                 if (sgp->part[n]->nr_sects == 0)
 275                         continue;
 276                 seq_printf(part, "%4d  %4d %10llu %s\n",
 277                         sgp->major, n + 1 + sgp->first_minor,
 278                         (unsigned long long)sgp->part[n]->nr_sects >> 1 ,
 279                         disk_name(sgp, n + 1, buf));
 280         }
 281
 282         return 0;
 283 }
 284
 285 struct seq_operations partitions_op = {
 286         .start =part_start,
 287         .next = part_next,
 288         .stop = part_stop,
 289         .show = show_partition
 290 };
 291 #endif
 292
 293
 294 extern int blk_dev_init(void);
 295
 296 static struct kobject *base_probe(dev_t dev, int *part, void *data)
 297 {
 298         if (request_module("block-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0)
 299                 /* Make old-style 2.4 aliases work */
 300                 request_module("block-major-%d", MAJOR(dev));
 301         return NULL;
 302 }
 303
 304 static int __init genhd_device_init(void)
 305 {
 306         bdev_map = kobj_map_init(base_probe, &block_subsys_sem);
 307         blk_dev_init();
 308         subsystem_register(&block_subsys);
 309         return 0;
 310 }
 311
 312 subsys_initcall(genhd_device_init);
 313
 314
 315
 316 /*
 317  * kobject & sysfs bindings for block devices
 318  */
 319 static ssize_t disk_attr_show(struct kobject *kobj, struct attribute *attr,
 320                               char *page)
 321 {
 322         struct gendisk *disk = to_disk(kobj);
 323         struct disk_attribute *disk_attr =
 324                 container_of(attr,struct disk_attribute,attr);
 325         ssize_t ret = 0;
 326
 327         if (disk_attr->show)
 328                 ret = disk_attr->show(disk,page);
 329         return ret;
 330 }
 331
 332 static struct sysfs_ops disk_sysfs_ops = {
 333         .show   = &disk_attr_show,
 334 };
 335
 336 static ssize_t disk_dev_read(struct gendisk * disk, char *page)
 337 {
 338         dev_t base = MKDEV(disk->major, disk->first_minor);
 339         return print_dev_t(page, base);
 340 }
 341 static ssize_t disk_range_read(struct gendisk * disk, char *page)
 342 {
 343         return sprintf(page, "%d\n", disk->minors);
 344 }
 345 static ssize_t disk_removable_read(struct gendisk * disk, char *page)
 346 {
 347         return sprintf(page, "%d\n",
 348                        (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
 349
 350 }
 351 static ssize_t disk_size_read(struct gendisk * disk, char *page)
 352 {
 353         return sprintf(page, "%llu\n", (unsigned long long)get_capacity(disk));
 354 }
 355
 356 static ssize_t disk_stats_read(struct gendisk * disk, char *page)
 357 {
 358         preempt_disable();
 359         disk_round_stats(disk);
 360         preempt_enable();
 361         return sprintf(page,
 362                 "%8u %8u %8llu %8u "
 363                 "%8u %8u %8llu %8u "
 364                 "%8u %8u %8u"
 365                 "\n",
 366                 disk_stat_read(disk, reads), disk_stat_read(disk, read_merges),
 367                 (unsigned long long)disk_stat_read(disk, read_sectors),
 368                 jiffies_to_msecs(disk_stat_read(disk, read_ticks)),
 369                 disk_stat_read(disk, writes),
 370                 disk_stat_read(disk, write_merges),
 371                 (unsigned long long)disk_stat_read(disk, write_sectors),
 372                 jiffies_to_msecs(disk_stat_read(disk, write_ticks)),
 373                 disk->in_flight,
 374                 jiffies_to_msecs(disk_stat_read(disk, io_ticks)),
 375                 jiffies_to_msecs(disk_stat_read(disk, time_in_queue)));
 376 }
 377 static struct disk_attribute disk_attr_dev = {
 378         .attr = {.name = "dev", .mode = S_IRUGO },
 379         .show   = disk_dev_read
 380 };
 381 static struct disk_attribute disk_attr_range = {
 382         .attr = {.name = "range", .mode = S_IRUGO },
 383         .show   = disk_range_read
 384 };
 385 static struct disk_attribute disk_attr_removable = {
 386         .attr = {.name = "removable", .mode = S_IRUGO },
 387         .show   = disk_removable_read
 388 };
 389 static struct disk_attribute disk_attr_size = {
 390         .attr = {.name = "size", .mode = S_IRUGO },
 391         .show   = disk_size_read
 392 };
 393 static struct disk_attribute disk_attr_stat = {
 394         .attr = {.name = "stat", .mode = S_IRUGO },
 395         .show   = disk_stats_read
 396 };
 397
 398 static struct attribute * default_attrs[] = {
 399         &disk_attr_dev.attr,
 400         &disk_attr_range.attr,
 401         &disk_attr_removable.attr,
 402         &disk_attr_size.attr,
 403         &disk_attr_stat.attr,
 404         NULL,
 405 };
 406
 407 static void disk_release(struct kobject * kobj)
 408 {
 409         struct gendisk *disk = to_disk(kobj);
 410         kfree(disk->random);
 411         kfree(disk->part);
 412         free_disk_stats(disk);
 413         kfree(disk);
 414 }
 415
 416 static struct kobj_type ktype_block = {
 417         .release        = disk_release,
 418         .sysfs_ops      = &disk_sysfs_ops,
 419         .default_attrs  = default_attrs,
 420 };
 421
 422 extern struct kobj_type ktype_part;
 423
 424 static int block_hotplug_filter(struct kset *kset, struct kobject *kobj)
 425 {
 426         struct kobj_type *ktype = get_ktype(kobj);
 427
 428         return ((ktype == &ktype_block) || (ktype == &ktype_part));
 429 }
 430
 431 static int block_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
 432                          int num_envp, char *buffer, int buffer_size)
 433 {
 434         struct kobj_type *ktype = get_ktype(kobj);
 435         struct device *physdev;
 436         struct gendisk *disk;
 437         struct hd_struct *part;
 438         int length = 0;
 439         int i = 0;
 440
 441         if (ktype == &ktype_block) {
 442                 disk = container_of(kobj, struct gendisk, kobj);
 443                 add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
 444                                     &length, "MINOR=%u", disk->first_minor);
 445         } else if (ktype == &ktype_part) {
 446                 disk = container_of(kobj->parent, struct gendisk, kobj);
 447                 part = container_of(kobj, struct hd_struct, kobj);
 448                 add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
 449                                     &length, "MINOR=%u",
 450                                     disk->first_minor + part->partno);
 451         } else
 452                 return 0;
 453
 454         add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &length,
 455                             "MAJOR=%u", disk->major);
 456
 457         /* add physical device, backing this device  */
 458         physdev = disk->driverfs_dev;
 459         if (physdev) {
 460                 char *path = kobject_get_path(&physdev->kobj, GFP_KERNEL);
 461
 462                 add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
 463                                     &length, "PHYSDEVPATH=%s", path);
 464                 kfree(path);
 465
 466                 if (physdev->bus)
 467                         add_hotplug_env_var(envp, num_envp, &i,
 468                                             buffer, buffer_size, &length,
 469                                             "PHYSDEVBUS=%s",
 470                                             physdev->bus->name);
 471
 472                 if (physdev->driver)
 473                         add_hotplug_env_var(envp, num_envp, &i,
 474                                             buffer, buffer_size, &length,
 475                                             "PHYSDEVDRIVER=%s",
 476                                             physdev->driver->name);
 477         }
 478
 479         /* terminate, set to next free slot, shrink available space */
 480         envp[i] = NULL;
 481         envp = &envp[i];
 482         num_envp -= i;
 483         buffer = &buffer[length];
 484         buffer_size -= length;
 485
 486         return 0;
 487 }
 488
 489 static struct kset_hotplug_ops block_hotplug_ops = {
 490         .filter         = block_hotplug_filter,
 491         .hotplug        = block_hotplug,
 492 };
 493
 494 /* declare block_subsys. */
 495 static decl_subsys(block, &ktype_block, &block_hotplug_ops);
 496
 497
 498 /*
 499  * aggregate disk stat collector.  Uses the same stats that the sysfs
 500  * entries do, above, but makes them available through one seq_file.
 501  * Watching a few disks may be efficient through sysfs, but watching
 502  * all of them will be more efficient through this interface.
 503  *
 504  * The output looks suspiciously like /proc/partitions with a bunch of
 505  * extra fields.
 506  */
 507
 508 /* iterator */
 509 static void *diskstats_start(struct seq_file *part, loff_t *pos)
 510 {
 511         loff_t k = *pos;
 512         struct list_head *p;
 513
 514         down(&block_subsys_sem);
 515         list_for_each(p, &block_subsys.kset.list)
 516                 if (!k--)
 517                         return list_entry(p, struct gendisk, kobj.entry);
 518         return NULL;
 519 }
 520
 521 static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos)
 522 {
 523         struct list_head *p = ((struct gendisk *)v)->kobj.entry.next;
 524         ++*pos;
 525         return p==&block_subsys.kset.list ? NULL :
 526                 list_entry(p, struct gendisk, kobj.entry);
 527 }
 528
 529 static void diskstats_stop(struct seq_file *part, void *v)
 530 {
 531         up(&block_subsys_sem);
 532 }
 533
 534 static int diskstats_show(struct seq_file *s, void *v)
 535 {
 536         struct gendisk *gp = v;
 537         char buf[BDEVNAME_SIZE];
 538         int n = 0;
 539
 540         /*
 541         if (&sgp->kobj.entry == block_subsys.kset.list.next)
 542                 seq_puts(s,     "major minor name"
 543                                 "     rio rmerge rsect ruse wio wmerge "
 544                                 "wsect wuse running use aveq"
 545                                 "\n\n");
 546         */
 547
 548         preempt_disable();
 549         disk_round_stats(gp);
 550         preempt_enable();
 551         seq_printf(s, "%4d %4d %s %u %u %llu %u %u %u %llu %u %u %u %u\n",
 552                 gp->major, n + gp->first_minor, disk_name(gp, n, buf),
 553                 disk_stat_read(gp, reads), disk_stat_read(gp, read_merges),
 554                 (unsigned long long)disk_stat_read(gp, read_sectors),
 555                 jiffies_to_msecs(disk_stat_read(gp, read_ticks)),
 556                 disk_stat_read(gp, writes), disk_stat_read(gp, write_merges),
 557                 (unsigned long long)disk_stat_read(gp, write_sectors),
 558                 jiffies_to_msecs(disk_stat_read(gp, write_ticks)),
 559                 gp->in_flight,
 560                 jiffies_to_msecs(disk_stat_read(gp, io_ticks)),
 561                 jiffies_to_msecs(disk_stat_read(gp, time_in_queue)));
 562
 563         /* now show all non-0 size partitions of it */
 564         for (n = 0; n < gp->minors - 1; n++) {
 565                 struct hd_struct *hd = gp->part[n];
 566
 567                 if (hd && hd->nr_sects)
 568                         seq_printf(s, "%4d %4d %s %u %u %u %u\n",
 569                                 gp->major, n + gp->first_minor + 1,
 570                                 disk_name(gp, n + 1, buf),
 571                                 hd->reads, hd->read_sectors,
 572                                 hd->writes, hd->write_sectors);
 573         }
 574
 575         return 0;
 576 }
 577
 578 struct seq_operations diskstats_op = {
 579         .start  = diskstats_start,
 580         .next   = diskstats_next,
 581         .stop   = diskstats_stop,
 582         .show   = diskstats_show
 583 };
 584
 585
 586 struct gendisk *alloc_disk(int minors)
 587 {
 588         struct gendisk *disk = kmalloc(sizeof(struct gendisk), GFP_KERNEL);
 589         if (disk) {
 590                 memset(disk, 0, sizeof(struct gendisk));
 591                 if (!init_disk_stats(disk)) {
 592                         kfree(disk);
 593                         return NULL;
 594                 }
 595                 if (minors > 1) {
 596                         int size = (minors - 1) * sizeof(struct hd_struct *);
 597                         disk->part = kmalloc(size, GFP_KERNEL);
 598                         if (!disk->part) {
 599                                 kfree(disk);
 600                                 return NULL;
 601                         }
 602                         memset(disk->part, 0, size);
 603                 }
 604                 disk->minors = minors;
 605                 kobj_set_kset_s(disk,block_subsys);
 606                 kobject_init(&disk->kobj);
 607                 rand_initialize_disk(disk);
 608         }
 609         return disk;
 610 }
 611
 612 EXPORT_SYMBOL(alloc_disk);
 613
 614 struct kobject *get_disk(struct gendisk *disk)
 615 {
 616         struct module *owner;
 617         struct kobject *kobj;
 618
 619         if (!disk->fops)
 620                 return NULL;
 621         owner = disk->fops->owner;
 622         if (owner && !try_module_get(owner))
 623                 return NULL;
 624         kobj = kobject_get(&disk->kobj);
 625         if (kobj == NULL) {
 626                 module_put(owner);
 627                 return NULL;
 628         }
 629         return kobj;
 630
 631 }
 632
 633 EXPORT_SYMBOL(get_disk);
 634
 635 void put_disk(struct gendisk *disk)
 636 {
 637         if (disk)
 638                 kobject_put(&disk->kobj);
 639 }
 640
 641 EXPORT_SYMBOL(put_disk);
 642
 643 void set_device_ro(struct block_device *bdev, int flag)
 644 {
 645         if (bdev->bd_contains != bdev)
 646                 bdev->bd_part->policy = flag;
 647         else
 648                 bdev->bd_disk->policy = flag;
 649 }
 650
 651 EXPORT_SYMBOL(set_device_ro);
 652
 653 void set_disk_ro(struct gendisk *disk, int flag)
 654 {
 655         int i;
 656         disk->policy = flag;
 657         for (i = 0; i < disk->minors - 1; i++)
 658                 if (disk->part[i]) disk->part[i]->policy = flag;
 659 }
 660
 661 EXPORT_SYMBOL(set_disk_ro);
 662
 663 int bdev_read_only(struct block_device *bdev)
 664 {
 665         if (!bdev)
 666                 return 0;
 667         else if (bdev->bd_contains != bdev)
 668                 return bdev->bd_part->policy;
 669         else
 670                 return bdev->bd_disk->policy;
 671 }
 672
 673 EXPORT_SYMBOL(bdev_read_only);
 674
 675 int invalidate_partition(struct gendisk *disk, int index)
 676 {
 677         int res = 0;
 678         struct block_device *bdev = bdget_disk(disk, index);
 679         if (bdev) {
 680                 fsync_bdev(bdev);
 681                 res = __invalidate_device(bdev);
 682                 bdput(bdev);
 683         }
 684         return res;
 685 }
 686
 687 EXPORT_SYMBOL(invalidate_partition);