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, int used)
  44 {
  45         struct blk_major_name *n;
  46         int i, len;
  47
  48         len = snprintf(p, (PAGE_SIZE-used), "\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                         /*
  54                          * If the curent string plus the 5 extra characters
  55                          * in the line would run us off the page, then we're done
  56                          */
  57                         if ((len + used + strlen(n->name) + 5) >= PAGE_SIZE)
  58                                 goto page_full;
  59                         len += sprintf(p+len, "%3d %s\n",
  60                                        n->major, n->name);
  61                 }
  62         }
  63 page_full:
  64         up(&block_subsys_sem);
  65
  66         return len;
  67 }
  68 #endif
  69
  70 int register_blkdev(unsigned int major, const char *name)
  71 {
  72         struct blk_major_name **n, *p;
  73         int index, ret = 0;
  74
  75         down(&block_subsys_sem);
  76
  77         /* temporary */
  78         if (major == 0) {
  79                 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
  80                         if (major_names[index] == NULL)
  81                                 break;
  82                 }
  83
  84                 if (index == 0) {
  85                         printk("register_blkdev: failed to get major for %s\n",
  86                                name);
  87                         ret = -EBUSY;
  88                         goto out;
  89                 }
  90                 major = index;
  91                 ret = major;
  92         }
  93
  94         p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
  95         if (p == NULL) {
  96                 ret = -ENOMEM;
  97                 goto out;
  98         }
  99
 100         p->major = major;
 101         strlcpy(p->name, name, sizeof(p->name));
 102         p->next = NULL;
 103         index = major_to_index(major);
 104
 105         for (n = &major_names[index]; *n; n = &(*n)->next) {
 106                 if ((*n)->major == major)
 107                         break;
 108         }
 109         if (!*n)
 110                 *n = p;
 111         else
 112                 ret = -EBUSY;
 113
 114         if (ret < 0) {
 115                 printk("register_blkdev: cannot get major %d for %s\n",
 116                        major, name);
 117                 kfree(p);
 118         }
 119 out:
 120         up(&block_subsys_sem);
 121         return ret;
 122 }
 123
 124 EXPORT_SYMBOL(register_blkdev);
 125
 126 /* todo: make void - error printk here */
 127 int unregister_blkdev(unsigned int major, const char *name)
 128 {
 129         struct blk_major_name **n;
 130         struct blk_major_name *p = NULL;
 131         int index = major_to_index(major);
 132         int ret = 0;
 133
 134         down(&block_subsys_sem);
 135         for (n = &major_names[index]; *n; n = &(*n)->next)
 136                 if ((*n)->major == major)
 137                         break;
 138         if (!*n || strcmp((*n)->name, name))
 139                 ret = -EINVAL;
 140         else {
 141                 p = *n;
 142                 *n = p->next;
 143         }
 144         up(&block_subsys_sem);
 145         kfree(p);
 146
 147         return ret;
 148 }
 149
 150 EXPORT_SYMBOL(unregister_blkdev);
 151
 152 static struct kobj_map *bdev_map;
 153
 154 /*
 155  * Register device numbers dev..(dev+range-1)
 156  * range must be nonzero
 157  * The hash chain is sorted on range, so that subranges can override.
 158  */
 159 void blk_register_region(dev_t dev, unsigned long range, struct module *module,
 160                          struct kobject *(*probe)(dev_t, int *, void *),
 161                          int (*lock)(dev_t, void *), void *data)
 162 {
 163         kobj_map(bdev_map, dev, range, module, probe, lock, data);
 164 }
 165
 166 EXPORT_SYMBOL(blk_register_region);
 167
 168 void blk_unregister_region(dev_t dev, unsigned long range)
 169 {
 170         kobj_unmap(bdev_map, dev, range);
 171 }
 172
 173 EXPORT_SYMBOL(blk_unregister_region);
 174
 175 static struct kobject *exact_match(dev_t dev, int *part, void *data)
 176 {
 177         struct gendisk *p = data;
 178         return &p->kobj;
 179 }
 180
 181 static int exact_lock(dev_t dev, void *data)
 182 {
 183         struct gendisk *p = data;
 184
 185         if (!get_disk(p))
 186                 return -1;
 187         return 0;
 188 }
 189
 190 /**
 191  * add_disk - add partitioning information to kernel list
 192  * @disk: per-device partitioning information
 193  *
 194  * This function registers the partitioning information in @disk
 195  * with the kernel.
 196  */
 197 void add_disk(struct gendisk *disk)
 198 {
 199         disk->flags |= GENHD_FL_UP;
 200         blk_register_region(MKDEV(disk->major, disk->first_minor),
 201                             disk->minors, NULL, exact_match, exact_lock, disk);
 202         register_disk(disk);
 203         blk_register_queue(disk);
 204 }
 205
 206 EXPORT_SYMBOL(add_disk);
 207 EXPORT_SYMBOL(del_gendisk);     /* in partitions/check.c */
 208
 209 void unlink_gendisk(struct gendisk *disk)
 210 {
 211         blk_unregister_queue(disk);
 212         blk_unregister_region(MKDEV(disk->major, disk->first_minor),
 213                               disk->minors);
 214 }
 215
 216 #define to_disk(obj) container_of(obj,struct gendisk,kobj)
 217
 218 /**
 219  * get_gendisk - get partitioning information for a given device
 220  * @dev: device to get partitioning information for
 221  *
 222  * This function gets the structure containing partitioning
 223  * information for the given device @dev.
 224  */
 225 struct gendisk *get_gendisk(dev_t dev, int *part)
 226 {
 227         struct kobject *kobj = kobj_lookup(bdev_map, dev, part);
 228         return  kobj ? to_disk(kobj) : NULL;
 229 }
 230
 231 #ifdef CONFIG_PROC_FS
 232 /* iterator */
 233 static void *part_start(struct seq_file *part, loff_t *pos)
 234 {
 235         struct list_head *p;
 236         loff_t l = *pos;
 237
 238         down(&block_subsys_sem);
 239         list_for_each(p, &block_subsys.kset.list)
 240                 if (!l--)
 241                         return list_entry(p, struct gendisk, kobj.entry);
 242         return NULL;
 243 }
 244
 245 static void *part_next(struct seq_file *part, void *v, loff_t *pos)
 246 {
 247         struct list_head *p = ((struct gendisk *)v)->kobj.entry.next;
 248         ++*pos;
 249         return p==&block_subsys.kset.list ? NULL :
 250                 list_entry(p, struct gendisk, kobj.entry);
 251 }
 252
 253 static void part_stop(struct seq_file *part, void *v)
 254 {
 255         up(&block_subsys_sem);
 256 }
 257
 258 static int show_partition(struct seq_file *part, void *v)
 259 {
 260         struct gendisk *sgp = v;
 261         int n;
 262         char buf[BDEVNAME_SIZE];
 263
 264         if (&sgp->kobj.entry == block_subsys.kset.list.next)
 265                 seq_puts(part, "major minor  #blocks  name\n\n");
 266
 267         /* Don't show non-partitionable removeable devices or empty devices */
 268         if (!get_capacity(sgp) ||
 269                         (sgp->minors == 1 && (sgp->flags & GENHD_FL_REMOVABLE)))
 270                 return 0;
 271         if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
 272                 return 0;
 273
 274         /* show the full disk and all non-0 size partitions of it */
 275         seq_printf(part, "%4d  %4d %10llu %s\n",
 276                 sgp->major, sgp->first_minor,
 277                 (unsigned long long)get_capacity(sgp) >> 1,
 278                 disk_name(sgp, 0, buf));
 279         for (n = 0; n < sgp->minors - 1; n++) {
 280                 if (!sgp->part[n])
 281                         continue;
 282                 if (sgp->part[n]->nr_sects == 0)
 283                         continue;
 284                 seq_printf(part, "%4d  %4d %10llu %s\n",
 285                         sgp->major, n + 1 + sgp->first_minor,
 286                         (unsigned long long)sgp->part[n]->nr_sects >> 1 ,
 287                         disk_name(sgp, n + 1, buf));
 288         }
 289
 290         return 0;
 291 }
 292
 293 struct seq_operations partitions_op = {
 294         .start =part_start,
 295         .next = part_next,
 296         .stop = part_stop,
 297         .show = show_partition
 298 };
 299 #endif
 300
 301
 302 extern int blk_dev_init(void);
 303
 304 static struct kobject *base_probe(dev_t dev, int *part, void *data)
 305 {
 306         if (request_module("block-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0)
 307                 /* Make old-style 2.4 aliases work */
 308                 request_module("block-major-%d", MAJOR(dev));
 309         return NULL;
 310 }
 311
 312 static int __init genhd_device_init(void)
 313 {
 314         bdev_map = kobj_map_init(base_probe, &block_subsys_sem);
 315         blk_dev_init();
 316         subsystem_register(&block_subsys);
 317         return 0;
 318 }
 319
 320 subsys_initcall(genhd_device_init);
 321
 322
 323
 324 /*
 325  * kobject & sysfs bindings for block devices
 326  */
 327 static ssize_t disk_attr_show(struct kobject *kobj, struct attribute *attr,
 328                               char *page)
 329 {
 330         struct gendisk *disk = to_disk(kobj);
 331         struct disk_attribute *disk_attr =
 332                 container_of(attr,struct disk_attribute,attr);
 333         ssize_t ret = -EIO;
 334
 335         if (disk_attr->show)
 336                 ret = disk_attr->show(disk,page);
 337         return ret;
 338 }
 339
 340 static struct sysfs_ops disk_sysfs_ops = {
 341         .show   = &disk_attr_show,
 342 };
 343
 344 static ssize_t disk_dev_read(struct gendisk * disk, char *page)
 345 {
 346         dev_t base = MKDEV(disk->major, disk->first_minor);
 347         return print_dev_t(page, base);
 348 }
 349 static ssize_t disk_range_read(struct gendisk * disk, char *page)
 350 {
 351         return sprintf(page, "%d\n", disk->minors);
 352 }
 353 static ssize_t disk_removable_read(struct gendisk * disk, char *page)
 354 {
 355         return sprintf(page, "%d\n",
 356                        (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
 357
 358 }
 359 static ssize_t disk_size_read(struct gendisk * disk, char *page)
 360 {
 361         return sprintf(page, "%llu\n", (unsigned long long)get_capacity(disk));
 362 }
 363
 364 static ssize_t disk_stats_read(struct gendisk * disk, char *page)
 365 {
 366         preempt_disable();
 367         disk_round_stats(disk);
 368         preempt_enable();
 369         return sprintf(page,
 370                 "%8u %8u %8llu %8u "
 371                 "%8u %8u %8llu %8u "
 372                 "%8u %8u %8u"
 373                 "\n",
 374                 disk_stat_read(disk, reads), disk_stat_read(disk, read_merges),
 375                 (unsigned long long)disk_stat_read(disk, read_sectors),
 376                 jiffies_to_msecs(disk_stat_read(disk, read_ticks)),
 377                 disk_stat_read(disk, writes),
 378                 disk_stat_read(disk, write_merges),
 379                 (unsigned long long)disk_stat_read(disk, write_sectors),
 380                 jiffies_to_msecs(disk_stat_read(disk, write_ticks)),
 381                 disk->in_flight,
 382                 jiffies_to_msecs(disk_stat_read(disk, io_ticks)),
 383                 jiffies_to_msecs(disk_stat_read(disk, time_in_queue)));
 384 }
 385 static struct disk_attribute disk_attr_dev = {
 386         .attr = {.name = "dev", .mode = S_IRUGO },
 387         .show   = disk_dev_read
 388 };
 389 static struct disk_attribute disk_attr_range = {
 390         .attr = {.name = "range", .mode = S_IRUGO },
 391         .show   = disk_range_read
 392 };
 393 static struct disk_attribute disk_attr_removable = {
 394         .attr = {.name = "removable", .mode = S_IRUGO },
 395         .show   = disk_removable_read
 396 };
 397 static struct disk_attribute disk_attr_size = {
 398         .attr = {.name = "size", .mode = S_IRUGO },
 399         .show   = disk_size_read
 400 };
 401 static struct disk_attribute disk_attr_stat = {
 402         .attr = {.name = "stat", .mode = S_IRUGO },
 403         .show   = disk_stats_read
 404 };
 405
 406 static struct attribute * default_attrs[] = {
 407         &disk_attr_dev.attr,
 408         &disk_attr_range.attr,
 409         &disk_attr_removable.attr,
 410         &disk_attr_size.attr,
 411         &disk_attr_stat.attr,
 412         NULL,
 413 };
 414
 415 static void disk_release(struct kobject * kobj)
 416 {
 417         struct gendisk *disk = to_disk(kobj);
 418         kfree(disk->random);
 419         kfree(disk->part);
 420         free_disk_stats(disk);
 421         kfree(disk);
 422 }
 423
 424 static struct kobj_type ktype_block = {
 425         .release        = disk_release,
 426         .sysfs_ops      = &disk_sysfs_ops,
 427         .default_attrs  = default_attrs,
 428 };
 429
 430 extern struct kobj_type ktype_part;
 431
 432 static int block_hotplug_filter(struct kset *kset, struct kobject *kobj)
 433 {
 434         struct kobj_type *ktype = get_ktype(kobj);
 435
 436         return ((ktype == &ktype_block) || (ktype == &ktype_part));
 437 }
 438
 439 static int block_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
 440                          int num_envp, char *buffer, int buffer_size)
 441 {
 442         struct kobj_type *ktype = get_ktype(kobj);
 443         struct device *physdev;
 444         struct gendisk *disk;
 445         struct hd_struct *part;
 446         int length = 0;
 447         int i = 0;
 448
 449         if (ktype == &ktype_block) {
 450                 disk = container_of(kobj, struct gendisk, kobj);
 451                 add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
 452                                     &length, "MINOR=%u", disk->first_minor);
 453         } else if (ktype == &ktype_part) {
 454                 disk = container_of(kobj->parent, struct gendisk, kobj);
 455                 part = container_of(kobj, struct hd_struct, kobj);
 456                 add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
 457                                     &length, "MINOR=%u",
 458                                     disk->first_minor + part->partno);
 459         } else
 460                 return 0;
 461
 462         add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &length,
 463                             "MAJOR=%u", disk->major);
 464
 465         /* add physical device, backing this device  */
 466         physdev = disk->driverfs_dev;
 467         if (physdev) {
 468                 char *path = kobject_get_path(&physdev->kobj, GFP_KERNEL);
 469
 470                 add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
 471                                     &length, "PHYSDEVPATH=%s", path);
 472                 kfree(path);
 473
 474                 if (physdev->bus)
 475                         add_hotplug_env_var(envp, num_envp, &i,
 476                                             buffer, buffer_size, &length,
 477                                             "PHYSDEVBUS=%s",
 478                                             physdev->bus->name);
 479
 480                 if (physdev->driver)
 481                         add_hotplug_env_var(envp, num_envp, &i,
 482                                             buffer, buffer_size, &length,
 483                                             "PHYSDEVDRIVER=%s",
 484                                             physdev->driver->name);
 485         }
 486
 487         /* terminate, set to next free slot, shrink available space */
 488         envp[i] = NULL;
 489         envp = &envp[i];
 490         num_envp -= i;
 491         buffer = &buffer[length];
 492         buffer_size -= length;
 493
 494         return 0;
 495 }
 496
 497 static struct kset_hotplug_ops block_hotplug_ops = {
 498         .filter         = block_hotplug_filter,
 499         .hotplug        = block_hotplug,
 500 };
 501
 502 /* declare block_subsys. */
 503 static decl_subsys(block, &ktype_block, &block_hotplug_ops);
 504
 505
 506 /*
 507  * aggregate disk stat collector.  Uses the same stats that the sysfs
 508  * entries do, above, but makes them available through one seq_file.
 509  * Watching a few disks may be efficient through sysfs, but watching
 510  * all of them will be more efficient through this interface.
 511  *
 512  * The output looks suspiciously like /proc/partitions with a bunch of
 513  * extra fields.
 514  */
 515
 516 /* iterator */
 517 static void *diskstats_start(struct seq_file *part, loff_t *pos)
 518 {
 519         loff_t k = *pos;
 520         struct list_head *p;
 521
 522         down(&block_subsys_sem);
 523         list_for_each(p, &block_subsys.kset.list)
 524                 if (!k--)
 525                         return list_entry(p, struct gendisk, kobj.entry);
 526         return NULL;
 527 }
 528
 529 static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos)
 530 {
 531         struct list_head *p = ((struct gendisk *)v)->kobj.entry.next;
 532         ++*pos;
 533         return p==&block_subsys.kset.list ? NULL :
 534                 list_entry(p, struct gendisk, kobj.entry);
 535 }
 536
 537 static void diskstats_stop(struct seq_file *part, void *v)
 538 {
 539         up(&block_subsys_sem);
 540 }
 541
 542 static int diskstats_show(struct seq_file *s, void *v)
 543 {
 544         struct gendisk *gp = v;
 545         char buf[BDEVNAME_SIZE];
 546         int n = 0;
 547
 548         /*
 549         if (&sgp->kobj.entry == block_subsys.kset.list.next)
 550                 seq_puts(s,     "major minor name"
 551                                 "     rio rmerge rsect ruse wio wmerge "
 552                                 "wsect wuse running use aveq"
 553                                 "\n\n");
 554         */
 555
 556         preempt_disable();
 557         disk_round_stats(gp);
 558         preempt_enable();
 559         seq_printf(s, "%4d %4d %s %u %u %llu %u %u %u %llu %u %u %u %u\n",
 560                 gp->major, n + gp->first_minor, disk_name(gp, n, buf),
 561                 disk_stat_read(gp, reads), disk_stat_read(gp, read_merges),
 562                 (unsigned long long)disk_stat_read(gp, read_sectors),
 563                 jiffies_to_msecs(disk_stat_read(gp, read_ticks)),
 564                 disk_stat_read(gp, writes), disk_stat_read(gp, write_merges),
 565                 (unsigned long long)disk_stat_read(gp, write_sectors),
 566                 jiffies_to_msecs(disk_stat_read(gp, write_ticks)),
 567                 gp->in_flight,
 568                 jiffies_to_msecs(disk_stat_read(gp, io_ticks)),
 569                 jiffies_to_msecs(disk_stat_read(gp, time_in_queue)));
 570
 571         /* now show all non-0 size partitions of it */
 572         for (n = 0; n < gp->minors - 1; n++) {
 573                 struct hd_struct *hd = gp->part[n];
 574
 575                 if (hd && hd->nr_sects)
 576                         seq_printf(s, "%4d %4d %s %u %u %u %u\n",
 577                                 gp->major, n + gp->first_minor + 1,
 578                                 disk_name(gp, n + 1, buf),
 579                                 hd->reads, hd->read_sectors,
 580                                 hd->writes, hd->write_sectors);
 581         }
 582
 583         return 0;
 584 }
 585
 586 struct seq_operations diskstats_op = {
 587         .start  = diskstats_start,
 588         .next   = diskstats_next,
 589         .stop   = diskstats_stop,
 590         .show   = diskstats_show
 591 };
 592
 593 struct gendisk *alloc_disk(int minors)
 594 {
 595         return alloc_disk_node(minors, -1);
 596 }
 597
 598 struct gendisk *alloc_disk_node(int minors, int node_id)
 599 {
 600         struct gendisk *disk;
 601
 602         disk = kmalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
 603         if (disk) {
 604                 memset(disk, 0, sizeof(struct gendisk));
 605                 if (!init_disk_stats(disk)) {
 606                         kfree(disk);
 607                         return NULL;
 608                 }
 609                 if (minors > 1) {
 610                         int size = (minors - 1) * sizeof(struct hd_struct *);
 611                         disk->part = kmalloc_node(size, GFP_KERNEL, node_id);
 612                         if (!disk->part) {
 613                                 kfree(disk);
 614                                 return NULL;
 615                         }
 616                         memset(disk->part, 0, size);
 617                 }
 618                 disk->minors = minors;
 619                 kobj_set_kset_s(disk,block_subsys);
 620                 kobject_init(&disk->kobj);
 621                 rand_initialize_disk(disk);
 622         }
 623         return disk;
 624 }
 625
 626 EXPORT_SYMBOL(alloc_disk);
 627 EXPORT_SYMBOL(alloc_disk_node);
 628
 629 struct kobject *get_disk(struct gendisk *disk)
 630 {
 631         struct module *owner;
 632         struct kobject *kobj;
 633
 634         if (!disk->fops)
 635                 return NULL;
 636         owner = disk->fops->owner;
 637         if (owner && !try_module_get(owner))
 638                 return NULL;
 639         kobj = kobject_get(&disk->kobj);
 640         if (kobj == NULL) {
 641                 module_put(owner);
 642                 return NULL;
 643         }
 644         return kobj;
 645
 646 }
 647
 648 EXPORT_SYMBOL(get_disk);
 649
 650 void put_disk(struct gendisk *disk)
 651 {
 652         if (disk)
 653                 kobject_put(&disk->kobj);
 654 }
 655
 656 EXPORT_SYMBOL(put_disk);
 657
 658 void set_device_ro(struct block_device *bdev, int flag)
 659 {
 660         if (bdev->bd_contains != bdev)
 661                 bdev->bd_part->policy = flag;
 662         else
 663                 bdev->bd_disk->policy = flag;
 664 }
 665
 666 EXPORT_SYMBOL(set_device_ro);
 667
 668 void set_disk_ro(struct gendisk *disk, int flag)
 669 {
 670         int i;
 671         disk->policy = flag;
 672         for (i = 0; i < disk->minors - 1; i++)
 673                 if (disk->part[i]) disk->part[i]->policy = flag;
 674 }
 675
 676 EXPORT_SYMBOL(set_disk_ro);
 677
 678 int bdev_read_only(struct block_device *bdev)
 679 {
 680         if (!bdev)
 681                 return 0;
 682         else if (bdev->bd_contains != bdev)
 683                 return bdev->bd_part->policy;
 684         else
 685                 return bdev->bd_disk->policy;
 686 }
 687
 688 EXPORT_SYMBOL(bdev_read_only);
 689
 690 int invalidate_partition(struct gendisk *disk, int index)
 691 {
 692         int res = 0;
 693         struct block_device *bdev = bdget_disk(disk, index);
 694         if (bdev) {
 695                 fsync_bdev(bdev);
 696                 res = __invalidate_device(bdev);
 697                 bdput(bdev);
 698         }
 699         return res;
 700 }
 701
 702 EXPORT_SYMBOL(invalidate_partition);