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TOMOYO Linux Cross Reference
Linux/block/genhd.c

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  1 /*
  2  *  gendisk handling
  3  */
  4 
  5 #include <linux/module.h>
  6 #include <linux/fs.h>
  7 #include <linux/genhd.h>
  8 #include <linux/kdev_t.h>
  9 #include <linux/kernel.h>
 10 #include <linux/blkdev.h>
 11 #include <linux/backing-dev.h>
 12 #include <linux/init.h>
 13 #include <linux/spinlock.h>
 14 #include <linux/proc_fs.h>
 15 #include <linux/seq_file.h>
 16 #include <linux/slab.h>
 17 #include <linux/kmod.h>
 18 #include <linux/kobj_map.h>
 19 #include <linux/mutex.h>
 20 #include <linux/idr.h>
 21 #include <linux/log2.h>
 22 #include <linux/pm_runtime.h>
 23 #include <linux/badblocks.h>
 24 
 25 #include "blk.h"
 26 
 27 static DEFINE_MUTEX(block_class_lock);
 28 struct kobject *block_depr;
 29 
 30 /* for extended dynamic devt allocation, currently only one major is used */
 31 #define NR_EXT_DEVT             (1 << MINORBITS)
 32 
 33 /* For extended devt allocation.  ext_devt_lock prevents look up
 34  * results from going away underneath its user.
 35  */
 36 static DEFINE_SPINLOCK(ext_devt_lock);
 37 static DEFINE_IDR(ext_devt_idr);
 38 
 39 static const struct device_type disk_type;
 40 
 41 static void disk_check_events(struct disk_events *ev,
 42                               unsigned int *clearing_ptr);
 43 static void disk_alloc_events(struct gendisk *disk);
 44 static void disk_add_events(struct gendisk *disk);
 45 static void disk_del_events(struct gendisk *disk);
 46 static void disk_release_events(struct gendisk *disk);
 47 
 48 void part_inc_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
 49 {
 50         if (queue_is_mq(q))
 51                 return;
 52 
 53         part_stat_local_inc(part, in_flight[rw]);
 54         if (part->partno)
 55                 part_stat_local_inc(&part_to_disk(part)->part0, in_flight[rw]);
 56 }
 57 
 58 void part_dec_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
 59 {
 60         if (queue_is_mq(q))
 61                 return;
 62 
 63         part_stat_local_dec(part, in_flight[rw]);
 64         if (part->partno)
 65                 part_stat_local_dec(&part_to_disk(part)->part0, in_flight[rw]);
 66 }
 67 
 68 unsigned int part_in_flight(struct request_queue *q, struct hd_struct *part)
 69 {
 70         int cpu;
 71         unsigned int inflight;
 72 
 73         if (queue_is_mq(q)) {
 74                 return blk_mq_in_flight(q, part);
 75         }
 76 
 77         inflight = 0;
 78         for_each_possible_cpu(cpu) {
 79                 inflight += part_stat_local_read_cpu(part, in_flight[0], cpu) +
 80                             part_stat_local_read_cpu(part, in_flight[1], cpu);
 81         }
 82         if ((int)inflight < 0)
 83                 inflight = 0;
 84 
 85         return inflight;
 86 }
 87 
 88 void part_in_flight_rw(struct request_queue *q, struct hd_struct *part,
 89                        unsigned int inflight[2])
 90 {
 91         int cpu;
 92 
 93         if (queue_is_mq(q)) {
 94                 blk_mq_in_flight_rw(q, part, inflight);
 95                 return;
 96         }
 97 
 98         inflight[0] = 0;
 99         inflight[1] = 0;
100         for_each_possible_cpu(cpu) {
101                 inflight[0] += part_stat_local_read_cpu(part, in_flight[0], cpu);
102                 inflight[1] += part_stat_local_read_cpu(part, in_flight[1], cpu);
103         }
104         if ((int)inflight[0] < 0)
105                 inflight[0] = 0;
106         if ((int)inflight[1] < 0)
107                 inflight[1] = 0;
108 }
109 
110 struct hd_struct *__disk_get_part(struct gendisk *disk, int partno)
111 {
112         struct disk_part_tbl *ptbl = rcu_dereference(disk->part_tbl);
113 
114         if (unlikely(partno < 0 || partno >= ptbl->len))
115                 return NULL;
116         return rcu_dereference(ptbl->part[partno]);
117 }
118 
119 /**
120  * disk_get_part - get partition
121  * @disk: disk to look partition from
122  * @partno: partition number
123  *
124  * Look for partition @partno from @disk.  If found, increment
125  * reference count and return it.
126  *
127  * CONTEXT:
128  * Don't care.
129  *
130  * RETURNS:
131  * Pointer to the found partition on success, NULL if not found.
132  */
133 struct hd_struct *disk_get_part(struct gendisk *disk, int partno)
134 {
135         struct hd_struct *part;
136 
137         rcu_read_lock();
138         part = __disk_get_part(disk, partno);
139         if (part)
140                 get_device(part_to_dev(part));
141         rcu_read_unlock();
142 
143         return part;
144 }
145 EXPORT_SYMBOL_GPL(disk_get_part);
146 
147 /**
148  * disk_part_iter_init - initialize partition iterator
149  * @piter: iterator to initialize
150  * @disk: disk to iterate over
151  * @flags: DISK_PITER_* flags
152  *
153  * Initialize @piter so that it iterates over partitions of @disk.
154  *
155  * CONTEXT:
156  * Don't care.
157  */
158 void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk,
159                           unsigned int flags)
160 {
161         struct disk_part_tbl *ptbl;
162 
163         rcu_read_lock();
164         ptbl = rcu_dereference(disk->part_tbl);
165 
166         piter->disk = disk;
167         piter->part = NULL;
168 
169         if (flags & DISK_PITER_REVERSE)
170                 piter->idx = ptbl->len - 1;
171         else if (flags & (DISK_PITER_INCL_PART0 | DISK_PITER_INCL_EMPTY_PART0))
172                 piter->idx = 0;
173         else
174                 piter->idx = 1;
175 
176         piter->flags = flags;
177 
178         rcu_read_unlock();
179 }
180 EXPORT_SYMBOL_GPL(disk_part_iter_init);
181 
182 /**
183  * disk_part_iter_next - proceed iterator to the next partition and return it
184  * @piter: iterator of interest
185  *
186  * Proceed @piter to the next partition and return it.
187  *
188  * CONTEXT:
189  * Don't care.
190  */
191 struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
192 {
193         struct disk_part_tbl *ptbl;
194         int inc, end;
195 
196         /* put the last partition */
197         disk_put_part(piter->part);
198         piter->part = NULL;
199 
200         /* get part_tbl */
201         rcu_read_lock();
202         ptbl = rcu_dereference(piter->disk->part_tbl);
203 
204         /* determine iteration parameters */
205         if (piter->flags & DISK_PITER_REVERSE) {
206                 inc = -1;
207                 if (piter->flags & (DISK_PITER_INCL_PART0 |
208                                     DISK_PITER_INCL_EMPTY_PART0))
209                         end = -1;
210                 else
211                         end = 0;
212         } else {
213                 inc = 1;
214                 end = ptbl->len;
215         }
216 
217         /* iterate to the next partition */
218         for (; piter->idx != end; piter->idx += inc) {
219                 struct hd_struct *part;
220 
221                 part = rcu_dereference(ptbl->part[piter->idx]);
222                 if (!part)
223                         continue;
224                 if (!part_nr_sects_read(part) &&
225                     !(piter->flags & DISK_PITER_INCL_EMPTY) &&
226                     !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&
227                       piter->idx == 0))
228                         continue;
229 
230                 get_device(part_to_dev(part));
231                 piter->part = part;
232                 piter->idx += inc;
233                 break;
234         }
235 
236         rcu_read_unlock();
237 
238         return piter->part;
239 }
240 EXPORT_SYMBOL_GPL(disk_part_iter_next);
241 
242 /**
243  * disk_part_iter_exit - finish up partition iteration
244  * @piter: iter of interest
245  *
246  * Called when iteration is over.  Cleans up @piter.
247  *
248  * CONTEXT:
249  * Don't care.
250  */
251 void disk_part_iter_exit(struct disk_part_iter *piter)
252 {
253         disk_put_part(piter->part);
254         piter->part = NULL;
255 }
256 EXPORT_SYMBOL_GPL(disk_part_iter_exit);
257 
258 static inline int sector_in_part(struct hd_struct *part, sector_t sector)
259 {
260         return part->start_sect <= sector &&
261                 sector < part->start_sect + part_nr_sects_read(part);
262 }
263 
264 /**
265  * disk_map_sector_rcu - map sector to partition
266  * @disk: gendisk of interest
267  * @sector: sector to map
268  *
269  * Find out which partition @sector maps to on @disk.  This is
270  * primarily used for stats accounting.
271  *
272  * CONTEXT:
273  * RCU read locked.  The returned partition pointer is valid only
274  * while preemption is disabled.
275  *
276  * RETURNS:
277  * Found partition on success, part0 is returned if no partition matches
278  */
279 struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector)
280 {
281         struct disk_part_tbl *ptbl;
282         struct hd_struct *part;
283         int i;
284 
285         ptbl = rcu_dereference(disk->part_tbl);
286 
287         part = rcu_dereference(ptbl->last_lookup);
288         if (part && sector_in_part(part, sector))
289                 return part;
290 
291         for (i = 1; i < ptbl->len; i++) {
292                 part = rcu_dereference(ptbl->part[i]);
293 
294                 if (part && sector_in_part(part, sector)) {
295                         rcu_assign_pointer(ptbl->last_lookup, part);
296                         return part;
297                 }
298         }
299         return &disk->part0;
300 }
301 EXPORT_SYMBOL_GPL(disk_map_sector_rcu);
302 
303 /*
304  * Can be deleted altogether. Later.
305  *
306  */
307 #define BLKDEV_MAJOR_HASH_SIZE 255
308 static struct blk_major_name {
309         struct blk_major_name *next;
310         int major;
311         char name[16];
312 } *major_names[BLKDEV_MAJOR_HASH_SIZE];
313 
314 /* index in the above - for now: assume no multimajor ranges */
315 static inline int major_to_index(unsigned major)
316 {
317         return major % BLKDEV_MAJOR_HASH_SIZE;
318 }
319 
320 #ifdef CONFIG_PROC_FS
321 void blkdev_show(struct seq_file *seqf, off_t offset)
322 {
323         struct blk_major_name *dp;
324 
325         mutex_lock(&block_class_lock);
326         for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next)
327                 if (dp->major == offset)
328                         seq_printf(seqf, "%3d %s\n", dp->major, dp->name);
329         mutex_unlock(&block_class_lock);
330 }
331 #endif /* CONFIG_PROC_FS */
332 
333 /**
334  * register_blkdev - register a new block device
335  *
336  * @major: the requested major device number [1..BLKDEV_MAJOR_MAX-1]. If
337  *         @major = 0, try to allocate any unused major number.
338  * @name: the name of the new block device as a zero terminated string
339  *
340  * The @name must be unique within the system.
341  *
342  * The return value depends on the @major input parameter:
343  *
344  *  - if a major device number was requested in range [1..BLKDEV_MAJOR_MAX-1]
345  *    then the function returns zero on success, or a negative error code
346  *  - if any unused major number was requested with @major = 0 parameter
347  *    then the return value is the allocated major number in range
348  *    [1..BLKDEV_MAJOR_MAX-1] or a negative error code otherwise
349  *
350  * See Documentation/admin-guide/devices.txt for the list of allocated
351  * major numbers.
352  */
353 int register_blkdev(unsigned int major, const char *name)
354 {
355         struct blk_major_name **n, *p;
356         int index, ret = 0;
357 
358         mutex_lock(&block_class_lock);
359 
360         /* temporary */
361         if (major == 0) {
362                 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
363                         if (major_names[index] == NULL)
364                                 break;
365                 }
366 
367                 if (index == 0) {
368                         printk("%s: failed to get major for %s\n",
369                                __func__, name);
370                         ret = -EBUSY;
371                         goto out;
372                 }
373                 major = index;
374                 ret = major;
375         }
376 
377         if (major >= BLKDEV_MAJOR_MAX) {
378                 pr_err("%s: major requested (%u) is greater than the maximum (%u) for %s\n",
379                        __func__, major, BLKDEV_MAJOR_MAX-1, name);
380 
381                 ret = -EINVAL;
382                 goto out;
383         }
384 
385         p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
386         if (p == NULL) {
387                 ret = -ENOMEM;
388                 goto out;
389         }
390 
391         p->major = major;
392         strlcpy(p->name, name, sizeof(p->name));
393         p->next = NULL;
394         index = major_to_index(major);
395 
396         for (n = &major_names[index]; *n; n = &(*n)->next) {
397                 if ((*n)->major == major)
398                         break;
399         }
400         if (!*n)
401                 *n = p;
402         else
403                 ret = -EBUSY;
404 
405         if (ret < 0) {
406                 printk("register_blkdev: cannot get major %u for %s\n",
407                        major, name);
408                 kfree(p);
409         }
410 out:
411         mutex_unlock(&block_class_lock);
412         return ret;
413 }
414 
415 EXPORT_SYMBOL(register_blkdev);
416 
417 void unregister_blkdev(unsigned int major, const char *name)
418 {
419         struct blk_major_name **n;
420         struct blk_major_name *p = NULL;
421         int index = major_to_index(major);
422 
423         mutex_lock(&block_class_lock);
424         for (n = &major_names[index]; *n; n = &(*n)->next)
425                 if ((*n)->major == major)
426                         break;
427         if (!*n || strcmp((*n)->name, name)) {
428                 WARN_ON(1);
429         } else {
430                 p = *n;
431                 *n = p->next;
432         }
433         mutex_unlock(&block_class_lock);
434         kfree(p);
435 }
436 
437 EXPORT_SYMBOL(unregister_blkdev);
438 
439 static struct kobj_map *bdev_map;
440 
441 /**
442  * blk_mangle_minor - scatter minor numbers apart
443  * @minor: minor number to mangle
444  *
445  * Scatter consecutively allocated @minor number apart if MANGLE_DEVT
446  * is enabled.  Mangling twice gives the original value.
447  *
448  * RETURNS:
449  * Mangled value.
450  *
451  * CONTEXT:
452  * Don't care.
453  */
454 static int blk_mangle_minor(int minor)
455 {
456 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
457         int i;
458 
459         for (i = 0; i < MINORBITS / 2; i++) {
460                 int low = minor & (1 << i);
461                 int high = minor & (1 << (MINORBITS - 1 - i));
462                 int distance = MINORBITS - 1 - 2 * i;
463 
464                 minor ^= low | high;    /* clear both bits */
465                 low <<= distance;       /* swap the positions */
466                 high >>= distance;
467                 minor |= low | high;    /* and set */
468         }
469 #endif
470         return minor;
471 }
472 
473 /**
474  * blk_alloc_devt - allocate a dev_t for a partition
475  * @part: partition to allocate dev_t for
476  * @devt: out parameter for resulting dev_t
477  *
478  * Allocate a dev_t for block device.
479  *
480  * RETURNS:
481  * 0 on success, allocated dev_t is returned in *@devt.  -errno on
482  * failure.
483  *
484  * CONTEXT:
485  * Might sleep.
486  */
487 int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
488 {
489         struct gendisk *disk = part_to_disk(part);
490         int idx;
491 
492         /* in consecutive minor range? */
493         if (part->partno < disk->minors) {
494                 *devt = MKDEV(disk->major, disk->first_minor + part->partno);
495                 return 0;
496         }
497 
498         /* allocate ext devt */
499         idr_preload(GFP_KERNEL);
500 
501         spin_lock_bh(&ext_devt_lock);
502         idx = idr_alloc(&ext_devt_idr, part, 0, NR_EXT_DEVT, GFP_NOWAIT);
503         spin_unlock_bh(&ext_devt_lock);
504 
505         idr_preload_end();
506         if (idx < 0)
507                 return idx == -ENOSPC ? -EBUSY : idx;
508 
509         *devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx));
510         return 0;
511 }
512 
513 /**
514  * blk_free_devt - free a dev_t
515  * @devt: dev_t to free
516  *
517  * Free @devt which was allocated using blk_alloc_devt().
518  *
519  * CONTEXT:
520  * Might sleep.
521  */
522 void blk_free_devt(dev_t devt)
523 {
524         if (devt == MKDEV(0, 0))
525                 return;
526 
527         if (MAJOR(devt) == BLOCK_EXT_MAJOR) {
528                 spin_lock_bh(&ext_devt_lock);
529                 idr_remove(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
530                 spin_unlock_bh(&ext_devt_lock);
531         }
532 }
533 
534 static char *bdevt_str(dev_t devt, char *buf)
535 {
536         if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) {
537                 char tbuf[BDEVT_SIZE];
538                 snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt));
539                 snprintf(buf, BDEVT_SIZE, "%-9s", tbuf);
540         } else
541                 snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt));
542 
543         return buf;
544 }
545 
546 /*
547  * Register device numbers dev..(dev+range-1)
548  * range must be nonzero
549  * The hash chain is sorted on range, so that subranges can override.
550  */
551 void blk_register_region(dev_t devt, unsigned long range, struct module *module,
552                          struct kobject *(*probe)(dev_t, int *, void *),
553                          int (*lock)(dev_t, void *), void *data)
554 {
555         kobj_map(bdev_map, devt, range, module, probe, lock, data);
556 }
557 
558 EXPORT_SYMBOL(blk_register_region);
559 
560 void blk_unregister_region(dev_t devt, unsigned long range)
561 {
562         kobj_unmap(bdev_map, devt, range);
563 }
564 
565 EXPORT_SYMBOL(blk_unregister_region);
566 
567 static struct kobject *exact_match(dev_t devt, int *partno, void *data)
568 {
569         struct gendisk *p = data;
570 
571         return &disk_to_dev(p)->kobj;
572 }
573 
574 static int exact_lock(dev_t devt, void *data)
575 {
576         struct gendisk *p = data;
577 
578         if (!get_disk_and_module(p))
579                 return -1;
580         return 0;
581 }
582 
583 static void register_disk(struct device *parent, struct gendisk *disk,
584                           const struct attribute_group **groups)
585 {
586         struct device *ddev = disk_to_dev(disk);
587         struct block_device *bdev;
588         struct disk_part_iter piter;
589         struct hd_struct *part;
590         int err;
591 
592         ddev->parent = parent;
593 
594         dev_set_name(ddev, "%s", disk->disk_name);
595 
596         /* delay uevents, until we scanned partition table */
597         dev_set_uevent_suppress(ddev, 1);
598 
599         if (groups) {
600                 WARN_ON(ddev->groups);
601                 ddev->groups = groups;
602         }
603         if (device_add(ddev))
604                 return;
605         if (!sysfs_deprecated) {
606                 err = sysfs_create_link(block_depr, &ddev->kobj,
607                                         kobject_name(&ddev->kobj));
608                 if (err) {
609                         device_del(ddev);
610                         return;
611                 }
612         }
613 
614         /*
615          * avoid probable deadlock caused by allocating memory with
616          * GFP_KERNEL in runtime_resume callback of its all ancestor
617          * devices
618          */
619         pm_runtime_set_memalloc_noio(ddev, true);
620 
621         disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
622         disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
623 
624         if (disk->flags & GENHD_FL_HIDDEN) {
625                 dev_set_uevent_suppress(ddev, 0);
626                 return;
627         }
628 
629         /* No minors to use for partitions */
630         if (!disk_part_scan_enabled(disk))
631                 goto exit;
632 
633         /* No such device (e.g., media were just removed) */
634         if (!get_capacity(disk))
635                 goto exit;
636 
637         bdev = bdget_disk(disk, 0);
638         if (!bdev)
639                 goto exit;
640 
641         bdev->bd_invalidated = 1;
642         err = blkdev_get(bdev, FMODE_READ, NULL);
643         if (err < 0)
644                 goto exit;
645         blkdev_put(bdev, FMODE_READ);
646 
647 exit:
648         /* announce disk after possible partitions are created */
649         dev_set_uevent_suppress(ddev, 0);
650         kobject_uevent(&ddev->kobj, KOBJ_ADD);
651 
652         /* announce possible partitions */
653         disk_part_iter_init(&piter, disk, 0);
654         while ((part = disk_part_iter_next(&piter)))
655                 kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
656         disk_part_iter_exit(&piter);
657 
658         if (disk->queue->backing_dev_info->dev) {
659                 err = sysfs_create_link(&ddev->kobj,
660                           &disk->queue->backing_dev_info->dev->kobj,
661                           "bdi");
662                 WARN_ON(err);
663         }
664 }
665 
666 /**
667  * __device_add_disk - add disk information to kernel list
668  * @parent: parent device for the disk
669  * @disk: per-device partitioning information
670  * @groups: Additional per-device sysfs groups
671  * @register_queue: register the queue if set to true
672  *
673  * This function registers the partitioning information in @disk
674  * with the kernel.
675  *
676  * FIXME: error handling
677  */
678 static void __device_add_disk(struct device *parent, struct gendisk *disk,
679                               const struct attribute_group **groups,
680                               bool register_queue)
681 {
682         dev_t devt;
683         int retval;
684 
685         /* minors == 0 indicates to use ext devt from part0 and should
686          * be accompanied with EXT_DEVT flag.  Make sure all
687          * parameters make sense.
688          */
689         WARN_ON(disk->minors && !(disk->major || disk->first_minor));
690         WARN_ON(!disk->minors &&
691                 !(disk->flags & (GENHD_FL_EXT_DEVT | GENHD_FL_HIDDEN)));
692 
693         disk->flags |= GENHD_FL_UP;
694 
695         retval = blk_alloc_devt(&disk->part0, &devt);
696         if (retval) {
697                 WARN_ON(1);
698                 return;
699         }
700         disk->major = MAJOR(devt);
701         disk->first_minor = MINOR(devt);
702 
703         disk_alloc_events(disk);
704 
705         if (disk->flags & GENHD_FL_HIDDEN) {
706                 /*
707                  * Don't let hidden disks show up in /proc/partitions,
708                  * and don't bother scanning for partitions either.
709                  */
710                 disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
711                 disk->flags |= GENHD_FL_NO_PART_SCAN;
712         } else {
713                 int ret;
714 
715                 /* Register BDI before referencing it from bdev */
716                 disk_to_dev(disk)->devt = devt;
717                 ret = bdi_register_owner(disk->queue->backing_dev_info,
718                                                 disk_to_dev(disk));
719                 WARN_ON(ret);
720                 blk_register_region(disk_devt(disk), disk->minors, NULL,
721                                     exact_match, exact_lock, disk);
722         }
723         register_disk(parent, disk, groups);
724         if (register_queue)
725                 blk_register_queue(disk);
726 
727         /*
728          * Take an extra ref on queue which will be put on disk_release()
729          * so that it sticks around as long as @disk is there.
730          */
731         WARN_ON_ONCE(!blk_get_queue(disk->queue));
732 
733         disk_add_events(disk);
734         blk_integrity_add(disk);
735 }
736 
737 void device_add_disk(struct device *parent, struct gendisk *disk,
738                      const struct attribute_group **groups)
739 
740 {
741         __device_add_disk(parent, disk, groups, true);
742 }
743 EXPORT_SYMBOL(device_add_disk);
744 
745 void device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk)
746 {
747         __device_add_disk(parent, disk, NULL, false);
748 }
749 EXPORT_SYMBOL(device_add_disk_no_queue_reg);
750 
751 void del_gendisk(struct gendisk *disk)
752 {
753         struct disk_part_iter piter;
754         struct hd_struct *part;
755 
756         blk_integrity_del(disk);
757         disk_del_events(disk);
758 
759         /*
760          * Block lookups of the disk until all bdevs are unhashed and the
761          * disk is marked as dead (GENHD_FL_UP cleared).
762          */
763         down_write(&disk->lookup_sem);
764         /* invalidate stuff */
765         disk_part_iter_init(&piter, disk,
766                              DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
767         while ((part = disk_part_iter_next(&piter))) {
768                 invalidate_partition(disk, part->partno);
769                 bdev_unhash_inode(part_devt(part));
770                 delete_partition(disk, part->partno);
771         }
772         disk_part_iter_exit(&piter);
773 
774         invalidate_partition(disk, 0);
775         bdev_unhash_inode(disk_devt(disk));
776         set_capacity(disk, 0);
777         disk->flags &= ~GENHD_FL_UP;
778         up_write(&disk->lookup_sem);
779 
780         if (!(disk->flags & GENHD_FL_HIDDEN))
781                 sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
782         if (disk->queue) {
783                 /*
784                  * Unregister bdi before releasing device numbers (as they can
785                  * get reused and we'd get clashes in sysfs).
786                  */
787                 if (!(disk->flags & GENHD_FL_HIDDEN))
788                         bdi_unregister(disk->queue->backing_dev_info);
789                 blk_unregister_queue(disk);
790         } else {
791                 WARN_ON(1);
792         }
793 
794         if (!(disk->flags & GENHD_FL_HIDDEN))
795                 blk_unregister_region(disk_devt(disk), disk->minors);
796 
797         kobject_put(disk->part0.holder_dir);
798         kobject_put(disk->slave_dir);
799 
800         part_stat_set_all(&disk->part0, 0);
801         disk->part0.stamp = 0;
802         if (!sysfs_deprecated)
803                 sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
804         pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);
805         device_del(disk_to_dev(disk));
806 }
807 EXPORT_SYMBOL(del_gendisk);
808 
809 /* sysfs access to bad-blocks list. */
810 static ssize_t disk_badblocks_show(struct device *dev,
811                                         struct device_attribute *attr,
812                                         char *page)
813 {
814         struct gendisk *disk = dev_to_disk(dev);
815 
816         if (!disk->bb)
817                 return sprintf(page, "\n");
818 
819         return badblocks_show(disk->bb, page, 0);
820 }
821 
822 static ssize_t disk_badblocks_store(struct device *dev,
823                                         struct device_attribute *attr,
824                                         const char *page, size_t len)
825 {
826         struct gendisk *disk = dev_to_disk(dev);
827 
828         if (!disk->bb)
829                 return -ENXIO;
830 
831         return badblocks_store(disk->bb, page, len, 0);
832 }
833 
834 /**
835  * get_gendisk - get partitioning information for a given device
836  * @devt: device to get partitioning information for
837  * @partno: returned partition index
838  *
839  * This function gets the structure containing partitioning
840  * information for the given device @devt.
841  */
842 struct gendisk *get_gendisk(dev_t devt, int *partno)
843 {
844         struct gendisk *disk = NULL;
845 
846         if (MAJOR(devt) != BLOCK_EXT_MAJOR) {
847                 struct kobject *kobj;
848 
849                 kobj = kobj_lookup(bdev_map, devt, partno);
850                 if (kobj)
851                         disk = dev_to_disk(kobj_to_dev(kobj));
852         } else {
853                 struct hd_struct *part;
854 
855                 spin_lock_bh(&ext_devt_lock);
856                 part = idr_find(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
857                 if (part && get_disk_and_module(part_to_disk(part))) {
858                         *partno = part->partno;
859                         disk = part_to_disk(part);
860                 }
861                 spin_unlock_bh(&ext_devt_lock);
862         }
863 
864         if (!disk)
865                 return NULL;
866 
867         /*
868          * Synchronize with del_gendisk() to not return disk that is being
869          * destroyed.
870          */
871         down_read(&disk->lookup_sem);
872         if (unlikely((disk->flags & GENHD_FL_HIDDEN) ||
873                      !(disk->flags & GENHD_FL_UP))) {
874                 up_read(&disk->lookup_sem);
875                 put_disk_and_module(disk);
876                 disk = NULL;
877         } else {
878                 up_read(&disk->lookup_sem);
879         }
880         return disk;
881 }
882 EXPORT_SYMBOL(get_gendisk);
883 
884 /**
885  * bdget_disk - do bdget() by gendisk and partition number
886  * @disk: gendisk of interest
887  * @partno: partition number
888  *
889  * Find partition @partno from @disk, do bdget() on it.
890  *
891  * CONTEXT:
892  * Don't care.
893  *
894  * RETURNS:
895  * Resulting block_device on success, NULL on failure.
896  */
897 struct block_device *bdget_disk(struct gendisk *disk, int partno)
898 {
899         struct hd_struct *part;
900         struct block_device *bdev = NULL;
901 
902         part = disk_get_part(disk, partno);
903         if (part)
904                 bdev = bdget(part_devt(part));
905         disk_put_part(part);
906 
907         return bdev;
908 }
909 EXPORT_SYMBOL(bdget_disk);
910 
911 /*
912  * print a full list of all partitions - intended for places where the root
913  * filesystem can't be mounted and thus to give the victim some idea of what
914  * went wrong
915  */
916 void __init printk_all_partitions(void)
917 {
918         struct class_dev_iter iter;
919         struct device *dev;
920 
921         class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
922         while ((dev = class_dev_iter_next(&iter))) {
923                 struct gendisk *disk = dev_to_disk(dev);
924                 struct disk_part_iter piter;
925                 struct hd_struct *part;
926                 char name_buf[BDEVNAME_SIZE];
927                 char devt_buf[BDEVT_SIZE];
928 
929                 /*
930                  * Don't show empty devices or things that have been
931                  * suppressed
932                  */
933                 if (get_capacity(disk) == 0 ||
934                     (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
935                         continue;
936 
937                 /*
938                  * Note, unlike /proc/partitions, I am showing the
939                  * numbers in hex - the same format as the root=
940                  * option takes.
941                  */
942                 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
943                 while ((part = disk_part_iter_next(&piter))) {
944                         bool is_part0 = part == &disk->part0;
945 
946                         printk("%s%s %10llu %s %s", is_part0 ? "" : "  ",
947                                bdevt_str(part_devt(part), devt_buf),
948                                (unsigned long long)part_nr_sects_read(part) >> 1
949                                , disk_name(disk, part->partno, name_buf),
950                                part->info ? part->info->uuid : "");
951                         if (is_part0) {
952                                 if (dev->parent && dev->parent->driver)
953                                         printk(" driver: %s\n",
954                                               dev->parent->driver->name);
955                                 else
956                                         printk(" (driver?)\n");
957                         } else
958                                 printk("\n");
959                 }
960                 disk_part_iter_exit(&piter);
961         }
962         class_dev_iter_exit(&iter);
963 }
964 
965 #ifdef CONFIG_PROC_FS
966 /* iterator */
967 static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)
968 {
969         loff_t skip = *pos;
970         struct class_dev_iter *iter;
971         struct device *dev;
972 
973         iter = kmalloc(sizeof(*iter), GFP_KERNEL);
974         if (!iter)
975                 return ERR_PTR(-ENOMEM);
976 
977         seqf->private = iter;
978         class_dev_iter_init(iter, &block_class, NULL, &disk_type);
979         do {
980                 dev = class_dev_iter_next(iter);
981                 if (!dev)
982                         return NULL;
983         } while (skip--);
984 
985         return dev_to_disk(dev);
986 }
987 
988 static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)
989 {
990         struct device *dev;
991 
992         (*pos)++;
993         dev = class_dev_iter_next(seqf->private);
994         if (dev)
995                 return dev_to_disk(dev);
996 
997         return NULL;
998 }
999 
1000 static void disk_seqf_stop(struct seq_file *seqf, void *v)
1001 {
1002         struct class_dev_iter *iter = seqf->private;
1003 
1004         /* stop is called even after start failed :-( */
1005         if (iter) {
1006                 class_dev_iter_exit(iter);
1007                 kfree(iter);
1008                 seqf->private = NULL;
1009         }
1010 }
1011 
1012 static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
1013 {
1014         void *p;
1015 
1016         p = disk_seqf_start(seqf, pos);
1017         if (!IS_ERR_OR_NULL(p) && !*pos)
1018                 seq_puts(seqf, "major minor  #blocks  name\n\n");
1019         return p;
1020 }
1021 
1022 static int show_partition(struct seq_file *seqf, void *v)
1023 {
1024         struct gendisk *sgp = v;
1025         struct disk_part_iter piter;
1026         struct hd_struct *part;
1027         char buf[BDEVNAME_SIZE];
1028 
1029         /* Don't show non-partitionable removeable devices or empty devices */
1030         if (!get_capacity(sgp) || (!disk_max_parts(sgp) &&
1031                                    (sgp->flags & GENHD_FL_REMOVABLE)))
1032                 return 0;
1033         if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
1034                 return 0;
1035 
1036         /* show the full disk and all non-0 size partitions of it */
1037         disk_part_iter_init(&piter, sgp, DISK_PITER_INCL_PART0);
1038         while ((part = disk_part_iter_next(&piter)))
1039                 seq_printf(seqf, "%4d  %7d %10llu %s\n",
1040                            MAJOR(part_devt(part)), MINOR(part_devt(part)),
1041                            (unsigned long long)part_nr_sects_read(part) >> 1,
1042                            disk_name(sgp, part->partno, buf));
1043         disk_part_iter_exit(&piter);
1044 
1045         return 0;
1046 }
1047 
1048 static const struct seq_operations partitions_op = {
1049         .start  = show_partition_start,
1050         .next   = disk_seqf_next,
1051         .stop   = disk_seqf_stop,
1052         .show   = show_partition
1053 };
1054 #endif
1055 
1056 
1057 static struct kobject *base_probe(dev_t devt, int *partno, void *data)
1058 {
1059         if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
1060                 /* Make old-style 2.4 aliases work */
1061                 request_module("block-major-%d", MAJOR(devt));
1062         return NULL;
1063 }
1064 
1065 static int __init genhd_device_init(void)
1066 {
1067         int error;
1068 
1069         block_class.dev_kobj = sysfs_dev_block_kobj;
1070         error = class_register(&block_class);
1071         if (unlikely(error))
1072                 return error;
1073         bdev_map = kobj_map_init(base_probe, &block_class_lock);
1074         blk_dev_init();
1075 
1076         register_blkdev(BLOCK_EXT_MAJOR, "blkext");
1077 
1078         /* create top-level block dir */
1079         if (!sysfs_deprecated)
1080                 block_depr = kobject_create_and_add("block", NULL);
1081         return 0;
1082 }
1083 
1084 subsys_initcall(genhd_device_init);
1085 
1086 static ssize_t disk_range_show(struct device *dev,
1087                                struct device_attribute *attr, char *buf)
1088 {
1089         struct gendisk *disk = dev_to_disk(dev);
1090 
1091         return sprintf(buf, "%d\n", disk->minors);
1092 }
1093 
1094 static ssize_t disk_ext_range_show(struct device *dev,
1095                                    struct device_attribute *attr, char *buf)
1096 {
1097         struct gendisk *disk = dev_to_disk(dev);
1098 
1099         return sprintf(buf, "%d\n", disk_max_parts(disk));
1100 }
1101 
1102 static ssize_t disk_removable_show(struct device *dev,
1103                                    struct device_attribute *attr, char *buf)
1104 {
1105         struct gendisk *disk = dev_to_disk(dev);
1106 
1107         return sprintf(buf, "%d\n",
1108                        (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
1109 }
1110 
1111 static ssize_t disk_hidden_show(struct device *dev,
1112                                    struct device_attribute *attr, char *buf)
1113 {
1114         struct gendisk *disk = dev_to_disk(dev);
1115 
1116         return sprintf(buf, "%d\n",
1117                        (disk->flags & GENHD_FL_HIDDEN ? 1 : 0));
1118 }
1119 
1120 static ssize_t disk_ro_show(struct device *dev,
1121                                    struct device_attribute *attr, char *buf)
1122 {
1123         struct gendisk *disk = dev_to_disk(dev);
1124 
1125         return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0);
1126 }
1127 
1128 static ssize_t disk_capability_show(struct device *dev,
1129                                     struct device_attribute *attr, char *buf)
1130 {
1131         struct gendisk *disk = dev_to_disk(dev);
1132 
1133         return sprintf(buf, "%x\n", disk->flags);
1134 }
1135 
1136 static ssize_t disk_alignment_offset_show(struct device *dev,
1137                                           struct device_attribute *attr,
1138                                           char *buf)
1139 {
1140         struct gendisk *disk = dev_to_disk(dev);
1141 
1142         return sprintf(buf, "%d\n", queue_alignment_offset(disk->queue));
1143 }
1144 
1145 static ssize_t disk_discard_alignment_show(struct device *dev,
1146                                            struct device_attribute *attr,
1147                                            char *buf)
1148 {
1149         struct gendisk *disk = dev_to_disk(dev);
1150 
1151         return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue));
1152 }
1153 
1154 static DEVICE_ATTR(range, 0444, disk_range_show, NULL);
1155 static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL);
1156 static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL);
1157 static DEVICE_ATTR(hidden, 0444, disk_hidden_show, NULL);
1158 static DEVICE_ATTR(ro, 0444, disk_ro_show, NULL);
1159 static DEVICE_ATTR(size, 0444, part_size_show, NULL);
1160 static DEVICE_ATTR(alignment_offset, 0444, disk_alignment_offset_show, NULL);
1161 static DEVICE_ATTR(discard_alignment, 0444, disk_discard_alignment_show, NULL);
1162 static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL);
1163 static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
1164 static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
1165 static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store);
1166 #ifdef CONFIG_FAIL_MAKE_REQUEST
1167 static struct device_attribute dev_attr_fail =
1168         __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
1169 #endif
1170 #ifdef CONFIG_FAIL_IO_TIMEOUT
1171 static struct device_attribute dev_attr_fail_timeout =
1172         __ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store);
1173 #endif
1174 
1175 static struct attribute *disk_attrs[] = {
1176         &dev_attr_range.attr,
1177         &dev_attr_ext_range.attr,
1178         &dev_attr_removable.attr,
1179         &dev_attr_hidden.attr,
1180         &dev_attr_ro.attr,
1181         &dev_attr_size.attr,
1182         &dev_attr_alignment_offset.attr,
1183         &dev_attr_discard_alignment.attr,
1184         &dev_attr_capability.attr,
1185         &dev_attr_stat.attr,
1186         &dev_attr_inflight.attr,
1187         &dev_attr_badblocks.attr,
1188 #ifdef CONFIG_FAIL_MAKE_REQUEST
1189         &dev_attr_fail.attr,
1190 #endif
1191 #ifdef CONFIG_FAIL_IO_TIMEOUT
1192         &dev_attr_fail_timeout.attr,
1193 #endif
1194         NULL
1195 };
1196 
1197 static umode_t disk_visible(struct kobject *kobj, struct attribute *a, int n)
1198 {
1199         struct device *dev = container_of(kobj, typeof(*dev), kobj);
1200         struct gendisk *disk = dev_to_disk(dev);
1201 
1202         if (a == &dev_attr_badblocks.attr && !disk->bb)
1203                 return 0;
1204         return a->mode;
1205 }
1206 
1207 static struct attribute_group disk_attr_group = {
1208         .attrs = disk_attrs,
1209         .is_visible = disk_visible,
1210 };
1211 
1212 static const struct attribute_group *disk_attr_groups[] = {
1213         &disk_attr_group,
1214         NULL
1215 };
1216 
1217 /**
1218  * disk_replace_part_tbl - replace disk->part_tbl in RCU-safe way
1219  * @disk: disk to replace part_tbl for
1220  * @new_ptbl: new part_tbl to install
1221  *
1222  * Replace disk->part_tbl with @new_ptbl in RCU-safe way.  The
1223  * original ptbl is freed using RCU callback.
1224  *
1225  * LOCKING:
1226  * Matching bd_mutex locked or the caller is the only user of @disk.
1227  */
1228 static void disk_replace_part_tbl(struct gendisk *disk,
1229                                   struct disk_part_tbl *new_ptbl)
1230 {
1231         struct disk_part_tbl *old_ptbl =
1232                 rcu_dereference_protected(disk->part_tbl, 1);
1233 
1234         rcu_assign_pointer(disk->part_tbl, new_ptbl);
1235 
1236         if (old_ptbl) {
1237                 rcu_assign_pointer(old_ptbl->last_lookup, NULL);
1238                 kfree_rcu(old_ptbl, rcu_head);
1239         }
1240 }
1241 
1242 /**
1243  * disk_expand_part_tbl - expand disk->part_tbl
1244  * @disk: disk to expand part_tbl for
1245  * @partno: expand such that this partno can fit in
1246  *
1247  * Expand disk->part_tbl such that @partno can fit in.  disk->part_tbl
1248  * uses RCU to allow unlocked dereferencing for stats and other stuff.
1249  *
1250  * LOCKING:
1251  * Matching bd_mutex locked or the caller is the only user of @disk.
1252  * Might sleep.
1253  *
1254  * RETURNS:
1255  * 0 on success, -errno on failure.
1256  */
1257 int disk_expand_part_tbl(struct gendisk *disk, int partno)
1258 {
1259         struct disk_part_tbl *old_ptbl =
1260                 rcu_dereference_protected(disk->part_tbl, 1);
1261         struct disk_part_tbl *new_ptbl;
1262         int len = old_ptbl ? old_ptbl->len : 0;
1263         int i, target;
1264         size_t size;
1265 
1266         /*
1267          * check for int overflow, since we can get here from blkpg_ioctl()
1268          * with a user passed 'partno'.
1269          */
1270         target = partno + 1;
1271         if (target < 0)
1272                 return -EINVAL;
1273 
1274         /* disk_max_parts() is zero during initialization, ignore if so */
1275         if (disk_max_parts(disk) && target > disk_max_parts(disk))
1276                 return -EINVAL;
1277 
1278         if (target <= len)
1279                 return 0;
1280 
1281         size = sizeof(*new_ptbl) + target * sizeof(new_ptbl->part[0]);
1282         new_ptbl = kzalloc_node(size, GFP_KERNEL, disk->node_id);
1283         if (!new_ptbl)
1284                 return -ENOMEM;
1285 
1286         new_ptbl->len = target;
1287 
1288         for (i = 0; i < len; i++)
1289                 rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]);
1290 
1291         disk_replace_part_tbl(disk, new_ptbl);
1292         return 0;
1293 }
1294 
1295 static void disk_release(struct device *dev)
1296 {
1297         struct gendisk *disk = dev_to_disk(dev);
1298 
1299         blk_free_devt(dev->devt);
1300         disk_release_events(disk);
1301         kfree(disk->random);
1302         disk_replace_part_tbl(disk, NULL);
1303         hd_free_part(&disk->part0);
1304         if (disk->queue)
1305                 blk_put_queue(disk->queue);
1306         kfree(disk);
1307 }
1308 struct class block_class = {
1309         .name           = "block",
1310 };
1311 
1312 static char *block_devnode(struct device *dev, umode_t *mode,
1313                            kuid_t *uid, kgid_t *gid)
1314 {
1315         struct gendisk *disk = dev_to_disk(dev);
1316 
1317         if (disk->devnode)
1318                 return disk->devnode(disk, mode);
1319         return NULL;
1320 }
1321 
1322 static const struct device_type disk_type = {
1323         .name           = "disk",
1324         .groups         = disk_attr_groups,
1325         .release        = disk_release,
1326         .devnode        = block_devnode,
1327 };
1328 
1329 #ifdef CONFIG_PROC_FS
1330 /*
1331  * aggregate disk stat collector.  Uses the same stats that the sysfs
1332  * entries do, above, but makes them available through one seq_file.
1333  *
1334  * The output looks suspiciously like /proc/partitions with a bunch of
1335  * extra fields.
1336  */
1337 static int diskstats_show(struct seq_file *seqf, void *v)
1338 {
1339         struct gendisk *gp = v;
1340         struct disk_part_iter piter;
1341         struct hd_struct *hd;
1342         char buf[BDEVNAME_SIZE];
1343         unsigned int inflight;
1344 
1345         /*
1346         if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next)
1347                 seq_puts(seqf,  "major minor name"
1348                                 "     rio rmerge rsect ruse wio wmerge "
1349                                 "wsect wuse running use aveq"
1350                                 "\n\n");
1351         */
1352 
1353         disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0);
1354         while ((hd = disk_part_iter_next(&piter))) {
1355                 inflight = part_in_flight(gp->queue, hd);
1356                 seq_printf(seqf, "%4d %7d %s "
1357                            "%lu %lu %lu %u "
1358                            "%lu %lu %lu %u "
1359                            "%u %u %u "
1360                            "%lu %lu %lu %u\n",
1361                            MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
1362                            disk_name(gp, hd->partno, buf),
1363                            part_stat_read(hd, ios[STAT_READ]),
1364                            part_stat_read(hd, merges[STAT_READ]),
1365                            part_stat_read(hd, sectors[STAT_READ]),
1366                            (unsigned int)part_stat_read_msecs(hd, STAT_READ),
1367                            part_stat_read(hd, ios[STAT_WRITE]),
1368                            part_stat_read(hd, merges[STAT_WRITE]),
1369                            part_stat_read(hd, sectors[STAT_WRITE]),
1370                            (unsigned int)part_stat_read_msecs(hd, STAT_WRITE),
1371                            inflight,
1372                            jiffies_to_msecs(part_stat_read(hd, io_ticks)),
1373                            jiffies_to_msecs(part_stat_read(hd, time_in_queue)),
1374                            part_stat_read(hd, ios[STAT_DISCARD]),
1375                            part_stat_read(hd, merges[STAT_DISCARD]),
1376                            part_stat_read(hd, sectors[STAT_DISCARD]),
1377                            (unsigned int)part_stat_read_msecs(hd, STAT_DISCARD)
1378                         );
1379         }
1380         disk_part_iter_exit(&piter);
1381 
1382         return 0;
1383 }
1384 
1385 static const struct seq_operations diskstats_op = {
1386         .start  = disk_seqf_start,
1387         .next   = disk_seqf_next,
1388         .stop   = disk_seqf_stop,
1389         .show   = diskstats_show
1390 };
1391 
1392 static int __init proc_genhd_init(void)
1393 {
1394         proc_create_seq("diskstats", 0, NULL, &diskstats_op);
1395         proc_create_seq("partitions", 0, NULL, &partitions_op);
1396         return 0;
1397 }
1398 module_init(proc_genhd_init);
1399 #endif /* CONFIG_PROC_FS */
1400 
1401 dev_t blk_lookup_devt(const char *name, int partno)
1402 {
1403         dev_t devt = MKDEV(0, 0);
1404         struct class_dev_iter iter;
1405         struct device *dev;
1406 
1407         class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
1408         while ((dev = class_dev_iter_next(&iter))) {
1409                 struct gendisk *disk = dev_to_disk(dev);
1410                 struct hd_struct *part;
1411 
1412                 if (strcmp(dev_name(dev), name))
1413                         continue;
1414 
1415                 if (partno < disk->minors) {
1416                         /* We need to return the right devno, even
1417                          * if the partition doesn't exist yet.
1418                          */
1419                         devt = MKDEV(MAJOR(dev->devt),
1420                                      MINOR(dev->devt) + partno);
1421                         break;
1422                 }
1423                 part = disk_get_part(disk, partno);
1424                 if (part) {
1425                         devt = part_devt(part);
1426                         disk_put_part(part);
1427                         break;
1428                 }
1429                 disk_put_part(part);
1430         }
1431         class_dev_iter_exit(&iter);
1432         return devt;
1433 }
1434 EXPORT_SYMBOL(blk_lookup_devt);
1435 
1436 struct gendisk *__alloc_disk_node(int minors, int node_id)
1437 {
1438         struct gendisk *disk;
1439         struct disk_part_tbl *ptbl;
1440 
1441         if (minors > DISK_MAX_PARTS) {
1442                 printk(KERN_ERR
1443                         "block: can't allocate more than %d partitions\n",
1444                         DISK_MAX_PARTS);
1445                 minors = DISK_MAX_PARTS;
1446         }
1447 
1448         disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
1449         if (disk) {
1450                 if (!init_part_stats(&disk->part0)) {
1451                         kfree(disk);
1452                         return NULL;
1453                 }
1454                 init_rwsem(&disk->lookup_sem);
1455                 disk->node_id = node_id;
1456                 if (disk_expand_part_tbl(disk, 0)) {
1457                         free_part_stats(&disk->part0);
1458                         kfree(disk);
1459                         return NULL;
1460                 }
1461                 ptbl = rcu_dereference_protected(disk->part_tbl, 1);
1462                 rcu_assign_pointer(ptbl->part[0], &disk->part0);
1463 
1464                 /*
1465                  * set_capacity() and get_capacity() currently don't use
1466                  * seqcounter to read/update the part0->nr_sects. Still init
1467                  * the counter as we can read the sectors in IO submission
1468                  * patch using seqence counters.
1469                  *
1470                  * TODO: Ideally set_capacity() and get_capacity() should be
1471                  * converted to make use of bd_mutex and sequence counters.
1472                  */
1473                 seqcount_init(&disk->part0.nr_sects_seq);
1474                 if (hd_ref_init(&disk->part0)) {
1475                         hd_free_part(&disk->part0);
1476                         kfree(disk);
1477                         return NULL;
1478                 }
1479 
1480                 disk->minors = minors;
1481                 rand_initialize_disk(disk);
1482                 disk_to_dev(disk)->class = &block_class;
1483                 disk_to_dev(disk)->type = &disk_type;
1484                 device_initialize(disk_to_dev(disk));
1485         }
1486         return disk;
1487 }
1488 EXPORT_SYMBOL(__alloc_disk_node);
1489 
1490 struct kobject *get_disk_and_module(struct gendisk *disk)
1491 {
1492         struct module *owner;
1493         struct kobject *kobj;
1494 
1495         if (!disk->fops)
1496                 return NULL;
1497         owner = disk->fops->owner;
1498         if (owner && !try_module_get(owner))
1499                 return NULL;
1500         kobj = kobject_get_unless_zero(&disk_to_dev(disk)->kobj);
1501         if (kobj == NULL) {
1502                 module_put(owner);
1503                 return NULL;
1504         }
1505         return kobj;
1506 
1507 }
1508 EXPORT_SYMBOL(get_disk_and_module);
1509 
1510 void put_disk(struct gendisk *disk)
1511 {
1512         if (disk)
1513                 kobject_put(&disk_to_dev(disk)->kobj);
1514 }
1515 EXPORT_SYMBOL(put_disk);
1516 
1517 /*
1518  * This is a counterpart of get_disk_and_module() and thus also of
1519  * get_gendisk().
1520  */
1521 void put_disk_and_module(struct gendisk *disk)
1522 {
1523         if (disk) {
1524                 struct module *owner = disk->fops->owner;
1525 
1526                 put_disk(disk);
1527                 module_put(owner);
1528         }
1529 }
1530 EXPORT_SYMBOL(put_disk_and_module);
1531 
1532 static void set_disk_ro_uevent(struct gendisk *gd, int ro)
1533 {
1534         char event[] = "DISK_RO=1";
1535         char *envp[] = { event, NULL };
1536 
1537         if (!ro)
1538                 event[8] = '';
1539         kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
1540 }
1541 
1542 void set_device_ro(struct block_device *bdev, int flag)
1543 {
1544         bdev->bd_part->policy = flag;
1545 }
1546 
1547 EXPORT_SYMBOL(set_device_ro);
1548 
1549 void set_disk_ro(struct gendisk *disk, int flag)
1550 {
1551         struct disk_part_iter piter;
1552         struct hd_struct *part;
1553 
1554         if (disk->part0.policy != flag) {
1555                 set_disk_ro_uevent(disk, flag);
1556                 disk->part0.policy = flag;
1557         }
1558 
1559         disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
1560         while ((part = disk_part_iter_next(&piter)))
1561                 part->policy = flag;
1562         disk_part_iter_exit(&piter);
1563 }
1564 
1565 EXPORT_SYMBOL(set_disk_ro);
1566 
1567 int bdev_read_only(struct block_device *bdev)
1568 {
1569         if (!bdev)
1570                 return 0;
1571         return bdev->bd_part->policy;
1572 }
1573 
1574 EXPORT_SYMBOL(bdev_read_only);
1575 
1576 int invalidate_partition(struct gendisk *disk, int partno)
1577 {
1578         int res = 0;
1579         struct block_device *bdev = bdget_disk(disk, partno);
1580         if (bdev) {
1581                 fsync_bdev(bdev);
1582                 res = __invalidate_device(bdev, true);
1583                 bdput(bdev);
1584         }
1585         return res;
1586 }
1587 
1588 EXPORT_SYMBOL(invalidate_partition);
1589 
1590 /*
1591  * Disk events - monitor disk events like media change and eject request.
1592  */
1593 struct disk_events {
1594         struct list_head        node;           /* all disk_event's */
1595         struct gendisk          *disk;          /* the associated disk */
1596         spinlock_t              lock;
1597 
1598         struct mutex            block_mutex;    /* protects blocking */
1599         int                     block;          /* event blocking depth */
1600         unsigned int            pending;        /* events already sent out */
1601         unsigned int            clearing;       /* events being cleared */
1602 
1603         long                    poll_msecs;     /* interval, -1 for default */
1604         struct delayed_work     dwork;
1605 };
1606 
1607 static const char *disk_events_strs[] = {
1608         [ilog2(DISK_EVENT_MEDIA_CHANGE)]        = "media_change",
1609         [ilog2(DISK_EVENT_EJECT_REQUEST)]       = "eject_request",
1610 };
1611 
1612 static char *disk_uevents[] = {
1613         [ilog2(DISK_EVENT_MEDIA_CHANGE)]        = "DISK_MEDIA_CHANGE=1",
1614         [ilog2(DISK_EVENT_EJECT_REQUEST)]       = "DISK_EJECT_REQUEST=1",
1615 };
1616 
1617 /* list of all disk_events */
1618 static DEFINE_MUTEX(disk_events_mutex);
1619 static LIST_HEAD(disk_events);
1620 
1621 /* disable in-kernel polling by default */
1622 static unsigned long disk_events_dfl_poll_msecs;
1623 
1624 static unsigned long disk_events_poll_jiffies(struct gendisk *disk)
1625 {
1626         struct disk_events *ev = disk->ev;
1627         long intv_msecs = 0;
1628 
1629         /*
1630          * If device-specific poll interval is set, always use it.  If
1631          * the default is being used, poll iff there are events which
1632          * can't be monitored asynchronously.
1633          */
1634         if (ev->poll_msecs >= 0)
1635                 intv_msecs = ev->poll_msecs;
1636         else if (disk->events & ~disk->async_events)
1637                 intv_msecs = disk_events_dfl_poll_msecs;
1638 
1639         return msecs_to_jiffies(intv_msecs);
1640 }
1641 
1642 /**
1643  * disk_block_events - block and flush disk event checking
1644  * @disk: disk to block events for
1645  *
1646  * On return from this function, it is guaranteed that event checking
1647  * isn't in progress and won't happen until unblocked by
1648  * disk_unblock_events().  Events blocking is counted and the actual
1649  * unblocking happens after the matching number of unblocks are done.
1650  *
1651  * Note that this intentionally does not block event checking from
1652  * disk_clear_events().
1653  *
1654  * CONTEXT:
1655  * Might sleep.
1656  */
1657 void disk_block_events(struct gendisk *disk)
1658 {
1659         struct disk_events *ev = disk->ev;
1660         unsigned long flags;
1661         bool cancel;
1662 
1663         if (!ev)
1664                 return;
1665 
1666         /*
1667          * Outer mutex ensures that the first blocker completes canceling
1668          * the event work before further blockers are allowed to finish.
1669          */
1670         mutex_lock(&ev->block_mutex);
1671 
1672         spin_lock_irqsave(&ev->lock, flags);
1673         cancel = !ev->block++;
1674         spin_unlock_irqrestore(&ev->lock, flags);
1675 
1676         if (cancel)
1677                 cancel_delayed_work_sync(&disk->ev->dwork);
1678 
1679         mutex_unlock(&ev->block_mutex);
1680 }
1681 
1682 static void __disk_unblock_events(struct gendisk *disk, bool check_now)
1683 {
1684         struct disk_events *ev = disk->ev;
1685         unsigned long intv;
1686         unsigned long flags;
1687 
1688         spin_lock_irqsave(&ev->lock, flags);
1689 
1690         if (WARN_ON_ONCE(ev->block <= 0))
1691                 goto out_unlock;
1692 
1693         if (--ev->block)
1694                 goto out_unlock;
1695 
1696         intv = disk_events_poll_jiffies(disk);
1697         if (check_now)
1698                 queue_delayed_work(system_freezable_power_efficient_wq,
1699                                 &ev->dwork, 0);
1700         else if (intv)
1701                 queue_delayed_work(system_freezable_power_efficient_wq,
1702                                 &ev->dwork, intv);
1703 out_unlock:
1704         spin_unlock_irqrestore(&ev->lock, flags);
1705 }
1706 
1707 /**
1708  * disk_unblock_events - unblock disk event checking
1709  * @disk: disk to unblock events for
1710  *
1711  * Undo disk_block_events().  When the block count reaches zero, it
1712  * starts events polling if configured.
1713  *
1714  * CONTEXT:
1715  * Don't care.  Safe to call from irq context.
1716  */
1717 void disk_unblock_events(struct gendisk *disk)
1718 {
1719         if (disk->ev)
1720                 __disk_unblock_events(disk, false);
1721 }
1722 
1723 /**
1724  * disk_flush_events - schedule immediate event checking and flushing
1725  * @disk: disk to check and flush events for
1726  * @mask: events to flush
1727  *
1728  * Schedule immediate event checking on @disk if not blocked.  Events in
1729  * @mask are scheduled to be cleared from the driver.  Note that this
1730  * doesn't clear the events from @disk->ev.
1731  *
1732  * CONTEXT:
1733  * If @mask is non-zero must be called with bdev->bd_mutex held.
1734  */
1735 void disk_flush_events(struct gendisk *disk, unsigned int mask)
1736 {
1737         struct disk_events *ev = disk->ev;
1738 
1739         if (!ev)
1740                 return;
1741 
1742         spin_lock_irq(&ev->lock);
1743         ev->clearing |= mask;
1744         if (!ev->block)
1745                 mod_delayed_work(system_freezable_power_efficient_wq,
1746                                 &ev->dwork, 0);
1747         spin_unlock_irq(&ev->lock);
1748 }
1749 
1750 /**
1751  * disk_clear_events - synchronously check, clear and return pending events
1752  * @disk: disk to fetch and clear events from
1753  * @mask: mask of events to be fetched and cleared
1754  *
1755  * Disk events are synchronously checked and pending events in @mask
1756  * are cleared and returned.  This ignores the block count.
1757  *
1758  * CONTEXT:
1759  * Might sleep.
1760  */
1761 unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask)
1762 {
1763         const struct block_device_operations *bdops = disk->fops;
1764         struct disk_events *ev = disk->ev;
1765         unsigned int pending;
1766         unsigned int clearing = mask;
1767 
1768         if (!ev) {
1769                 /* for drivers still using the old ->media_changed method */
1770                 if ((mask & DISK_EVENT_MEDIA_CHANGE) &&
1771                     bdops->media_changed && bdops->media_changed(disk))
1772                         return DISK_EVENT_MEDIA_CHANGE;
1773                 return 0;
1774         }
1775 
1776         disk_block_events(disk);
1777 
1778         /*
1779          * store the union of mask and ev->clearing on the stack so that the
1780          * race with disk_flush_events does not cause ambiguity (ev->clearing
1781          * can still be modified even if events are blocked).
1782          */
1783         spin_lock_irq(&ev->lock);
1784         clearing |= ev->clearing;
1785         ev->clearing = 0;
1786         spin_unlock_irq(&ev->lock);
1787 
1788         disk_check_events(ev, &clearing);
1789         /*
1790          * if ev->clearing is not 0, the disk_flush_events got called in the
1791          * middle of this function, so we want to run the workfn without delay.
1792          */
1793         __disk_unblock_events(disk, ev->clearing ? true : false);
1794 
1795         /* then, fetch and clear pending events */
1796         spin_lock_irq(&ev->lock);
1797         pending = ev->pending & mask;
1798         ev->pending &= ~mask;
1799         spin_unlock_irq(&ev->lock);
1800         WARN_ON_ONCE(clearing & mask);
1801 
1802         return pending;
1803 }
1804 
1805 /*
1806  * Separate this part out so that a different pointer for clearing_ptr can be
1807  * passed in for disk_clear_events.
1808  */
1809 static void disk_events_workfn(struct work_struct *work)
1810 {
1811         struct delayed_work *dwork = to_delayed_work(work);
1812         struct disk_events *ev = container_of(dwork, struct disk_events, dwork);
1813 
1814         disk_check_events(ev, &ev->clearing);
1815 }
1816 
1817 static void disk_check_events(struct disk_events *ev,
1818                               unsigned int *clearing_ptr)
1819 {
1820         struct gendisk *disk = ev->disk;
1821         char *envp[ARRAY_SIZE(disk_uevents) + 1] = { };
1822         unsigned int clearing = *clearing_ptr;
1823         unsigned int events;
1824         unsigned long intv;
1825         int nr_events = 0, i;
1826 
1827         /* check events */
1828         events = disk->fops->check_events(disk, clearing);
1829 
1830         /* accumulate pending events and schedule next poll if necessary */
1831         spin_lock_irq(&ev->lock);
1832 
1833         events &= ~ev->pending;
1834         ev->pending |= events;
1835         *clearing_ptr &= ~clearing;
1836 
1837         intv = disk_events_poll_jiffies(disk);
1838         if (!ev->block && intv)
1839                 queue_delayed_work(system_freezable_power_efficient_wq,
1840                                 &ev->dwork, intv);
1841 
1842         spin_unlock_irq(&ev->lock);
1843 
1844         /*
1845          * Tell userland about new events.  Only the events listed in
1846          * @disk->events are reported.  Unlisted events are processed the
1847          * same internally but never get reported to userland.
1848          */
1849         for (i = 0; i < ARRAY_SIZE(disk_uevents); i++)
1850                 if (events & disk->events & (1 << i))
1851                         envp[nr_events++] = disk_uevents[i];
1852 
1853         if (nr_events)
1854                 kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
1855 }
1856 
1857 /*
1858  * A disk events enabled device has the following sysfs nodes under
1859  * its /sys/block/X/ directory.
1860  *
1861  * events               : list of all supported events
1862  * events_async         : list of events which can be detected w/o polling
1863  * events_poll_msecs    : polling interval, 0: disable, -1: system default
1864  */
1865 static ssize_t __disk_events_show(unsigned int events, char *buf)
1866 {
1867         const char *delim = "";
1868         ssize_t pos = 0;
1869         int i;
1870 
1871         for (i = 0; i < ARRAY_SIZE(disk_events_strs); i++)
1872                 if (events & (1 << i)) {
1873                         pos += sprintf(buf + pos, "%s%s",
1874                                        delim, disk_events_strs[i]);
1875                         delim = " ";
1876                 }
1877         if (pos)
1878                 pos += sprintf(buf + pos, "\n");
1879         return pos;
1880 }
1881 
1882 static ssize_t disk_events_show(struct device *dev,
1883                                 struct device_attribute *attr, char *buf)
1884 {
1885         struct gendisk *disk = dev_to_disk(dev);
1886 
1887         return __disk_events_show(disk->events, buf);
1888 }
1889 
1890 static ssize_t disk_events_async_show(struct device *dev,
1891                                       struct device_attribute *attr, char *buf)
1892 {
1893         struct gendisk *disk = dev_to_disk(dev);
1894 
1895         return __disk_events_show(disk->async_events, buf);
1896 }
1897 
1898 static ssize_t disk_events_poll_msecs_show(struct device *dev,
1899                                            struct device_attribute *attr,
1900                                            char *buf)
1901 {
1902         struct gendisk *disk = dev_to_disk(dev);
1903 
1904         return sprintf(buf, "%ld\n", disk->ev->poll_msecs);
1905 }
1906 
1907 static ssize_t disk_events_poll_msecs_store(struct device *dev,
1908                                             struct device_attribute *attr,
1909                                             const char *buf, size_t count)
1910 {
1911         struct gendisk *disk = dev_to_disk(dev);
1912         long intv;
1913 
1914         if (!count || !sscanf(buf, "%ld", &intv))
1915                 return -EINVAL;
1916 
1917         if (intv < 0 && intv != -1)
1918                 return -EINVAL;
1919 
1920         disk_block_events(disk);
1921         disk->ev->poll_msecs = intv;
1922         __disk_unblock_events(disk, true);
1923 
1924         return count;
1925 }
1926 
1927 static const DEVICE_ATTR(events, 0444, disk_events_show, NULL);
1928 static const DEVICE_ATTR(events_async, 0444, disk_events_async_show, NULL);
1929 static const DEVICE_ATTR(events_poll_msecs, 0644,
1930                          disk_events_poll_msecs_show,
1931                          disk_events_poll_msecs_store);
1932 
1933 static const struct attribute *disk_events_attrs[] = {
1934         &dev_attr_events.attr,
1935         &dev_attr_events_async.attr,
1936         &dev_attr_events_poll_msecs.attr,
1937         NULL,
1938 };
1939 
1940 /*
1941  * The default polling interval can be specified by the kernel
1942  * parameter block.events_dfl_poll_msecs which defaults to 0
1943  * (disable).  This can also be modified runtime by writing to
1944  * /sys/module/block/events_dfl_poll_msecs.
1945  */
1946 static int disk_events_set_dfl_poll_msecs(const char *val,
1947                                           const struct kernel_param *kp)
1948 {
1949         struct disk_events *ev;
1950         int ret;
1951 
1952         ret = param_set_ulong(val, kp);
1953         if (ret < 0)
1954                 return ret;
1955 
1956         mutex_lock(&disk_events_mutex);
1957 
1958         list_for_each_entry(ev, &disk_events, node)
1959                 disk_flush_events(ev->disk, 0);
1960 
1961         mutex_unlock(&disk_events_mutex);
1962 
1963         return 0;
1964 }
1965 
1966 static const struct kernel_param_ops disk_events_dfl_poll_msecs_param_ops = {
1967         .set    = disk_events_set_dfl_poll_msecs,
1968         .get    = param_get_ulong,
1969 };
1970 
1971 #undef MODULE_PARAM_PREFIX
1972 #define MODULE_PARAM_PREFIX     "block."
1973 
1974 module_param_cb(events_dfl_poll_msecs, &disk_events_dfl_poll_msecs_param_ops,
1975                 &disk_events_dfl_poll_msecs, 0644);
1976 
1977 /*
1978  * disk_{alloc|add|del|release}_events - initialize and destroy disk_events.
1979  */
1980 static void disk_alloc_events(struct gendisk *disk)
1981 {
1982         struct disk_events *ev;
1983 
1984         if (!disk->fops->check_events)
1985                 return;
1986 
1987         ev = kzalloc(sizeof(*ev), GFP_KERNEL);
1988         if (!ev) {
1989                 pr_warn("%s: failed to initialize events\n", disk->disk_name);
1990                 return;
1991         }
1992 
1993         INIT_LIST_HEAD(&ev->node);
1994         ev->disk = disk;
1995         spin_lock_init(&ev->lock);
1996         mutex_init(&ev->block_mutex);
1997         ev->block = 1;
1998         ev->poll_msecs = -1;
1999         INIT_DELAYED_WORK(&ev->dwork, disk_events_workfn);
2000 
2001         disk->ev = ev;
2002 }
2003 
2004 static void disk_add_events(struct gendisk *disk)
2005 {
2006         if (!disk->ev)
2007                 return;
2008 
2009         /* FIXME: error handling */
2010         if (sysfs_create_files(&disk_to_dev(disk)->kobj, disk_events_attrs) < 0)
2011                 pr_warn("%s: failed to create sysfs files for events\n",
2012                         disk->disk_name);
2013 
2014         mutex_lock(&disk_events_mutex);
2015         list_add_tail(&disk->ev->node, &disk_events);
2016         mutex_unlock(&disk_events_mutex);
2017 
2018         /*
2019          * Block count is initialized to 1 and the following initial
2020          * unblock kicks it into action.
2021          */
2022         __disk_unblock_events(disk, true);
2023 }
2024 
2025 static void disk_del_events(struct gendisk *disk)
2026 {
2027         if (!disk->ev)
2028                 return;
2029 
2030         disk_block_events(disk);
2031 
2032         mutex_lock(&disk_events_mutex);
2033         list_del_init(&disk->ev->node);
2034         mutex_unlock(&disk_events_mutex);
2035 
2036         sysfs_remove_files(&disk_to_dev(disk)->kobj, disk_events_attrs);
2037 }
2038 
2039 static void disk_release_events(struct gendisk *disk)
2040 {
2041         /* the block count should be 1 from disk_del_events() */
2042         WARN_ON_ONCE(disk->ev && disk->ev->block != 1);
2043         kfree(disk->ev);
2044 }
2045 

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