1 /* SPDX-License-Identifier: GPL-2.0 */
6 * genhd.h Copyright (C) 1992 Drew Eckhardt
7 * Generic hard disk header file by
13 #include <linux/types.h>
14 #include <linux/kdev_t.h>
15 #include <linux/rcupdate.h>
16 #include <linux/slab.h>
17 #include <linux/percpu-refcount.h>
18 #include <linux/uuid.h>
19 #include <linux/blk_types.h>
20 #include <asm/local.h>
24 #define dev_to_disk(device) container_of((device), struct gendisk, part0.__dev)
25 #define dev_to_part(device) container_of((device), struct hd_struct, __dev)
26 #define disk_to_dev(disk) (&(disk)->part0.__dev)
27 #define part_to_dev(part) (&((part)->__dev))
29 extern struct device_type part_type;
30 extern struct kobject *block_depr;
31 extern struct class block_class;
33 #define DISK_MAX_PARTS 256
34 #define DISK_NAME_LEN 32
36 #include <linux/major.h>
37 #include <linux/device.h>
38 #include <linux/smp.h>
39 #include <linux/string.h>
41 #include <linux/workqueue.h>
44 u64 nsecs[NR_STAT_GROUPS];
45 unsigned long sectors[NR_STAT_GROUPS];
46 unsigned long ios[NR_STAT_GROUPS];
47 unsigned long merges[NR_STAT_GROUPS];
48 unsigned long io_ticks;
49 unsigned long time_in_queue;
53 #define PARTITION_META_INFO_VOLNAMELTH 64
55 * Enough for the string representation of any kind of UUID plus NULL.
56 * EFI UUID is 36 characters. MSDOS UUID is 11 characters.
58 #define PARTITION_META_INFO_UUIDLTH (UUID_STRING_LEN + 1)
60 struct partition_meta_info {
61 char uuid[PARTITION_META_INFO_UUIDLTH];
62 u8 volname[PARTITION_META_INFO_VOLNAMELTH];
68 * nr_sects is protected by sequence counter. One might extend a
69 * partition while IO is happening to it and update of nr_sects
70 * can be non-atomic on 32bit machines with 64bit sector_t.
73 seqcount_t nr_sects_seq;
74 sector_t alignment_offset;
75 unsigned int discard_alignment;
77 struct kobject *holder_dir;
79 struct partition_meta_info *info;
80 #ifdef CONFIG_FAIL_MAKE_REQUEST
85 struct disk_stats __percpu *dkstats;
87 struct disk_stats dkstats;
89 struct percpu_ref ref;
90 struct rcu_work rcu_work;
94 * DOC: genhd capability flags
96 * ``GENHD_FL_REMOVABLE`` (0x0001): indicates that the block device
97 * gives access to removable media.
98 * When set, the device remains present even when media is not
100 * Must not be set for devices which are removed entirely when the
103 * ``GENHD_FL_CD`` (0x0008): the block device is a CD-ROM-style
105 * Affects responses to the ``CDROM_GET_CAPABILITY`` ioctl.
107 * ``GENHD_FL_UP`` (0x0010): indicates that the block device is "up",
108 * with a similar meaning to network interfaces.
110 * ``GENHD_FL_SUPPRESS_PARTITION_INFO`` (0x0020): don't include
111 * partition information in ``/proc/partitions`` or in the output of
112 * printk_all_partitions().
113 * Used for the null block device and some MMC devices.
115 * ``GENHD_FL_EXT_DEVT`` (0x0040): the driver supports extended
116 * dynamic ``dev_t``, i.e. it wants extended device numbers
117 * (``BLOCK_EXT_MAJOR``).
118 * This affects the maximum number of partitions.
120 * ``GENHD_FL_NATIVE_CAPACITY`` (0x0080): based on information in the
121 * partition table, the device's capacity has been extended to its
122 * native capacity; i.e. the device has hidden capacity used by one
123 * of the partitions (this is a flag used so that native capacity is
124 * only ever unlocked once).
126 * ``GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE`` (0x0100): event polling is
127 * blocked whenever a writer holds an exclusive lock.
129 * ``GENHD_FL_NO_PART_SCAN`` (0x0200): partition scanning is disabled.
130 * Used for loop devices in their default settings and some MMC
133 * ``GENHD_FL_HIDDEN`` (0x0400): the block device is hidden; it
134 * doesn't produce events, doesn't appear in sysfs, and doesn't have
135 * an associated ``bdev``.
136 * Implies ``GENHD_FL_SUPPRESS_PARTITION_INFO`` and
137 * ``GENHD_FL_NO_PART_SCAN``.
138 * Used for multipath devices.
140 #define GENHD_FL_REMOVABLE 0x0001
141 /* 2 is unused (used to be GENHD_FL_DRIVERFS) */
142 /* 4 is unused (used to be GENHD_FL_MEDIA_CHANGE_NOTIFY) */
143 #define GENHD_FL_CD 0x0008
144 #define GENHD_FL_UP 0x0010
145 #define GENHD_FL_SUPPRESS_PARTITION_INFO 0x0020
146 #define GENHD_FL_EXT_DEVT 0x0040
147 #define GENHD_FL_NATIVE_CAPACITY 0x0080
148 #define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE 0x0100
149 #define GENHD_FL_NO_PART_SCAN 0x0200
150 #define GENHD_FL_HIDDEN 0x0400
153 DISK_EVENT_MEDIA_CHANGE = 1 << 0, /* media changed */
154 DISK_EVENT_EJECT_REQUEST = 1 << 1, /* eject requested */
158 /* Poll even if events_poll_msecs is unset */
159 DISK_EVENT_FLAG_POLL = 1 << 0,
160 /* Forward events to udev */
161 DISK_EVENT_FLAG_UEVENT = 1 << 1,
164 struct disk_part_tbl {
165 struct rcu_head rcu_head;
167 struct hd_struct __rcu *last_lookup;
168 struct hd_struct __rcu *part[];
174 #if defined(CONFIG_BLK_DEV_INTEGRITY)
176 struct blk_integrity {
177 const struct blk_integrity_profile *profile;
179 unsigned char tuple_size;
180 unsigned char interval_exp;
181 unsigned char tag_size;
184 #endif /* CONFIG_BLK_DEV_INTEGRITY */
187 /* major, first_minor and minors are input parameters only,
188 * don't use directly. Use disk_devt() and disk_max_parts().
190 int major; /* major number of driver */
192 int minors; /* maximum number of minors, =1 for
193 * disks that can't be partitioned. */
195 char disk_name[DISK_NAME_LEN]; /* name of major driver */
196 char *(*devnode)(struct gendisk *gd, umode_t *mode);
198 unsigned short events; /* supported events */
199 unsigned short event_flags; /* flags related to event processing */
201 /* Array of pointers to partitions indexed by partno.
202 * Protected with matching bdev lock but stat and other
203 * non-critical accesses use RCU. Always access through
206 struct disk_part_tbl __rcu *part_tbl;
207 struct hd_struct part0;
209 const struct block_device_operations *fops;
210 struct request_queue *queue;
214 struct rw_semaphore lookup_sem;
215 struct kobject *slave_dir;
217 struct timer_rand_state *random;
218 atomic_t sync_io; /* RAID */
219 struct disk_events *ev;
220 #ifdef CONFIG_BLK_DEV_INTEGRITY
221 struct kobject integrity_kobj;
222 #endif /* CONFIG_BLK_DEV_INTEGRITY */
224 struct badblocks *bb;
225 struct lockdep_map lockdep_map;
228 static inline struct gendisk *part_to_disk(struct hd_struct *part)
232 return dev_to_disk(part_to_dev(part)->parent);
234 return dev_to_disk(part_to_dev(part));
239 static inline int disk_max_parts(struct gendisk *disk)
241 if (disk->flags & GENHD_FL_EXT_DEVT)
242 return DISK_MAX_PARTS;
246 static inline bool disk_part_scan_enabled(struct gendisk *disk)
248 return disk_max_parts(disk) > 1 &&
249 !(disk->flags & GENHD_FL_NO_PART_SCAN);
252 static inline bool disk_has_partitions(struct gendisk *disk)
257 if (rcu_dereference(disk->part_tbl)->len > 1)
264 static inline dev_t disk_devt(struct gendisk *disk)
266 return MKDEV(disk->major, disk->first_minor);
269 static inline dev_t part_devt(struct hd_struct *part)
271 return part_to_dev(part)->devt;
274 extern struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);
275 extern struct hd_struct *disk_get_part(struct gendisk *disk, int partno);
277 static inline void disk_put_part(struct hd_struct *part)
280 put_device(part_to_dev(part));
284 * Smarter partition iterator without context limits.
286 #define DISK_PITER_REVERSE (1 << 0) /* iterate in the reverse direction */
287 #define DISK_PITER_INCL_EMPTY (1 << 1) /* include 0-sized parts */
288 #define DISK_PITER_INCL_PART0 (1 << 2) /* include partition 0 */
289 #define DISK_PITER_INCL_EMPTY_PART0 (1 << 3) /* include empty partition 0 */
291 struct disk_part_iter {
292 struct gendisk *disk;
293 struct hd_struct *part;
298 extern void disk_part_iter_init(struct disk_part_iter *piter,
299 struct gendisk *disk, unsigned int flags);
300 extern struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter);
301 extern void disk_part_iter_exit(struct disk_part_iter *piter);
303 extern struct hd_struct *disk_map_sector_rcu(struct gendisk *disk,
307 * Macros to operate on percpu disk statistics:
309 * {disk|part|all}_stat_{add|sub|inc|dec}() modify the stat counters
310 * and should be called between disk_stat_lock() and
311 * disk_stat_unlock().
313 * part_stat_read() can be called at any time.
315 * part_stat_{add|set_all}() and {init|free}_part_stats are for
319 #define part_stat_lock() ({ rcu_read_lock(); get_cpu(); })
320 #define part_stat_unlock() do { put_cpu(); rcu_read_unlock(); } while (0)
322 #define part_stat_get_cpu(part, field, cpu) \
323 (per_cpu_ptr((part)->dkstats, (cpu))->field)
325 #define part_stat_get(part, field) \
326 part_stat_get_cpu(part, field, smp_processor_id())
328 #define part_stat_read(part, field) \
330 typeof((part)->dkstats->field) res = 0; \
332 for_each_possible_cpu(_cpu) \
333 res += per_cpu_ptr((part)->dkstats, _cpu)->field; \
337 static inline void part_stat_set_all(struct hd_struct *part, int value)
341 for_each_possible_cpu(i)
342 memset(per_cpu_ptr(part->dkstats, i), value,
343 sizeof(struct disk_stats));
346 static inline int init_part_stats(struct hd_struct *part)
348 part->dkstats = alloc_percpu(struct disk_stats);
354 static inline void free_part_stats(struct hd_struct *part)
356 free_percpu(part->dkstats);
359 #else /* !CONFIG_SMP */
360 #define part_stat_lock() ({ rcu_read_lock(); 0; })
361 #define part_stat_unlock() rcu_read_unlock()
363 #define part_stat_get(part, field) ((part)->dkstats.field)
364 #define part_stat_get_cpu(part, field, cpu) part_stat_get(part, field)
365 #define part_stat_read(part, field) part_stat_get(part, field)
367 static inline void part_stat_set_all(struct hd_struct *part, int value)
369 memset(&part->dkstats, value, sizeof(struct disk_stats));
372 static inline int init_part_stats(struct hd_struct *part)
377 static inline void free_part_stats(struct hd_struct *part)
381 #endif /* CONFIG_SMP */
383 #define part_stat_read_accum(part, field) \
384 (part_stat_read(part, field[STAT_READ]) + \
385 part_stat_read(part, field[STAT_WRITE]) + \
386 part_stat_read(part, field[STAT_DISCARD]))
388 #define __part_stat_add(part, field, addnd) \
389 (part_stat_get(part, field) += (addnd))
391 #define part_stat_add(part, field, addnd) do { \
392 __part_stat_add((part), field, addnd); \
393 if ((part)->partno) \
394 __part_stat_add(&part_to_disk((part))->part0, \
398 #define part_stat_dec(gendiskp, field) \
399 part_stat_add(gendiskp, field, -1)
400 #define part_stat_inc(gendiskp, field) \
401 part_stat_add(gendiskp, field, 1)
402 #define part_stat_sub(gendiskp, field, subnd) \
403 part_stat_add(gendiskp, field, -subnd)
405 #define part_stat_local_dec(gendiskp, field) \
406 local_dec(&(part_stat_get(gendiskp, field)))
407 #define part_stat_local_inc(gendiskp, field) \
408 local_inc(&(part_stat_get(gendiskp, field)))
409 #define part_stat_local_read(gendiskp, field) \
410 local_read(&(part_stat_get(gendiskp, field)))
411 #define part_stat_local_read_cpu(gendiskp, field, cpu) \
412 local_read(&(part_stat_get_cpu(gendiskp, field, cpu)))
414 unsigned int part_in_flight(struct request_queue *q, struct hd_struct *part);
415 void part_in_flight_rw(struct request_queue *q, struct hd_struct *part,
416 unsigned int inflight[2]);
417 void part_dec_in_flight(struct request_queue *q, struct hd_struct *part,
419 void part_inc_in_flight(struct request_queue *q, struct hd_struct *part,
422 void update_io_ticks(struct hd_struct *part, unsigned long now, bool end);
425 extern void device_add_disk(struct device *parent, struct gendisk *disk,
426 const struct attribute_group **groups);
427 static inline void add_disk(struct gendisk *disk)
429 device_add_disk(NULL, disk, NULL);
431 extern void device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk);
432 static inline void add_disk_no_queue_reg(struct gendisk *disk)
434 device_add_disk_no_queue_reg(NULL, disk);
437 extern void del_gendisk(struct gendisk *gp);
438 extern struct gendisk *get_gendisk(dev_t dev, int *partno);
439 extern struct block_device *bdget_disk(struct gendisk *disk, int partno);
441 extern void set_device_ro(struct block_device *bdev, int flag);
442 extern void set_disk_ro(struct gendisk *disk, int flag);
444 static inline int get_disk_ro(struct gendisk *disk)
446 return disk->part0.policy;
449 extern void disk_block_events(struct gendisk *disk);
450 extern void disk_unblock_events(struct gendisk *disk);
451 extern void disk_flush_events(struct gendisk *disk, unsigned int mask);
452 extern void set_capacity_revalidate_and_notify(struct gendisk *disk,
453 sector_t size, bool revalidate);
454 extern unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask);
456 /* drivers/char/random.c */
457 extern void add_disk_randomness(struct gendisk *disk) __latent_entropy;
458 extern void rand_initialize_disk(struct gendisk *disk);
460 static inline sector_t get_start_sect(struct block_device *bdev)
462 return bdev->bd_part->start_sect;
464 static inline sector_t get_capacity(struct gendisk *disk)
466 return disk->part0.nr_sects;
468 static inline void set_capacity(struct gendisk *disk, sector_t size)
470 disk->part0.nr_sects = size;
473 #define ADDPART_FLAG_NONE 0
474 #define ADDPART_FLAG_RAID 1
475 #define ADDPART_FLAG_WHOLEDISK 2
477 extern int blk_alloc_devt(struct hd_struct *part, dev_t *devt);
478 extern void blk_free_devt(dev_t devt);
479 extern void blk_invalidate_devt(dev_t devt);
480 extern dev_t blk_lookup_devt(const char *name, int partno);
481 extern char *disk_name (struct gendisk *hd, int partno, char *buf);
483 int bdev_disk_changed(struct block_device *bdev, bool invalidate);
484 int blk_add_partitions(struct gendisk *disk, struct block_device *bdev);
485 int blk_drop_partitions(struct gendisk *disk, struct block_device *bdev);
486 extern int disk_expand_part_tbl(struct gendisk *disk, int target);
487 extern struct hd_struct * __must_check add_partition(struct gendisk *disk,
488 int partno, sector_t start,
489 sector_t len, int flags,
490 struct partition_meta_info
492 extern void __delete_partition(struct percpu_ref *);
493 extern void delete_partition(struct gendisk *, int);
494 extern void printk_all_partitions(void);
496 extern struct gendisk *__alloc_disk_node(int minors, int node_id);
497 extern struct kobject *get_disk_and_module(struct gendisk *disk);
498 extern void put_disk(struct gendisk *disk);
499 extern void put_disk_and_module(struct gendisk *disk);
500 extern void blk_register_region(dev_t devt, unsigned long range,
501 struct module *module,
502 struct kobject *(*probe)(dev_t, int *, void *),
503 int (*lock)(dev_t, void *),
505 extern void blk_unregister_region(dev_t devt, unsigned long range);
507 #define alloc_disk_node(minors, node_id) \
509 static struct lock_class_key __key; \
510 const char *__name; \
511 struct gendisk *__disk; \
513 __name = "(gendisk_completion)"#minors"("#node_id")"; \
515 __disk = __alloc_disk_node(minors, node_id); \
518 lockdep_init_map(&__disk->lockdep_map, __name, &__key, 0); \
523 #define alloc_disk(minors) alloc_disk_node(minors, NUMA_NO_NODE)
525 static inline int hd_ref_init(struct hd_struct *part)
527 if (percpu_ref_init(&part->ref, __delete_partition, 0,
533 static inline void hd_struct_get(struct hd_struct *part)
535 percpu_ref_get(&part->ref);
538 static inline int hd_struct_try_get(struct hd_struct *part)
540 return percpu_ref_tryget_live(&part->ref);
543 static inline void hd_struct_put(struct hd_struct *part)
545 percpu_ref_put(&part->ref);
548 static inline void hd_struct_kill(struct hd_struct *part)
550 percpu_ref_kill(&part->ref);
553 static inline void hd_free_part(struct hd_struct *part)
555 free_part_stats(part);
557 percpu_ref_exit(&part->ref);
561 * Any access of part->nr_sects which is not protected by partition
562 * bd_mutex or gendisk bdev bd_mutex, should be done using this
565 * Code written along the lines of i_size_read() and i_size_write().
566 * CONFIG_PREEMPTION case optimizes the case of UP kernel with preemption
569 static inline sector_t part_nr_sects_read(struct hd_struct *part)
571 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
575 seq = read_seqcount_begin(&part->nr_sects_seq);
576 nr_sects = part->nr_sects;
577 } while (read_seqcount_retry(&part->nr_sects_seq, seq));
579 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
583 nr_sects = part->nr_sects;
587 return part->nr_sects;
592 * Should be called with mutex lock held (typically bd_mutex) of partition
593 * to provide mutual exlusion among writers otherwise seqcount might be
594 * left in wrong state leaving the readers spinning infinitely.
596 static inline void part_nr_sects_write(struct hd_struct *part, sector_t size)
598 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
599 write_seqcount_begin(&part->nr_sects_seq);
600 part->nr_sects = size;
601 write_seqcount_end(&part->nr_sects_seq);
602 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
604 part->nr_sects = size;
607 part->nr_sects = size;
611 #if defined(CONFIG_BLK_DEV_INTEGRITY)
612 extern void blk_integrity_add(struct gendisk *);
613 extern void blk_integrity_del(struct gendisk *);
614 #else /* CONFIG_BLK_DEV_INTEGRITY */
615 static inline void blk_integrity_add(struct gendisk *disk) { }
616 static inline void blk_integrity_del(struct gendisk *disk) { }
617 #endif /* CONFIG_BLK_DEV_INTEGRITY */
619 #else /* CONFIG_BLOCK */
621 static inline void printk_all_partitions(void) { }
623 static inline dev_t blk_lookup_devt(const char *name, int partno)
625 dev_t devt = MKDEV(0, 0);
628 #endif /* CONFIG_BLOCK */
630 #endif /* _LINUX_GENHD_H */