LXR linux/include/linux/genhd.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _LINUX_GENHD_H
   3#define _LINUX_GENHD_H
   4
   5/*
   6 *      genhd.h Copyright (C) 1992 Drew Eckhardt
   7 *      Generic hard disk header file by  
   8 *              Drew Eckhardt
   9 *
  10 *              <drew@colorado.edu>
  11 */
  12
  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>
  21
  22extern const struct device_type disk_type;
  23extern struct device_type part_type;
  24extern struct class block_class;
  25
  26#define DISK_MAX_PARTS                  256
  27#define DISK_NAME_LEN                   32
  28
  29#include <linux/major.h>
  30#include <linux/device.h>
  31#include <linux/smp.h>
  32#include <linux/string.h>
  33#include <linux/fs.h>
  34#include <linux/workqueue.h>
  35
  36#define PARTITION_META_INFO_VOLNAMELTH  64
  37/*
  38 * Enough for the string representation of any kind of UUID plus NULL.
  39 * EFI UUID is 36 characters. MSDOS UUID is 11 characters.
  40 */
  41#define PARTITION_META_INFO_UUIDLTH     (UUID_STRING_LEN + 1)
  42
  43struct partition_meta_info {
  44        char uuid[PARTITION_META_INFO_UUIDLTH];
  45        u8 volname[PARTITION_META_INFO_VOLNAMELTH];
  46};
  47
  48/**
  49 * DOC: genhd capability flags
  50 *
  51 * ``GENHD_FL_REMOVABLE`` (0x0001): indicates that the block device
  52 * gives access to removable media.
  53 * When set, the device remains present even when media is not
  54 * inserted.
  55 * Must not be set for devices which are removed entirely when the
  56 * media is removed.
  57 *
  58 * ``GENHD_FL_CD`` (0x0008): the block device is a CD-ROM-style
  59 * device.
  60 * Affects responses to the ``CDROM_GET_CAPABILITY`` ioctl.
  61 *
  62 * ``GENHD_FL_UP`` (0x0010): indicates that the block device is "up",
  63 * with a similar meaning to network interfaces.
  64 *
  65 * ``GENHD_FL_SUPPRESS_PARTITION_INFO`` (0x0020): don't include
  66 * partition information in ``/proc/partitions`` or in the output of
  67 * printk_all_partitions().
  68 * Used for the null block device and some MMC devices.
  69 *
  70 * ``GENHD_FL_EXT_DEVT`` (0x0040): the driver supports extended
  71 * dynamic ``dev_t``, i.e. it wants extended device numbers
  72 * (``BLOCK_EXT_MAJOR``).
  73 * This affects the maximum number of partitions.
  74 *
  75 * ``GENHD_FL_NATIVE_CAPACITY`` (0x0080): based on information in the
  76 * partition table, the device's capacity has been extended to its
  77 * native capacity; i.e. the device has hidden capacity used by one
  78 * of the partitions (this is a flag used so that native capacity is
  79 * only ever unlocked once).
  80 *
  81 * ``GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE`` (0x0100): event polling is
  82 * blocked whenever a writer holds an exclusive lock.
  83 *
  84 * ``GENHD_FL_NO_PART_SCAN`` (0x0200): partition scanning is disabled.
  85 * Used for loop devices in their default settings and some MMC
  86 * devices.
  87 *
  88 * ``GENHD_FL_HIDDEN`` (0x0400): the block device is hidden; it
  89 * doesn't produce events, doesn't appear in sysfs, and doesn't have
  90 * an associated ``bdev``.
  91 * Implies ``GENHD_FL_SUPPRESS_PARTITION_INFO`` and
  92 * ``GENHD_FL_NO_PART_SCAN``.
  93 * Used for multipath devices.
  94 */
  95#define GENHD_FL_REMOVABLE                      0x0001
  96/* 2 is unused (used to be GENHD_FL_DRIVERFS) */
  97/* 4 is unused (used to be GENHD_FL_MEDIA_CHANGE_NOTIFY) */
  98#define GENHD_FL_CD                             0x0008
  99#define GENHD_FL_UP                             0x0010
 100#define GENHD_FL_SUPPRESS_PARTITION_INFO        0x0020
 101#define GENHD_FL_EXT_DEVT                       0x0040
 102#define GENHD_FL_NATIVE_CAPACITY                0x0080
 103#define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE     0x0100
 104#define GENHD_FL_NO_PART_SCAN                   0x0200
 105#define GENHD_FL_HIDDEN                         0x0400
 106
 107enum {
 108        DISK_EVENT_MEDIA_CHANGE                 = 1 << 0, /* media changed */
 109        DISK_EVENT_EJECT_REQUEST                = 1 << 1, /* eject requested */
 110};
 111
 112enum {
 113        /* Poll even if events_poll_msecs is unset */
 114        DISK_EVENT_FLAG_POLL                    = 1 << 0,
 115        /* Forward events to udev */
 116        DISK_EVENT_FLAG_UEVENT                  = 1 << 1,
 117};
 118
 119struct disk_part_tbl {
 120        struct rcu_head rcu_head;
 121        int len;
 122        struct block_device __rcu *last_lookup;
 123        struct block_device __rcu *part[];
 124};
 125
 126struct disk_events;
 127struct badblocks;
 128
 129struct blk_integrity {
 130        const struct blk_integrity_profile      *profile;
 131        unsigned char                           flags;
 132        unsigned char                           tuple_size;
 133        unsigned char                           interval_exp;
 134        unsigned char                           tag_size;
 135};
 136
 137struct gendisk {
 138        /* major, first_minor and minors are input parameters only,
 139         * don't use directly.  Use disk_devt() and disk_max_parts().
 140         */
 141        int major;                      /* major number of driver */
 142        int first_minor;
 143        int minors;                     /* maximum number of minors, =1 for
 144                                         * disks that can't be partitioned. */
 145
 146        char disk_name[DISK_NAME_LEN];  /* name of major driver */
 147
 148        unsigned short events;          /* supported events */
 149        unsigned short event_flags;     /* flags related to event processing */
 150
 151        /* Array of pointers to partitions indexed by partno.
 152         * Protected with matching bdev lock but stat and other
 153         * non-critical accesses use RCU.  Always access through
 154         * helpers.
 155         */
 156        struct disk_part_tbl __rcu *part_tbl;
 157        struct block_device *part0;
 158
 159        const struct block_device_operations *fops;
 160        struct request_queue *queue;
 161        void *private_data;
 162
 163        int flags;
 164        unsigned long state;
 165#define GD_NEED_PART_SCAN               0
 166        struct kobject *slave_dir;
 167
 168        struct timer_rand_state *random;
 169        atomic_t sync_io;               /* RAID */
 170        struct disk_events *ev;
 171#ifdef  CONFIG_BLK_DEV_INTEGRITY
 172        struct kobject integrity_kobj;
 173#endif  /* CONFIG_BLK_DEV_INTEGRITY */
 174#if IS_ENABLED(CONFIG_CDROM)
 175        struct cdrom_device_info *cdi;
 176#endif
 177        int node_id;
 178        struct badblocks *bb;
 179        struct lockdep_map lockdep_map;
 180};
 181
 182/*
 183 * The gendisk is refcounted by the part0 block_device, and the bd_device
 184 * therein is also used for device model presentation in sysfs.
 185 */
 186#define dev_to_disk(device) \
 187        (dev_to_bdev(device)->bd_disk)
 188#define disk_to_dev(disk) \
 189        (&((disk)->part0->bd_device))
 190
 191#if IS_REACHABLE(CONFIG_CDROM)
 192#define disk_to_cdi(disk)       ((disk)->cdi)
 193#else
 194#define disk_to_cdi(disk)       NULL
 195#endif
 196
 197static inline int disk_max_parts(struct gendisk *disk)
 198{
 199        if (disk->flags & GENHD_FL_EXT_DEVT)
 200                return DISK_MAX_PARTS;
 201        return disk->minors;
 202}
 203
 204static inline bool disk_part_scan_enabled(struct gendisk *disk)
 205{
 206        return disk_max_parts(disk) > 1 &&
 207                !(disk->flags & GENHD_FL_NO_PART_SCAN);
 208}
 209
 210static inline dev_t disk_devt(struct gendisk *disk)
 211{
 212        return MKDEV(disk->major, disk->first_minor);
 213}
 214
 215/*
 216 * Smarter partition iterator without context limits.
 217 */
 218#define DISK_PITER_REVERSE      (1 << 0) /* iterate in the reverse direction */
 219#define DISK_PITER_INCL_EMPTY   (1 << 1) /* include 0-sized parts */
 220#define DISK_PITER_INCL_PART0   (1 << 2) /* include partition 0 */
 221#define DISK_PITER_INCL_EMPTY_PART0 (1 << 3) /* include empty partition 0 */
 222
 223struct disk_part_iter {
 224        struct gendisk          *disk;
 225        struct block_device     *part;
 226        int                     idx;
 227        unsigned int            flags;
 228};
 229
 230extern void disk_part_iter_init(struct disk_part_iter *piter,
 231                                 struct gendisk *disk, unsigned int flags);
 232struct block_device *disk_part_iter_next(struct disk_part_iter *piter);
 233extern void disk_part_iter_exit(struct disk_part_iter *piter);
 234extern bool disk_has_partitions(struct gendisk *disk);
 235
 236/* block/genhd.c */
 237extern void device_add_disk(struct device *parent, struct gendisk *disk,
 238                            const struct attribute_group **groups);
 239static inline void add_disk(struct gendisk *disk)
 240{
 241        device_add_disk(NULL, disk, NULL);
 242}
 243extern void device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk);
 244static inline void add_disk_no_queue_reg(struct gendisk *disk)
 245{
 246        device_add_disk_no_queue_reg(NULL, disk);
 247}
 248
 249extern void del_gendisk(struct gendisk *gp);
 250extern struct block_device *bdget_disk(struct gendisk *disk, int partno);
 251
 252extern void set_disk_ro(struct gendisk *disk, int flag);
 253
 254static inline int get_disk_ro(struct gendisk *disk)
 255{
 256        return disk->part0->bd_read_only;
 257}
 258
 259extern void disk_block_events(struct gendisk *disk);
 260extern void disk_unblock_events(struct gendisk *disk);
 261extern void disk_flush_events(struct gendisk *disk, unsigned int mask);
 262bool set_capacity_and_notify(struct gendisk *disk, sector_t size);
 263
 264/* drivers/char/random.c */
 265extern void add_disk_randomness(struct gendisk *disk) __latent_entropy;
 266extern void rand_initialize_disk(struct gendisk *disk);
 267
 268static inline sector_t get_start_sect(struct block_device *bdev)
 269{
 270        return bdev->bd_start_sect;
 271}
 272
 273static inline sector_t bdev_nr_sectors(struct block_device *bdev)
 274{
 275        return i_size_read(bdev->bd_inode) >> 9;
 276}
 277
 278static inline sector_t get_capacity(struct gendisk *disk)
 279{
 280        return bdev_nr_sectors(disk->part0);
 281}
 282
 283int bdev_disk_changed(struct block_device *bdev, bool invalidate);
 284int blk_add_partitions(struct gendisk *disk, struct block_device *bdev);
 285int blk_drop_partitions(struct block_device *bdev);
 286
 287extern struct gendisk *__alloc_disk_node(int minors, int node_id);
 288extern void put_disk(struct gendisk *disk);
 289
 290#define alloc_disk_node(minors, node_id)                                \
 291({                                                                      \
 292        static struct lock_class_key __key;                             \
 293        const char *__name;                                             \
 294        struct gendisk *__disk;                                         \
 295                                                                        \
 296        __name = "(gendisk_completion)"#minors"("#node_id")";           \
 297                                                                        \
 298        __disk = __alloc_disk_node(minors, node_id);                    \
 299                                                                        \
 300        if (__disk)                                                     \
 301                lockdep_init_map(&__disk->lockdep_map, __name, &__key, 0); \
 302                                                                        \
 303        __disk;                                                         \
 304})
 305
 306#define alloc_disk(minors) alloc_disk_node(minors, NUMA_NO_NODE)
 307
 308int __register_blkdev(unsigned int major, const char *name,
 309                void (*probe)(dev_t devt));
 310#define register_blkdev(major, name) \
 311        __register_blkdev(major, name, NULL)
 312void unregister_blkdev(unsigned int major, const char *name);
 313
 314bool bdev_check_media_change(struct block_device *bdev);
 315int __invalidate_device(struct block_device *bdev, bool kill_dirty);
 316void set_capacity(struct gendisk *disk, sector_t size);
 317
 318/* for drivers/char/raw.c: */
 319int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
 320long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
 321
 322#ifdef CONFIG_SYSFS
 323int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
 324void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk);
 325#else
 326static inline int bd_link_disk_holder(struct block_device *bdev,
 327                                      struct gendisk *disk)
 328{
 329        return 0;
 330}
 331static inline void bd_unlink_disk_holder(struct block_device *bdev,
 332                                         struct gendisk *disk)
 333{
 334}
 335#endif /* CONFIG_SYSFS */
 336
 337extern struct rw_semaphore bdev_lookup_sem;
 338
 339dev_t blk_lookup_devt(const char *name, int partno);
 340void blk_request_module(dev_t devt);
 341#ifdef CONFIG_BLOCK
 342void printk_all_partitions(void);
 343#else /* CONFIG_BLOCK */
 344static inline void printk_all_partitions(void)
 345{
 346}
 347#endif /* CONFIG_BLOCK */
 348
 349#endif /* _LINUX_GENHD_H */
 350