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
  22 #define dev_to_disk(device)     container_of((device), struct gendisk, part0.__dev)
  23 #define dev_to_part(device)     container_of((device), struct hd_struct, __dev)
  24 #define disk_to_dev(disk)       (&(disk)->part0.__dev)
  25 #define part_to_dev(part)       (&((part)->__dev))
  26
  27 extern const struct device_type disk_type;
  28 extern struct device_type part_type;
  29 extern struct class block_class;
  30
  31 #define DISK_MAX_PARTS                  256
  32 #define DISK_NAME_LEN                   32
  33
  34 #include <linux/major.h>
  35 #include <linux/device.h>
  36 #include <linux/smp.h>
  37 #include <linux/string.h>
  38 #include <linux/fs.h>
  39 #include <linux/workqueue.h>
  40
  41 #define PARTITION_META_INFO_VOLNAMELTH  64
  42 /*
  43  * Enough for the string representation of any kind of UUID plus NULL.
  44  * EFI UUID is 36 characters. MSDOS UUID is 11 characters.
  45  */
  46 #define PARTITION_META_INFO_UUIDLTH     (UUID_STRING_LEN + 1)
  47
  48 struct partition_meta_info {
  49         char uuid[PARTITION_META_INFO_UUIDLTH];
  50         u8 volname[PARTITION_META_INFO_VOLNAMELTH];
  51 };
  52
  53 struct hd_struct {
  54         sector_t start_sect;
  55         unsigned long stamp;
  56         struct disk_stats __percpu *dkstats;
  57         struct percpu_ref ref;
  58
  59         struct block_device *bdev;
  60         struct device __dev;
  61         struct kobject *holder_dir;
  62         int policy, partno;
  63         struct partition_meta_info *info;
  64 #ifdef CONFIG_FAIL_MAKE_REQUEST
  65         int make_it_fail;
  66 #endif
  67         struct rcu_work rcu_work;
  68 };
  69
  70 /**
  71  * DOC: genhd capability flags
  72  *
  73  * ``GENHD_FL_REMOVABLE`` (0x0001): indicates that the block device
  74  * gives access to removable media.
  75  * When set, the device remains present even when media is not
  76  * inserted.
  77  * Must not be set for devices which are removed entirely when the
  78  * media is removed.
  79  *
  80  * ``GENHD_FL_CD`` (0x0008): the block device is a CD-ROM-style
  81  * device.
  82  * Affects responses to the ``CDROM_GET_CAPABILITY`` ioctl.
  83  *
  84  * ``GENHD_FL_UP`` (0x0010): indicates that the block device is "up",
  85  * with a similar meaning to network interfaces.
  86  *
  87  * ``GENHD_FL_SUPPRESS_PARTITION_INFO`` (0x0020): don't include
  88  * partition information in ``/proc/partitions`` or in the output of
  89  * printk_all_partitions().
  90  * Used for the null block device and some MMC devices.
  91  *
  92  * ``GENHD_FL_EXT_DEVT`` (0x0040): the driver supports extended
  93  * dynamic ``dev_t``, i.e. it wants extended device numbers
  94  * (``BLOCK_EXT_MAJOR``).
  95  * This affects the maximum number of partitions.
  96  *
  97  * ``GENHD_FL_NATIVE_CAPACITY`` (0x0080): based on information in the
  98  * partition table, the device's capacity has been extended to its
  99  * native capacity; i.e. the device has hidden capacity used by one
 100  * of the partitions (this is a flag used so that native capacity is
 101  * only ever unlocked once).
 102  *
 103  * ``GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE`` (0x0100): event polling is
 104  * blocked whenever a writer holds an exclusive lock.
 105  *
 106  * ``GENHD_FL_NO_PART_SCAN`` (0x0200): partition scanning is disabled.
 107  * Used for loop devices in their default settings and some MMC
 108  * devices.
 109  *
 110  * ``GENHD_FL_HIDDEN`` (0x0400): the block device is hidden; it
 111  * doesn't produce events, doesn't appear in sysfs, and doesn't have
 112  * an associated ``bdev``.
 113  * Implies ``GENHD_FL_SUPPRESS_PARTITION_INFO`` and
 114  * ``GENHD_FL_NO_PART_SCAN``.
 115  * Used for multipath devices.
 116  */
 117 #define GENHD_FL_REMOVABLE                      0x0001
 118 /* 2 is unused (used to be GENHD_FL_DRIVERFS) */
 119 /* 4 is unused (used to be GENHD_FL_MEDIA_CHANGE_NOTIFY) */
 120 #define GENHD_FL_CD                             0x0008
 121 #define GENHD_FL_UP                             0x0010
 122 #define GENHD_FL_SUPPRESS_PARTITION_INFO        0x0020
 123 #define GENHD_FL_EXT_DEVT                       0x0040
 124 #define GENHD_FL_NATIVE_CAPACITY                0x0080
 125 #define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE     0x0100
 126 #define GENHD_FL_NO_PART_SCAN                   0x0200
 127 #define GENHD_FL_HIDDEN                         0x0400
 128
 129 enum {
 130         DISK_EVENT_MEDIA_CHANGE                 = 1 << 0, /* media changed */
 131         DISK_EVENT_EJECT_REQUEST                = 1 << 1, /* eject requested */
 132 };
 133
 134 enum {
 135         /* Poll even if events_poll_msecs is unset */
 136         DISK_EVENT_FLAG_POLL                    = 1 << 0,
 137         /* Forward events to udev */
 138         DISK_EVENT_FLAG_UEVENT                  = 1 << 1,
 139 };
 140
 141 struct disk_part_tbl {
 142         struct rcu_head rcu_head;
 143         int len;
 144         struct hd_struct __rcu *last_lookup;
 145         struct hd_struct __rcu *part[];
 146 };
 147
 148 struct disk_events;
 149 struct badblocks;
 150
 151 struct blk_integrity {
 152         const struct blk_integrity_profile      *profile;
 153         unsigned char                           flags;
 154         unsigned char                           tuple_size;
 155         unsigned char                           interval_exp;
 156         unsigned char                           tag_size;
 157 };
 158
 159 struct gendisk {
 160         /* major, first_minor and minors are input parameters only,
 161          * don't use directly.  Use disk_devt() and disk_max_parts().
 162          */
 163         int major;                      /* major number of driver */
 164         int first_minor;
 165         int minors;                     /* maximum number of minors, =1 for
 166                                          * disks that can't be partitioned. */
 167
 168         char disk_name[DISK_NAME_LEN];  /* name of major driver */
 169
 170         unsigned short events;          /* supported events */
 171         unsigned short event_flags;     /* flags related to event processing */
 172
 173         /* Array of pointers to partitions indexed by partno.
 174          * Protected with matching bdev lock but stat and other
 175          * non-critical accesses use RCU.  Always access through
 176          * helpers.
 177          */
 178         struct disk_part_tbl __rcu *part_tbl;
 179         struct hd_struct part0;
 180
 181         const struct block_device_operations *fops;
 182         struct request_queue *queue;
 183         void *private_data;
 184
 185         int flags;
 186         unsigned long state;
 187 #define GD_NEED_PART_SCAN               0
 188         struct kobject *slave_dir;
 189
 190         struct timer_rand_state *random;
 191         atomic_t sync_io;               /* RAID */
 192         struct disk_events *ev;
 193 #ifdef  CONFIG_BLK_DEV_INTEGRITY
 194         struct kobject integrity_kobj;
 195 #endif  /* CONFIG_BLK_DEV_INTEGRITY */
 196 #if IS_ENABLED(CONFIG_CDROM)
 197         struct cdrom_device_info *cdi;
 198 #endif
 199         int node_id;
 200         struct badblocks *bb;
 201         struct lockdep_map lockdep_map;
 202 };
 203
 204 #if IS_REACHABLE(CONFIG_CDROM)
 205 #define disk_to_cdi(disk)       ((disk)->cdi)
 206 #else
 207 #define disk_to_cdi(disk)       NULL
 208 #endif
 209
 210 static inline struct gendisk *part_to_disk(struct hd_struct *part)
 211 {
 212         if (unlikely(!part))
 213                 return NULL;
 214         return part->bdev->bd_disk;
 215 }
 216
 217 static inline int disk_max_parts(struct gendisk *disk)
 218 {
 219         if (disk->flags & GENHD_FL_EXT_DEVT)
 220                 return DISK_MAX_PARTS;
 221         return disk->minors;
 222 }
 223
 224 static inline bool disk_part_scan_enabled(struct gendisk *disk)
 225 {
 226         return disk_max_parts(disk) > 1 &&
 227                 !(disk->flags & GENHD_FL_NO_PART_SCAN);
 228 }
 229
 230 static inline dev_t disk_devt(struct gendisk *disk)
 231 {
 232         return MKDEV(disk->major, disk->first_minor);
 233 }
 234
 235 static inline dev_t part_devt(struct hd_struct *part)
 236 {
 237         return part_to_dev(part)->devt;
 238 }
 239
 240 extern struct hd_struct *disk_get_part(struct gendisk *disk, int partno);
 241
 242 static inline void disk_put_part(struct hd_struct *part)
 243 {
 244         if (likely(part))
 245                 put_device(part_to_dev(part));
 246 }
 247
 248 /*
 249  * Smarter partition iterator without context limits.
 250  */
 251 #define DISK_PITER_REVERSE      (1 << 0) /* iterate in the reverse direction */
 252 #define DISK_PITER_INCL_EMPTY   (1 << 1) /* include 0-sized parts */
 253 #define DISK_PITER_INCL_PART0   (1 << 2) /* include partition 0 */
 254 #define DISK_PITER_INCL_EMPTY_PART0 (1 << 3) /* include empty partition 0 */
 255
 256 struct disk_part_iter {
 257         struct gendisk          *disk;
 258         struct hd_struct        *part;
 259         int                     idx;
 260         unsigned int            flags;
 261 };
 262
 263 extern void disk_part_iter_init(struct disk_part_iter *piter,
 264                                  struct gendisk *disk, unsigned int flags);
 265 extern struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter);
 266 extern void disk_part_iter_exit(struct disk_part_iter *piter);
 267 extern bool disk_has_partitions(struct gendisk *disk);
 268
 269 /* block/genhd.c */
 270 extern void device_add_disk(struct device *parent, struct gendisk *disk,
 271                             const struct attribute_group **groups);
 272 static inline void add_disk(struct gendisk *disk)
 273 {
 274         device_add_disk(NULL, disk, NULL);
 275 }
 276 extern void device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk);
 277 static inline void add_disk_no_queue_reg(struct gendisk *disk)
 278 {
 279         device_add_disk_no_queue_reg(NULL, disk);
 280 }
 281
 282 extern void del_gendisk(struct gendisk *gp);
 283 extern struct block_device *bdget_disk(struct gendisk *disk, int partno);
 284
 285 extern void set_disk_ro(struct gendisk *disk, int flag);
 286
 287 static inline int get_disk_ro(struct gendisk *disk)
 288 {
 289         return disk->part0.policy;
 290 }
 291
 292 extern void disk_block_events(struct gendisk *disk);
 293 extern void disk_unblock_events(struct gendisk *disk);
 294 extern void disk_flush_events(struct gendisk *disk, unsigned int mask);
 295 bool set_capacity_and_notify(struct gendisk *disk, sector_t size);
 296
 297 /* drivers/char/random.c */
 298 extern void add_disk_randomness(struct gendisk *disk) __latent_entropy;
 299 extern void rand_initialize_disk(struct gendisk *disk);
 300
 301 static inline sector_t get_start_sect(struct block_device *bdev)
 302 {
 303         return bdev->bd_part->start_sect;
 304 }
 305
 306 static inline sector_t bdev_nr_sectors(struct block_device *bdev)
 307 {
 308         return i_size_read(bdev->bd_inode) >> 9;
 309 }
 310
 311 static inline sector_t get_capacity(struct gendisk *disk)
 312 {
 313         return bdev_nr_sectors(disk->part0.bdev);
 314 }
 315
 316 int bdev_disk_changed(struct block_device *bdev, bool invalidate);
 317 int blk_add_partitions(struct gendisk *disk, struct block_device *bdev);
 318 int blk_drop_partitions(struct block_device *bdev);
 319
 320 extern struct gendisk *__alloc_disk_node(int minors, int node_id);
 321 extern void put_disk(struct gendisk *disk);
 322
 323 #define alloc_disk_node(minors, node_id)                                \
 324 ({                                                                      \
 325         static struct lock_class_key __key;                             \
 326         const char *__name;                                             \
 327         struct gendisk *__disk;                                         \
 328                                                                         \
 329         __name = "(gendisk_completion)"#minors"("#node_id")";           \
 330                                                                         \
 331         __disk = __alloc_disk_node(minors, node_id);                    \
 332                                                                         \
 333         if (__disk)                                                     \
 334                 lockdep_init_map(&__disk->lockdep_map, __name, &__key, 0); \
 335                                                                         \
 336         __disk;                                                         \
 337 })
 338
 339 #define alloc_disk(minors) alloc_disk_node(minors, NUMA_NO_NODE)
 340
 341 int __register_blkdev(unsigned int major, const char *name,
 342                 void (*probe)(dev_t devt));
 343 #define register_blkdev(major, name) \
 344         __register_blkdev(major, name, NULL)
 345 void unregister_blkdev(unsigned int major, const char *name);
 346
 347 bool bdev_check_media_change(struct block_device *bdev);
 348 int __invalidate_device(struct block_device *bdev, bool kill_dirty);
 349 void set_capacity(struct gendisk *disk, sector_t size);
 350
 351 /* for drivers/char/raw.c: */
 352 int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
 353 long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
 354
 355 #ifdef CONFIG_SYSFS
 356 int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
 357 void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk);
 358 #else
 359 static inline int bd_link_disk_holder(struct block_device *bdev,
 360                                       struct gendisk *disk)
 361 {
 362         return 0;
 363 }
 364 static inline void bd_unlink_disk_holder(struct block_device *bdev,
 365                                          struct gendisk *disk)
 366 {
 367 }
 368 #endif /* CONFIG_SYSFS */
 369
 370 extern struct rw_semaphore bdev_lookup_sem;
 371
 372 dev_t blk_lookup_devt(const char *name, int partno);
 373 void blk_request_module(dev_t devt);
 374 #ifdef CONFIG_BLOCK
 375 void printk_all_partitions(void);
 376 #else /* CONFIG_BLOCK */
 377 static inline void printk_all_partitions(void)
 378 {
 379 }
 380 #endif /* CONFIG_BLOCK */
 381
 382 #endif /* _LINUX_GENHD_H */