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 extern const struct device_type disk_type;
  23 extern struct device_type part_type;
  24 extern 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 #include <linux/xarray.h>
  36
  37 #define PARTITION_META_INFO_VOLNAMELTH  64
  38 /*
  39  * Enough for the string representation of any kind of UUID plus NULL.
  40  * EFI UUID is 36 characters. MSDOS UUID is 11 characters.
  41  */
  42 #define PARTITION_META_INFO_UUIDLTH     (UUID_STRING_LEN + 1)
  43
  44 struct partition_meta_info {
  45         char uuid[PARTITION_META_INFO_UUIDLTH];
  46         u8 volname[PARTITION_META_INFO_VOLNAMELTH];
  47 };
  48
  49 /**
  50  * DOC: genhd capability flags
  51  *
  52  * ``GENHD_FL_REMOVABLE`` (0x0001): indicates that the block device
  53  * gives access to removable media.
  54  * When set, the device remains present even when media is not
  55  * inserted.
  56  * Must not be set for devices which are removed entirely when the
  57  * media is removed.
  58  *
  59  * ``GENHD_FL_CD`` (0x0008): the block device is a CD-ROM-style
  60  * device.
  61  * Affects responses to the ``CDROM_GET_CAPABILITY`` ioctl.
  62  *
  63  * ``GENHD_FL_SUPPRESS_PARTITION_INFO`` (0x0020): don't include
  64  * partition information in ``/proc/partitions`` or in the output of
  65  * printk_all_partitions().
  66  * Used for the null block device and some MMC devices.
  67  *
  68  * ``GENHD_FL_EXT_DEVT`` (0x0040): the driver supports extended
  69  * dynamic ``dev_t``, i.e. it wants extended device numbers
  70  * (``BLOCK_EXT_MAJOR``).
  71  * This affects the maximum number of partitions.
  72  *
  73  * ``GENHD_FL_NATIVE_CAPACITY`` (0x0080): based on information in the
  74  * partition table, the device's capacity has been extended to its
  75  * native capacity; i.e. the device has hidden capacity used by one
  76  * of the partitions (this is a flag used so that native capacity is
  77  * only ever unlocked once).
  78  *
  79  * ``GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE`` (0x0100): event polling is
  80  * blocked whenever a writer holds an exclusive lock.
  81  *
  82  * ``GENHD_FL_NO_PART_SCAN`` (0x0200): partition scanning is disabled.
  83  * Used for loop devices in their default settings and some MMC
  84  * devices.
  85  *
  86  * ``GENHD_FL_HIDDEN`` (0x0400): the block device is hidden; it
  87  * doesn't produce events, doesn't appear in sysfs, and doesn't have
  88  * an associated ``bdev``.
  89  * Implies ``GENHD_FL_SUPPRESS_PARTITION_INFO`` and
  90  * ``GENHD_FL_NO_PART_SCAN``.
  91  * Used for multipath devices.
  92  */
  93 #define GENHD_FL_REMOVABLE                      0x0001
  94 /* 2 is unused (used to be GENHD_FL_DRIVERFS) */
  95 /* 4 is unused (used to be GENHD_FL_MEDIA_CHANGE_NOTIFY) */
  96 #define GENHD_FL_CD                             0x0008
  97 #define GENHD_FL_SUPPRESS_PARTITION_INFO        0x0020
  98 #define GENHD_FL_EXT_DEVT                       0x0040
  99 #define GENHD_FL_NATIVE_CAPACITY                0x0080
 100 #define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE     0x0100
 101 #define GENHD_FL_NO_PART_SCAN                   0x0200
 102 #define GENHD_FL_HIDDEN                         0x0400
 103
 104 enum {
 105         DISK_EVENT_MEDIA_CHANGE                 = 1 << 0, /* media changed */
 106         DISK_EVENT_EJECT_REQUEST                = 1 << 1, /* eject requested */
 107 };
 108
 109 enum {
 110         /* Poll even if events_poll_msecs is unset */
 111         DISK_EVENT_FLAG_POLL                    = 1 << 0,
 112         /* Forward events to udev */
 113         DISK_EVENT_FLAG_UEVENT                  = 1 << 1,
 114 };
 115
 116 struct disk_events;
 117 struct badblocks;
 118
 119 struct blk_integrity {
 120         const struct blk_integrity_profile      *profile;
 121         unsigned char                           flags;
 122         unsigned char                           tuple_size;
 123         unsigned char                           interval_exp;
 124         unsigned char                           tag_size;
 125 };
 126
 127 struct gendisk {
 128         /* major, first_minor and minors are input parameters only,
 129          * don't use directly.  Use disk_devt() and disk_max_parts().
 130          */
 131         int major;                      /* major number of driver */
 132         int first_minor;
 133         int minors;                     /* maximum number of minors, =1 for
 134                                          * disks that can't be partitioned. */
 135
 136         char disk_name[DISK_NAME_LEN];  /* name of major driver */
 137
 138         unsigned short events;          /* supported events */
 139         unsigned short event_flags;     /* flags related to event processing */
 140
 141         struct xarray part_tbl;
 142         struct block_device *part0;
 143
 144         const struct block_device_operations *fops;
 145         struct request_queue *queue;
 146         void *private_data;
 147
 148         int flags;
 149         unsigned long state;
 150 #define GD_NEED_PART_SCAN               0
 151 #define GD_READ_ONLY                    1
 152
 153         struct mutex open_mutex;        /* open/close mutex */
 154         unsigned open_partitions;       /* number of open partitions */
 155
 156         struct backing_dev_info *bdi;
 157         struct kobject *slave_dir;
 158 #ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
 159         struct list_head slave_bdevs;
 160 #endif
 161         struct timer_rand_state *random;
 162         atomic_t sync_io;               /* RAID */
 163         struct disk_events *ev;
 164 #ifdef  CONFIG_BLK_DEV_INTEGRITY
 165         struct kobject integrity_kobj;
 166 #endif  /* CONFIG_BLK_DEV_INTEGRITY */
 167 #if IS_ENABLED(CONFIG_CDROM)
 168         struct cdrom_device_info *cdi;
 169 #endif
 170         int node_id;
 171         struct badblocks *bb;
 172         struct lockdep_map lockdep_map;
 173         u64 diskseq;
 174 };
 175
 176 static inline bool disk_live(struct gendisk *disk)
 177 {
 178         return !inode_unhashed(disk->part0->bd_inode);
 179 }
 180
 181 /*
 182  * The gendisk is refcounted by the part0 block_device, and the bd_device
 183  * therein is also used for device model presentation in sysfs.
 184  */
 185 #define dev_to_disk(device) \
 186         (dev_to_bdev(device)->bd_disk)
 187 #define disk_to_dev(disk) \
 188         (&((disk)->part0->bd_device))
 189
 190 #if IS_REACHABLE(CONFIG_CDROM)
 191 #define disk_to_cdi(disk)       ((disk)->cdi)
 192 #else
 193 #define disk_to_cdi(disk)       NULL
 194 #endif
 195
 196 static inline int disk_max_parts(struct gendisk *disk)
 197 {
 198         if (disk->flags & GENHD_FL_EXT_DEVT)
 199                 return DISK_MAX_PARTS;
 200         return disk->minors;
 201 }
 202
 203 static inline bool disk_part_scan_enabled(struct gendisk *disk)
 204 {
 205         return disk_max_parts(disk) > 1 &&
 206                 !(disk->flags & GENHD_FL_NO_PART_SCAN);
 207 }
 208
 209 static inline dev_t disk_devt(struct gendisk *disk)
 210 {
 211         return MKDEV(disk->major, disk->first_minor);
 212 }
 213
 214 void disk_uevent(struct gendisk *disk, enum kobject_action action);
 215
 216 /* block/genhd.c */
 217 int device_add_disk(struct device *parent, struct gendisk *disk,
 218                 const struct attribute_group **groups);
 219 static inline int add_disk(struct gendisk *disk)
 220 {
 221         return device_add_disk(NULL, disk, NULL);
 222 }
 223 extern void del_gendisk(struct gendisk *gp);
 224
 225 void set_disk_ro(struct gendisk *disk, bool read_only);
 226
 227 static inline int get_disk_ro(struct gendisk *disk)
 228 {
 229         return disk->part0->bd_read_only ||
 230                 test_bit(GD_READ_ONLY, &disk->state);
 231 }
 232
 233 extern void disk_block_events(struct gendisk *disk);
 234 extern void disk_unblock_events(struct gendisk *disk);
 235 extern void disk_flush_events(struct gendisk *disk, unsigned int mask);
 236 bool set_capacity_and_notify(struct gendisk *disk, sector_t size);
 237 bool disk_force_media_change(struct gendisk *disk, unsigned int events);
 238
 239 /* drivers/char/random.c */
 240 extern void add_disk_randomness(struct gendisk *disk) __latent_entropy;
 241 extern void rand_initialize_disk(struct gendisk *disk);
 242
 243 static inline sector_t get_start_sect(struct block_device *bdev)
 244 {
 245         return bdev->bd_start_sect;
 246 }
 247
 248 static inline sector_t bdev_nr_sectors(struct block_device *bdev)
 249 {
 250         return i_size_read(bdev->bd_inode) >> 9;
 251 }
 252
 253 static inline sector_t get_capacity(struct gendisk *disk)
 254 {
 255         return bdev_nr_sectors(disk->part0);
 256 }
 257
 258 int bdev_disk_changed(struct gendisk *disk, bool invalidate);
 259 void blk_drop_partitions(struct gendisk *disk);
 260
 261 struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
 262                 struct lock_class_key *lkclass);
 263 extern void put_disk(struct gendisk *disk);
 264 struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass);
 265
 266 /**
 267  * blk_alloc_disk - allocate a gendisk structure
 268  * @node_id: numa node to allocate on
 269  *
 270  * Allocate and pre-initialize a gendisk structure for use with BIO based
 271  * drivers.
 272  *
 273  * Context: can sleep
 274  */
 275 #define blk_alloc_disk(node_id)                                         \
 276 ({                                                                      \
 277         static struct lock_class_key __key;                             \
 278                                                                         \
 279         __blk_alloc_disk(node_id, &__key);                              \
 280 })
 281 void blk_cleanup_disk(struct gendisk *disk);
 282
 283 int __register_blkdev(unsigned int major, const char *name,
 284                 void (*probe)(dev_t devt));
 285 #define register_blkdev(major, name) \
 286         __register_blkdev(major, name, NULL)
 287 void unregister_blkdev(unsigned int major, const char *name);
 288
 289 bool bdev_check_media_change(struct block_device *bdev);
 290 int __invalidate_device(struct block_device *bdev, bool kill_dirty);
 291 void set_capacity(struct gendisk *disk, sector_t size);
 292
 293 /* for drivers/char/raw.c: */
 294 int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
 295 long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
 296
 297 #ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
 298 int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
 299 void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk);
 300 int bd_register_pending_holders(struct gendisk *disk);
 301 #else
 302 static inline int bd_link_disk_holder(struct block_device *bdev,
 303                                       struct gendisk *disk)
 304 {
 305         return 0;
 306 }
 307 static inline void bd_unlink_disk_holder(struct block_device *bdev,
 308                                          struct gendisk *disk)
 309 {
 310 }
 311 static inline int bd_register_pending_holders(struct gendisk *disk)
 312 {
 313         return 0;
 314 }
 315 #endif /* CONFIG_BLOCK_HOLDER_DEPRECATED */
 316
 317 dev_t part_devt(struct gendisk *disk, u8 partno);
 318 void inc_diskseq(struct gendisk *disk);
 319 dev_t blk_lookup_devt(const char *name, int partno);
 320 void blk_request_module(dev_t devt);
 321 #ifdef CONFIG_BLOCK
 322 void printk_all_partitions(void);
 323 #else /* CONFIG_BLOCK */
 324 static inline void printk_all_partitions(void)
 325 {
 326 }
 327 #endif /* CONFIG_BLOCK */
 328
 329 #endif /* _LINUX_GENHD_H */