drivers/mtd/ubi/ubi.h

   1 /*
   2  * Copyright (c) International Business Machines Corp., 2006
   3  * Copyright (c) Nokia Corporation, 2006, 2007
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  *
   7  * Author: Artem Bityutskiy (Битюцкий Артём)
   8  */
   9
  10 #ifndef __UBI_UBI_H__
  11 #define __UBI_UBI_H__
  12
  13 #ifdef UBI_LINUX
  14 #include <linux/init.h>
  15 #include <linux/types.h>
  16 #include <linux/list.h>
  17 #include <linux/rbtree.h>
  18 #include <linux/sched.h>
  19 #include <linux/wait.h>
  20 #include <linux/mutex.h>
  21 #include <linux/rwsem.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/fs.h>
  24 #include <linux/cdev.h>
  25 #include <linux/device.h>
  26 #include <linux/string.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/mtd/mtd.h>
  29 #include <linux/mtd/ubi.h>
  30 #endif
  31
  32 #include <linux/types.h>
  33 #include <linux/list.h>
  34 #include <linux/rbtree.h>
  35 #include <linux/string.h>
  36 #include <linux/mtd/mtd.h>
  37 #include <linux/mtd/ubi.h>
  38
  39 #include "ubi-media.h"
  40 #include "scan.h"
  41 #include "debug.h"
  42
  43 /* Maximum number of supported UBI devices */
  44 #define UBI_MAX_DEVICES 32
  45
  46 /* UBI name used for character devices, sysfs, etc */
  47 #define UBI_NAME_STR "ubi"
  48
  49 /* Normal UBI messages */
  50 #ifdef CONFIG_UBI_SILENCE_MSG
  51 #define ubi_msg(fmt, ...)
  52 #else
  53 #define ubi_msg(fmt, ...) printk(KERN_NOTICE "UBI: " fmt "\n", ##__VA_ARGS__)
  54 #endif
  55 /* UBI warning messages */
  56 #define ubi_warn(fmt, ...) printk(KERN_WARNING "UBI warning: %s: " fmt "\n", \
  57                                   __func__, ##__VA_ARGS__)
  58 /* UBI error messages */
  59 #define ubi_err(fmt, ...) printk(KERN_ERR "UBI error: %s: " fmt "\n", \
  60                                  __func__, ##__VA_ARGS__)
  61
  62 /* Lowest number PEBs reserved for bad PEB handling */
  63 #define MIN_RESEVED_PEBS 2
  64
  65 /* Background thread name pattern */
  66 #define UBI_BGT_NAME_PATTERN "ubi_bgt%dd"
  67
  68 /* This marker in the EBA table means that the LEB is um-mapped */
  69 #define UBI_LEB_UNMAPPED -1
  70
  71 /*
  72  * In case of errors, UBI tries to repeat the operation several times before
  73  * returning error. The below constant defines how many times UBI re-tries.
  74  */
  75 #define UBI_IO_RETRIES 3
  76
  77 /*
  78  * Error codes returned by the I/O unit.
  79  *
  80  * UBI_IO_PEB_EMPTY: the physical eraseblock is empty, i.e. it contains only
  81  * 0xFF bytes
  82  * UBI_IO_PEB_FREE: the physical eraseblock is free, i.e. it contains only a
  83  * valid erase counter header, and the rest are %0xFF bytes
  84  * UBI_IO_BAD_EC_HDR: the erase counter header is corrupted (bad magic or CRC)
  85  * UBI_IO_BAD_VID_HDR: the volume identifier header is corrupted (bad magic or
  86  * CRC)
  87  * UBI_IO_BITFLIPS: bit-flips were detected and corrected
  88  */
  89 enum {
  90         UBI_IO_PEB_EMPTY = 1,
  91         UBI_IO_PEB_FREE,
  92         UBI_IO_BAD_EC_HDR,
  93         UBI_IO_BAD_VID_HDR,
  94         UBI_IO_BITFLIPS
  95 };
  96
  97 /**
  98  * struct ubi_wl_entry - wear-leveling entry.
  99  * @rb: link in the corresponding RB-tree
 100  * @ec: erase counter
 101  * @pnum: physical eraseblock number
 102  *
 103  * This data structure is used in the WL unit. Each physical eraseblock has a
 104  * corresponding &struct wl_entry object which may be kept in different
 105  * RB-trees. See WL unit for details.
 106  */
 107 struct ubi_wl_entry {
 108         struct rb_node rb;
 109         int ec;
 110         int pnum;
 111 };
 112
 113 /**
 114  * struct ubi_ltree_entry - an entry in the lock tree.
 115  * @rb: links RB-tree nodes
 116  * @vol_id: volume ID of the locked logical eraseblock
 117  * @lnum: locked logical eraseblock number
 118  * @users: how many tasks are using this logical eraseblock or wait for it
 119  * @mutex: read/write mutex to implement read/write access serialization to
 120  *         the (@vol_id, @lnum) logical eraseblock
 121  *
 122  * This data structure is used in the EBA unit to implement per-LEB locking.
 123  * When a logical eraseblock is being locked - corresponding
 124  * &struct ubi_ltree_entry object is inserted to the lock tree (@ubi->ltree).
 125  * See EBA unit for details.
 126  */
 127 struct ubi_ltree_entry {
 128         struct rb_node rb;
 129         int vol_id;
 130         int lnum;
 131         int users;
 132         struct rw_semaphore mutex;
 133 };
 134
 135 struct ubi_volume_desc;
 136
 137 /**
 138  * struct ubi_volume - UBI volume description data structure.
 139  * @dev: device object to make use of the the Linux device model
 140  * @cdev: character device object to create character device
 141  * @ubi: reference to the UBI device description object
 142  * @vol_id: volume ID
 143  * @ref_count: volume reference count
 144  * @readers: number of users holding this volume in read-only mode
 145  * @writers: number of users holding this volume in read-write mode
 146  * @exclusive: whether somebody holds this volume in exclusive mode
 147  *
 148  * @reserved_pebs: how many physical eraseblocks are reserved for this volume
 149  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
 150  * @usable_leb_size: logical eraseblock size without padding
 151  * @used_ebs: how many logical eraseblocks in this volume contain data
 152  * @last_eb_bytes: how many bytes are stored in the last logical eraseblock
 153  * @used_bytes: how many bytes of data this volume contains
 154  * @alignment: volume alignment
 155  * @data_pad: how many bytes are not used at the end of physical eraseblocks to
 156  *            satisfy the requested alignment
 157  * @name_len: volume name length
 158  * @name: volume name
 159  *
 160  * @upd_ebs: how many eraseblocks are expected to be updated
 161  * @ch_lnum: LEB number which is being changing by the atomic LEB change
 162  *           operation
 163  * @ch_dtype: data persistency type which is being changing by the atomic LEB
 164  *            change operation
 165  * @upd_bytes: how many bytes are expected to be received for volume update or
 166  *             atomic LEB change
 167  * @upd_received: how many bytes were already received for volume update or
 168  *                atomic LEB change
 169  * @upd_buf: update buffer which is used to collect update data or data for
 170  *           atomic LEB change
 171  *
 172  * @eba_tbl: EBA table of this volume (LEB->PEB mapping)
 173  * @checked: %1 if this static volume was checked
 174  * @corrupted: %1 if the volume is corrupted (static volumes only)
 175  * @upd_marker: %1 if the update marker is set for this volume
 176  * @updating: %1 if the volume is being updated
 177  * @changing_leb: %1 if the atomic LEB change ioctl command is in progress
 178  *
 179  * @gluebi_desc: gluebi UBI volume descriptor
 180  * @gluebi_refcount: reference count of the gluebi MTD device
 181  * @gluebi_mtd: MTD device description object of the gluebi MTD device
 182  *
 183  * The @corrupted field indicates that the volume's contents is corrupted.
 184  * Since UBI protects only static volumes, this field is not relevant to
 185  * dynamic volumes - it is user's responsibility to assure their data
 186  * integrity.
 187  *
 188  * The @upd_marker flag indicates that this volume is either being updated at
 189  * the moment or is damaged because of an unclean reboot.
 190  */
 191 struct ubi_volume {
 192         struct device dev;
 193         struct cdev cdev;
 194         struct ubi_device *ubi;
 195         int vol_id;
 196         int ref_count;
 197         int readers;
 198         int writers;
 199         int exclusive;
 200
 201         int reserved_pebs;
 202         int vol_type;
 203         int usable_leb_size;
 204         int used_ebs;
 205         int last_eb_bytes;
 206         long long used_bytes;
 207         int alignment;
 208         int data_pad;
 209         int name_len;
 210         char name[UBI_VOL_NAME_MAX+1];
 211
 212         int upd_ebs;
 213         int ch_lnum;
 214         int ch_dtype;
 215         long long upd_bytes;
 216         long long upd_received;
 217         void *upd_buf;
 218
 219         int *eba_tbl;
 220         unsigned int checked:1;
 221         unsigned int corrupted:1;
 222         unsigned int upd_marker:1;
 223         unsigned int updating:1;
 224         unsigned int changing_leb:1;
 225
 226 #ifdef CONFIG_MTD_UBI_GLUEBI
 227         /*
 228          * Gluebi-related stuff may be compiled out.
 229          * TODO: this should not be built into UBI but should be a separate
 230          * ubimtd driver which works on top of UBI and emulates MTD devices.
 231          */
 232         struct ubi_volume_desc *gluebi_desc;
 233         int gluebi_refcount;
 234         struct mtd_info gluebi_mtd;
 235 #endif
 236 };
 237
 238 /**
 239  * struct ubi_volume_desc - descriptor of the UBI volume returned when it is
 240  * opened.
 241  * @vol: reference to the corresponding volume description object
 242  * @mode: open mode (%UBI_READONLY, %UBI_READWRITE, or %UBI_EXCLUSIVE)
 243  */
 244 struct ubi_volume_desc {
 245         struct ubi_volume *vol;
 246         int mode;
 247 };
 248
 249 struct ubi_wl_entry;
 250
 251 /**
 252  * struct ubi_device - UBI device description structure
 253  * @dev: UBI device object to use the the Linux device model
 254  * @cdev: character device object to create character device
 255  * @ubi_num: UBI device number
 256  * @ubi_name: UBI device name
 257  * @vol_count: number of volumes in this UBI device
 258  * @volumes: volumes of this UBI device
 259  * @volumes_lock: protects @volumes, @rsvd_pebs, @avail_pebs, beb_rsvd_pebs,
 260  *                @beb_rsvd_level, @bad_peb_count, @good_peb_count, @vol_count,
 261  *                @vol->readers, @vol->writers, @vol->exclusive,
 262  *                @vol->ref_count, @vol->mapping and @vol->eba_tbl.
 263  * @ref_count: count of references on the UBI device
 264  *
 265  * @rsvd_pebs: count of reserved physical eraseblocks
 266  * @avail_pebs: count of available physical eraseblocks
 267  * @beb_rsvd_pebs: how many physical eraseblocks are reserved for bad PEB
 268  *                 handling
 269  * @beb_rsvd_level: normal level of PEBs reserved for bad PEB handling
 270  *
 271  * @autoresize_vol_id: ID of the volume which has to be auto-resized at the end
 272  *                     of UBI ititializetion
 273  * @vtbl_slots: how many slots are available in the volume table
 274  * @vtbl_size: size of the volume table in bytes
 275  * @vtbl: in-RAM volume table copy
 276  * @volumes_mutex: protects on-flash volume table and serializes volume
 277  *                 changes, like creation, deletion, update, resize
 278  *
 279  * @max_ec: current highest erase counter value
 280  * @mean_ec: current mean erase counter value
 281  *
 282  * @global_sqnum: global sequence number
 283  * @ltree_lock: protects the lock tree and @global_sqnum
 284  * @ltree: the lock tree
 285  * @alc_mutex: serializes "atomic LEB change" operations
 286  *
 287  * @used: RB-tree of used physical eraseblocks
 288  * @free: RB-tree of free physical eraseblocks
 289  * @scrub: RB-tree of physical eraseblocks which need scrubbing
 290  * @prot: protection trees
 291  * @prot.pnum: protection tree indexed by physical eraseblock numbers
 292  * @prot.aec: protection tree indexed by absolute erase counter value
 293  * @wl_lock: protects the @used, @free, @prot, @lookuptbl, @abs_ec, @move_from,
 294  *           @move_to, @move_to_put @erase_pending, @wl_scheduled, and @works
 295  *           fields
 296  * @move_mutex: serializes eraseblock moves
 297  * @wl_scheduled: non-zero if the wear-leveling was scheduled
 298  * @lookuptbl: a table to quickly find a &struct ubi_wl_entry object for any
 299  *             physical eraseblock
 300  * @abs_ec: absolute erase counter
 301  * @move_from: physical eraseblock from where the data is being moved
 302  * @move_to: physical eraseblock where the data is being moved to
 303  * @move_to_put: if the "to" PEB was put
 304  * @works: list of pending works
 305  * @works_count: count of pending works
 306  * @bgt_thread: background thread description object
 307  * @thread_enabled: if the background thread is enabled
 308  * @bgt_name: background thread name
 309  *
 310  * @flash_size: underlying MTD device size (in bytes)
 311  * @peb_count: count of physical eraseblocks on the MTD device
 312  * @peb_size: physical eraseblock size
 313  * @bad_peb_count: count of bad physical eraseblocks
 314  * @good_peb_count: count of good physical eraseblocks
 315  * @min_io_size: minimal input/output unit size of the underlying MTD device
 316  * @hdrs_min_io_size: minimal I/O unit size used for VID and EC headers
 317  * @ro_mode: if the UBI device is in read-only mode
 318  * @leb_size: logical eraseblock size
 319  * @leb_start: starting offset of logical eraseblocks within physical
 320  * eraseblocks
 321  * @ec_hdr_alsize: size of the EC header aligned to @hdrs_min_io_size
 322  * @vid_hdr_alsize: size of the VID header aligned to @hdrs_min_io_size
 323  * @vid_hdr_offset: starting offset of the volume identifier header (might be
 324  * unaligned)
 325  * @vid_hdr_aloffset: starting offset of the VID header aligned to
 326  * @hdrs_min_io_size
 327  * @vid_hdr_shift: contains @vid_hdr_offset - @vid_hdr_aloffset
 328  * @bad_allowed: whether the MTD device admits of bad physical eraseblocks or
 329  *               not
 330  * @mtd: MTD device descriptor
 331  *
 332  * @peb_buf1: a buffer of PEB size used for different purposes
 333  * @peb_buf2: another buffer of PEB size used for different purposes
 334  * @buf_mutex: proptects @peb_buf1 and @peb_buf2
 335  * @dbg_peb_buf: buffer of PEB size used for debugging
 336  * @dbg_buf_mutex: proptects @dbg_peb_buf
 337  */
 338 struct ubi_device {
 339         struct cdev cdev;
 340         struct device dev;
 341         int ubi_num;
 342         char ubi_name[sizeof(UBI_NAME_STR)+5];
 343         int vol_count;
 344         struct ubi_volume *volumes[UBI_MAX_VOLUMES+UBI_INT_VOL_COUNT];
 345         spinlock_t volumes_lock;
 346         int ref_count;
 347
 348         int rsvd_pebs;
 349         int avail_pebs;
 350         int beb_rsvd_pebs;
 351         int beb_rsvd_level;
 352
 353         int autoresize_vol_id;
 354         int vtbl_slots;
 355         int vtbl_size;
 356         struct ubi_vtbl_record *vtbl;
 357         struct mutex volumes_mutex;
 358
 359         int max_ec;
 360         /* TODO: mean_ec is not updated run-time, fix */
 361         int mean_ec;
 362
 363         /* EBA unit's stuff */
 364         unsigned long long global_sqnum;
 365         spinlock_t ltree_lock;
 366         struct rb_root ltree;
 367         struct mutex alc_mutex;
 368
 369         /* Wear-leveling unit's stuff */
 370         struct rb_root used;
 371         struct rb_root free;
 372         struct rb_root scrub;
 373         struct {
 374                 struct rb_root pnum;
 375                 struct rb_root aec;
 376         } prot;
 377         spinlock_t wl_lock;
 378         struct mutex move_mutex;
 379         struct rw_semaphore work_sem;
 380         int wl_scheduled;
 381         struct ubi_wl_entry **lookuptbl;
 382         unsigned long long abs_ec;
 383         struct ubi_wl_entry *move_from;
 384         struct ubi_wl_entry *move_to;
 385         int move_to_put;
 386         struct list_head works;
 387         int works_count;
 388         struct task_struct *bgt_thread;
 389         int thread_enabled;
 390         char bgt_name[sizeof(UBI_BGT_NAME_PATTERN)+2];
 391
 392         /* I/O unit's stuff */
 393         long long flash_size;
 394         int peb_count;
 395         int peb_size;
 396         int bad_peb_count;
 397         int good_peb_count;
 398         int min_io_size;
 399         int hdrs_min_io_size;
 400         int ro_mode;
 401         int leb_size;
 402         int leb_start;
 403         int ec_hdr_alsize;
 404         int vid_hdr_alsize;
 405         int vid_hdr_offset;
 406         int vid_hdr_aloffset;
 407         int vid_hdr_shift;
 408         int bad_allowed;
 409         struct mtd_info *mtd;
 410
 411         void *peb_buf1;
 412         void *peb_buf2;
 413         struct mutex buf_mutex;
 414         struct mutex ckvol_mutex;
 415 #ifdef CONFIG_MTD_UBI_DEBUG
 416         void *dbg_peb_buf;
 417         struct mutex dbg_buf_mutex;
 418 #endif
 419 };
 420
 421 extern struct kmem_cache *ubi_wl_entry_slab;
 422 extern struct file_operations ubi_ctrl_cdev_operations;
 423 extern struct file_operations ubi_cdev_operations;
 424 extern struct file_operations ubi_vol_cdev_operations;
 425 extern struct class *ubi_class;
 426 extern struct mutex ubi_devices_mutex;
 427
 428 /* vtbl.c */
 429 int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
 430                            struct ubi_vtbl_record *vtbl_rec);
 431 int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_scan_info *si);
 432
 433 /* vmt.c */
 434 int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req);
 435 int ubi_remove_volume(struct ubi_volume_desc *desc);
 436 int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs);
 437 int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol);
 438 void ubi_free_volume(struct ubi_device *ubi, struct ubi_volume *vol);
 439
 440 /* upd.c */
 441 int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
 442                      long long bytes);
 443 int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
 444                          const void __user *buf, int count);
 445 int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
 446                          const struct ubi_leb_change_req *req);
 447 int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol,
 448                              const void __user *buf, int count);
 449
 450 /* misc.c */
 451 int ubi_calc_data_len(const struct ubi_device *ubi, const void *buf, int length);
 452 int ubi_check_volume(struct ubi_device *ubi, int vol_id);
 453 void ubi_calculate_reserved(struct ubi_device *ubi);
 454
 455 /* gluebi.c */
 456 #ifdef CONFIG_MTD_UBI_GLUEBI
 457 int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol);
 458 int ubi_destroy_gluebi(struct ubi_volume *vol);
 459 void ubi_gluebi_updated(struct ubi_volume *vol);
 460 #else
 461 #define ubi_create_gluebi(ubi, vol) 0
 462
 463 static inline int ubi_destroy_gluebi(struct ubi_volume *vol)
 464 {
 465         return 0;
 466 }
 467
 468 #define ubi_gluebi_updated(vol)
 469 #endif
 470
 471 /* eba.c */
 472 int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
 473                       int lnum);
 474 int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
 475                      void *buf, int offset, int len, int check);
 476 int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
 477                       const void *buf, int offset, int len, int dtype);
 478 int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
 479                          int lnum, const void *buf, int len, int dtype,
 480                          int used_ebs);
 481 int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
 482                               int lnum, const void *buf, int len, int dtype);
 483 int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 484                      struct ubi_vid_hdr *vid_hdr);
 485 int ubi_eba_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
 486 void ubi_eba_close(const struct ubi_device *ubi);
 487
 488 /* wl.c */
 489 int ubi_wl_get_peb(struct ubi_device *ubi, int dtype);
 490 int ubi_wl_put_peb(struct ubi_device *ubi, int pnum, int torture);
 491 int ubi_wl_flush(struct ubi_device *ubi);
 492 int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum);
 493 int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
 494 void ubi_wl_close(struct ubi_device *ubi);
 495 int ubi_thread(void *u);
 496
 497 /* io.c */
 498 int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
 499                 int len);
 500 int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
 501                  int len);
 502 int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture);
 503 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum);
 504 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum);
 505 int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 506                        struct ubi_ec_hdr *ec_hdr, int verbose);
 507 int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
 508                         struct ubi_ec_hdr *ec_hdr);
 509 int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 510                         struct ubi_vid_hdr *vid_hdr, int verbose);
 511 int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
 512                          struct ubi_vid_hdr *vid_hdr);
 513
 514 /* build.c */
 515 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset);
 516 int ubi_detach_mtd_dev(int ubi_num, int anyway);
 517 struct ubi_device *ubi_get_device(int ubi_num);
 518 void ubi_put_device(struct ubi_device *ubi);
 519 struct ubi_device *ubi_get_by_major(int major);
 520 int ubi_major2num(int major);
 521
 522 /*
 523  * ubi_rb_for_each_entry - walk an RB-tree.
 524  * @rb: a pointer to type 'struct rb_node' to to use as a loop counter
 525  * @pos: a pointer to RB-tree entry type to use as a loop counter
 526  * @root: RB-tree's root
 527  * @member: the name of the 'struct rb_node' within the RB-tree entry
 528  */
 529 #define ubi_rb_for_each_entry(rb, pos, root, member)                         \
 530         for (rb = rb_first(root),                                            \
 531              pos = (rb ? container_of(rb, typeof(*pos), member) : NULL);     \
 532              rb;                                                             \
 533              rb = rb_next(rb), pos = container_of(rb, typeof(*pos), member))
 534
 535 /**
 536  * ubi_zalloc_vid_hdr - allocate a volume identifier header object.
 537  * @ubi: UBI device description object
 538  * @gfp_flags: GFP flags to allocate with
 539  *
 540  * This function returns a pointer to the newly allocated and zero-filled
 541  * volume identifier header object in case of success and %NULL in case of
 542  * failure.
 543  */
 544 static inline struct ubi_vid_hdr *
 545 ubi_zalloc_vid_hdr(const struct ubi_device *ubi, gfp_t gfp_flags)
 546 {
 547         void *vid_hdr;
 548
 549         vid_hdr = kzalloc(ubi->vid_hdr_alsize, gfp_flags);
 550         if (!vid_hdr)
 551                 return NULL;
 552
 553         /*
 554          * VID headers may be stored at un-aligned flash offsets, so we shift
 555          * the pointer.
 556          */
 557         return vid_hdr + ubi->vid_hdr_shift;
 558 }
 559
 560 /**
 561  * ubi_free_vid_hdr - free a volume identifier header object.
 562  * @ubi: UBI device description object
 563  * @vid_hdr: the object to free
 564  */
 565 static inline void ubi_free_vid_hdr(const struct ubi_device *ubi,
 566                                     struct ubi_vid_hdr *vid_hdr)
 567 {
 568         void *p = vid_hdr;
 569
 570         if (!p)
 571                 return;
 572
 573         kfree(p - ubi->vid_hdr_shift);
 574 }
 575
 576 /*
 577  * This function is equivalent to 'ubi_io_read()', but @offset is relative to
 578  * the beginning of the logical eraseblock, not to the beginning of the
 579  * physical eraseblock.
 580  */
 581 static inline int ubi_io_read_data(const struct ubi_device *ubi, void *buf,
 582                                    int pnum, int offset, int len)
 583 {
 584         ubi_assert(offset >= 0);
 585         return ubi_io_read(ubi, buf, pnum, offset + ubi->leb_start, len);
 586 }
 587
 588 /*
 589  * This function is equivalent to 'ubi_io_write()', but @offset is relative to
 590  * the beginning of the logical eraseblock, not to the beginning of the
 591  * physical eraseblock.
 592  */
 593 static inline int ubi_io_write_data(struct ubi_device *ubi, const void *buf,
 594                                     int pnum, int offset, int len)
 595 {
 596         ubi_assert(offset >= 0);
 597         return ubi_io_write(ubi, buf, pnum, offset + ubi->leb_start, len);
 598 }
 599
 600 /**
 601  * ubi_ro_mode - switch to read-only mode.
 602  * @ubi: UBI device description object
 603  */
 604 static inline void ubi_ro_mode(struct ubi_device *ubi)
 605 {
 606         if (!ubi->ro_mode) {
 607                 ubi->ro_mode = 1;
 608                 ubi_warn("switch to read-only mode");
 609         }
 610 }
 611
 612 /**
 613  * vol_id2idx - get table index by volume ID.
 614  * @ubi: UBI device description object
 615  * @vol_id: volume ID
 616  */
 617 static inline int vol_id2idx(const struct ubi_device *ubi, int vol_id)
 618 {
 619         if (vol_id >= UBI_INTERNAL_VOL_START)
 620                 return vol_id - UBI_INTERNAL_VOL_START + ubi->vtbl_slots;
 621         else
 622                 return vol_id;
 623 }
 624
 625 /**
 626  * idx2vol_id - get volume ID by table index.
 627  * @ubi: UBI device description object
 628  * @idx: table index
 629  */
 630 static inline int idx2vol_id(const struct ubi_device *ubi, int idx)
 631 {
 632         if (idx >= ubi->vtbl_slots)
 633                 return idx - ubi->vtbl_slots + UBI_INTERNAL_VOL_START;
 634         else
 635                 return idx;
 636 }
 637
 638 #endif /* !__UBI_UBI_H__ */