xref: /openbmc/linux/drivers/mtd/ubi/ubi.h (revision 82ced6fd)
1 /*
2  * Copyright (c) International Business Machines Corp., 2006
3  * Copyright (c) Nokia Corporation, 2006, 2007
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13  * the GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18  *
19  * Author: Artem Bityutskiy (Битюцкий Артём)
20  */
21 
22 #ifndef __UBI_UBI_H__
23 #define __UBI_UBI_H__
24 
25 #include <linux/init.h>
26 #include <linux/types.h>
27 #include <linux/list.h>
28 #include <linux/rbtree.h>
29 #include <linux/sched.h>
30 #include <linux/wait.h>
31 #include <linux/mutex.h>
32 #include <linux/rwsem.h>
33 #include <linux/spinlock.h>
34 #include <linux/fs.h>
35 #include <linux/cdev.h>
36 #include <linux/device.h>
37 #include <linux/string.h>
38 #include <linux/vmalloc.h>
39 #include <linux/mtd/mtd.h>
40 #include <linux/mtd/ubi.h>
41 
42 #include "ubi-media.h"
43 #include "scan.h"
44 #include "debug.h"
45 
46 /* Maximum number of supported UBI devices */
47 #define UBI_MAX_DEVICES 32
48 
49 /* UBI name used for character devices, sysfs, etc */
50 #define UBI_NAME_STR "ubi"
51 
52 /* Normal UBI messages */
53 #define ubi_msg(fmt, ...) printk(KERN_NOTICE "UBI: " fmt "\n", ##__VA_ARGS__)
54 /* UBI warning messages */
55 #define ubi_warn(fmt, ...) printk(KERN_WARNING "UBI warning: %s: " fmt "\n", \
56 				  __func__, ##__VA_ARGS__)
57 /* UBI error messages */
58 #define ubi_err(fmt, ...) printk(KERN_ERR "UBI error: %s: " fmt "\n", \
59 				 __func__, ##__VA_ARGS__)
60 
61 /* Lowest number PEBs reserved for bad PEB handling */
62 #define MIN_RESEVED_PEBS 2
63 
64 /* Background thread name pattern */
65 #define UBI_BGT_NAME_PATTERN "ubi_bgt%dd"
66 
67 /* This marker in the EBA table means that the LEB is um-mapped */
68 #define UBI_LEB_UNMAPPED -1
69 
70 /*
71  * In case of errors, UBI tries to repeat the operation several times before
72  * returning error. The below constant defines how many times UBI re-tries.
73  */
74 #define UBI_IO_RETRIES 3
75 
76 /*
77  * Length of the protection queue. The length is effectively equivalent to the
78  * number of (global) erase cycles PEBs are protected from the wear-leveling
79  * worker.
80  */
81 #define UBI_PROT_QUEUE_LEN 10
82 
83 /*
84  * Error codes returned by the I/O sub-system.
85  *
86  * UBI_IO_PEB_EMPTY: the physical eraseblock is empty, i.e. it contains only
87  *                   %0xFF bytes
88  * UBI_IO_PEB_FREE: the physical eraseblock is free, i.e. it contains only a
89  *                  valid erase counter header, and the rest are %0xFF bytes
90  * UBI_IO_BAD_EC_HDR: the erase counter header is corrupted (bad magic or CRC)
91  * UBI_IO_BAD_VID_HDR: the volume identifier header is corrupted (bad magic or
92  *                     CRC)
93  * UBI_IO_BITFLIPS: bit-flips were detected and corrected
94  */
95 enum {
96 	UBI_IO_PEB_EMPTY = 1,
97 	UBI_IO_PEB_FREE,
98 	UBI_IO_BAD_EC_HDR,
99 	UBI_IO_BAD_VID_HDR,
100 	UBI_IO_BITFLIPS
101 };
102 
103 /**
104  * struct ubi_wl_entry - wear-leveling entry.
105  * @u.rb: link in the corresponding (free/used) RB-tree
106  * @u.list: link in the protection queue
107  * @ec: erase counter
108  * @pnum: physical eraseblock number
109  *
110  * This data structure is used in the WL sub-system. Each physical eraseblock
111  * has a corresponding &struct wl_entry object which may be kept in different
112  * RB-trees. See WL sub-system for details.
113  */
114 struct ubi_wl_entry {
115 	union {
116 		struct rb_node rb;
117 		struct list_head list;
118 	} u;
119 	int ec;
120 	int pnum;
121 };
122 
123 /**
124  * struct ubi_ltree_entry - an entry in the lock tree.
125  * @rb: links RB-tree nodes
126  * @vol_id: volume ID of the locked logical eraseblock
127  * @lnum: locked logical eraseblock number
128  * @users: how many tasks are using this logical eraseblock or wait for it
129  * @mutex: read/write mutex to implement read/write access serialization to
130  *         the (@vol_id, @lnum) logical eraseblock
131  *
132  * This data structure is used in the EBA sub-system to implement per-LEB
133  * locking. When a logical eraseblock is being locked - corresponding
134  * &struct ubi_ltree_entry object is inserted to the lock tree (@ubi->ltree).
135  * See EBA sub-system for details.
136  */
137 struct ubi_ltree_entry {
138 	struct rb_node rb;
139 	int vol_id;
140 	int lnum;
141 	int users;
142 	struct rw_semaphore mutex;
143 };
144 
145 /**
146  * struct ubi_rename_entry - volume re-name description data structure.
147  * @new_name_len: new volume name length
148  * @new_name: new volume name
149  * @remove: if not zero, this volume should be removed, not re-named
150  * @desc: descriptor of the volume
151  * @list: links re-name entries into a list
152  *
153  * This data structure is utilized in the multiple volume re-name code. Namely,
154  * UBI first creates a list of &struct ubi_rename_entry objects from the
155  * &struct ubi_rnvol_req request object, and then utilizes this list to do all
156  * the job.
157  */
158 struct ubi_rename_entry {
159 	int new_name_len;
160 	char new_name[UBI_VOL_NAME_MAX + 1];
161 	int remove;
162 	struct ubi_volume_desc *desc;
163 	struct list_head list;
164 };
165 
166 struct ubi_volume_desc;
167 
168 /**
169  * struct ubi_volume - UBI volume description data structure.
170  * @dev: device object to make use of the the Linux device model
171  * @cdev: character device object to create character device
172  * @ubi: reference to the UBI device description object
173  * @vol_id: volume ID
174  * @ref_count: volume reference count
175  * @readers: number of users holding this volume in read-only mode
176  * @writers: number of users holding this volume in read-write mode
177  * @exclusive: whether somebody holds this volume in exclusive mode
178  *
179  * @reserved_pebs: how many physical eraseblocks are reserved for this volume
180  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
181  * @usable_leb_size: logical eraseblock size without padding
182  * @used_ebs: how many logical eraseblocks in this volume contain data
183  * @last_eb_bytes: how many bytes are stored in the last logical eraseblock
184  * @used_bytes: how many bytes of data this volume contains
185  * @alignment: volume alignment
186  * @data_pad: how many bytes are not used at the end of physical eraseblocks to
187  *            satisfy the requested alignment
188  * @name_len: volume name length
189  * @name: volume name
190  *
191  * @upd_ebs: how many eraseblocks are expected to be updated
192  * @ch_lnum: LEB number which is being changing by the atomic LEB change
193  *           operation
194  * @ch_dtype: data persistency type which is being changing by the atomic LEB
195  *            change operation
196  * @upd_bytes: how many bytes are expected to be received for volume update or
197  *             atomic LEB change
198  * @upd_received: how many bytes were already received for volume update or
199  *                atomic LEB change
200  * @upd_buf: update buffer which is used to collect update data or data for
201  *           atomic LEB change
202  *
203  * @eba_tbl: EBA table of this volume (LEB->PEB mapping)
204  * @checked: %1 if this static volume was checked
205  * @corrupted: %1 if the volume is corrupted (static volumes only)
206  * @upd_marker: %1 if the update marker is set for this volume
207  * @updating: %1 if the volume is being updated
208  * @changing_leb: %1 if the atomic LEB change ioctl command is in progress
209  * @direct_writes: %1 if direct writes are enabled for this volume
210  *
211  * @gluebi_desc: gluebi UBI volume descriptor
212  * @gluebi_refcount: reference count of the gluebi MTD device
213  * @gluebi_mtd: MTD device description object of the gluebi MTD device
214  *
215  * The @corrupted field indicates that the volume's contents is corrupted.
216  * Since UBI protects only static volumes, this field is not relevant to
217  * dynamic volumes - it is user's responsibility to assure their data
218  * integrity.
219  *
220  * The @upd_marker flag indicates that this volume is either being updated at
221  * the moment or is damaged because of an unclean reboot.
222  */
223 struct ubi_volume {
224 	struct device dev;
225 	struct cdev cdev;
226 	struct ubi_device *ubi;
227 	int vol_id;
228 	int ref_count;
229 	int readers;
230 	int writers;
231 	int exclusive;
232 
233 	int reserved_pebs;
234 	int vol_type;
235 	int usable_leb_size;
236 	int used_ebs;
237 	int last_eb_bytes;
238 	long long used_bytes;
239 	int alignment;
240 	int data_pad;
241 	int name_len;
242 	char name[UBI_VOL_NAME_MAX + 1];
243 
244 	int upd_ebs;
245 	int ch_lnum;
246 	int ch_dtype;
247 	long long upd_bytes;
248 	long long upd_received;
249 	void *upd_buf;
250 
251 	int *eba_tbl;
252 	unsigned int checked:1;
253 	unsigned int corrupted:1;
254 	unsigned int upd_marker:1;
255 	unsigned int updating:1;
256 	unsigned int changing_leb:1;
257 	unsigned int direct_writes:1;
258 
259 #ifdef CONFIG_MTD_UBI_GLUEBI
260 	/*
261 	 * Gluebi-related stuff may be compiled out.
262 	 * Note: this should not be built into UBI but should be a separate
263 	 * ubimtd driver which works on top of UBI and emulates MTD devices.
264 	 */
265 	struct ubi_volume_desc *gluebi_desc;
266 	int gluebi_refcount;
267 	struct mtd_info gluebi_mtd;
268 #endif
269 };
270 
271 /**
272  * struct ubi_volume_desc - UBI volume descriptor returned when it is opened.
273  * @vol: reference to the corresponding volume description object
274  * @mode: open mode (%UBI_READONLY, %UBI_READWRITE, or %UBI_EXCLUSIVE)
275  */
276 struct ubi_volume_desc {
277 	struct ubi_volume *vol;
278 	int mode;
279 };
280 
281 struct ubi_wl_entry;
282 
283 /**
284  * struct ubi_device - UBI device description structure
285  * @dev: UBI device object to use the the Linux device model
286  * @cdev: character device object to create character device
287  * @ubi_num: UBI device number
288  * @ubi_name: UBI device name
289  * @vol_count: number of volumes in this UBI device
290  * @volumes: volumes of this UBI device
291  * @volumes_lock: protects @volumes, @rsvd_pebs, @avail_pebs, beb_rsvd_pebs,
292  *                @beb_rsvd_level, @bad_peb_count, @good_peb_count, @vol_count,
293  *                @vol->readers, @vol->writers, @vol->exclusive,
294  *                @vol->ref_count, @vol->mapping and @vol->eba_tbl.
295  * @ref_count: count of references on the UBI device
296  *
297  * @rsvd_pebs: count of reserved physical eraseblocks
298  * @avail_pebs: count of available physical eraseblocks
299  * @beb_rsvd_pebs: how many physical eraseblocks are reserved for bad PEB
300  *                 handling
301  * @beb_rsvd_level: normal level of PEBs reserved for bad PEB handling
302  *
303  * @autoresize_vol_id: ID of the volume which has to be auto-resized at the end
304  *                     of UBI initialization
305  * @vtbl_slots: how many slots are available in the volume table
306  * @vtbl_size: size of the volume table in bytes
307  * @vtbl: in-RAM volume table copy
308  * @volumes_mutex: protects on-flash volume table and serializes volume
309  *                 changes, like creation, deletion, update, re-size,
310  *                 re-name and set property
311  *
312  * @max_ec: current highest erase counter value
313  * @mean_ec: current mean erase counter value
314  *
315  * @global_sqnum: global sequence number
316  * @ltree_lock: protects the lock tree and @global_sqnum
317  * @ltree: the lock tree
318  * @alc_mutex: serializes "atomic LEB change" operations
319  *
320  * @used: RB-tree of used physical eraseblocks
321  * @free: RB-tree of free physical eraseblocks
322  * @scrub: RB-tree of physical eraseblocks which need scrubbing
323  * @pq: protection queue (contain physical eraseblocks which are temporarily
324  *      protected from the wear-leveling worker)
325  * @pq_head: protection queue head
326  * @wl_lock: protects the @used, @free, @pq, @pq_head, @lookuptbl, @move_from,
327  * 	     @move_to, @move_to_put @erase_pending, @wl_scheduled and @works
328  * 	     fields
329  * @move_mutex: serializes eraseblock moves
330  * @work_sem: synchronizes the WL worker with use tasks
331  * @wl_scheduled: non-zero if the wear-leveling was scheduled
332  * @lookuptbl: a table to quickly find a &struct ubi_wl_entry object for any
333  *             physical eraseblock
334  * @move_from: physical eraseblock from where the data is being moved
335  * @move_to: physical eraseblock where the data is being moved to
336  * @move_to_put: if the "to" PEB was put
337  * @works: list of pending works
338  * @works_count: count of pending works
339  * @bgt_thread: background thread description object
340  * @thread_enabled: if the background thread is enabled
341  * @bgt_name: background thread name
342  *
343  * @flash_size: underlying MTD device size (in bytes)
344  * @peb_count: count of physical eraseblocks on the MTD device
345  * @peb_size: physical eraseblock size
346  * @bad_peb_count: count of bad physical eraseblocks
347  * @good_peb_count: count of good physical eraseblocks
348  * @min_io_size: minimal input/output unit size of the underlying MTD device
349  * @hdrs_min_io_size: minimal I/O unit size used for VID and EC headers
350  * @ro_mode: if the UBI device is in read-only mode
351  * @leb_size: logical eraseblock size
352  * @leb_start: starting offset of logical eraseblocks within physical
353  *             eraseblocks
354  * @ec_hdr_alsize: size of the EC header aligned to @hdrs_min_io_size
355  * @vid_hdr_alsize: size of the VID header aligned to @hdrs_min_io_size
356  * @vid_hdr_offset: starting offset of the volume identifier header (might be
357  *                  unaligned)
358  * @vid_hdr_aloffset: starting offset of the VID header aligned to
359  * @hdrs_min_io_size
360  * @vid_hdr_shift: contains @vid_hdr_offset - @vid_hdr_aloffset
361  * @bad_allowed: whether the MTD device admits of bad physical eraseblocks or
362  *               not
363  * @mtd: MTD device descriptor
364  *
365  * @peb_buf1: a buffer of PEB size used for different purposes
366  * @peb_buf2: another buffer of PEB size used for different purposes
367  * @buf_mutex: protects @peb_buf1 and @peb_buf2
368  * @ckvol_mutex: serializes static volume checking when opening
369  * @mult_mutex: serializes operations on multiple volumes, like re-naming
370  * @dbg_peb_buf: buffer of PEB size used for debugging
371  * @dbg_buf_mutex: protects @dbg_peb_buf
372  */
373 struct ubi_device {
374 	struct cdev cdev;
375 	struct device dev;
376 	int ubi_num;
377 	char ubi_name[sizeof(UBI_NAME_STR)+5];
378 	int vol_count;
379 	struct ubi_volume *volumes[UBI_MAX_VOLUMES+UBI_INT_VOL_COUNT];
380 	spinlock_t volumes_lock;
381 	int ref_count;
382 
383 	int rsvd_pebs;
384 	int avail_pebs;
385 	int beb_rsvd_pebs;
386 	int beb_rsvd_level;
387 
388 	int autoresize_vol_id;
389 	int vtbl_slots;
390 	int vtbl_size;
391 	struct ubi_vtbl_record *vtbl;
392 	struct mutex volumes_mutex;
393 
394 	int max_ec;
395 	/* Note, mean_ec is not updated run-time - should be fixed */
396 	int mean_ec;
397 
398 	/* EBA sub-system's stuff */
399 	unsigned long long global_sqnum;
400 	spinlock_t ltree_lock;
401 	struct rb_root ltree;
402 	struct mutex alc_mutex;
403 
404 	/* Wear-leveling sub-system's stuff */
405 	struct rb_root used;
406 	struct rb_root free;
407 	struct rb_root scrub;
408 	struct list_head pq[UBI_PROT_QUEUE_LEN];
409 	int pq_head;
410 	spinlock_t wl_lock;
411 	struct mutex move_mutex;
412 	struct rw_semaphore work_sem;
413 	int wl_scheduled;
414 	struct ubi_wl_entry **lookuptbl;
415 	struct ubi_wl_entry *move_from;
416 	struct ubi_wl_entry *move_to;
417 	int move_to_put;
418 	struct list_head works;
419 	int works_count;
420 	struct task_struct *bgt_thread;
421 	int thread_enabled;
422 	char bgt_name[sizeof(UBI_BGT_NAME_PATTERN)+2];
423 
424 	/* I/O sub-system's stuff */
425 	long long flash_size;
426 	int peb_count;
427 	int peb_size;
428 	int bad_peb_count;
429 	int good_peb_count;
430 	int min_io_size;
431 	int hdrs_min_io_size;
432 	int ro_mode;
433 	int leb_size;
434 	int leb_start;
435 	int ec_hdr_alsize;
436 	int vid_hdr_alsize;
437 	int vid_hdr_offset;
438 	int vid_hdr_aloffset;
439 	int vid_hdr_shift;
440 	int bad_allowed;
441 	struct mtd_info *mtd;
442 
443 	void *peb_buf1;
444 	void *peb_buf2;
445 	struct mutex buf_mutex;
446 	struct mutex ckvol_mutex;
447 	struct mutex mult_mutex;
448 #ifdef CONFIG_MTD_UBI_DEBUG
449 	void *dbg_peb_buf;
450 	struct mutex dbg_buf_mutex;
451 #endif
452 };
453 
454 extern struct kmem_cache *ubi_wl_entry_slab;
455 extern const struct file_operations ubi_ctrl_cdev_operations;
456 extern const struct file_operations ubi_cdev_operations;
457 extern const struct file_operations ubi_vol_cdev_operations;
458 extern struct class *ubi_class;
459 extern struct mutex ubi_devices_mutex;
460 
461 /* vtbl.c */
462 int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
463 			   struct ubi_vtbl_record *vtbl_rec);
464 int ubi_vtbl_rename_volumes(struct ubi_device *ubi,
465 			    struct list_head *rename_list);
466 int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_scan_info *si);
467 
468 /* vmt.c */
469 int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req);
470 int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl);
471 int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs);
472 int ubi_rename_volumes(struct ubi_device *ubi, struct list_head *rename_list);
473 int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol);
474 void ubi_free_volume(struct ubi_device *ubi, struct ubi_volume *vol);
475 
476 /* upd.c */
477 int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
478 		     long long bytes);
479 int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
480 			 const void __user *buf, int count);
481 int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
482 			 const struct ubi_leb_change_req *req);
483 int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol,
484 			     const void __user *buf, int count);
485 
486 /* misc.c */
487 int ubi_calc_data_len(const struct ubi_device *ubi, const void *buf,
488 		      int length);
489 int ubi_check_volume(struct ubi_device *ubi, int vol_id);
490 void ubi_calculate_reserved(struct ubi_device *ubi);
491 
492 /* gluebi.c */
493 #ifdef CONFIG_MTD_UBI_GLUEBI
494 int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol);
495 int ubi_destroy_gluebi(struct ubi_volume *vol);
496 void ubi_gluebi_updated(struct ubi_volume *vol);
497 #else
498 #define ubi_create_gluebi(ubi, vol) 0
499 #define ubi_destroy_gluebi(vol) 0
500 #define ubi_gluebi_updated(vol)
501 #endif
502 
503 /* eba.c */
504 int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
505 		      int lnum);
506 int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
507 		     void *buf, int offset, int len, int check);
508 int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
509 		      const void *buf, int offset, int len, int dtype);
510 int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
511 			 int lnum, const void *buf, int len, int dtype,
512 			 int used_ebs);
513 int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
514 			      int lnum, const void *buf, int len, int dtype);
515 int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
516 		     struct ubi_vid_hdr *vid_hdr);
517 int ubi_eba_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
518 
519 /* wl.c */
520 int ubi_wl_get_peb(struct ubi_device *ubi, int dtype);
521 int ubi_wl_put_peb(struct ubi_device *ubi, int pnum, int torture);
522 int ubi_wl_flush(struct ubi_device *ubi);
523 int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum);
524 int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
525 void ubi_wl_close(struct ubi_device *ubi);
526 int ubi_thread(void *u);
527 
528 /* io.c */
529 int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
530 		int len);
531 int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
532 		 int len);
533 int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture);
534 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum);
535 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum);
536 int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
537 		       struct ubi_ec_hdr *ec_hdr, int verbose);
538 int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
539 			struct ubi_ec_hdr *ec_hdr);
540 int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
541 			struct ubi_vid_hdr *vid_hdr, int verbose);
542 int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
543 			 struct ubi_vid_hdr *vid_hdr);
544 
545 /* build.c */
546 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset);
547 int ubi_detach_mtd_dev(int ubi_num, int anyway);
548 struct ubi_device *ubi_get_device(int ubi_num);
549 void ubi_put_device(struct ubi_device *ubi);
550 struct ubi_device *ubi_get_by_major(int major);
551 int ubi_major2num(int major);
552 
553 /*
554  * ubi_rb_for_each_entry - walk an RB-tree.
555  * @rb: a pointer to type 'struct rb_node' to to use as a loop counter
556  * @pos: a pointer to RB-tree entry type to use as a loop counter
557  * @root: RB-tree's root
558  * @member: the name of the 'struct rb_node' within the RB-tree entry
559  */
560 #define ubi_rb_for_each_entry(rb, pos, root, member)                         \
561 	for (rb = rb_first(root),                                            \
562 	     pos = (rb ? container_of(rb, typeof(*pos), member) : NULL);     \
563 	     rb;                                                             \
564 	     rb = rb_next(rb), pos = container_of(rb, typeof(*pos), member))
565 
566 /**
567  * ubi_zalloc_vid_hdr - allocate a volume identifier header object.
568  * @ubi: UBI device description object
569  * @gfp_flags: GFP flags to allocate with
570  *
571  * This function returns a pointer to the newly allocated and zero-filled
572  * volume identifier header object in case of success and %NULL in case of
573  * failure.
574  */
575 static inline struct ubi_vid_hdr *
576 ubi_zalloc_vid_hdr(const struct ubi_device *ubi, gfp_t gfp_flags)
577 {
578 	void *vid_hdr;
579 
580 	vid_hdr = kzalloc(ubi->vid_hdr_alsize, gfp_flags);
581 	if (!vid_hdr)
582 		return NULL;
583 
584 	/*
585 	 * VID headers may be stored at un-aligned flash offsets, so we shift
586 	 * the pointer.
587 	 */
588 	return vid_hdr + ubi->vid_hdr_shift;
589 }
590 
591 /**
592  * ubi_free_vid_hdr - free a volume identifier header object.
593  * @ubi: UBI device description object
594  * @vid_hdr: the object to free
595  */
596 static inline void ubi_free_vid_hdr(const struct ubi_device *ubi,
597 				    struct ubi_vid_hdr *vid_hdr)
598 {
599 	void *p = vid_hdr;
600 
601 	if (!p)
602 		return;
603 
604 	kfree(p - ubi->vid_hdr_shift);
605 }
606 
607 /*
608  * This function is equivalent to 'ubi_io_read()', but @offset is relative to
609  * the beginning of the logical eraseblock, not to the beginning of the
610  * physical eraseblock.
611  */
612 static inline int ubi_io_read_data(const struct ubi_device *ubi, void *buf,
613 				   int pnum, int offset, int len)
614 {
615 	ubi_assert(offset >= 0);
616 	return ubi_io_read(ubi, buf, pnum, offset + ubi->leb_start, len);
617 }
618 
619 /*
620  * This function is equivalent to 'ubi_io_write()', but @offset is relative to
621  * the beginning of the logical eraseblock, not to the beginning of the
622  * physical eraseblock.
623  */
624 static inline int ubi_io_write_data(struct ubi_device *ubi, const void *buf,
625 				    int pnum, int offset, int len)
626 {
627 	ubi_assert(offset >= 0);
628 	return ubi_io_write(ubi, buf, pnum, offset + ubi->leb_start, len);
629 }
630 
631 /**
632  * ubi_ro_mode - switch to read-only mode.
633  * @ubi: UBI device description object
634  */
635 static inline void ubi_ro_mode(struct ubi_device *ubi)
636 {
637 	if (!ubi->ro_mode) {
638 		ubi->ro_mode = 1;
639 		ubi_warn("switch to read-only mode");
640 	}
641 }
642 
643 /**
644  * vol_id2idx - get table index by volume ID.
645  * @ubi: UBI device description object
646  * @vol_id: volume ID
647  */
648 static inline int vol_id2idx(const struct ubi_device *ubi, int vol_id)
649 {
650 	if (vol_id >= UBI_INTERNAL_VOL_START)
651 		return vol_id - UBI_INTERNAL_VOL_START + ubi->vtbl_slots;
652 	else
653 		return vol_id;
654 }
655 
656 /**
657  * idx2vol_id - get volume ID by table index.
658  * @ubi: UBI device description object
659  * @idx: table index
660  */
661 static inline int idx2vol_id(const struct ubi_device *ubi, int idx)
662 {
663 	if (idx >= ubi->vtbl_slots)
664 		return idx - ubi->vtbl_slots + UBI_INTERNAL_VOL_START;
665 	else
666 		return idx;
667 }
668 
669 #endif /* !__UBI_UBI_H__ */
670