xref: /openbmc/linux/drivers/mtd/ubi/ubi.h (revision 367b8112)
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  * Error codes returned by the I/O sub-system.
78  *
79  * UBI_IO_PEB_EMPTY: the physical eraseblock is empty, i.e. it contains only
80  *                   %0xFF bytes
81  * UBI_IO_PEB_FREE: the physical eraseblock is free, i.e. it contains only a
82  *                  valid erase counter header, and the rest are %0xFF bytes
83  * UBI_IO_BAD_EC_HDR: the erase counter header is corrupted (bad magic or CRC)
84  * UBI_IO_BAD_VID_HDR: the volume identifier header is corrupted (bad magic or
85  *                     CRC)
86  * UBI_IO_BITFLIPS: bit-flips were detected and corrected
87  */
88 enum {
89 	UBI_IO_PEB_EMPTY = 1,
90 	UBI_IO_PEB_FREE,
91 	UBI_IO_BAD_EC_HDR,
92 	UBI_IO_BAD_VID_HDR,
93 	UBI_IO_BITFLIPS
94 };
95 
96 /**
97  * struct ubi_wl_entry - wear-leveling entry.
98  * @rb: link in the corresponding RB-tree
99  * @ec: erase counter
100  * @pnum: physical eraseblock number
101  *
102  * This data structure is used in the WL sub-system. Each physical eraseblock
103  * has a corresponding &struct wl_entry object which may be kept in different
104  * RB-trees. See WL sub-system for details.
105  */
106 struct ubi_wl_entry {
107 	struct rb_node rb;
108 	int ec;
109 	int pnum;
110 };
111 
112 /**
113  * struct ubi_ltree_entry - an entry in the lock tree.
114  * @rb: links RB-tree nodes
115  * @vol_id: volume ID of the locked logical eraseblock
116  * @lnum: locked logical eraseblock number
117  * @users: how many tasks are using this logical eraseblock or wait for it
118  * @mutex: read/write mutex to implement read/write access serialization to
119  *         the (@vol_id, @lnum) logical eraseblock
120  *
121  * This data structure is used in the EBA sub-system to implement per-LEB
122  * locking. When a logical eraseblock is being locked - corresponding
123  * &struct ubi_ltree_entry object is inserted to the lock tree (@ubi->ltree).
124  * See EBA sub-system for details.
125  */
126 struct ubi_ltree_entry {
127 	struct rb_node rb;
128 	int vol_id;
129 	int lnum;
130 	int users;
131 	struct rw_semaphore mutex;
132 };
133 
134 /**
135  * struct ubi_rename_entry - volume re-name description data structure.
136  * @new_name_len: new volume name length
137  * @new_name: new volume name
138  * @remove: if not zero, this volume should be removed, not re-named
139  * @desc: descriptor of the volume
140  * @list: links re-name entries into a list
141  *
142  * This data structure is utilized in the multiple volume re-name code. Namely,
143  * UBI first creates a list of &struct ubi_rename_entry objects from the
144  * &struct ubi_rnvol_req request object, and then utilizes this list to do all
145  * the job.
146  */
147 struct ubi_rename_entry {
148 	int new_name_len;
149 	char new_name[UBI_VOL_NAME_MAX + 1];
150 	int remove;
151 	struct ubi_volume_desc *desc;
152 	struct list_head list;
153 };
154 
155 struct ubi_volume_desc;
156 
157 /**
158  * struct ubi_volume - UBI volume description data structure.
159  * @dev: device object to make use of the the Linux device model
160  * @cdev: character device object to create character device
161  * @ubi: reference to the UBI device description object
162  * @vol_id: volume ID
163  * @ref_count: volume reference count
164  * @readers: number of users holding this volume in read-only mode
165  * @writers: number of users holding this volume in read-write mode
166  * @exclusive: whether somebody holds this volume in exclusive mode
167  *
168  * @reserved_pebs: how many physical eraseblocks are reserved for this volume
169  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
170  * @usable_leb_size: logical eraseblock size without padding
171  * @used_ebs: how many logical eraseblocks in this volume contain data
172  * @last_eb_bytes: how many bytes are stored in the last logical eraseblock
173  * @used_bytes: how many bytes of data this volume contains
174  * @alignment: volume alignment
175  * @data_pad: how many bytes are not used at the end of physical eraseblocks to
176  *            satisfy the requested alignment
177  * @name_len: volume name length
178  * @name: volume name
179  *
180  * @upd_ebs: how many eraseblocks are expected to be updated
181  * @ch_lnum: LEB number which is being changing by the atomic LEB change
182  *           operation
183  * @ch_dtype: data persistency type which is being changing by the atomic LEB
184  *            change operation
185  * @upd_bytes: how many bytes are expected to be received for volume update or
186  *             atomic LEB change
187  * @upd_received: how many bytes were already received for volume update or
188  *                atomic LEB change
189  * @upd_buf: update buffer which is used to collect update data or data for
190  *           atomic LEB change
191  *
192  * @eba_tbl: EBA table of this volume (LEB->PEB mapping)
193  * @checked: %1 if this static volume was checked
194  * @corrupted: %1 if the volume is corrupted (static volumes only)
195  * @upd_marker: %1 if the update marker is set for this volume
196  * @updating: %1 if the volume is being updated
197  * @changing_leb: %1 if the atomic LEB change ioctl command is in progress
198  *
199  * @gluebi_desc: gluebi UBI volume descriptor
200  * @gluebi_refcount: reference count of the gluebi MTD device
201  * @gluebi_mtd: MTD device description object of the gluebi MTD device
202  *
203  * The @corrupted field indicates that the volume's contents is corrupted.
204  * Since UBI protects only static volumes, this field is not relevant to
205  * dynamic volumes - it is user's responsibility to assure their data
206  * integrity.
207  *
208  * The @upd_marker flag indicates that this volume is either being updated at
209  * the moment or is damaged because of an unclean reboot.
210  */
211 struct ubi_volume {
212 	struct device dev;
213 	struct cdev cdev;
214 	struct ubi_device *ubi;
215 	int vol_id;
216 	int ref_count;
217 	int readers;
218 	int writers;
219 	int exclusive;
220 
221 	int reserved_pebs;
222 	int vol_type;
223 	int usable_leb_size;
224 	int used_ebs;
225 	int last_eb_bytes;
226 	long long used_bytes;
227 	int alignment;
228 	int data_pad;
229 	int name_len;
230 	char name[UBI_VOL_NAME_MAX + 1];
231 
232 	int upd_ebs;
233 	int ch_lnum;
234 	int ch_dtype;
235 	long long upd_bytes;
236 	long long upd_received;
237 	void *upd_buf;
238 
239 	int *eba_tbl;
240 	unsigned int checked:1;
241 	unsigned int corrupted:1;
242 	unsigned int upd_marker:1;
243 	unsigned int updating:1;
244 	unsigned int changing_leb:1;
245 
246 #ifdef CONFIG_MTD_UBI_GLUEBI
247 	/*
248 	 * Gluebi-related stuff may be compiled out.
249 	 * Note: this should not be built into UBI but should be a separate
250 	 * ubimtd driver which works on top of UBI and emulates MTD devices.
251 	 */
252 	struct ubi_volume_desc *gluebi_desc;
253 	int gluebi_refcount;
254 	struct mtd_info gluebi_mtd;
255 #endif
256 };
257 
258 /**
259  * struct ubi_volume_desc - UBI volume descriptor returned when it is opened.
260  * @vol: reference to the corresponding volume description object
261  * @mode: open mode (%UBI_READONLY, %UBI_READWRITE, or %UBI_EXCLUSIVE)
262  */
263 struct ubi_volume_desc {
264 	struct ubi_volume *vol;
265 	int mode;
266 };
267 
268 struct ubi_wl_entry;
269 
270 /**
271  * struct ubi_device - UBI device description structure
272  * @dev: UBI device object to use the the Linux device model
273  * @cdev: character device object to create character device
274  * @ubi_num: UBI device number
275  * @ubi_name: UBI device name
276  * @vol_count: number of volumes in this UBI device
277  * @volumes: volumes of this UBI device
278  * @volumes_lock: protects @volumes, @rsvd_pebs, @avail_pebs, beb_rsvd_pebs,
279  *                @beb_rsvd_level, @bad_peb_count, @good_peb_count, @vol_count,
280  *                @vol->readers, @vol->writers, @vol->exclusive,
281  *                @vol->ref_count, @vol->mapping and @vol->eba_tbl.
282  * @ref_count: count of references on the UBI device
283  *
284  * @rsvd_pebs: count of reserved physical eraseblocks
285  * @avail_pebs: count of available physical eraseblocks
286  * @beb_rsvd_pebs: how many physical eraseblocks are reserved for bad PEB
287  *                 handling
288  * @beb_rsvd_level: normal level of PEBs reserved for bad PEB handling
289  *
290  * @autoresize_vol_id: ID of the volume which has to be auto-resized at the end
291  *                     of UBI ititializetion
292  * @vtbl_slots: how many slots are available in the volume table
293  * @vtbl_size: size of the volume table in bytes
294  * @vtbl: in-RAM volume table copy
295  * @volumes_mutex: protects on-flash volume table and serializes volume
296  *                 changes, like creation, deletion, update, re-size and re-name
297  *
298  * @max_ec: current highest erase counter value
299  * @mean_ec: current mean erase counter value
300  *
301  * @global_sqnum: global sequence number
302  * @ltree_lock: protects the lock tree and @global_sqnum
303  * @ltree: the lock tree
304  * @alc_mutex: serializes "atomic LEB change" operations
305  *
306  * @used: RB-tree of used physical eraseblocks
307  * @free: RB-tree of free physical eraseblocks
308  * @scrub: RB-tree of physical eraseblocks which need scrubbing
309  * @prot: protection trees
310  * @prot.pnum: protection tree indexed by physical eraseblock numbers
311  * @prot.aec: protection tree indexed by absolute erase counter value
312  * @wl_lock: protects the @used, @free, @prot, @lookuptbl, @abs_ec, @move_from,
313  *           @move_to, @move_to_put @erase_pending, @wl_scheduled, and @works
314  *           fields
315  * @move_mutex: serializes eraseblock moves
316  * @work_sem: sycnhronizes the WL worker with use tasks
317  * @wl_scheduled: non-zero if the wear-leveling was scheduled
318  * @lookuptbl: a table to quickly find a &struct ubi_wl_entry object for any
319  *             physical eraseblock
320  * @abs_ec: absolute erase counter
321  * @move_from: physical eraseblock from where the data is being moved
322  * @move_to: physical eraseblock where the data is being moved to
323  * @move_to_put: if the "to" PEB was put
324  * @works: list of pending works
325  * @works_count: count of pending works
326  * @bgt_thread: background thread description object
327  * @thread_enabled: if the background thread is enabled
328  * @bgt_name: background thread name
329  *
330  * @flash_size: underlying MTD device size (in bytes)
331  * @peb_count: count of physical eraseblocks on the MTD device
332  * @peb_size: physical eraseblock size
333  * @bad_peb_count: count of bad physical eraseblocks
334  * @good_peb_count: count of good physical eraseblocks
335  * @min_io_size: minimal input/output unit size of the underlying MTD device
336  * @hdrs_min_io_size: minimal I/O unit size used for VID and EC headers
337  * @ro_mode: if the UBI device is in read-only mode
338  * @leb_size: logical eraseblock size
339  * @leb_start: starting offset of logical eraseblocks within physical
340  *             eraseblocks
341  * @ec_hdr_alsize: size of the EC header aligned to @hdrs_min_io_size
342  * @vid_hdr_alsize: size of the VID header aligned to @hdrs_min_io_size
343  * @vid_hdr_offset: starting offset of the volume identifier header (might be
344  *                  unaligned)
345  * @vid_hdr_aloffset: starting offset of the VID header aligned to
346  * @hdrs_min_io_size
347  * @vid_hdr_shift: contains @vid_hdr_offset - @vid_hdr_aloffset
348  * @bad_allowed: whether the MTD device admits of bad physical eraseblocks or
349  *               not
350  * @mtd: MTD device descriptor
351  *
352  * @peb_buf1: a buffer of PEB size used for different purposes
353  * @peb_buf2: another buffer of PEB size used for different purposes
354  * @buf_mutex: proptects @peb_buf1 and @peb_buf2
355  * @ckvol_mutex: serializes static volume checking when opening
356  * @mult_mutex: serializes operations on multiple volumes, like re-nameing
357  * @dbg_peb_buf: buffer of PEB size used for debugging
358  * @dbg_buf_mutex: proptects @dbg_peb_buf
359  */
360 struct ubi_device {
361 	struct cdev cdev;
362 	struct device dev;
363 	int ubi_num;
364 	char ubi_name[sizeof(UBI_NAME_STR)+5];
365 	int vol_count;
366 	struct ubi_volume *volumes[UBI_MAX_VOLUMES+UBI_INT_VOL_COUNT];
367 	spinlock_t volumes_lock;
368 	int ref_count;
369 
370 	int rsvd_pebs;
371 	int avail_pebs;
372 	int beb_rsvd_pebs;
373 	int beb_rsvd_level;
374 
375 	int autoresize_vol_id;
376 	int vtbl_slots;
377 	int vtbl_size;
378 	struct ubi_vtbl_record *vtbl;
379 	struct mutex volumes_mutex;
380 
381 	int max_ec;
382 	/* Note, mean_ec is not updated run-time - should be fixed */
383 	int mean_ec;
384 
385 	/* EBA sub-system's stuff */
386 	unsigned long long global_sqnum;
387 	spinlock_t ltree_lock;
388 	struct rb_root ltree;
389 	struct mutex alc_mutex;
390 
391 	/* Wear-leveling sub-system's stuff */
392 	struct rb_root used;
393 	struct rb_root free;
394 	struct rb_root scrub;
395 	struct {
396 		struct rb_root pnum;
397 		struct rb_root aec;
398 	} prot;
399 	spinlock_t wl_lock;
400 	struct mutex move_mutex;
401 	struct rw_semaphore work_sem;
402 	int wl_scheduled;
403 	struct ubi_wl_entry **lookuptbl;
404 	unsigned long long abs_ec;
405 	struct ubi_wl_entry *move_from;
406 	struct ubi_wl_entry *move_to;
407 	int move_to_put;
408 	struct list_head works;
409 	int works_count;
410 	struct task_struct *bgt_thread;
411 	int thread_enabled;
412 	char bgt_name[sizeof(UBI_BGT_NAME_PATTERN)+2];
413 
414 	/* I/O sub-system's stuff */
415 	long long flash_size;
416 	int peb_count;
417 	int peb_size;
418 	int bad_peb_count;
419 	int good_peb_count;
420 	int min_io_size;
421 	int hdrs_min_io_size;
422 	int ro_mode;
423 	int leb_size;
424 	int leb_start;
425 	int ec_hdr_alsize;
426 	int vid_hdr_alsize;
427 	int vid_hdr_offset;
428 	int vid_hdr_aloffset;
429 	int vid_hdr_shift;
430 	int bad_allowed;
431 	struct mtd_info *mtd;
432 
433 	void *peb_buf1;
434 	void *peb_buf2;
435 	struct mutex buf_mutex;
436 	struct mutex ckvol_mutex;
437 	struct mutex mult_mutex;
438 #ifdef CONFIG_MTD_UBI_DEBUG
439 	void *dbg_peb_buf;
440 	struct mutex dbg_buf_mutex;
441 #endif
442 };
443 
444 extern struct kmem_cache *ubi_wl_entry_slab;
445 extern struct file_operations ubi_ctrl_cdev_operations;
446 extern struct file_operations ubi_cdev_operations;
447 extern struct file_operations ubi_vol_cdev_operations;
448 extern struct class *ubi_class;
449 extern struct mutex ubi_devices_mutex;
450 
451 /* vtbl.c */
452 int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
453 			   struct ubi_vtbl_record *vtbl_rec);
454 int ubi_vtbl_rename_volumes(struct ubi_device *ubi,
455 			    struct list_head *rename_list);
456 int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_scan_info *si);
457 
458 /* vmt.c */
459 int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req);
460 int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl);
461 int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs);
462 int ubi_rename_volumes(struct ubi_device *ubi, struct list_head *rename_list);
463 int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol);
464 void ubi_free_volume(struct ubi_device *ubi, struct ubi_volume *vol);
465 
466 /* upd.c */
467 int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
468 		     long long bytes);
469 int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
470 			 const void __user *buf, int count);
471 int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
472 			 const struct ubi_leb_change_req *req);
473 int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol,
474 			     const void __user *buf, int count);
475 
476 /* misc.c */
477 int ubi_calc_data_len(const struct ubi_device *ubi, const void *buf,
478 		      int length);
479 int ubi_check_volume(struct ubi_device *ubi, int vol_id);
480 void ubi_calculate_reserved(struct ubi_device *ubi);
481 
482 /* gluebi.c */
483 #ifdef CONFIG_MTD_UBI_GLUEBI
484 int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol);
485 int ubi_destroy_gluebi(struct ubi_volume *vol);
486 void ubi_gluebi_updated(struct ubi_volume *vol);
487 #else
488 #define ubi_create_gluebi(ubi, vol) 0
489 #define ubi_destroy_gluebi(vol) 0
490 #define ubi_gluebi_updated(vol)
491 #endif
492 
493 /* eba.c */
494 int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
495 		      int lnum);
496 int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
497 		     void *buf, int offset, int len, int check);
498 int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
499 		      const void *buf, int offset, int len, int dtype);
500 int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
501 			 int lnum, const void *buf, int len, int dtype,
502 			 int used_ebs);
503 int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
504 			      int lnum, const void *buf, int len, int dtype);
505 int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
506 		     struct ubi_vid_hdr *vid_hdr);
507 int ubi_eba_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
508 
509 /* wl.c */
510 int ubi_wl_get_peb(struct ubi_device *ubi, int dtype);
511 int ubi_wl_put_peb(struct ubi_device *ubi, int pnum, int torture);
512 int ubi_wl_flush(struct ubi_device *ubi);
513 int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum);
514 int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
515 void ubi_wl_close(struct ubi_device *ubi);
516 int ubi_thread(void *u);
517 
518 /* io.c */
519 int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
520 		int len);
521 int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
522 		 int len);
523 int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture);
524 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum);
525 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum);
526 int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
527 		       struct ubi_ec_hdr *ec_hdr, int verbose);
528 int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
529 			struct ubi_ec_hdr *ec_hdr);
530 int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
531 			struct ubi_vid_hdr *vid_hdr, int verbose);
532 int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
533 			 struct ubi_vid_hdr *vid_hdr);
534 
535 /* build.c */
536 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset);
537 int ubi_detach_mtd_dev(int ubi_num, int anyway);
538 struct ubi_device *ubi_get_device(int ubi_num);
539 void ubi_put_device(struct ubi_device *ubi);
540 struct ubi_device *ubi_get_by_major(int major);
541 int ubi_major2num(int major);
542 
543 /*
544  * ubi_rb_for_each_entry - walk an RB-tree.
545  * @rb: a pointer to type 'struct rb_node' to to use as a loop counter
546  * @pos: a pointer to RB-tree entry type to use as a loop counter
547  * @root: RB-tree's root
548  * @member: the name of the 'struct rb_node' within the RB-tree entry
549  */
550 #define ubi_rb_for_each_entry(rb, pos, root, member)                         \
551 	for (rb = rb_first(root),                                            \
552 	     pos = (rb ? container_of(rb, typeof(*pos), member) : NULL);     \
553 	     rb;                                                             \
554 	     rb = rb_next(rb), pos = container_of(rb, typeof(*pos), member))
555 
556 /**
557  * ubi_zalloc_vid_hdr - allocate a volume identifier header object.
558  * @ubi: UBI device description object
559  * @gfp_flags: GFP flags to allocate with
560  *
561  * This function returns a pointer to the newly allocated and zero-filled
562  * volume identifier header object in case of success and %NULL in case of
563  * failure.
564  */
565 static inline struct ubi_vid_hdr *
566 ubi_zalloc_vid_hdr(const struct ubi_device *ubi, gfp_t gfp_flags)
567 {
568 	void *vid_hdr;
569 
570 	vid_hdr = kzalloc(ubi->vid_hdr_alsize, gfp_flags);
571 	if (!vid_hdr)
572 		return NULL;
573 
574 	/*
575 	 * VID headers may be stored at un-aligned flash offsets, so we shift
576 	 * the pointer.
577 	 */
578 	return vid_hdr + ubi->vid_hdr_shift;
579 }
580 
581 /**
582  * ubi_free_vid_hdr - free a volume identifier header object.
583  * @ubi: UBI device description object
584  * @vid_hdr: the object to free
585  */
586 static inline void ubi_free_vid_hdr(const struct ubi_device *ubi,
587 				    struct ubi_vid_hdr *vid_hdr)
588 {
589 	void *p = vid_hdr;
590 
591 	if (!p)
592 		return;
593 
594 	kfree(p - ubi->vid_hdr_shift);
595 }
596 
597 /*
598  * This function is equivalent to 'ubi_io_read()', but @offset is relative to
599  * the beginning of the logical eraseblock, not to the beginning of the
600  * physical eraseblock.
601  */
602 static inline int ubi_io_read_data(const struct ubi_device *ubi, void *buf,
603 				   int pnum, int offset, int len)
604 {
605 	ubi_assert(offset >= 0);
606 	return ubi_io_read(ubi, buf, pnum, offset + ubi->leb_start, len);
607 }
608 
609 /*
610  * This function is equivalent to 'ubi_io_write()', but @offset is relative to
611  * the beginning of the logical eraseblock, not to the beginning of the
612  * physical eraseblock.
613  */
614 static inline int ubi_io_write_data(struct ubi_device *ubi, const void *buf,
615 				    int pnum, int offset, int len)
616 {
617 	ubi_assert(offset >= 0);
618 	return ubi_io_write(ubi, buf, pnum, offset + ubi->leb_start, len);
619 }
620 
621 /**
622  * ubi_ro_mode - switch to read-only mode.
623  * @ubi: UBI device description object
624  */
625 static inline void ubi_ro_mode(struct ubi_device *ubi)
626 {
627 	if (!ubi->ro_mode) {
628 		ubi->ro_mode = 1;
629 		ubi_warn("switch to read-only mode");
630 	}
631 }
632 
633 /**
634  * vol_id2idx - get table index by volume ID.
635  * @ubi: UBI device description object
636  * @vol_id: volume ID
637  */
638 static inline int vol_id2idx(const struct ubi_device *ubi, int vol_id)
639 {
640 	if (vol_id >= UBI_INTERNAL_VOL_START)
641 		return vol_id - UBI_INTERNAL_VOL_START + ubi->vtbl_slots;
642 	else
643 		return vol_id;
644 }
645 
646 /**
647  * idx2vol_id - get volume ID by table index.
648  * @ubi: UBI device description object
649  * @idx: table index
650  */
651 static inline int idx2vol_id(const struct ubi_device *ubi, int idx)
652 {
653 	if (idx >= ubi->vtbl_slots)
654 		return idx - ubi->vtbl_slots + UBI_INTERNAL_VOL_START;
655 	else
656 		return idx;
657 }
658 
659 #endif /* !__UBI_UBI_H__ */
660