1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) International Business Machines Corp., 2006
4 *
5 * Authors: Artem Bityutskiy (Битюцкий Артём), Thomas Gleixner
6 */
7
8/*
9 * UBI wear-leveling sub-system.
10 *
11 * This sub-system is responsible for wear-leveling. It works in terms of
12 * physical eraseblocks and erase counters and knows nothing about logical
13 * eraseblocks, volumes, etc. From this sub-system's perspective all physical
14 * eraseblocks are of two types - used and free. Used physical eraseblocks are
15 * those that were "get" by the 'ubi_wl_get_peb()' function, and free physical
16 * eraseblocks are those that were put by the 'ubi_wl_put_peb()' function.
17 *
18 * Physical eraseblocks returned by 'ubi_wl_get_peb()' have only erase counter
19 * header. The rest of the physical eraseblock contains only %0xFF bytes.
20 *
21 * When physical eraseblocks are returned to the WL sub-system by means of the
22 * 'ubi_wl_put_peb()' function, they are scheduled for erasure. The erasure is
23 * done asynchronously in context of the per-UBI device background thread,
24 * which is also managed by the WL sub-system.
25 *
26 * The wear-leveling is ensured by means of moving the contents of used
27 * physical eraseblocks with low erase counter to free physical eraseblocks
28 * with high erase counter.
29 *
30 * If the WL sub-system fails to erase a physical eraseblock, it marks it as
31 * bad.
32 *
33 * This sub-system is also responsible for scrubbing. If a bit-flip is detected
34 * in a physical eraseblock, it has to be moved. Technically this is the same
35 * as moving it for wear-leveling reasons.
36 *
37 * As it was said, for the UBI sub-system all physical eraseblocks are either
38 * "free" or "used". Free eraseblock are kept in the @wl->free RB-tree, while
39 * used eraseblocks are kept in @wl->used, @wl->erroneous, or @wl->scrub
40 * RB-trees, as well as (temporarily) in the @wl->pq queue.
41 *
42 * When the WL sub-system returns a physical eraseblock, the physical
43 * eraseblock is protected from being moved for some "time". For this reason,
44 * the physical eraseblock is not directly moved from the @wl->free tree to the
45 * @wl->used tree. There is a protection queue in between where this
46 * physical eraseblock is temporarily stored (@wl->pq).
47 *
48 * All this protection stuff is needed because:
49 * o we don't want to move physical eraseblocks just after we have given them
50 * to the user; instead, we first want to let users fill them up with data;
51 *
52 * o there is a chance that the user will put the physical eraseblock very
53 * soon, so it makes sense not to move it for some time, but wait.
54 *
55 * Physical eraseblocks stay protected only for limited time. But the "time" is
56 * measured in erase cycles in this case. This is implemented with help of the
57 * protection queue. Eraseblocks are put to the tail of this queue when they
58 * are returned by the 'ubi_wl_get_peb()', and eraseblocks are removed from the
59 * head of the queue on each erase operation (for any eraseblock). So the
60 * length of the queue defines how may (global) erase cycles PEBs are protected.
61 *
62 * To put it differently, each physical eraseblock has 2 main states: free and
63 * used. The former state corresponds to the @wl->free tree. The latter state
64 * is split up on several sub-states:
65 * o the WL movement is allowed (@wl->used tree);
66 * o the WL movement is disallowed (@wl->erroneous) because the PEB is
67 * erroneous - e.g., there was a read error;
68 * o the WL movement is temporarily prohibited (@wl->pq queue);
69 * o scrubbing is needed (@wl->scrub tree).
70 *
71 * Depending on the sub-state, wear-leveling entries of the used physical
72 * eraseblocks may be kept in one of those structures.
73 *
74 * Note, in this implementation, we keep a small in-RAM object for each physical
75 * eraseblock. This is surely not a scalable solution. But it appears to be good
76 * enough for moderately large flashes and it is simple. In future, one may
77 * re-work this sub-system and make it more scalable.
78 *
79 * At the moment this sub-system does not utilize the sequence number, which
80 * was introduced relatively recently. But it would be wise to do this because
81 * the sequence number of a logical eraseblock characterizes how old is it. For
82 * example, when we move a PEB with low erase counter, and we need to pick the
83 * target PEB, we pick a PEB with the highest EC if our PEB is "old" and we
84 * pick target PEB with an average EC if our PEB is not very "old". This is a
85 * room for future re-works of the WL sub-system.
86 */
87
88#include <linux/slab.h>
89#include <linux/crc32.h>
90#include <linux/freezer.h>
91#include <linux/kthread.h>
92#include "ubi.h"
93#include "wl.h"
94
95/* Number of physical eraseblocks reserved for wear-leveling purposes */
96#define WL_RESERVED_PEBS 1
97
98/*
99 * Maximum difference between two erase counters. If this threshold is
100 * exceeded, the WL sub-system starts moving data from used physical
101 * eraseblocks with low erase counter to free physical eraseblocks with high
102 * erase counter.
103 */
104#define UBI_WL_THRESHOLD CONFIG_MTD_UBI_WL_THRESHOLD
105
106/*
107 * When a physical eraseblock is moved, the WL sub-system has to pick the target
108 * physical eraseblock to move to. The simplest way would be just to pick the
109 * one with the highest erase counter. But in certain workloads this could lead
110 * to an unlimited wear of one or few physical eraseblock. Indeed, imagine a
111 * situation when the picked physical eraseblock is constantly erased after the
112 * data is written to it. So, we have a constant which limits the highest erase
113 * counter of the free physical eraseblock to pick. Namely, the WL sub-system
114 * does not pick eraseblocks with erase counter greater than the lowest erase
115 * counter plus %WL_FREE_MAX_DIFF.
116 */
117#define WL_FREE_MAX_DIFF (2*UBI_WL_THRESHOLD)
118
119/*
120 * Maximum number of consecutive background thread failures which is enough to
121 * switch to read-only mode.
122 */
123#define WL_MAX_FAILURES 32
124
125static int self_check_ec(struct ubi_device *ubi, int pnum, int ec);
126static int self_check_in_wl_tree(const struct ubi_device *ubi,
127 struct ubi_wl_entry *e, struct rb_root *root);
128static int self_check_in_pq(const struct ubi_device *ubi,
129 struct ubi_wl_entry *e);
130
131/**
132 * wl_tree_add - add a wear-leveling entry to a WL RB-tree.
133 * @e: the wear-leveling entry to add
134 * @root: the root of the tree
135 *
136 * Note, we use (erase counter, physical eraseblock number) pairs as keys in
137 * the @ubi->used and @ubi->free RB-trees.
138 */
139static void wl_tree_add(struct ubi_wl_entry *e, struct rb_root *root)
140{
141 struct rb_node **p, *parent = NULL;
142
143 p = &root->rb_node;
144 while (*p) {
145 struct ubi_wl_entry *e1;
146
147 parent = *p;
148 e1 = rb_entry(parent, struct ubi_wl_entry, u.rb);
149
150 if (e->ec < e1->ec)
151 p = &(*p)->rb_left;
152 else if (e->ec > e1->ec)
153 p = &(*p)->rb_right;
154 else {
155 ubi_assert(e->pnum != e1->pnum);
156 if (e->pnum < e1->pnum)
157 p = &(*p)->rb_left;
158 else
159 p = &(*p)->rb_right;
160 }
161 }
162
163 rb_link_node(node: &e->u.rb, parent, rb_link: p);
164 rb_insert_color(&e->u.rb, root);
165}
166
167/**
168 * wl_entry_destroy - destroy a wear-leveling entry.
169 * @ubi: UBI device description object
170 * @e: the wear-leveling entry to add
171 *
172 * This function destroys a wear leveling entry and removes
173 * the reference from the lookup table.
174 */
175static void wl_entry_destroy(struct ubi_device *ubi, struct ubi_wl_entry *e)
176{
177 ubi->lookuptbl[e->pnum] = NULL;
178 kmem_cache_free(s: ubi_wl_entry_slab, objp: e);
179}
180
181/**
182 * do_work - do one pending work.
183 * @ubi: UBI device description object
184 * @executed: whether there is one work is executed
185 *
186 * This function returns zero in case of success and a negative error code in
187 * case of failure. If @executed is not NULL and there is one work executed,
188 * @executed is set as %1, otherwise @executed is set as %0.
189 */
190static int do_work(struct ubi_device *ubi, int *executed)
191{
192 int err;
193 struct ubi_work *wrk;
194
195 cond_resched();
196
197 /*
198 * @ubi->work_sem is used to synchronize with the workers. Workers take
199 * it in read mode, so many of them may be doing works at a time. But
200 * the queue flush code has to be sure the whole queue of works is
201 * done, and it takes the mutex in write mode.
202 */
203 down_read(sem: &ubi->work_sem);
204 spin_lock(lock: &ubi->wl_lock);
205 if (list_empty(head: &ubi->works)) {
206 spin_unlock(lock: &ubi->wl_lock);
207 up_read(sem: &ubi->work_sem);
208 if (executed)
209 *executed = 0;
210 return 0;
211 }
212
213 if (executed)
214 *executed = 1;
215 wrk = list_entry(ubi->works.next, struct ubi_work, list);
216 list_del(entry: &wrk->list);
217 ubi->works_count -= 1;
218 ubi_assert(ubi->works_count >= 0);
219 spin_unlock(lock: &ubi->wl_lock);
220
221 /*
222 * Call the worker function. Do not touch the work structure
223 * after this call as it will have been freed or reused by that
224 * time by the worker function.
225 */
226 err = wrk->func(ubi, wrk, 0);
227 if (err)
228 ubi_err(ubi, fmt: "work failed with error code %d", err);
229 up_read(sem: &ubi->work_sem);
230
231 return err;
232}
233
234/**
235 * in_wl_tree - check if wear-leveling entry is present in a WL RB-tree.
236 * @e: the wear-leveling entry to check
237 * @root: the root of the tree
238 *
239 * This function returns non-zero if @e is in the @root RB-tree and zero if it
240 * is not.
241 */
242static int in_wl_tree(struct ubi_wl_entry *e, struct rb_root *root)
243{
244 struct rb_node *p;
245
246 p = root->rb_node;
247 while (p) {
248 struct ubi_wl_entry *e1;
249
250 e1 = rb_entry(p, struct ubi_wl_entry, u.rb);
251
252 if (e->pnum == e1->pnum) {
253 ubi_assert(e == e1);
254 return 1;
255 }
256
257 if (e->ec < e1->ec)
258 p = p->rb_left;
259 else if (e->ec > e1->ec)
260 p = p->rb_right;
261 else {
262 ubi_assert(e->pnum != e1->pnum);
263 if (e->pnum < e1->pnum)
264 p = p->rb_left;
265 else
266 p = p->rb_right;
267 }
268 }
269
270 return 0;
271}
272
273/**
274 * in_pq - check if a wear-leveling entry is present in the protection queue.
275 * @ubi: UBI device description object
276 * @e: the wear-leveling entry to check
277 *
278 * This function returns non-zero if @e is in the protection queue and zero
279 * if it is not.
280 */
281static inline int in_pq(const struct ubi_device *ubi, struct ubi_wl_entry *e)
282{
283 struct ubi_wl_entry *p;
284 int i;
285
286 for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i)
287 list_for_each_entry(p, &ubi->pq[i], u.list)
288 if (p == e)
289 return 1;
290
291 return 0;
292}
293
294/**
295 * prot_queue_add - add physical eraseblock to the protection queue.
296 * @ubi: UBI device description object
297 * @e: the physical eraseblock to add
298 *
299 * This function adds @e to the tail of the protection queue @ubi->pq, where
300 * @e will stay for %UBI_PROT_QUEUE_LEN erase operations and will be
301 * temporarily protected from the wear-leveling worker. Note, @wl->lock has to
302 * be locked.
303 */
304static void prot_queue_add(struct ubi_device *ubi, struct ubi_wl_entry *e)
305{
306 int pq_tail = ubi->pq_head - 1;
307
308 if (pq_tail < 0)
309 pq_tail = UBI_PROT_QUEUE_LEN - 1;
310 ubi_assert(pq_tail >= 0 && pq_tail < UBI_PROT_QUEUE_LEN);
311 list_add_tail(new: &e->u.list, head: &ubi->pq[pq_tail]);
312 dbg_wl("added PEB %d EC %d to the protection queue", e->pnum, e->ec);
313}
314
315/**
316 * find_wl_entry - find wear-leveling entry closest to certain erase counter.
317 * @ubi: UBI device description object
318 * @root: the RB-tree where to look for
319 * @diff: maximum possible difference from the smallest erase counter
320 * @pick_max: pick PEB even its erase counter beyonds 'min_ec + @diff'
321 *
322 * This function looks for a wear leveling entry with erase counter closest to
323 * min + @diff, where min is the smallest erase counter.
324 */
325static struct ubi_wl_entry *find_wl_entry(struct ubi_device *ubi,
326 struct rb_root *root, int diff,
327 int pick_max)
328{
329 struct rb_node *p;
330 struct ubi_wl_entry *e;
331 int max;
332
333 e = rb_entry(rb_first(root), struct ubi_wl_entry, u.rb);
334 max = e->ec + diff;
335
336 p = root->rb_node;
337 while (p) {
338 struct ubi_wl_entry *e1;
339
340 e1 = rb_entry(p, struct ubi_wl_entry, u.rb);
341 if (e1->ec >= max) {
342 if (pick_max)
343 e = e1;
344 p = p->rb_left;
345 } else {
346 p = p->rb_right;
347 e = e1;
348 }
349 }
350
351 return e;
352}
353
354/**
355 * find_mean_wl_entry - find wear-leveling entry with medium erase counter.
356 * @ubi: UBI device description object
357 * @root: the RB-tree where to look for
358 *
359 * This function looks for a wear leveling entry with medium erase counter,
360 * but not greater or equivalent than the lowest erase counter plus
361 * %WL_FREE_MAX_DIFF/2.
362 */
363static struct ubi_wl_entry *find_mean_wl_entry(struct ubi_device *ubi,
364 struct rb_root *root)
365{
366 struct ubi_wl_entry *e, *first, *last;
367
368 first = rb_entry(rb_first(root), struct ubi_wl_entry, u.rb);
369 last = rb_entry(rb_last(root), struct ubi_wl_entry, u.rb);
370
371 if (last->ec - first->ec < WL_FREE_MAX_DIFF) {
372 e = rb_entry(root->rb_node, struct ubi_wl_entry, u.rb);
373
374 /*
375 * If no fastmap has been written and fm_anchor is not
376 * reserved and this WL entry can be used as anchor PEB
377 * hold it back and return the second best WL entry such
378 * that fastmap can use the anchor PEB later.
379 */
380 e = may_reserve_for_fm(ubi, e, root);
381 } else
382 e = find_wl_entry(ubi, root, WL_FREE_MAX_DIFF/2, pick_max: 0);
383
384 return e;
385}
386
387/**
388 * wl_get_wle - get a mean wl entry to be used by ubi_wl_get_peb() or
389 * refill_wl_user_pool().
390 * @ubi: UBI device description object
391 *
392 * This function returns a wear leveling entry in case of success and
393 * NULL in case of failure.
394 */
395static struct ubi_wl_entry *wl_get_wle(struct ubi_device *ubi)
396{
397 struct ubi_wl_entry *e;
398
399 e = find_mean_wl_entry(ubi, root: &ubi->free);
400 if (!e) {
401 ubi_err(ubi, fmt: "no free eraseblocks");
402 return NULL;
403 }
404
405 self_check_in_wl_tree(ubi, e, root: &ubi->free);
406
407 /*
408 * Move the physical eraseblock to the protection queue where it will
409 * be protected from being moved for some time.
410 */
411 rb_erase(&e->u.rb, &ubi->free);
412 ubi->free_count--;
413 dbg_wl("PEB %d EC %d", e->pnum, e->ec);
414
415 return e;
416}
417
418/**
419 * prot_queue_del - remove a physical eraseblock from the protection queue.
420 * @ubi: UBI device description object
421 * @pnum: the physical eraseblock to remove
422 *
423 * This function deletes PEB @pnum from the protection queue and returns zero
424 * in case of success and %-ENODEV if the PEB was not found.
425 */
426static int prot_queue_del(struct ubi_device *ubi, int pnum)
427{
428 struct ubi_wl_entry *e;
429
430 e = ubi->lookuptbl[pnum];
431 if (!e)
432 return -ENODEV;
433
434 if (self_check_in_pq(ubi, e))
435 return -ENODEV;
436
437 list_del(entry: &e->u.list);
438 dbg_wl("deleted PEB %d from the protection queue", e->pnum);
439 return 0;
440}
441
442/**
443 * ubi_sync_erase - synchronously erase a physical eraseblock.
444 * @ubi: UBI device description object
445 * @e: the physical eraseblock to erase
446 * @torture: if the physical eraseblock has to be tortured
447 *
448 * This function returns zero in case of success and a negative error code in
449 * case of failure.
450 */
451int ubi_sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e, int torture)
452{
453 int err;
454 struct ubi_ec_hdr *ec_hdr;
455 unsigned long long ec = e->ec;
456
457 dbg_wl("erase PEB %d, old EC %llu", e->pnum, ec);
458
459 err = self_check_ec(ubi, pnum: e->pnum, ec: e->ec);
460 if (err)
461 return -EINVAL;
462
463 ec_hdr = kzalloc(size: ubi->ec_hdr_alsize, GFP_NOFS);
464 if (!ec_hdr)
465 return -ENOMEM;
466
467 err = ubi_io_sync_erase(ubi, pnum: e->pnum, torture);
468 if (err < 0)
469 goto out_free;
470
471 ec += err;
472 if (ec > UBI_MAX_ERASECOUNTER) {
473 /*
474 * Erase counter overflow. Upgrade UBI and use 64-bit
475 * erase counters internally.
476 */
477 ubi_err(ubi, fmt: "erase counter overflow at PEB %d, EC %llu",
478 e->pnum, ec);
479 err = -EINVAL;
480 goto out_free;
481 }
482
483 dbg_wl("erased PEB %d, new EC %llu", e->pnum, ec);
484
485 ec_hdr->ec = cpu_to_be64(ec);
486
487 err = ubi_io_write_ec_hdr(ubi, pnum: e->pnum, ec_hdr);
488 if (err)
489 goto out_free;
490
491 e->ec = ec;
492 spin_lock(lock: &ubi->wl_lock);
493 if (e->ec > ubi->max_ec)
494 ubi->max_ec = e->ec;
495 spin_unlock(lock: &ubi->wl_lock);
496
497out_free:
498 kfree(objp: ec_hdr);
499 return err;
500}
501
502/**
503 * serve_prot_queue - check if it is time to stop protecting PEBs.
504 * @ubi: UBI device description object
505 *
506 * This function is called after each erase operation and removes PEBs from the
507 * tail of the protection queue. These PEBs have been protected for long enough
508 * and should be moved to the used tree.
509 */
510static void serve_prot_queue(struct ubi_device *ubi)
511{
512 struct ubi_wl_entry *e, *tmp;
513 int count;
514
515 /*
516 * There may be several protected physical eraseblock to remove,
517 * process them all.
518 */
519repeat:
520 count = 0;
521 spin_lock(lock: &ubi->wl_lock);
522 list_for_each_entry_safe(e, tmp, &ubi->pq[ubi->pq_head], u.list) {
523 dbg_wl("PEB %d EC %d protection over, move to used tree",
524 e->pnum, e->ec);
525
526 list_del(entry: &e->u.list);
527 wl_tree_add(e, root: &ubi->used);
528 if (count++ > 32) {
529 /*
530 * Let's be nice and avoid holding the spinlock for
531 * too long.
532 */
533 spin_unlock(lock: &ubi->wl_lock);
534 cond_resched();
535 goto repeat;
536 }
537 }
538
539 ubi->pq_head += 1;
540 if (ubi->pq_head == UBI_PROT_QUEUE_LEN)
541 ubi->pq_head = 0;
542 ubi_assert(ubi->pq_head >= 0 && ubi->pq_head < UBI_PROT_QUEUE_LEN);
543 spin_unlock(lock: &ubi->wl_lock);
544}
545
546/**
547 * __schedule_ubi_work - schedule a work.
548 * @ubi: UBI device description object
549 * @wrk: the work to schedule
550 *
551 * This function adds a work defined by @wrk to the tail of the pending works
552 * list. Can only be used if ubi->work_sem is already held in read mode!
553 */
554static void __schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
555{
556 spin_lock(lock: &ubi->wl_lock);
557 list_add_tail(new: &wrk->list, head: &ubi->works);
558 ubi_assert(ubi->works_count >= 0);
559 ubi->works_count += 1;
560 if (ubi->thread_enabled && !ubi_dbg_is_bgt_disabled(ubi))
561 wake_up_process(tsk: ubi->bgt_thread);
562 spin_unlock(lock: &ubi->wl_lock);
563}
564
565/**
566 * schedule_ubi_work - schedule a work.
567 * @ubi: UBI device description object
568 * @wrk: the work to schedule
569 *
570 * This function adds a work defined by @wrk to the tail of the pending works
571 * list.
572 */
573static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
574{
575 down_read(sem: &ubi->work_sem);
576 __schedule_ubi_work(ubi, wrk);
577 up_read(sem: &ubi->work_sem);
578}
579
580static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
581 int shutdown);
582
583/**
584 * schedule_erase - schedule an erase work.
585 * @ubi: UBI device description object
586 * @e: the WL entry of the physical eraseblock to erase
587 * @vol_id: the volume ID that last used this PEB
588 * @lnum: the last used logical eraseblock number for the PEB
589 * @torture: if the physical eraseblock has to be tortured
590 * @nested: denotes whether the work_sem is already held
591 *
592 * This function returns zero in case of success and a %-ENOMEM in case of
593 * failure.
594 */
595static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
596 int vol_id, int lnum, int torture, bool nested)
597{
598 struct ubi_work *wl_wrk;
599
600 ubi_assert(e);
601
602 dbg_wl("schedule erasure of PEB %d, EC %d, torture %d",
603 e->pnum, e->ec, torture);
604
605 wl_wrk = kmalloc(size: sizeof(struct ubi_work), GFP_NOFS);
606 if (!wl_wrk)
607 return -ENOMEM;
608
609 wl_wrk->func = &erase_worker;
610 wl_wrk->e = e;
611 wl_wrk->vol_id = vol_id;
612 wl_wrk->lnum = lnum;
613 wl_wrk->torture = torture;
614
615 if (nested)
616 __schedule_ubi_work(ubi, wrk: wl_wrk);
617 else
618 schedule_ubi_work(ubi, wrk: wl_wrk);
619 return 0;
620}
621
622static int __erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk);
623/**
624 * do_sync_erase - run the erase worker synchronously.
625 * @ubi: UBI device description object
626 * @e: the WL entry of the physical eraseblock to erase
627 * @vol_id: the volume ID that last used this PEB
628 * @lnum: the last used logical eraseblock number for the PEB
629 * @torture: if the physical eraseblock has to be tortured
630 *
631 */
632static int do_sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
633 int vol_id, int lnum, int torture)
634{
635 struct ubi_work wl_wrk;
636
637 dbg_wl("sync erase of PEB %i", e->pnum);
638
639 wl_wrk.e = e;
640 wl_wrk.vol_id = vol_id;
641 wl_wrk.lnum = lnum;
642 wl_wrk.torture = torture;
643
644 return __erase_worker(ubi, wl_wrk: &wl_wrk);
645}
646
647static int ensure_wear_leveling(struct ubi_device *ubi, int nested);
648/**
649 * wear_leveling_worker - wear-leveling worker function.
650 * @ubi: UBI device description object
651 * @wrk: the work object
652 * @shutdown: non-zero if the worker has to free memory and exit
653 * because the WL-subsystem is shutting down
654 *
655 * This function copies a more worn out physical eraseblock to a less worn out
656 * one. Returns zero in case of success and a negative error code in case of
657 * failure.
658 */
659static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
660 int shutdown)
661{
662 int err, scrubbing = 0, torture = 0, protect = 0, erroneous = 0;
663 int erase = 0, keep = 0, vol_id = -1, lnum = -1;
664 struct ubi_wl_entry *e1, *e2;
665 struct ubi_vid_io_buf *vidb;
666 struct ubi_vid_hdr *vid_hdr;
667 int dst_leb_clean = 0;
668
669 kfree(objp: wrk);
670 if (shutdown)
671 return 0;
672
673 vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
674 if (!vidb)
675 return -ENOMEM;
676
677 vid_hdr = ubi_get_vid_hdr(vidb);
678
679 down_read(sem: &ubi->fm_eba_sem);
680 mutex_lock(&ubi->move_mutex);
681 spin_lock(lock: &ubi->wl_lock);
682 ubi_assert(!ubi->move_from && !ubi->move_to);
683 ubi_assert(!ubi->move_to_put);
684
685#ifdef CONFIG_MTD_UBI_FASTMAP
686 if (!next_peb_for_wl(ubi) ||
687#else
688 if (!ubi->free.rb_node ||
689#endif
690 (!ubi->used.rb_node && !ubi->scrub.rb_node)) {
691 /*
692 * No free physical eraseblocks? Well, they must be waiting in
693 * the queue to be erased. Cancel movement - it will be
694 * triggered again when a free physical eraseblock appears.
695 *
696 * No used physical eraseblocks? They must be temporarily
697 * protected from being moved. They will be moved to the
698 * @ubi->used tree later and the wear-leveling will be
699 * triggered again.
700 */
701 dbg_wl("cancel WL, a list is empty: free %d, used %d",
702 !ubi->free.rb_node, !ubi->used.rb_node);
703 goto out_cancel;
704 }
705
706#ifdef CONFIG_MTD_UBI_FASTMAP
707 e1 = find_anchor_wl_entry(root: &ubi->used);
708 if (e1 && ubi->fm_anchor &&
709 (ubi->fm_anchor->ec - e1->ec >= UBI_WL_THRESHOLD)) {
710 ubi->fm_do_produce_anchor = 1;
711 /*
712 * fm_anchor is no longer considered a good anchor.
713 * NULL assignment also prevents multiple wear level checks
714 * of this PEB.
715 */
716 wl_tree_add(e: ubi->fm_anchor, root: &ubi->free);
717 ubi->fm_anchor = NULL;
718 ubi->free_count++;
719 }
720
721 if (ubi->fm_do_produce_anchor) {
722 if (!e1)
723 goto out_cancel;
724 e2 = get_peb_for_wl(ubi);
725 if (!e2)
726 goto out_cancel;
727
728 self_check_in_wl_tree(ubi, e: e1, root: &ubi->used);
729 rb_erase(&e1->u.rb, &ubi->used);
730 dbg_wl("anchor-move PEB %d to PEB %d", e1->pnum, e2->pnum);
731 ubi->fm_do_produce_anchor = 0;
732 } else if (!ubi->scrub.rb_node) {
733#else
734 if (!ubi->scrub.rb_node) {
735#endif
736 /*
737 * Now pick the least worn-out used physical eraseblock and a
738 * highly worn-out free physical eraseblock. If the erase
739 * counters differ much enough, start wear-leveling.
740 */
741 e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
742 e2 = get_peb_for_wl(ubi);
743 if (!e2)
744 goto out_cancel;
745
746 if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD)) {
747 dbg_wl("no WL needed: min used EC %d, max free EC %d",
748 e1->ec, e2->ec);
749
750 /* Give the unused PEB back */
751 wl_tree_add(e: e2, root: &ubi->free);
752 ubi->free_count++;
753 goto out_cancel;
754 }
755 self_check_in_wl_tree(ubi, e: e1, root: &ubi->used);
756 rb_erase(&e1->u.rb, &ubi->used);
757 dbg_wl("move PEB %d EC %d to PEB %d EC %d",
758 e1->pnum, e1->ec, e2->pnum, e2->ec);
759 } else {
760 /* Perform scrubbing */
761 scrubbing = 1;
762 e1 = rb_entry(rb_first(&ubi->scrub), struct ubi_wl_entry, u.rb);
763 e2 = get_peb_for_wl(ubi);
764 if (!e2)
765 goto out_cancel;
766
767 self_check_in_wl_tree(ubi, e: e1, root: &ubi->scrub);
768 rb_erase(&e1->u.rb, &ubi->scrub);
769 dbg_wl("scrub PEB %d to PEB %d", e1->pnum, e2->pnum);
770 }
771
772 ubi->move_from = e1;
773 ubi->move_to = e2;
774 spin_unlock(lock: &ubi->wl_lock);
775
776 /*
777 * Now we are going to copy physical eraseblock @e1->pnum to @e2->pnum.
778 * We so far do not know which logical eraseblock our physical
779 * eraseblock (@e1) belongs to. We have to read the volume identifier
780 * header first.
781 *
782 * Note, we are protected from this PEB being unmapped and erased. The
783 * 'ubi_wl_put_peb()' would wait for moving to be finished if the PEB
784 * which is being moved was unmapped.
785 */
786
787 err = ubi_io_read_vid_hdr(ubi, pnum: e1->pnum, vidb, verbose: 0);
788 if (err && err != UBI_IO_BITFLIPS) {
789 dst_leb_clean = 1;
790 if (err == UBI_IO_FF) {
791 /*
792 * We are trying to move PEB without a VID header. UBI
793 * always write VID headers shortly after the PEB was
794 * given, so we have a situation when it has not yet
795 * had a chance to write it, because it was preempted.
796 * So add this PEB to the protection queue so far,
797 * because presumably more data will be written there
798 * (including the missing VID header), and then we'll
799 * move it.
800 */
801 dbg_wl("PEB %d has no VID header", e1->pnum);
802 protect = 1;
803 goto out_not_moved;
804 } else if (err == UBI_IO_FF_BITFLIPS) {
805 /*
806 * The same situation as %UBI_IO_FF, but bit-flips were
807 * detected. It is better to schedule this PEB for
808 * scrubbing.
809 */
810 dbg_wl("PEB %d has no VID header but has bit-flips",
811 e1->pnum);
812 scrubbing = 1;
813 goto out_not_moved;
814 } else if (ubi->fast_attach && err == UBI_IO_BAD_HDR_EBADMSG) {
815 /*
816 * While a full scan would detect interrupted erasures
817 * at attach time we can face them here when attached from
818 * Fastmap.
819 */
820 dbg_wl("PEB %d has ECC errors, maybe from an interrupted erasure",
821 e1->pnum);
822 erase = 1;
823 goto out_not_moved;
824 }
825
826 ubi_err(ubi, fmt: "error %d while reading VID header from PEB %d",
827 err, e1->pnum);
828 goto out_error;
829 }
830
831 vol_id = be32_to_cpu(vid_hdr->vol_id);
832 lnum = be32_to_cpu(vid_hdr->lnum);
833
834 err = ubi_eba_copy_leb(ubi, from: e1->pnum, to: e2->pnum, vidb);
835 if (err) {
836 if (err == MOVE_CANCEL_RACE) {
837 /*
838 * The LEB has not been moved because the volume is
839 * being deleted or the PEB has been put meanwhile. We
840 * should prevent this PEB from being selected for
841 * wear-leveling movement again, so put it to the
842 * protection queue.
843 */
844 protect = 1;
845 dst_leb_clean = 1;
846 goto out_not_moved;
847 }
848 if (err == MOVE_RETRY) {
849 scrubbing = 1;
850 dst_leb_clean = 1;
851 goto out_not_moved;
852 }
853 if (err == MOVE_TARGET_BITFLIPS || err == MOVE_TARGET_WR_ERR ||
854 err == MOVE_TARGET_RD_ERR) {
855 /*
856 * Target PEB had bit-flips or write error - torture it.
857 */
858 torture = 1;
859 keep = 1;
860 goto out_not_moved;
861 }
862
863 if (err == MOVE_SOURCE_RD_ERR) {
864 /*
865 * An error happened while reading the source PEB. Do
866 * not switch to R/O mode in this case, and give the
867 * upper layers a possibility to recover from this,
868 * e.g. by unmapping corresponding LEB. Instead, just
869 * put this PEB to the @ubi->erroneous list to prevent
870 * UBI from trying to move it over and over again.
871 */
872 if (ubi->erroneous_peb_count > ubi->max_erroneous) {
873 ubi_err(ubi, fmt: "too many erroneous eraseblocks (%d)",
874 ubi->erroneous_peb_count);
875 goto out_error;
876 }
877 dst_leb_clean = 1;
878 erroneous = 1;
879 goto out_not_moved;
880 }
881
882 if (err < 0)
883 goto out_error;
884
885 ubi_assert(0);
886 }
887
888 /* The PEB has been successfully moved */
889 if (scrubbing)
890 ubi_msg(ubi, fmt: "scrubbed PEB %d (LEB %d:%d), data moved to PEB %d",
891 e1->pnum, vol_id, lnum, e2->pnum);
892 ubi_free_vid_buf(vidb);
893
894 spin_lock(lock: &ubi->wl_lock);
895 if (!ubi->move_to_put) {
896 wl_tree_add(e: e2, root: &ubi->used);
897 e2 = NULL;
898 }
899 ubi->move_from = ubi->move_to = NULL;
900 ubi->move_to_put = ubi->wl_scheduled = 0;
901 spin_unlock(lock: &ubi->wl_lock);
902
903 err = do_sync_erase(ubi, e: e1, vol_id, lnum, torture: 0);
904 if (err) {
905 if (e2) {
906 spin_lock(lock: &ubi->wl_lock);
907 wl_entry_destroy(ubi, e: e2);
908 spin_unlock(lock: &ubi->wl_lock);
909 }
910 goto out_ro;
911 }
912
913 if (e2) {
914 /*
915 * Well, the target PEB was put meanwhile, schedule it for
916 * erasure.
917 */
918 dbg_wl("PEB %d (LEB %d:%d) was put meanwhile, erase",
919 e2->pnum, vol_id, lnum);
920 err = do_sync_erase(ubi, e: e2, vol_id, lnum, torture: 0);
921 if (err)
922 goto out_ro;
923 }
924
925 dbg_wl("done");
926 mutex_unlock(lock: &ubi->move_mutex);
927 up_read(sem: &ubi->fm_eba_sem);
928 return 0;
929
930 /*
931 * For some reasons the LEB was not moved, might be an error, might be
932 * something else. @e1 was not changed, so return it back. @e2 might
933 * have been changed, schedule it for erasure.
934 */
935out_not_moved:
936 if (vol_id != -1)
937 dbg_wl("cancel moving PEB %d (LEB %d:%d) to PEB %d (%d)",
938 e1->pnum, vol_id, lnum, e2->pnum, err);
939 else
940 dbg_wl("cancel moving PEB %d to PEB %d (%d)",
941 e1->pnum, e2->pnum, err);
942 spin_lock(lock: &ubi->wl_lock);
943 if (protect)
944 prot_queue_add(ubi, e: e1);
945 else if (erroneous) {
946 wl_tree_add(e: e1, root: &ubi->erroneous);
947 ubi->erroneous_peb_count += 1;
948 } else if (scrubbing)
949 wl_tree_add(e: e1, root: &ubi->scrub);
950 else if (keep)
951 wl_tree_add(e: e1, root: &ubi->used);
952 if (dst_leb_clean) {
953 wl_tree_add(e: e2, root: &ubi->free);
954 ubi->free_count++;
955 }
956
957 ubi_assert(!ubi->move_to_put);
958 ubi->move_from = ubi->move_to = NULL;
959 ubi->wl_scheduled = 0;
960 spin_unlock(lock: &ubi->wl_lock);
961
962 ubi_free_vid_buf(vidb);
963 if (dst_leb_clean) {
964 ensure_wear_leveling(ubi, nested: 1);
965 } else {
966 err = do_sync_erase(ubi, e: e2, vol_id, lnum, torture);
967 if (err)
968 goto out_ro;
969 }
970
971 if (erase) {
972 err = do_sync_erase(ubi, e: e1, vol_id, lnum, torture: 1);
973 if (err)
974 goto out_ro;
975 }
976
977 mutex_unlock(lock: &ubi->move_mutex);
978 up_read(sem: &ubi->fm_eba_sem);
979 return 0;
980
981out_error:
982 if (vol_id != -1)
983 ubi_err(ubi, fmt: "error %d while moving PEB %d to PEB %d",
984 err, e1->pnum, e2->pnum);
985 else
986 ubi_err(ubi, fmt: "error %d while moving PEB %d (LEB %d:%d) to PEB %d",
987 err, e1->pnum, vol_id, lnum, e2->pnum);
988 spin_lock(lock: &ubi->wl_lock);
989 ubi->move_from = ubi->move_to = NULL;
990 ubi->move_to_put = ubi->wl_scheduled = 0;
991 wl_entry_destroy(ubi, e: e1);
992 wl_entry_destroy(ubi, e: e2);
993 spin_unlock(lock: &ubi->wl_lock);
994
995 ubi_free_vid_buf(vidb);
996
997out_ro:
998 ubi_ro_mode(ubi);
999 mutex_unlock(lock: &ubi->move_mutex);
1000 up_read(sem: &ubi->fm_eba_sem);
1001 ubi_assert(err != 0);
1002 return err < 0 ? err : -EIO;
1003
1004out_cancel:
1005 ubi->wl_scheduled = 0;
1006 spin_unlock(lock: &ubi->wl_lock);
1007 mutex_unlock(lock: &ubi->move_mutex);
1008 up_read(sem: &ubi->fm_eba_sem);
1009 ubi_free_vid_buf(vidb);
1010 return 0;
1011}
1012
1013/**
1014 * ensure_wear_leveling - schedule wear-leveling if it is needed.
1015 * @ubi: UBI device description object
1016 * @nested: set to non-zero if this function is called from UBI worker
1017 *
1018 * This function checks if it is time to start wear-leveling and schedules it
1019 * if yes. This function returns zero in case of success and a negative error
1020 * code in case of failure.
1021 */
1022static int ensure_wear_leveling(struct ubi_device *ubi, int nested)
1023{
1024 int err = 0;
1025 struct ubi_work *wrk;
1026
1027 spin_lock(lock: &ubi->wl_lock);
1028 if (ubi->wl_scheduled)
1029 /* Wear-leveling is already in the work queue */
1030 goto out_unlock;
1031
1032 /*
1033 * If the ubi->scrub tree is not empty, scrubbing is needed, and the
1034 * WL worker has to be scheduled anyway.
1035 */
1036 if (!ubi->scrub.rb_node) {
1037#ifdef CONFIG_MTD_UBI_FASTMAP
1038 if (!need_wear_leveling(ubi))
1039 goto out_unlock;
1040#else
1041 struct ubi_wl_entry *e1;
1042 struct ubi_wl_entry *e2;
1043
1044 if (!ubi->used.rb_node || !ubi->free.rb_node)
1045 /* No physical eraseblocks - no deal */
1046 goto out_unlock;
1047
1048 /*
1049 * We schedule wear-leveling only if the difference between the
1050 * lowest erase counter of used physical eraseblocks and a high
1051 * erase counter of free physical eraseblocks is greater than
1052 * %UBI_WL_THRESHOLD.
1053 */
1054 e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
1055 e2 = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF, 0);
1056
1057 if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD))
1058 goto out_unlock;
1059#endif
1060 dbg_wl("schedule wear-leveling");
1061 } else
1062 dbg_wl("schedule scrubbing");
1063
1064 ubi->wl_scheduled = 1;
1065 spin_unlock(lock: &ubi->wl_lock);
1066
1067 wrk = kmalloc(size: sizeof(struct ubi_work), GFP_NOFS);
1068 if (!wrk) {
1069 err = -ENOMEM;
1070 goto out_cancel;
1071 }
1072
1073 wrk->func = &wear_leveling_worker;
1074 if (nested)
1075 __schedule_ubi_work(ubi, wrk);
1076 else
1077 schedule_ubi_work(ubi, wrk);
1078 return err;
1079
1080out_cancel:
1081 spin_lock(lock: &ubi->wl_lock);
1082 ubi->wl_scheduled = 0;
1083out_unlock:
1084 spin_unlock(lock: &ubi->wl_lock);
1085 return err;
1086}
1087
1088/**
1089 * __erase_worker - physical eraseblock erase worker function.
1090 * @ubi: UBI device description object
1091 * @wl_wrk: the work object
1092 *
1093 * This function erases a physical eraseblock and perform torture testing if
1094 * needed. It also takes care about marking the physical eraseblock bad if
1095 * needed. Returns zero in case of success and a negative error code in case of
1096 * failure.
1097 */
1098static int __erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk)
1099{
1100 struct ubi_wl_entry *e = wl_wrk->e;
1101 int pnum = e->pnum;
1102 int vol_id = wl_wrk->vol_id;
1103 int lnum = wl_wrk->lnum;
1104 int err, available_consumed = 0;
1105
1106 dbg_wl("erase PEB %d EC %d LEB %d:%d",
1107 pnum, e->ec, wl_wrk->vol_id, wl_wrk->lnum);
1108
1109 err = ubi_sync_erase(ubi, e, torture: wl_wrk->torture);
1110 if (!err) {
1111 spin_lock(lock: &ubi->wl_lock);
1112
1113 if (!ubi->fm_disabled && !ubi->fm_anchor &&
1114 e->pnum < UBI_FM_MAX_START) {
1115 /*
1116 * Abort anchor production, if needed it will be
1117 * enabled again in the wear leveling started below.
1118 */
1119 ubi->fm_anchor = e;
1120 ubi->fm_do_produce_anchor = 0;
1121 } else {
1122 wl_tree_add(e, root: &ubi->free);
1123 ubi->free_count++;
1124 }
1125
1126 spin_unlock(lock: &ubi->wl_lock);
1127
1128 /*
1129 * One more erase operation has happened, take care about
1130 * protected physical eraseblocks.
1131 */
1132 serve_prot_queue(ubi);
1133
1134 /* And take care about wear-leveling */
1135 err = ensure_wear_leveling(ubi, nested: 1);
1136 return err;
1137 }
1138
1139 ubi_err(ubi, fmt: "failed to erase PEB %d, error %d", pnum, err);
1140
1141 if (err == -EINTR || err == -ENOMEM || err == -EAGAIN ||
1142 err == -EBUSY) {
1143 int err1;
1144
1145 /* Re-schedule the LEB for erasure */
1146 err1 = schedule_erase(ubi, e, vol_id, lnum, torture: 0, nested: true);
1147 if (err1) {
1148 spin_lock(lock: &ubi->wl_lock);
1149 wl_entry_destroy(ubi, e);
1150 spin_unlock(lock: &ubi->wl_lock);
1151 err = err1;
1152 goto out_ro;
1153 }
1154 return err;
1155 }
1156
1157 spin_lock(lock: &ubi->wl_lock);
1158 wl_entry_destroy(ubi, e);
1159 spin_unlock(lock: &ubi->wl_lock);
1160 if (err != -EIO)
1161 /*
1162 * If this is not %-EIO, we have no idea what to do. Scheduling
1163 * this physical eraseblock for erasure again would cause
1164 * errors again and again. Well, lets switch to R/O mode.
1165 */
1166 goto out_ro;
1167
1168 /* It is %-EIO, the PEB went bad */
1169
1170 if (!ubi->bad_allowed) {
1171 ubi_err(ubi, fmt: "bad physical eraseblock %d detected", pnum);
1172 goto out_ro;
1173 }
1174
1175 spin_lock(lock: &ubi->volumes_lock);
1176 if (ubi->beb_rsvd_pebs == 0) {
1177 if (ubi->avail_pebs == 0) {
1178 spin_unlock(lock: &ubi->volumes_lock);
1179 ubi_err(ubi, fmt: "no reserved/available physical eraseblocks");
1180 goto out_ro;
1181 }
1182 ubi->avail_pebs -= 1;
1183 available_consumed = 1;
1184 }
1185 spin_unlock(lock: &ubi->volumes_lock);
1186
1187 ubi_msg(ubi, fmt: "mark PEB %d as bad", pnum);
1188 err = ubi_io_mark_bad(ubi, pnum);
1189 if (err)
1190 goto out_ro;
1191
1192 spin_lock(lock: &ubi->volumes_lock);
1193 if (ubi->beb_rsvd_pebs > 0) {
1194 if (available_consumed) {
1195 /*
1196 * The amount of reserved PEBs increased since we last
1197 * checked.
1198 */
1199 ubi->avail_pebs += 1;
1200 available_consumed = 0;
1201 }
1202 ubi->beb_rsvd_pebs -= 1;
1203 }
1204 ubi->bad_peb_count += 1;
1205 ubi->good_peb_count -= 1;
1206 ubi_calculate_reserved(ubi);
1207 if (available_consumed)
1208 ubi_warn(ubi, fmt: "no PEBs in the reserved pool, used an available PEB");
1209 else if (ubi->beb_rsvd_pebs)
1210 ubi_msg(ubi, fmt: "%d PEBs left in the reserve",
1211 ubi->beb_rsvd_pebs);
1212 else
1213 ubi_warn(ubi, fmt: "last PEB from the reserve was used");
1214 spin_unlock(lock: &ubi->volumes_lock);
1215
1216 return err;
1217
1218out_ro:
1219 if (available_consumed) {
1220 spin_lock(lock: &ubi->volumes_lock);
1221 ubi->avail_pebs += 1;
1222 spin_unlock(lock: &ubi->volumes_lock);
1223 }
1224 ubi_ro_mode(ubi);
1225 return err;
1226}
1227
1228static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
1229 int shutdown)
1230{
1231 int ret;
1232
1233 if (shutdown) {
1234 struct ubi_wl_entry *e = wl_wrk->e;
1235
1236 dbg_wl("cancel erasure of PEB %d EC %d", e->pnum, e->ec);
1237 kfree(objp: wl_wrk);
1238 wl_entry_destroy(ubi, e);
1239 return 0;
1240 }
1241
1242 ret = __erase_worker(ubi, wl_wrk);
1243 kfree(objp: wl_wrk);
1244 return ret;
1245}
1246
1247/**
1248 * ubi_wl_put_peb - return a PEB to the wear-leveling sub-system.
1249 * @ubi: UBI device description object
1250 * @vol_id: the volume ID that last used this PEB
1251 * @lnum: the last used logical eraseblock number for the PEB
1252 * @pnum: physical eraseblock to return
1253 * @torture: if this physical eraseblock has to be tortured
1254 *
1255 * This function is called to return physical eraseblock @pnum to the pool of
1256 * free physical eraseblocks. The @torture flag has to be set if an I/O error
1257 * occurred to this @pnum and it has to be tested. This function returns zero
1258 * in case of success, and a negative error code in case of failure.
1259 */
1260int ubi_wl_put_peb(struct ubi_device *ubi, int vol_id, int lnum,
1261 int pnum, int torture)
1262{
1263 int err;
1264 struct ubi_wl_entry *e;
1265
1266 dbg_wl("PEB %d", pnum);
1267 ubi_assert(pnum >= 0);
1268 ubi_assert(pnum < ubi->peb_count);
1269
1270 down_read(sem: &ubi->fm_protect);
1271
1272retry:
1273 spin_lock(lock: &ubi->wl_lock);
1274 e = ubi->lookuptbl[pnum];
1275 if (!e) {
1276 /*
1277 * This wl entry has been removed for some errors by other
1278 * process (eg. wear leveling worker), corresponding process
1279 * (except __erase_worker, which cannot concurrent with
1280 * ubi_wl_put_peb) will set ubi ro_mode at the same time,
1281 * just ignore this wl entry.
1282 */
1283 spin_unlock(lock: &ubi->wl_lock);
1284 up_read(sem: &ubi->fm_protect);
1285 return 0;
1286 }
1287 if (e == ubi->move_from) {
1288 /*
1289 * User is putting the physical eraseblock which was selected to
1290 * be moved. It will be scheduled for erasure in the
1291 * wear-leveling worker.
1292 */
1293 dbg_wl("PEB %d is being moved, wait", pnum);
1294 spin_unlock(lock: &ubi->wl_lock);
1295
1296 /* Wait for the WL worker by taking the @ubi->move_mutex */
1297 mutex_lock(&ubi->move_mutex);
1298 mutex_unlock(lock: &ubi->move_mutex);
1299 goto retry;
1300 } else if (e == ubi->move_to) {
1301 /*
1302 * User is putting the physical eraseblock which was selected
1303 * as the target the data is moved to. It may happen if the EBA
1304 * sub-system already re-mapped the LEB in 'ubi_eba_copy_leb()'
1305 * but the WL sub-system has not put the PEB to the "used" tree
1306 * yet, but it is about to do this. So we just set a flag which
1307 * will tell the WL worker that the PEB is not needed anymore
1308 * and should be scheduled for erasure.
1309 */
1310 dbg_wl("PEB %d is the target of data moving", pnum);
1311 ubi_assert(!ubi->move_to_put);
1312 ubi->move_to_put = 1;
1313 spin_unlock(lock: &ubi->wl_lock);
1314 up_read(sem: &ubi->fm_protect);
1315 return 0;
1316 } else {
1317 if (in_wl_tree(e, root: &ubi->used)) {
1318 self_check_in_wl_tree(ubi, e, root: &ubi->used);
1319 rb_erase(&e->u.rb, &ubi->used);
1320 } else if (in_wl_tree(e, root: &ubi->scrub)) {
1321 self_check_in_wl_tree(ubi, e, root: &ubi->scrub);
1322 rb_erase(&e->u.rb, &ubi->scrub);
1323 } else if (in_wl_tree(e, root: &ubi->erroneous)) {
1324 self_check_in_wl_tree(ubi, e, root: &ubi->erroneous);
1325 rb_erase(&e->u.rb, &ubi->erroneous);
1326 ubi->erroneous_peb_count -= 1;
1327 ubi_assert(ubi->erroneous_peb_count >= 0);
1328 /* Erroneous PEBs should be tortured */
1329 torture = 1;
1330 } else {
1331 err = prot_queue_del(ubi, pnum: e->pnum);
1332 if (err) {
1333 ubi_err(ubi, fmt: "PEB %d not found", pnum);
1334 ubi_ro_mode(ubi);
1335 spin_unlock(lock: &ubi->wl_lock);
1336 up_read(sem: &ubi->fm_protect);
1337 return err;
1338 }
1339 }
1340 }
1341 spin_unlock(lock: &ubi->wl_lock);
1342
1343 err = schedule_erase(ubi, e, vol_id, lnum, torture, nested: false);
1344 if (err) {
1345 spin_lock(lock: &ubi->wl_lock);
1346 wl_tree_add(e, root: &ubi->used);
1347 spin_unlock(lock: &ubi->wl_lock);
1348 }
1349
1350 up_read(sem: &ubi->fm_protect);
1351 return err;
1352}
1353
1354/**
1355 * ubi_wl_scrub_peb - schedule a physical eraseblock for scrubbing.
1356 * @ubi: UBI device description object
1357 * @pnum: the physical eraseblock to schedule
1358 *
1359 * If a bit-flip in a physical eraseblock is detected, this physical eraseblock
1360 * needs scrubbing. This function schedules a physical eraseblock for
1361 * scrubbing which is done in background. This function returns zero in case of
1362 * success and a negative error code in case of failure.
1363 */
1364int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum)
1365{
1366 struct ubi_wl_entry *e;
1367
1368 ubi_msg(ubi, fmt: "schedule PEB %d for scrubbing", pnum);
1369
1370retry:
1371 spin_lock(lock: &ubi->wl_lock);
1372 e = ubi->lookuptbl[pnum];
1373 if (e == ubi->move_from || in_wl_tree(e, root: &ubi->scrub) ||
1374 in_wl_tree(e, root: &ubi->erroneous)) {
1375 spin_unlock(lock: &ubi->wl_lock);
1376 return 0;
1377 }
1378
1379 if (e == ubi->move_to) {
1380 /*
1381 * This physical eraseblock was used to move data to. The data
1382 * was moved but the PEB was not yet inserted to the proper
1383 * tree. We should just wait a little and let the WL worker
1384 * proceed.
1385 */
1386 spin_unlock(lock: &ubi->wl_lock);
1387 dbg_wl("the PEB %d is not in proper tree, retry", pnum);
1388 yield();
1389 goto retry;
1390 }
1391
1392 if (in_wl_tree(e, root: &ubi->used)) {
1393 self_check_in_wl_tree(ubi, e, root: &ubi->used);
1394 rb_erase(&e->u.rb, &ubi->used);
1395 } else {
1396 int err;
1397
1398 err = prot_queue_del(ubi, pnum: e->pnum);
1399 if (err) {
1400 ubi_err(ubi, fmt: "PEB %d not found", pnum);
1401 ubi_ro_mode(ubi);
1402 spin_unlock(lock: &ubi->wl_lock);
1403 return err;
1404 }
1405 }
1406
1407 wl_tree_add(e, root: &ubi->scrub);
1408 spin_unlock(lock: &ubi->wl_lock);
1409
1410 /*
1411 * Technically scrubbing is the same as wear-leveling, so it is done
1412 * by the WL worker.
1413 */
1414 return ensure_wear_leveling(ubi, nested: 0);
1415}
1416
1417/**
1418 * ubi_wl_flush - flush all pending works.
1419 * @ubi: UBI device description object
1420 * @vol_id: the volume id to flush for
1421 * @lnum: the logical eraseblock number to flush for
1422 *
1423 * This function executes all pending works for a particular volume id /
1424 * logical eraseblock number pair. If either value is set to %UBI_ALL, then it
1425 * acts as a wildcard for all of the corresponding volume numbers or logical
1426 * eraseblock numbers. It returns zero in case of success and a negative error
1427 * code in case of failure.
1428 */
1429int ubi_wl_flush(struct ubi_device *ubi, int vol_id, int lnum)
1430{
1431 int err = 0;
1432 int found = 1;
1433
1434 /*
1435 * Erase while the pending works queue is not empty, but not more than
1436 * the number of currently pending works.
1437 */
1438 dbg_wl("flush pending work for LEB %d:%d (%d pending works)",
1439 vol_id, lnum, ubi->works_count);
1440
1441 while (found) {
1442 struct ubi_work *wrk, *tmp;
1443 found = 0;
1444
1445 down_read(sem: &ubi->work_sem);
1446 spin_lock(lock: &ubi->wl_lock);
1447 list_for_each_entry_safe(wrk, tmp, &ubi->works, list) {
1448 if ((vol_id == UBI_ALL || wrk->vol_id == vol_id) &&
1449 (lnum == UBI_ALL || wrk->lnum == lnum)) {
1450 list_del(entry: &wrk->list);
1451 ubi->works_count -= 1;
1452 ubi_assert(ubi->works_count >= 0);
1453 spin_unlock(lock: &ubi->wl_lock);
1454
1455 err = wrk->func(ubi, wrk, 0);
1456 if (err) {
1457 up_read(sem: &ubi->work_sem);
1458 return err;
1459 }
1460
1461 spin_lock(lock: &ubi->wl_lock);
1462 found = 1;
1463 break;
1464 }
1465 }
1466 spin_unlock(lock: &ubi->wl_lock);
1467 up_read(sem: &ubi->work_sem);
1468 }
1469
1470 /*
1471 * Make sure all the works which have been done in parallel are
1472 * finished.
1473 */
1474 down_write(sem: &ubi->work_sem);
1475 up_write(sem: &ubi->work_sem);
1476
1477 return err;
1478}
1479
1480static bool scrub_possible(struct ubi_device *ubi, struct ubi_wl_entry *e)
1481{
1482 if (in_wl_tree(e, root: &ubi->scrub))
1483 return false;
1484 else if (in_wl_tree(e, root: &ubi->erroneous))
1485 return false;
1486 else if (ubi->move_from == e)
1487 return false;
1488 else if (ubi->move_to == e)
1489 return false;
1490
1491 return true;
1492}
1493
1494/**
1495 * ubi_bitflip_check - Check an eraseblock for bitflips and scrub it if needed.
1496 * @ubi: UBI device description object
1497 * @pnum: the physical eraseblock to schedule
1498 * @force: don't read the block, assume bitflips happened and take action.
1499 *
1500 * This function reads the given eraseblock and checks if bitflips occured.
1501 * In case of bitflips, the eraseblock is scheduled for scrubbing.
1502 * If scrubbing is forced with @force, the eraseblock is not read,
1503 * but scheduled for scrubbing right away.
1504 *
1505 * Returns:
1506 * %EINVAL, PEB is out of range
1507 * %ENOENT, PEB is no longer used by UBI
1508 * %EBUSY, PEB cannot be checked now or a check is currently running on it
1509 * %EAGAIN, bit flips happened but scrubbing is currently not possible
1510 * %EUCLEAN, bit flips happened and PEB is scheduled for scrubbing
1511 * %0, no bit flips detected
1512 */
1513int ubi_bitflip_check(struct ubi_device *ubi, int pnum, int force)
1514{
1515 int err = 0;
1516 struct ubi_wl_entry *e;
1517
1518 if (pnum < 0 || pnum >= ubi->peb_count) {
1519 err = -EINVAL;
1520 goto out;
1521 }
1522
1523 /*
1524 * Pause all parallel work, otherwise it can happen that the
1525 * erase worker frees a wl entry under us.
1526 */
1527 down_write(sem: &ubi->work_sem);
1528
1529 /*
1530 * Make sure that the wl entry does not change state while
1531 * inspecting it.
1532 */
1533 spin_lock(lock: &ubi->wl_lock);
1534 e = ubi->lookuptbl[pnum];
1535 if (!e) {
1536 spin_unlock(lock: &ubi->wl_lock);
1537 err = -ENOENT;
1538 goto out_resume;
1539 }
1540
1541 /*
1542 * Does it make sense to check this PEB?
1543 */
1544 if (!scrub_possible(ubi, e)) {
1545 spin_unlock(lock: &ubi->wl_lock);
1546 err = -EBUSY;
1547 goto out_resume;
1548 }
1549 spin_unlock(lock: &ubi->wl_lock);
1550
1551 if (!force) {
1552 mutex_lock(&ubi->buf_mutex);
1553 err = ubi_io_read(ubi, buf: ubi->peb_buf, pnum, offset: 0, len: ubi->peb_size);
1554 mutex_unlock(lock: &ubi->buf_mutex);
1555 }
1556
1557 if (force || err == UBI_IO_BITFLIPS) {
1558 /*
1559 * Okay, bit flip happened, let's figure out what we can do.
1560 */
1561 spin_lock(lock: &ubi->wl_lock);
1562
1563 /*
1564 * Recheck. We released wl_lock, UBI might have killed the
1565 * wl entry under us.
1566 */
1567 e = ubi->lookuptbl[pnum];
1568 if (!e) {
1569 spin_unlock(lock: &ubi->wl_lock);
1570 err = -ENOENT;
1571 goto out_resume;
1572 }
1573
1574 /*
1575 * Need to re-check state
1576 */
1577 if (!scrub_possible(ubi, e)) {
1578 spin_unlock(lock: &ubi->wl_lock);
1579 err = -EBUSY;
1580 goto out_resume;
1581 }
1582
1583 if (in_pq(ubi, e)) {
1584 prot_queue_del(ubi, pnum: e->pnum);
1585 wl_tree_add(e, root: &ubi->scrub);
1586 spin_unlock(lock: &ubi->wl_lock);
1587
1588 err = ensure_wear_leveling(ubi, nested: 1);
1589 } else if (in_wl_tree(e, root: &ubi->used)) {
1590 rb_erase(&e->u.rb, &ubi->used);
1591 wl_tree_add(e, root: &ubi->scrub);
1592 spin_unlock(lock: &ubi->wl_lock);
1593
1594 err = ensure_wear_leveling(ubi, nested: 1);
1595 } else if (in_wl_tree(e, root: &ubi->free)) {
1596 rb_erase(&e->u.rb, &ubi->free);
1597 ubi->free_count--;
1598 spin_unlock(lock: &ubi->wl_lock);
1599
1600 /*
1601 * This PEB is empty we can schedule it for
1602 * erasure right away. No wear leveling needed.
1603 */
1604 err = schedule_erase(ubi, e, UBI_UNKNOWN, UBI_UNKNOWN,
1605 torture: force ? 0 : 1, nested: true);
1606 } else {
1607 spin_unlock(lock: &ubi->wl_lock);
1608 err = -EAGAIN;
1609 }
1610
1611 if (!err && !force)
1612 err = -EUCLEAN;
1613 } else {
1614 err = 0;
1615 }
1616
1617out_resume:
1618 up_write(sem: &ubi->work_sem);
1619out:
1620
1621 return err;
1622}
1623
1624/**
1625 * tree_destroy - destroy an RB-tree.
1626 * @ubi: UBI device description object
1627 * @root: the root of the tree to destroy
1628 */
1629static void tree_destroy(struct ubi_device *ubi, struct rb_root *root)
1630{
1631 struct rb_node *rb;
1632 struct ubi_wl_entry *e;
1633
1634 rb = root->rb_node;
1635 while (rb) {
1636 if (rb->rb_left)
1637 rb = rb->rb_left;
1638 else if (rb->rb_right)
1639 rb = rb->rb_right;
1640 else {
1641 e = rb_entry(rb, struct ubi_wl_entry, u.rb);
1642
1643 rb = rb_parent(rb);
1644 if (rb) {
1645 if (rb->rb_left == &e->u.rb)
1646 rb->rb_left = NULL;
1647 else
1648 rb->rb_right = NULL;
1649 }
1650
1651 wl_entry_destroy(ubi, e);
1652 }
1653 }
1654}
1655
1656/**
1657 * ubi_thread - UBI background thread.
1658 * @u: the UBI device description object pointer
1659 */
1660int ubi_thread(void *u)
1661{
1662 int failures = 0;
1663 struct ubi_device *ubi = u;
1664
1665 ubi_msg(ubi, fmt: "background thread \"%s\" started, PID %d",
1666 ubi->bgt_name, task_pid_nr(current));
1667
1668 set_freezable();
1669 for (;;) {
1670 int err;
1671
1672 if (kthread_should_stop())
1673 break;
1674
1675 if (try_to_freeze())
1676 continue;
1677
1678 spin_lock(lock: &ubi->wl_lock);
1679 if (list_empty(head: &ubi->works) || ubi->ro_mode ||
1680 !ubi->thread_enabled || ubi_dbg_is_bgt_disabled(ubi)) {
1681 set_current_state(TASK_INTERRUPTIBLE);
1682 spin_unlock(lock: &ubi->wl_lock);
1683
1684 /*
1685 * Check kthread_should_stop() after we set the task
1686 * state to guarantee that we either see the stop bit
1687 * and exit or the task state is reset to runnable such
1688 * that it's not scheduled out indefinitely and detects
1689 * the stop bit at kthread_should_stop().
1690 */
1691 if (kthread_should_stop()) {
1692 set_current_state(TASK_RUNNING);
1693 break;
1694 }
1695
1696 schedule();
1697 continue;
1698 }
1699 spin_unlock(lock: &ubi->wl_lock);
1700
1701 err = do_work(ubi, NULL);
1702 if (err) {
1703 ubi_err(ubi, fmt: "%s: work failed with error code %d",
1704 ubi->bgt_name, err);
1705 if (failures++ > WL_MAX_FAILURES) {
1706 /*
1707 * Too many failures, disable the thread and
1708 * switch to read-only mode.
1709 */
1710 ubi_msg(ubi, fmt: "%s: %d consecutive failures",
1711 ubi->bgt_name, WL_MAX_FAILURES);
1712 ubi_ro_mode(ubi);
1713 ubi->thread_enabled = 0;
1714 continue;
1715 }
1716 } else
1717 failures = 0;
1718
1719 cond_resched();
1720 }
1721
1722 dbg_wl("background thread \"%s\" is killed", ubi->bgt_name);
1723 ubi->thread_enabled = 0;
1724 return 0;
1725}
1726
1727/**
1728 * shutdown_work - shutdown all pending works.
1729 * @ubi: UBI device description object
1730 */
1731static void shutdown_work(struct ubi_device *ubi)
1732{
1733 while (!list_empty(head: &ubi->works)) {
1734 struct ubi_work *wrk;
1735
1736 wrk = list_entry(ubi->works.next, struct ubi_work, list);
1737 list_del(entry: &wrk->list);
1738 wrk->func(ubi, wrk, 1);
1739 ubi->works_count -= 1;
1740 ubi_assert(ubi->works_count >= 0);
1741 }
1742}
1743
1744/**
1745 * erase_aeb - erase a PEB given in UBI attach info PEB
1746 * @ubi: UBI device description object
1747 * @aeb: UBI attach info PEB
1748 * @sync: If true, erase synchronously. Otherwise schedule for erasure
1749 */
1750static int erase_aeb(struct ubi_device *ubi, struct ubi_ainf_peb *aeb, bool sync)
1751{
1752 struct ubi_wl_entry *e;
1753 int err;
1754
1755 e = kmem_cache_alloc(cachep: ubi_wl_entry_slab, GFP_KERNEL);
1756 if (!e)
1757 return -ENOMEM;
1758
1759 e->pnum = aeb->pnum;
1760 e->ec = aeb->ec;
1761 ubi->lookuptbl[e->pnum] = e;
1762
1763 if (sync) {
1764 err = ubi_sync_erase(ubi, e, torture: false);
1765 if (err)
1766 goto out_free;
1767
1768 wl_tree_add(e, root: &ubi->free);
1769 ubi->free_count++;
1770 } else {
1771 err = schedule_erase(ubi, e, vol_id: aeb->vol_id, lnum: aeb->lnum, torture: 0, nested: false);
1772 if (err)
1773 goto out_free;
1774 }
1775
1776 return 0;
1777
1778out_free:
1779 wl_entry_destroy(ubi, e);
1780
1781 return err;
1782}
1783
1784/**
1785 * ubi_wl_init - initialize the WL sub-system using attaching information.
1786 * @ubi: UBI device description object
1787 * @ai: attaching information
1788 *
1789 * This function returns zero in case of success, and a negative error code in
1790 * case of failure.
1791 */
1792int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
1793{
1794 int err, i, reserved_pebs, found_pebs = 0;
1795 struct rb_node *rb1, *rb2;
1796 struct ubi_ainf_volume *av;
1797 struct ubi_ainf_peb *aeb, *tmp;
1798 struct ubi_wl_entry *e;
1799
1800 ubi->used = ubi->erroneous = ubi->free = ubi->scrub = RB_ROOT;
1801 spin_lock_init(&ubi->wl_lock);
1802 mutex_init(&ubi->move_mutex);
1803 init_rwsem(&ubi->work_sem);
1804 ubi->max_ec = ai->max_ec;
1805 INIT_LIST_HEAD(list: &ubi->works);
1806
1807 sprintf(buf: ubi->bgt_name, UBI_BGT_NAME_PATTERN, ubi->ubi_num);
1808
1809 err = -ENOMEM;
1810 ubi->lookuptbl = kcalloc(n: ubi->peb_count, size: sizeof(void *), GFP_KERNEL);
1811 if (!ubi->lookuptbl)
1812 return err;
1813
1814 for (i = 0; i < UBI_PROT_QUEUE_LEN; i++)
1815 INIT_LIST_HEAD(list: &ubi->pq[i]);
1816 ubi->pq_head = 0;
1817
1818 ubi->free_count = 0;
1819 list_for_each_entry_safe(aeb, tmp, &ai->erase, u.list) {
1820 cond_resched();
1821
1822 err = erase_aeb(ubi, aeb, sync: false);
1823 if (err)
1824 goto out_free;
1825
1826 found_pebs++;
1827 }
1828
1829 list_for_each_entry(aeb, &ai->free, u.list) {
1830 cond_resched();
1831
1832 e = kmem_cache_alloc(cachep: ubi_wl_entry_slab, GFP_KERNEL);
1833 if (!e) {
1834 err = -ENOMEM;
1835 goto out_free;
1836 }
1837
1838 e->pnum = aeb->pnum;
1839 e->ec = aeb->ec;
1840 ubi_assert(e->ec >= 0);
1841
1842 wl_tree_add(e, root: &ubi->free);
1843 ubi->free_count++;
1844
1845 ubi->lookuptbl[e->pnum] = e;
1846
1847 found_pebs++;
1848 }
1849
1850 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
1851 ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) {
1852 cond_resched();
1853
1854 e = kmem_cache_alloc(cachep: ubi_wl_entry_slab, GFP_KERNEL);
1855 if (!e) {
1856 err = -ENOMEM;
1857 goto out_free;
1858 }
1859
1860 e->pnum = aeb->pnum;
1861 e->ec = aeb->ec;
1862 ubi->lookuptbl[e->pnum] = e;
1863
1864 if (!aeb->scrub) {
1865 dbg_wl("add PEB %d EC %d to the used tree",
1866 e->pnum, e->ec);
1867 wl_tree_add(e, root: &ubi->used);
1868 } else {
1869 dbg_wl("add PEB %d EC %d to the scrub tree",
1870 e->pnum, e->ec);
1871 wl_tree_add(e, root: &ubi->scrub);
1872 }
1873
1874 found_pebs++;
1875 }
1876 }
1877
1878 list_for_each_entry(aeb, &ai->fastmap, u.list) {
1879 cond_resched();
1880
1881 e = ubi_find_fm_block(ubi, pnum: aeb->pnum);
1882
1883 if (e) {
1884 ubi_assert(!ubi->lookuptbl[e->pnum]);
1885 ubi->lookuptbl[e->pnum] = e;
1886 } else {
1887 bool sync = false;
1888
1889 /*
1890 * Usually old Fastmap PEBs are scheduled for erasure
1891 * and we don't have to care about them but if we face
1892 * an power cut before scheduling them we need to
1893 * take care of them here.
1894 */
1895 if (ubi->lookuptbl[aeb->pnum])
1896 continue;
1897
1898 /*
1899 * The fastmap update code might not find a free PEB for
1900 * writing the fastmap anchor to and then reuses the
1901 * current fastmap anchor PEB. When this PEB gets erased
1902 * and a power cut happens before it is written again we
1903 * must make sure that the fastmap attach code doesn't
1904 * find any outdated fastmap anchors, hence we erase the
1905 * outdated fastmap anchor PEBs synchronously here.
1906 */
1907 if (aeb->vol_id == UBI_FM_SB_VOLUME_ID)
1908 sync = true;
1909
1910 err = erase_aeb(ubi, aeb, sync);
1911 if (err)
1912 goto out_free;
1913 }
1914
1915 found_pebs++;
1916 }
1917
1918 dbg_wl("found %i PEBs", found_pebs);
1919
1920 ubi_assert(ubi->good_peb_count == found_pebs);
1921
1922 reserved_pebs = WL_RESERVED_PEBS;
1923 ubi_fastmap_init(ubi, count: &reserved_pebs);
1924
1925 if (ubi->avail_pebs < reserved_pebs) {
1926 ubi_err(ubi, fmt: "no enough physical eraseblocks (%d, need %d)",
1927 ubi->avail_pebs, reserved_pebs);
1928 if (ubi->corr_peb_count)
1929 ubi_err(ubi, fmt: "%d PEBs are corrupted and not used",
1930 ubi->corr_peb_count);
1931 err = -ENOSPC;
1932 goto out_free;
1933 }
1934 ubi->avail_pebs -= reserved_pebs;
1935 ubi->rsvd_pebs += reserved_pebs;
1936
1937 /* Schedule wear-leveling if needed */
1938 err = ensure_wear_leveling(ubi, nested: 0);
1939 if (err)
1940 goto out_free;
1941
1942#ifdef CONFIG_MTD_UBI_FASTMAP
1943 if (!ubi->ro_mode && !ubi->fm_disabled)
1944 ubi_ensure_anchor_pebs(ubi);
1945#endif
1946 return 0;
1947
1948out_free:
1949 shutdown_work(ubi);
1950 tree_destroy(ubi, root: &ubi->used);
1951 tree_destroy(ubi, root: &ubi->free);
1952 tree_destroy(ubi, root: &ubi->scrub);
1953 kfree(objp: ubi->lookuptbl);
1954 return err;
1955}
1956
1957/**
1958 * protection_queue_destroy - destroy the protection queue.
1959 * @ubi: UBI device description object
1960 */
1961static void protection_queue_destroy(struct ubi_device *ubi)
1962{
1963 int i;
1964 struct ubi_wl_entry *e, *tmp;
1965
1966 for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i) {
1967 list_for_each_entry_safe(e, tmp, &ubi->pq[i], u.list) {
1968 list_del(entry: &e->u.list);
1969 wl_entry_destroy(ubi, e);
1970 }
1971 }
1972}
1973
1974/**
1975 * ubi_wl_close - close the wear-leveling sub-system.
1976 * @ubi: UBI device description object
1977 */
1978void ubi_wl_close(struct ubi_device *ubi)
1979{
1980 dbg_wl("close the WL sub-system");
1981 ubi_fastmap_close(ubi);
1982 shutdown_work(ubi);
1983 protection_queue_destroy(ubi);
1984 tree_destroy(ubi, root: &ubi->used);
1985 tree_destroy(ubi, root: &ubi->erroneous);
1986 tree_destroy(ubi, root: &ubi->free);
1987 tree_destroy(ubi, root: &ubi->scrub);
1988 kfree(objp: ubi->lookuptbl);
1989}
1990
1991/**
1992 * self_check_ec - make sure that the erase counter of a PEB is correct.
1993 * @ubi: UBI device description object
1994 * @pnum: the physical eraseblock number to check
1995 * @ec: the erase counter to check
1996 *
1997 * This function returns zero if the erase counter of physical eraseblock @pnum
1998 * is equivalent to @ec, and a negative error code if not or if an error
1999 * occurred.
2000 */
2001static int self_check_ec(struct ubi_device *ubi, int pnum, int ec)
2002{
2003 int err;
2004 long long read_ec;
2005 struct ubi_ec_hdr *ec_hdr;
2006
2007 if (!ubi_dbg_chk_gen(ubi))
2008 return 0;
2009
2010 ec_hdr = kzalloc(size: ubi->ec_hdr_alsize, GFP_NOFS);
2011 if (!ec_hdr)
2012 return -ENOMEM;
2013
2014 err = ubi_io_read_ec_hdr(ubi, pnum, ec_hdr, verbose: 0);
2015 if (err && err != UBI_IO_BITFLIPS) {
2016 /* The header does not have to exist */
2017 err = 0;
2018 goto out_free;
2019 }
2020
2021 read_ec = be64_to_cpu(ec_hdr->ec);
2022 if (ec != read_ec && read_ec - ec > 1) {
2023 ubi_err(ubi, fmt: "self-check failed for PEB %d", pnum);
2024 ubi_err(ubi, fmt: "read EC is %lld, should be %d", read_ec, ec);
2025 dump_stack();
2026 err = 1;
2027 } else
2028 err = 0;
2029
2030out_free:
2031 kfree(objp: ec_hdr);
2032 return err;
2033}
2034
2035/**
2036 * self_check_in_wl_tree - check that wear-leveling entry is in WL RB-tree.
2037 * @ubi: UBI device description object
2038 * @e: the wear-leveling entry to check
2039 * @root: the root of the tree
2040 *
2041 * This function returns zero if @e is in the @root RB-tree and %-EINVAL if it
2042 * is not.
2043 */
2044static int self_check_in_wl_tree(const struct ubi_device *ubi,
2045 struct ubi_wl_entry *e, struct rb_root *root)
2046{
2047 if (!ubi_dbg_chk_gen(ubi))
2048 return 0;
2049
2050 if (in_wl_tree(e, root))
2051 return 0;
2052
2053 ubi_err(ubi, fmt: "self-check failed for PEB %d, EC %d, RB-tree %p ",
2054 e->pnum, e->ec, root);
2055 dump_stack();
2056 return -EINVAL;
2057}
2058
2059/**
2060 * self_check_in_pq - check if wear-leveling entry is in the protection
2061 * queue.
2062 * @ubi: UBI device description object
2063 * @e: the wear-leveling entry to check
2064 *
2065 * This function returns zero if @e is in @ubi->pq and %-EINVAL if it is not.
2066 */
2067static int self_check_in_pq(const struct ubi_device *ubi,
2068 struct ubi_wl_entry *e)
2069{
2070 if (!ubi_dbg_chk_gen(ubi))
2071 return 0;
2072
2073 if (in_pq(ubi, e))
2074 return 0;
2075
2076 ubi_err(ubi, fmt: "self-check failed for PEB %d, EC %d, Protect queue",
2077 e->pnum, e->ec);
2078 dump_stack();
2079 return -EINVAL;
2080}
2081#ifndef CONFIG_MTD_UBI_FASTMAP
2082static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
2083{
2084 struct ubi_wl_entry *e;
2085
2086 e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF, 0);
2087 self_check_in_wl_tree(ubi, e, &ubi->free);
2088 ubi->free_count--;
2089 ubi_assert(ubi->free_count >= 0);
2090 rb_erase(&e->u.rb, &ubi->free);
2091
2092 return e;
2093}
2094
2095/**
2096 * produce_free_peb - produce a free physical eraseblock.
2097 * @ubi: UBI device description object
2098 *
2099 * This function tries to make a free PEB by means of synchronous execution of
2100 * pending works. This may be needed if, for example the background thread is
2101 * disabled. Returns zero in case of success and a negative error code in case
2102 * of failure.
2103 */
2104static int produce_free_peb(struct ubi_device *ubi)
2105{
2106 int err;
2107
2108 while (!ubi->free.rb_node && ubi->works_count) {
2109 spin_unlock(&ubi->wl_lock);
2110
2111 dbg_wl("do one work synchronously");
2112 err = do_work(ubi, NULL);
2113
2114 spin_lock(&ubi->wl_lock);
2115 if (err)
2116 return err;
2117 }
2118
2119 return 0;
2120}
2121
2122/**
2123 * ubi_wl_get_peb - get a physical eraseblock.
2124 * @ubi: UBI device description object
2125 *
2126 * This function returns a physical eraseblock in case of success and a
2127 * negative error code in case of failure.
2128 * Returns with ubi->fm_eba_sem held in read mode!
2129 */
2130int ubi_wl_get_peb(struct ubi_device *ubi)
2131{
2132 int err;
2133 struct ubi_wl_entry *e;
2134
2135retry:
2136 down_read(&ubi->fm_eba_sem);
2137 spin_lock(&ubi->wl_lock);
2138 if (!ubi->free.rb_node) {
2139 if (ubi->works_count == 0) {
2140 ubi_err(ubi, "no free eraseblocks");
2141 ubi_assert(list_empty(&ubi->works));
2142 spin_unlock(&ubi->wl_lock);
2143 return -ENOSPC;
2144 }
2145
2146 err = produce_free_peb(ubi);
2147 if (err < 0) {
2148 spin_unlock(&ubi->wl_lock);
2149 return err;
2150 }
2151 spin_unlock(&ubi->wl_lock);
2152 up_read(&ubi->fm_eba_sem);
2153 goto retry;
2154
2155 }
2156 e = wl_get_wle(ubi);
2157 prot_queue_add(ubi, e);
2158 spin_unlock(&ubi->wl_lock);
2159
2160 err = ubi_self_check_all_ff(ubi, e->pnum, ubi->vid_hdr_aloffset,
2161 ubi->peb_size - ubi->vid_hdr_aloffset);
2162 if (err) {
2163 ubi_err(ubi, "new PEB %d does not contain all 0xFF bytes", e->pnum);
2164 return err;
2165 }
2166
2167 return e->pnum;
2168}
2169#else
2170#include "fastmap-wl.c"
2171#endif
2172

source code of linux/drivers/mtd/ubi/wl.c