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