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 | */ |
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(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 | */ |
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(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 | */ |
190 | static 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 | */ |
242 | static 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 | */ |
281 | static 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 | */ |
304 | static 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 | */ |
325 | static 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 | */ |
363 | static 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 | */ |
395 | static 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 | */ |
426 | static 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 | */ |
451 | int 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 | |
497 | out_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 | */ |
510 | static 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 | */ |
519 | repeat: |
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 | */ |
554 | static 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 | */ |
573 | static 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 | |
580 | static 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 | */ |
595 | static 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 | |
622 | static 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 | */ |
632 | static 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 | |
647 | static 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 | */ |
659 | static 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 | */ |
935 | out_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 | |
981 | out_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 | |
997 | out_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 | |
1004 | out_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 | */ |
1022 | static 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 | |
1080 | out_cancel: |
1081 | spin_lock(lock: &ubi->wl_lock); |
1082 | ubi->wl_scheduled = 0; |
1083 | out_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 | */ |
1098 | static 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 | |
1218 | out_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 | |
1228 | static 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 | */ |
1260 | int 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 | |
1272 | retry: |
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 | */ |
1364 | int 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 | |
1370 | retry: |
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 | */ |
1429 | int 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 | |
1480 | static 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 | */ |
1513 | int 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 | |
1617 | out_resume: |
1618 | up_write(sem: &ubi->work_sem); |
1619 | out: |
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 | */ |
1629 | static 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 | */ |
1660 | int 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 | */ |
1731 | static 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 | */ |
1750 | static 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 | |
1778 | out_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 | */ |
1792 | int 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 | |
1948 | out_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 | */ |
1961 | static 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 | */ |
1978 | void 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 | */ |
2001 | static 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 | |
2030 | out_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 | */ |
2044 | static 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 | */ |
2067 | static 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 |
2082 | static 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 | */ |
2104 | static 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 | */ |
2130 | int ubi_wl_get_peb(struct ubi_device *ubi) |
2131 | { |
2132 | int err; |
2133 | struct ubi_wl_entry *e; |
2134 | |
2135 | retry: |
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 | |