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801c135c AB |
1 | /* |
2 | * Copyright (c) International Business Machines Corp., 2006 | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See | |
12 | * the GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
17 | * | |
18 | * Authors: Artem Bityutskiy (Битюцкий Артём), Thomas Gleixner | |
19 | */ | |
20 | ||
21 | /* | |
22 | * UBI wear-leveling unit. | |
23 | * | |
24 | * This unit is responsible for wear-leveling. It works in terms of physical | |
25 | * eraseblocks and erase counters and knows nothing about logical eraseblocks, | |
26 | * volumes, etc. From this unit's perspective all physical eraseblocks are of | |
27 | * two types - used and free. Used physical eraseblocks are those that were | |
28 | * "get" by the 'ubi_wl_get_peb()' function, and free physical eraseblocks are | |
29 | * those that were put by the 'ubi_wl_put_peb()' function. | |
30 | * | |
31 | * Physical eraseblocks returned by 'ubi_wl_get_peb()' have only erase counter | |
32 | * header. The rest of the physical eraseblock contains only 0xFF bytes. | |
33 | * | |
34 | * When physical eraseblocks are returned to the WL unit by means of the | |
35 | * 'ubi_wl_put_peb()' function, they are scheduled for erasure. The erasure is | |
36 | * done asynchronously in context of the per-UBI device background thread, | |
37 | * which is also managed by the WL unit. | |
38 | * | |
39 | * The wear-leveling is ensured by means of moving the contents of used | |
40 | * physical eraseblocks with low erase counter to free physical eraseblocks | |
41 | * with high erase counter. | |
42 | * | |
43 | * The 'ubi_wl_get_peb()' function accepts data type hints which help to pick | |
44 | * an "optimal" physical eraseblock. For example, when it is known that the | |
45 | * physical eraseblock will be "put" soon because it contains short-term data, | |
46 | * the WL unit may pick a free physical eraseblock with low erase counter, and | |
47 | * so forth. | |
48 | * | |
49 | * If the WL unit fails to erase a physical eraseblock, it marks it as bad. | |
50 | * | |
51 | * This unit is also responsible for scrubbing. If a bit-flip is detected in a | |
52 | * physical eraseblock, it has to be moved. Technically this is the same as | |
53 | * moving it for wear-leveling reasons. | |
54 | * | |
55 | * As it was said, for the UBI unit all physical eraseblocks are either "free" | |
56 | * or "used". Free eraseblock are kept in the @wl->free RB-tree, while used | |
57 | * eraseblocks are kept in a set of different RB-trees: @wl->used, | |
58 | * @wl->prot.pnum, @wl->prot.aec, and @wl->scrub. | |
59 | * | |
60 | * Note, in this implementation, we keep a small in-RAM object for each physical | |
61 | * eraseblock. This is surely not a scalable solution. But it appears to be good | |
62 | * enough for moderately large flashes and it is simple. In future, one may | |
63 | * re-work this unit and make it more scalable. | |
64 | * | |
65 | * At the moment this unit does not utilize the sequence number, which was | |
66 | * introduced relatively recently. But it would be wise to do this because the | |
67 | * sequence number of a logical eraseblock characterizes how old is it. For | |
68 | * example, when we move a PEB with low erase counter, and we need to pick the | |
69 | * target PEB, we pick a PEB with the highest EC if our PEB is "old" and we | |
70 | * pick target PEB with an average EC if our PEB is not very "old". This is a | |
71 | * room for future re-works of the WL unit. | |
72 | * | |
73 | * FIXME: looks too complex, should be simplified (later). | |
74 | */ | |
75 | ||
76 | #include <linux/slab.h> | |
77 | #include <linux/crc32.h> | |
78 | #include <linux/freezer.h> | |
79 | #include <linux/kthread.h> | |
80 | #include "ubi.h" | |
81 | ||
82 | /* Number of physical eraseblocks reserved for wear-leveling purposes */ | |
83 | #define WL_RESERVED_PEBS 1 | |
84 | ||
85 | /* | |
86 | * How many erase cycles are short term, unknown, and long term physical | |
87 | * eraseblocks protected. | |
88 | */ | |
89 | #define ST_PROTECTION 16 | |
90 | #define U_PROTECTION 10 | |
91 | #define LT_PROTECTION 4 | |
92 | ||
93 | /* | |
94 | * Maximum difference between two erase counters. If this threshold is | |
95 | * exceeded, the WL unit starts moving data from used physical eraseblocks with | |
96 | * low erase counter to free physical eraseblocks with high erase counter. | |
97 | */ | |
98 | #define UBI_WL_THRESHOLD CONFIG_MTD_UBI_WL_THRESHOLD | |
99 | ||
100 | /* | |
101 | * When a physical eraseblock is moved, the WL unit has to pick the target | |
102 | * physical eraseblock to move to. The simplest way would be just to pick the | |
103 | * one with the highest erase counter. But in certain workloads this could lead | |
104 | * to an unlimited wear of one or few physical eraseblock. Indeed, imagine a | |
105 | * situation when the picked physical eraseblock is constantly erased after the | |
106 | * data is written to it. So, we have a constant which limits the highest erase | |
107 | * counter of the free physical eraseblock to pick. Namely, the WL unit does | |
108 | * not pick eraseblocks with erase counter greater then the lowest erase | |
109 | * counter plus %WL_FREE_MAX_DIFF. | |
110 | */ | |
111 | #define WL_FREE_MAX_DIFF (2*UBI_WL_THRESHOLD) | |
112 | ||
113 | /* | |
114 | * Maximum number of consecutive background thread failures which is enough to | |
115 | * switch to read-only mode. | |
116 | */ | |
117 | #define WL_MAX_FAILURES 32 | |
118 | ||
119 | /** | |
120 | * struct ubi_wl_entry - wear-leveling entry. | |
121 | * @rb: link in the corresponding RB-tree | |
122 | * @ec: erase counter | |
123 | * @pnum: physical eraseblock number | |
124 | * | |
125 | * Each physical eraseblock has a corresponding &struct wl_entry object which | |
126 | * may be kept in different RB-trees. | |
127 | */ | |
128 | struct ubi_wl_entry { | |
129 | struct rb_node rb; | |
130 | int ec; | |
131 | int pnum; | |
132 | }; | |
133 | ||
134 | /** | |
135 | * struct ubi_wl_prot_entry - PEB protection entry. | |
136 | * @rb_pnum: link in the @wl->prot.pnum RB-tree | |
137 | * @rb_aec: link in the @wl->prot.aec RB-tree | |
138 | * @abs_ec: the absolute erase counter value when the protection ends | |
139 | * @e: the wear-leveling entry of the physical eraseblock under protection | |
140 | * | |
141 | * When the WL unit returns a physical eraseblock, the physical eraseblock is | |
142 | * protected from being moved for some "time". For this reason, the physical | |
143 | * eraseblock is not directly moved from the @wl->free tree to the @wl->used | |
144 | * tree. There is one more tree in between where this physical eraseblock is | |
145 | * temporarily stored (@wl->prot). | |
146 | * | |
147 | * All this protection stuff is needed because: | |
148 | * o we don't want to move physical eraseblocks just after we have given them | |
149 | * to the user; instead, we first want to let users fill them up with data; | |
150 | * | |
151 | * o there is a chance that the user will put the physical eraseblock very | |
152 | * soon, so it makes sense not to move it for some time, but wait; this is | |
153 | * especially important in case of "short term" physical eraseblocks. | |
154 | * | |
155 | * Physical eraseblocks stay protected only for limited time. But the "time" is | |
156 | * measured in erase cycles in this case. This is implemented with help of the | |
157 | * absolute erase counter (@wl->abs_ec). When it reaches certain value, the | |
158 | * physical eraseblocks are moved from the protection trees (@wl->prot.*) to | |
159 | * the @wl->used tree. | |
160 | * | |
161 | * Protected physical eraseblocks are searched by physical eraseblock number | |
162 | * (when they are put) and by the absolute erase counter (to check if it is | |
163 | * time to move them to the @wl->used tree). So there are actually 2 RB-trees | |
164 | * storing the protected physical eraseblocks: @wl->prot.pnum and | |
165 | * @wl->prot.aec. They are referred to as the "protection" trees. The | |
166 | * first one is indexed by the physical eraseblock number. The second one is | |
167 | * indexed by the absolute erase counter. Both trees store | |
168 | * &struct ubi_wl_prot_entry objects. | |
169 | * | |
170 | * Each physical eraseblock has 2 main states: free and used. The former state | |
171 | * corresponds to the @wl->free tree. The latter state is split up on several | |
172 | * sub-states: | |
173 | * o the WL movement is allowed (@wl->used tree); | |
174 | * o the WL movement is temporarily prohibited (@wl->prot.pnum and | |
175 | * @wl->prot.aec trees); | |
176 | * o scrubbing is needed (@wl->scrub tree). | |
177 | * | |
178 | * Depending on the sub-state, wear-leveling entries of the used physical | |
179 | * eraseblocks may be kept in one of those trees. | |
180 | */ | |
181 | struct ubi_wl_prot_entry { | |
182 | struct rb_node rb_pnum; | |
183 | struct rb_node rb_aec; | |
184 | unsigned long long abs_ec; | |
185 | struct ubi_wl_entry *e; | |
186 | }; | |
187 | ||
188 | /** | |
189 | * struct ubi_work - UBI work description data structure. | |
190 | * @list: a link in the list of pending works | |
191 | * @func: worker function | |
192 | * @priv: private data of the worker function | |
193 | * | |
194 | * @e: physical eraseblock to erase | |
195 | * @torture: if the physical eraseblock has to be tortured | |
196 | * | |
197 | * The @func pointer points to the worker function. If the @cancel argument is | |
198 | * not zero, the worker has to free the resources and exit immediately. The | |
199 | * worker has to return zero in case of success and a negative error code in | |
200 | * case of failure. | |
201 | */ | |
202 | struct ubi_work { | |
203 | struct list_head list; | |
204 | int (*func)(struct ubi_device *ubi, struct ubi_work *wrk, int cancel); | |
205 | /* The below fields are only relevant to erasure works */ | |
206 | struct ubi_wl_entry *e; | |
207 | int torture; | |
208 | }; | |
209 | ||
210 | #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID | |
e88d6e10 | 211 | static int paranoid_check_ec(struct ubi_device *ubi, int pnum, int ec); |
801c135c AB |
212 | static int paranoid_check_in_wl_tree(struct ubi_wl_entry *e, |
213 | struct rb_root *root); | |
214 | #else | |
215 | #define paranoid_check_ec(ubi, pnum, ec) 0 | |
216 | #define paranoid_check_in_wl_tree(e, root) | |
217 | #endif | |
218 | ||
219 | /* Slab cache for wear-leveling entries */ | |
220 | static struct kmem_cache *wl_entries_slab; | |
221 | ||
801c135c AB |
222 | /** |
223 | * wl_tree_add - add a wear-leveling entry to a WL RB-tree. | |
224 | * @e: the wear-leveling entry to add | |
225 | * @root: the root of the tree | |
226 | * | |
227 | * Note, we use (erase counter, physical eraseblock number) pairs as keys in | |
228 | * the @ubi->used and @ubi->free RB-trees. | |
229 | */ | |
230 | static void wl_tree_add(struct ubi_wl_entry *e, struct rb_root *root) | |
231 | { | |
232 | struct rb_node **p, *parent = NULL; | |
233 | ||
234 | p = &root->rb_node; | |
235 | while (*p) { | |
236 | struct ubi_wl_entry *e1; | |
237 | ||
238 | parent = *p; | |
239 | e1 = rb_entry(parent, struct ubi_wl_entry, rb); | |
240 | ||
241 | if (e->ec < e1->ec) | |
242 | p = &(*p)->rb_left; | |
243 | else if (e->ec > e1->ec) | |
244 | p = &(*p)->rb_right; | |
245 | else { | |
246 | ubi_assert(e->pnum != e1->pnum); | |
247 | if (e->pnum < e1->pnum) | |
248 | p = &(*p)->rb_left; | |
249 | else | |
250 | p = &(*p)->rb_right; | |
251 | } | |
252 | } | |
253 | ||
254 | rb_link_node(&e->rb, parent, p); | |
255 | rb_insert_color(&e->rb, root); | |
256 | } | |
257 | ||
801c135c AB |
258 | /** |
259 | * do_work - do one pending work. | |
260 | * @ubi: UBI device description object | |
261 | * | |
262 | * This function returns zero in case of success and a negative error code in | |
263 | * case of failure. | |
264 | */ | |
265 | static int do_work(struct ubi_device *ubi) | |
266 | { | |
267 | int err; | |
268 | struct ubi_work *wrk; | |
269 | ||
270 | spin_lock(&ubi->wl_lock); | |
271 | ||
272 | if (list_empty(&ubi->works)) { | |
273 | spin_unlock(&ubi->wl_lock); | |
274 | return 0; | |
275 | } | |
276 | ||
277 | wrk = list_entry(ubi->works.next, struct ubi_work, list); | |
278 | list_del(&wrk->list); | |
279 | spin_unlock(&ubi->wl_lock); | |
280 | ||
281 | /* | |
282 | * Call the worker function. Do not touch the work structure | |
283 | * after this call as it will have been freed or reused by that | |
284 | * time by the worker function. | |
285 | */ | |
286 | err = wrk->func(ubi, wrk, 0); | |
287 | if (err) | |
288 | ubi_err("work failed with error code %d", err); | |
289 | ||
290 | spin_lock(&ubi->wl_lock); | |
291 | ubi->works_count -= 1; | |
292 | ubi_assert(ubi->works_count >= 0); | |
293 | spin_unlock(&ubi->wl_lock); | |
294 | return err; | |
295 | } | |
296 | ||
297 | /** | |
298 | * produce_free_peb - produce a free physical eraseblock. | |
299 | * @ubi: UBI device description object | |
300 | * | |
301 | * This function tries to make a free PEB by means of synchronous execution of | |
302 | * pending works. This may be needed if, for example the background thread is | |
303 | * disabled. Returns zero in case of success and a negative error code in case | |
304 | * of failure. | |
305 | */ | |
306 | static int produce_free_peb(struct ubi_device *ubi) | |
307 | { | |
308 | int err; | |
309 | ||
310 | spin_lock(&ubi->wl_lock); | |
5abde384 | 311 | while (!ubi->free.rb_node) { |
801c135c AB |
312 | spin_unlock(&ubi->wl_lock); |
313 | ||
314 | dbg_wl("do one work synchronously"); | |
315 | err = do_work(ubi); | |
316 | if (err) | |
317 | return err; | |
318 | ||
319 | spin_lock(&ubi->wl_lock); | |
320 | } | |
321 | spin_unlock(&ubi->wl_lock); | |
322 | ||
323 | return 0; | |
324 | } | |
325 | ||
326 | /** | |
327 | * in_wl_tree - check if wear-leveling entry is present in a WL RB-tree. | |
328 | * @e: the wear-leveling entry to check | |
329 | * @root: the root of the tree | |
330 | * | |
331 | * This function returns non-zero if @e is in the @root RB-tree and zero if it | |
332 | * is not. | |
333 | */ | |
334 | static int in_wl_tree(struct ubi_wl_entry *e, struct rb_root *root) | |
335 | { | |
336 | struct rb_node *p; | |
337 | ||
338 | p = root->rb_node; | |
339 | while (p) { | |
340 | struct ubi_wl_entry *e1; | |
341 | ||
342 | e1 = rb_entry(p, struct ubi_wl_entry, rb); | |
343 | ||
344 | if (e->pnum == e1->pnum) { | |
345 | ubi_assert(e == e1); | |
346 | return 1; | |
347 | } | |
348 | ||
349 | if (e->ec < e1->ec) | |
350 | p = p->rb_left; | |
351 | else if (e->ec > e1->ec) | |
352 | p = p->rb_right; | |
353 | else { | |
354 | ubi_assert(e->pnum != e1->pnum); | |
355 | if (e->pnum < e1->pnum) | |
356 | p = p->rb_left; | |
357 | else | |
358 | p = p->rb_right; | |
359 | } | |
360 | } | |
361 | ||
362 | return 0; | |
363 | } | |
364 | ||
365 | /** | |
366 | * prot_tree_add - add physical eraseblock to protection trees. | |
367 | * @ubi: UBI device description object | |
368 | * @e: the physical eraseblock to add | |
369 | * @pe: protection entry object to use | |
370 | * @abs_ec: absolute erase counter value when this physical eraseblock has | |
371 | * to be removed from the protection trees. | |
372 | * | |
373 | * @wl->lock has to be locked. | |
374 | */ | |
375 | static void prot_tree_add(struct ubi_device *ubi, struct ubi_wl_entry *e, | |
376 | struct ubi_wl_prot_entry *pe, int abs_ec) | |
377 | { | |
378 | struct rb_node **p, *parent = NULL; | |
379 | struct ubi_wl_prot_entry *pe1; | |
380 | ||
381 | pe->e = e; | |
382 | pe->abs_ec = ubi->abs_ec + abs_ec; | |
383 | ||
384 | p = &ubi->prot.pnum.rb_node; | |
385 | while (*p) { | |
386 | parent = *p; | |
387 | pe1 = rb_entry(parent, struct ubi_wl_prot_entry, rb_pnum); | |
388 | ||
389 | if (e->pnum < pe1->e->pnum) | |
390 | p = &(*p)->rb_left; | |
391 | else | |
392 | p = &(*p)->rb_right; | |
393 | } | |
394 | rb_link_node(&pe->rb_pnum, parent, p); | |
395 | rb_insert_color(&pe->rb_pnum, &ubi->prot.pnum); | |
396 | ||
397 | p = &ubi->prot.aec.rb_node; | |
398 | parent = NULL; | |
399 | while (*p) { | |
400 | parent = *p; | |
401 | pe1 = rb_entry(parent, struct ubi_wl_prot_entry, rb_aec); | |
402 | ||
403 | if (pe->abs_ec < pe1->abs_ec) | |
404 | p = &(*p)->rb_left; | |
405 | else | |
406 | p = &(*p)->rb_right; | |
407 | } | |
408 | rb_link_node(&pe->rb_aec, parent, p); | |
409 | rb_insert_color(&pe->rb_aec, &ubi->prot.aec); | |
410 | } | |
411 | ||
412 | /** | |
413 | * find_wl_entry - find wear-leveling entry closest to certain erase counter. | |
414 | * @root: the RB-tree where to look for | |
415 | * @max: highest possible erase counter | |
416 | * | |
417 | * This function looks for a wear leveling entry with erase counter closest to | |
418 | * @max and less then @max. | |
419 | */ | |
420 | static struct ubi_wl_entry *find_wl_entry(struct rb_root *root, int max) | |
421 | { | |
422 | struct rb_node *p; | |
423 | struct ubi_wl_entry *e; | |
424 | ||
425 | e = rb_entry(rb_first(root), struct ubi_wl_entry, rb); | |
426 | max += e->ec; | |
427 | ||
428 | p = root->rb_node; | |
429 | while (p) { | |
430 | struct ubi_wl_entry *e1; | |
431 | ||
432 | e1 = rb_entry(p, struct ubi_wl_entry, rb); | |
433 | if (e1->ec >= max) | |
434 | p = p->rb_left; | |
435 | else { | |
436 | p = p->rb_right; | |
437 | e = e1; | |
438 | } | |
439 | } | |
440 | ||
441 | return e; | |
442 | } | |
443 | ||
444 | /** | |
445 | * ubi_wl_get_peb - get a physical eraseblock. | |
446 | * @ubi: UBI device description object | |
447 | * @dtype: type of data which will be stored in this physical eraseblock | |
448 | * | |
449 | * This function returns a physical eraseblock in case of success and a | |
450 | * negative error code in case of failure. Might sleep. | |
451 | */ | |
452 | int ubi_wl_get_peb(struct ubi_device *ubi, int dtype) | |
453 | { | |
454 | int err, protect, medium_ec; | |
455 | struct ubi_wl_entry *e, *first, *last; | |
456 | struct ubi_wl_prot_entry *pe; | |
457 | ||
458 | ubi_assert(dtype == UBI_LONGTERM || dtype == UBI_SHORTTERM || | |
459 | dtype == UBI_UNKNOWN); | |
460 | ||
33818bbb | 461 | pe = kmalloc(sizeof(struct ubi_wl_prot_entry), GFP_NOFS); |
801c135c AB |
462 | if (!pe) |
463 | return -ENOMEM; | |
464 | ||
465 | retry: | |
466 | spin_lock(&ubi->wl_lock); | |
5abde384 | 467 | if (!ubi->free.rb_node) { |
801c135c AB |
468 | if (ubi->works_count == 0) { |
469 | ubi_assert(list_empty(&ubi->works)); | |
470 | ubi_err("no free eraseblocks"); | |
471 | spin_unlock(&ubi->wl_lock); | |
472 | kfree(pe); | |
473 | return -ENOSPC; | |
474 | } | |
475 | spin_unlock(&ubi->wl_lock); | |
476 | ||
477 | err = produce_free_peb(ubi); | |
478 | if (err < 0) { | |
479 | kfree(pe); | |
480 | return err; | |
481 | } | |
482 | goto retry; | |
483 | } | |
484 | ||
485 | switch (dtype) { | |
486 | case UBI_LONGTERM: | |
487 | /* | |
488 | * For long term data we pick a physical eraseblock | |
489 | * with high erase counter. But the highest erase | |
490 | * counter we can pick is bounded by the the lowest | |
491 | * erase counter plus %WL_FREE_MAX_DIFF. | |
492 | */ | |
493 | e = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF); | |
494 | protect = LT_PROTECTION; | |
495 | break; | |
496 | case UBI_UNKNOWN: | |
497 | /* | |
498 | * For unknown data we pick a physical eraseblock with | |
499 | * medium erase counter. But we by no means can pick a | |
500 | * physical eraseblock with erase counter greater or | |
501 | * equivalent than the lowest erase counter plus | |
502 | * %WL_FREE_MAX_DIFF. | |
503 | */ | |
504 | first = rb_entry(rb_first(&ubi->free), | |
505 | struct ubi_wl_entry, rb); | |
506 | last = rb_entry(rb_last(&ubi->free), | |
507 | struct ubi_wl_entry, rb); | |
508 | ||
509 | if (last->ec - first->ec < WL_FREE_MAX_DIFF) | |
510 | e = rb_entry(ubi->free.rb_node, | |
511 | struct ubi_wl_entry, rb); | |
512 | else { | |
513 | medium_ec = (first->ec + WL_FREE_MAX_DIFF)/2; | |
514 | e = find_wl_entry(&ubi->free, medium_ec); | |
515 | } | |
516 | protect = U_PROTECTION; | |
517 | break; | |
518 | case UBI_SHORTTERM: | |
519 | /* | |
520 | * For short term data we pick a physical eraseblock | |
521 | * with the lowest erase counter as we expect it will | |
522 | * be erased soon. | |
523 | */ | |
524 | e = rb_entry(rb_first(&ubi->free), | |
525 | struct ubi_wl_entry, rb); | |
526 | protect = ST_PROTECTION; | |
527 | break; | |
528 | default: | |
529 | protect = 0; | |
530 | e = NULL; | |
531 | BUG(); | |
532 | } | |
533 | ||
534 | /* | |
535 | * Move the physical eraseblock to the protection trees where it will | |
536 | * be protected from being moved for some time. | |
537 | */ | |
5abde384 AB |
538 | paranoid_check_in_wl_tree(e, &ubi->free); |
539 | rb_erase(&e->rb, &ubi->free); | |
801c135c AB |
540 | prot_tree_add(ubi, e, pe, protect); |
541 | ||
542 | dbg_wl("PEB %d EC %d, protection %d", e->pnum, e->ec, protect); | |
543 | spin_unlock(&ubi->wl_lock); | |
544 | ||
545 | return e->pnum; | |
546 | } | |
547 | ||
548 | /** | |
549 | * prot_tree_del - remove a physical eraseblock from the protection trees | |
550 | * @ubi: UBI device description object | |
551 | * @pnum: the physical eraseblock to remove | |
552 | */ | |
553 | static void prot_tree_del(struct ubi_device *ubi, int pnum) | |
554 | { | |
555 | struct rb_node *p; | |
556 | struct ubi_wl_prot_entry *pe = NULL; | |
557 | ||
558 | p = ubi->prot.pnum.rb_node; | |
559 | while (p) { | |
560 | ||
561 | pe = rb_entry(p, struct ubi_wl_prot_entry, rb_pnum); | |
562 | ||
563 | if (pnum == pe->e->pnum) | |
564 | break; | |
565 | ||
566 | if (pnum < pe->e->pnum) | |
567 | p = p->rb_left; | |
568 | else | |
569 | p = p->rb_right; | |
570 | } | |
571 | ||
572 | ubi_assert(pe->e->pnum == pnum); | |
573 | rb_erase(&pe->rb_aec, &ubi->prot.aec); | |
574 | rb_erase(&pe->rb_pnum, &ubi->prot.pnum); | |
575 | kfree(pe); | |
576 | } | |
577 | ||
578 | /** | |
579 | * sync_erase - synchronously erase a physical eraseblock. | |
580 | * @ubi: UBI device description object | |
581 | * @e: the the physical eraseblock to erase | |
582 | * @torture: if the physical eraseblock has to be tortured | |
583 | * | |
584 | * This function returns zero in case of success and a negative error code in | |
585 | * case of failure. | |
586 | */ | |
587 | static int sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e, int torture) | |
588 | { | |
589 | int err; | |
590 | struct ubi_ec_hdr *ec_hdr; | |
591 | unsigned long long ec = e->ec; | |
592 | ||
593 | dbg_wl("erase PEB %d, old EC %llu", e->pnum, ec); | |
594 | ||
595 | err = paranoid_check_ec(ubi, e->pnum, e->ec); | |
596 | if (err > 0) | |
597 | return -EINVAL; | |
598 | ||
33818bbb | 599 | ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS); |
801c135c AB |
600 | if (!ec_hdr) |
601 | return -ENOMEM; | |
602 | ||
603 | err = ubi_io_sync_erase(ubi, e->pnum, torture); | |
604 | if (err < 0) | |
605 | goto out_free; | |
606 | ||
607 | ec += err; | |
608 | if (ec > UBI_MAX_ERASECOUNTER) { | |
609 | /* | |
610 | * Erase counter overflow. Upgrade UBI and use 64-bit | |
611 | * erase counters internally. | |
612 | */ | |
613 | ubi_err("erase counter overflow at PEB %d, EC %llu", | |
614 | e->pnum, ec); | |
615 | err = -EINVAL; | |
616 | goto out_free; | |
617 | } | |
618 | ||
619 | dbg_wl("erased PEB %d, new EC %llu", e->pnum, ec); | |
620 | ||
3261ebd7 | 621 | ec_hdr->ec = cpu_to_be64(ec); |
801c135c AB |
622 | |
623 | err = ubi_io_write_ec_hdr(ubi, e->pnum, ec_hdr); | |
624 | if (err) | |
625 | goto out_free; | |
626 | ||
627 | e->ec = ec; | |
628 | spin_lock(&ubi->wl_lock); | |
629 | if (e->ec > ubi->max_ec) | |
630 | ubi->max_ec = e->ec; | |
631 | spin_unlock(&ubi->wl_lock); | |
632 | ||
633 | out_free: | |
634 | kfree(ec_hdr); | |
635 | return err; | |
636 | } | |
637 | ||
638 | /** | |
639 | * check_protection_over - check if it is time to stop protecting some | |
640 | * physical eraseblocks. | |
641 | * @ubi: UBI device description object | |
642 | * | |
643 | * This function is called after each erase operation, when the absolute erase | |
644 | * counter is incremented, to check if some physical eraseblock have not to be | |
645 | * protected any longer. These physical eraseblocks are moved from the | |
646 | * protection trees to the used tree. | |
647 | */ | |
648 | static void check_protection_over(struct ubi_device *ubi) | |
649 | { | |
650 | struct ubi_wl_prot_entry *pe; | |
651 | ||
652 | /* | |
653 | * There may be several protected physical eraseblock to remove, | |
654 | * process them all. | |
655 | */ | |
656 | while (1) { | |
657 | spin_lock(&ubi->wl_lock); | |
5abde384 | 658 | if (!ubi->prot.aec.rb_node) { |
801c135c AB |
659 | spin_unlock(&ubi->wl_lock); |
660 | break; | |
661 | } | |
662 | ||
663 | pe = rb_entry(rb_first(&ubi->prot.aec), | |
664 | struct ubi_wl_prot_entry, rb_aec); | |
665 | ||
666 | if (pe->abs_ec > ubi->abs_ec) { | |
667 | spin_unlock(&ubi->wl_lock); | |
668 | break; | |
669 | } | |
670 | ||
671 | dbg_wl("PEB %d protection over, abs_ec %llu, PEB abs_ec %llu", | |
672 | pe->e->pnum, ubi->abs_ec, pe->abs_ec); | |
673 | rb_erase(&pe->rb_aec, &ubi->prot.aec); | |
674 | rb_erase(&pe->rb_pnum, &ubi->prot.pnum); | |
5abde384 | 675 | wl_tree_add(pe->e, &ubi->used); |
801c135c AB |
676 | spin_unlock(&ubi->wl_lock); |
677 | ||
678 | kfree(pe); | |
679 | cond_resched(); | |
680 | } | |
681 | } | |
682 | ||
683 | /** | |
684 | * schedule_ubi_work - schedule a work. | |
685 | * @ubi: UBI device description object | |
686 | * @wrk: the work to schedule | |
687 | * | |
688 | * This function enqueues a work defined by @wrk to the tail of the pending | |
689 | * works list. | |
690 | */ | |
691 | static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk) | |
692 | { | |
693 | spin_lock(&ubi->wl_lock); | |
694 | list_add_tail(&wrk->list, &ubi->works); | |
695 | ubi_assert(ubi->works_count >= 0); | |
696 | ubi->works_count += 1; | |
697 | if (ubi->thread_enabled) | |
698 | wake_up_process(ubi->bgt_thread); | |
699 | spin_unlock(&ubi->wl_lock); | |
700 | } | |
701 | ||
702 | static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk, | |
703 | int cancel); | |
704 | ||
705 | /** | |
706 | * schedule_erase - schedule an erase work. | |
707 | * @ubi: UBI device description object | |
708 | * @e: the WL entry of the physical eraseblock to erase | |
709 | * @torture: if the physical eraseblock has to be tortured | |
710 | * | |
711 | * This function returns zero in case of success and a %-ENOMEM in case of | |
712 | * failure. | |
713 | */ | |
714 | static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e, | |
715 | int torture) | |
716 | { | |
717 | struct ubi_work *wl_wrk; | |
718 | ||
719 | dbg_wl("schedule erasure of PEB %d, EC %d, torture %d", | |
720 | e->pnum, e->ec, torture); | |
721 | ||
33818bbb | 722 | wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS); |
801c135c AB |
723 | if (!wl_wrk) |
724 | return -ENOMEM; | |
725 | ||
726 | wl_wrk->func = &erase_worker; | |
727 | wl_wrk->e = e; | |
728 | wl_wrk->torture = torture; | |
729 | ||
730 | schedule_ubi_work(ubi, wl_wrk); | |
731 | return 0; | |
732 | } | |
733 | ||
734 | /** | |
735 | * wear_leveling_worker - wear-leveling worker function. | |
736 | * @ubi: UBI device description object | |
737 | * @wrk: the work object | |
738 | * @cancel: non-zero if the worker has to free memory and exit | |
739 | * | |
740 | * This function copies a more worn out physical eraseblock to a less worn out | |
741 | * one. Returns zero in case of success and a negative error code in case of | |
742 | * failure. | |
743 | */ | |
744 | static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk, | |
745 | int cancel) | |
746 | { | |
747 | int err, put = 0; | |
748 | struct ubi_wl_entry *e1, *e2; | |
749 | struct ubi_vid_hdr *vid_hdr; | |
750 | ||
751 | kfree(wrk); | |
752 | ||
753 | if (cancel) | |
754 | return 0; | |
755 | ||
33818bbb | 756 | vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS); |
801c135c AB |
757 | if (!vid_hdr) |
758 | return -ENOMEM; | |
759 | ||
760 | spin_lock(&ubi->wl_lock); | |
761 | ||
762 | /* | |
763 | * Only one WL worker at a time is supported at this implementation, so | |
764 | * make sure a PEB is not being moved already. | |
765 | */ | |
5abde384 AB |
766 | if (ubi->move_to || !ubi->free.rb_node || |
767 | (!ubi->used.rb_node && !ubi->scrub.rb_node)) { | |
801c135c AB |
768 | /* |
769 | * Only one WL worker at a time is supported at this | |
770 | * implementation, so if a LEB is already being moved, cancel. | |
771 | * | |
772 | * No free physical eraseblocks? Well, we cancel wear-leveling | |
773 | * then. It will be triggered again when a free physical | |
774 | * eraseblock appears. | |
775 | * | |
776 | * No used physical eraseblocks? They must be temporarily | |
777 | * protected from being moved. They will be moved to the | |
778 | * @ubi->used tree later and the wear-leveling will be | |
779 | * triggered again. | |
780 | */ | |
781 | dbg_wl("cancel WL, a list is empty: free %d, used %d", | |
5abde384 | 782 | !ubi->free.rb_node, !ubi->used.rb_node); |
801c135c AB |
783 | ubi->wl_scheduled = 0; |
784 | spin_unlock(&ubi->wl_lock); | |
785 | ubi_free_vid_hdr(ubi, vid_hdr); | |
786 | return 0; | |
787 | } | |
788 | ||
5abde384 | 789 | if (!ubi->scrub.rb_node) { |
801c135c AB |
790 | /* |
791 | * Now pick the least worn-out used physical eraseblock and a | |
792 | * highly worn-out free physical eraseblock. If the erase | |
793 | * counters differ much enough, start wear-leveling. | |
794 | */ | |
795 | e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, rb); | |
796 | e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF); | |
797 | ||
798 | if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD)) { | |
799 | dbg_wl("no WL needed: min used EC %d, max free EC %d", | |
800 | e1->ec, e2->ec); | |
801 | ubi->wl_scheduled = 0; | |
802 | spin_unlock(&ubi->wl_lock); | |
803 | ubi_free_vid_hdr(ubi, vid_hdr); | |
804 | return 0; | |
805 | } | |
5abde384 AB |
806 | paranoid_check_in_wl_tree(e1, &ubi->used); |
807 | rb_erase(&e1->rb, &ubi->used); | |
801c135c AB |
808 | dbg_wl("move PEB %d EC %d to PEB %d EC %d", |
809 | e1->pnum, e1->ec, e2->pnum, e2->ec); | |
810 | } else { | |
811 | e1 = rb_entry(rb_first(&ubi->scrub), struct ubi_wl_entry, rb); | |
812 | e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF); | |
5abde384 AB |
813 | paranoid_check_in_wl_tree(e1, &ubi->scrub); |
814 | rb_erase(&e1->rb, &ubi->scrub); | |
801c135c AB |
815 | dbg_wl("scrub PEB %d to PEB %d", e1->pnum, e2->pnum); |
816 | } | |
817 | ||
5abde384 AB |
818 | paranoid_check_in_wl_tree(e2, &ubi->free); |
819 | rb_erase(&e2->rb, &ubi->free); | |
801c135c AB |
820 | ubi_assert(!ubi->move_from && !ubi->move_to); |
821 | ubi_assert(!ubi->move_to_put && !ubi->move_from_put); | |
822 | ubi->move_from = e1; | |
823 | ubi->move_to = e2; | |
824 | spin_unlock(&ubi->wl_lock); | |
825 | ||
826 | /* | |
827 | * Now we are going to copy physical eraseblock @e1->pnum to @e2->pnum. | |
828 | * We so far do not know which logical eraseblock our physical | |
829 | * eraseblock (@e1) belongs to. We have to read the volume identifier | |
830 | * header first. | |
831 | */ | |
832 | ||
833 | err = ubi_io_read_vid_hdr(ubi, e1->pnum, vid_hdr, 0); | |
834 | if (err && err != UBI_IO_BITFLIPS) { | |
835 | if (err == UBI_IO_PEB_FREE) { | |
836 | /* | |
837 | * We are trying to move PEB without a VID header. UBI | |
838 | * always write VID headers shortly after the PEB was | |
839 | * given, so we have a situation when it did not have | |
840 | * chance to write it down because it was preempted. | |
841 | * Just re-schedule the work, so that next time it will | |
842 | * likely have the VID header in place. | |
843 | */ | |
844 | dbg_wl("PEB %d has no VID header", e1->pnum); | |
845 | err = 0; | |
846 | } else { | |
847 | ubi_err("error %d while reading VID header from PEB %d", | |
848 | err, e1->pnum); | |
849 | if (err > 0) | |
850 | err = -EIO; | |
851 | } | |
852 | goto error; | |
853 | } | |
854 | ||
855 | err = ubi_eba_copy_leb(ubi, e1->pnum, e2->pnum, vid_hdr); | |
856 | if (err) { | |
857 | if (err == UBI_IO_BITFLIPS) | |
858 | err = 0; | |
859 | goto error; | |
860 | } | |
861 | ||
862 | ubi_free_vid_hdr(ubi, vid_hdr); | |
863 | spin_lock(&ubi->wl_lock); | |
864 | if (!ubi->move_to_put) | |
5abde384 | 865 | wl_tree_add(e2, &ubi->used); |
801c135c AB |
866 | else |
867 | put = 1; | |
868 | ubi->move_from = ubi->move_to = NULL; | |
869 | ubi->move_from_put = ubi->move_to_put = 0; | |
870 | ubi->wl_scheduled = 0; | |
871 | spin_unlock(&ubi->wl_lock); | |
872 | ||
873 | if (put) { | |
874 | /* | |
875 | * Well, the target PEB was put meanwhile, schedule it for | |
876 | * erasure. | |
877 | */ | |
878 | dbg_wl("PEB %d was put meanwhile, erase", e2->pnum); | |
879 | err = schedule_erase(ubi, e2, 0); | |
880 | if (err) { | |
881 | kmem_cache_free(wl_entries_slab, e2); | |
882 | ubi_ro_mode(ubi); | |
883 | } | |
884 | } | |
885 | ||
886 | err = schedule_erase(ubi, e1, 0); | |
887 | if (err) { | |
888 | kmem_cache_free(wl_entries_slab, e1); | |
889 | ubi_ro_mode(ubi); | |
890 | } | |
891 | ||
892 | dbg_wl("done"); | |
893 | return err; | |
894 | ||
895 | /* | |
896 | * Some error occurred. @e1 was not changed, so return it back. @e2 | |
897 | * might be changed, schedule it for erasure. | |
898 | */ | |
899 | error: | |
900 | if (err) | |
901 | dbg_wl("error %d occurred, cancel operation", err); | |
902 | ubi_assert(err <= 0); | |
903 | ||
904 | ubi_free_vid_hdr(ubi, vid_hdr); | |
905 | spin_lock(&ubi->wl_lock); | |
906 | ubi->wl_scheduled = 0; | |
907 | if (ubi->move_from_put) | |
908 | put = 1; | |
909 | else | |
5abde384 | 910 | wl_tree_add(e1, &ubi->used); |
801c135c AB |
911 | ubi->move_from = ubi->move_to = NULL; |
912 | ubi->move_from_put = ubi->move_to_put = 0; | |
913 | spin_unlock(&ubi->wl_lock); | |
914 | ||
915 | if (put) { | |
916 | /* | |
917 | * Well, the target PEB was put meanwhile, schedule it for | |
918 | * erasure. | |
919 | */ | |
920 | dbg_wl("PEB %d was put meanwhile, erase", e1->pnum); | |
921 | err = schedule_erase(ubi, e1, 0); | |
922 | if (err) { | |
923 | kmem_cache_free(wl_entries_slab, e1); | |
924 | ubi_ro_mode(ubi); | |
925 | } | |
926 | } | |
927 | ||
928 | err = schedule_erase(ubi, e2, 0); | |
929 | if (err) { | |
930 | kmem_cache_free(wl_entries_slab, e2); | |
931 | ubi_ro_mode(ubi); | |
932 | } | |
933 | ||
934 | yield(); | |
935 | return err; | |
936 | } | |
937 | ||
938 | /** | |
939 | * ensure_wear_leveling - schedule wear-leveling if it is needed. | |
940 | * @ubi: UBI device description object | |
941 | * | |
942 | * This function checks if it is time to start wear-leveling and schedules it | |
943 | * if yes. This function returns zero in case of success and a negative error | |
944 | * code in case of failure. | |
945 | */ | |
946 | static int ensure_wear_leveling(struct ubi_device *ubi) | |
947 | { | |
948 | int err = 0; | |
949 | struct ubi_wl_entry *e1; | |
950 | struct ubi_wl_entry *e2; | |
951 | struct ubi_work *wrk; | |
952 | ||
953 | spin_lock(&ubi->wl_lock); | |
954 | if (ubi->wl_scheduled) | |
955 | /* Wear-leveling is already in the work queue */ | |
956 | goto out_unlock; | |
957 | ||
958 | /* | |
959 | * If the ubi->scrub tree is not empty, scrubbing is needed, and the | |
960 | * the WL worker has to be scheduled anyway. | |
961 | */ | |
5abde384 AB |
962 | if (!ubi->scrub.rb_node) { |
963 | if (!ubi->used.rb_node || !ubi->free.rb_node) | |
801c135c AB |
964 | /* No physical eraseblocks - no deal */ |
965 | goto out_unlock; | |
966 | ||
967 | /* | |
968 | * We schedule wear-leveling only if the difference between the | |
969 | * lowest erase counter of used physical eraseblocks and a high | |
970 | * erase counter of free physical eraseblocks is greater then | |
971 | * %UBI_WL_THRESHOLD. | |
972 | */ | |
973 | e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, rb); | |
974 | e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF); | |
975 | ||
976 | if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD)) | |
977 | goto out_unlock; | |
978 | dbg_wl("schedule wear-leveling"); | |
979 | } else | |
980 | dbg_wl("schedule scrubbing"); | |
981 | ||
982 | ubi->wl_scheduled = 1; | |
983 | spin_unlock(&ubi->wl_lock); | |
984 | ||
33818bbb | 985 | wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS); |
801c135c AB |
986 | if (!wrk) { |
987 | err = -ENOMEM; | |
988 | goto out_cancel; | |
989 | } | |
990 | ||
991 | wrk->func = &wear_leveling_worker; | |
992 | schedule_ubi_work(ubi, wrk); | |
993 | return err; | |
994 | ||
995 | out_cancel: | |
996 | spin_lock(&ubi->wl_lock); | |
997 | ubi->wl_scheduled = 0; | |
998 | out_unlock: | |
999 | spin_unlock(&ubi->wl_lock); | |
1000 | return err; | |
1001 | } | |
1002 | ||
1003 | /** | |
1004 | * erase_worker - physical eraseblock erase worker function. | |
1005 | * @ubi: UBI device description object | |
1006 | * @wl_wrk: the work object | |
1007 | * @cancel: non-zero if the worker has to free memory and exit | |
1008 | * | |
1009 | * This function erases a physical eraseblock and perform torture testing if | |
1010 | * needed. It also takes care about marking the physical eraseblock bad if | |
1011 | * needed. Returns zero in case of success and a negative error code in case of | |
1012 | * failure. | |
1013 | */ | |
1014 | static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk, | |
1015 | int cancel) | |
1016 | { | |
801c135c | 1017 | struct ubi_wl_entry *e = wl_wrk->e; |
784c1454 | 1018 | int pnum = e->pnum, err, need; |
801c135c AB |
1019 | |
1020 | if (cancel) { | |
1021 | dbg_wl("cancel erasure of PEB %d EC %d", pnum, e->ec); | |
1022 | kfree(wl_wrk); | |
1023 | kmem_cache_free(wl_entries_slab, e); | |
1024 | return 0; | |
1025 | } | |
1026 | ||
1027 | dbg_wl("erase PEB %d EC %d", pnum, e->ec); | |
1028 | ||
1029 | err = sync_erase(ubi, e, wl_wrk->torture); | |
1030 | if (!err) { | |
1031 | /* Fine, we've erased it successfully */ | |
1032 | kfree(wl_wrk); | |
1033 | ||
1034 | spin_lock(&ubi->wl_lock); | |
1035 | ubi->abs_ec += 1; | |
5abde384 | 1036 | wl_tree_add(e, &ubi->free); |
801c135c AB |
1037 | spin_unlock(&ubi->wl_lock); |
1038 | ||
1039 | /* | |
1040 | * One more erase operation has happened, take care about protected | |
1041 | * physical eraseblocks. | |
1042 | */ | |
1043 | check_protection_over(ubi); | |
1044 | ||
1045 | /* And take care about wear-leveling */ | |
1046 | err = ensure_wear_leveling(ubi); | |
1047 | return err; | |
1048 | } | |
1049 | ||
8d2d4011 | 1050 | ubi_err("failed to erase PEB %d, error %d", pnum, err); |
801c135c AB |
1051 | kfree(wl_wrk); |
1052 | kmem_cache_free(wl_entries_slab, e); | |
1053 | ||
784c1454 AB |
1054 | if (err == -EINTR || err == -ENOMEM || err == -EAGAIN || |
1055 | err == -EBUSY) { | |
1056 | int err1; | |
1057 | ||
1058 | /* Re-schedule the LEB for erasure */ | |
1059 | err1 = schedule_erase(ubi, e, 0); | |
1060 | if (err1) { | |
1061 | err = err1; | |
1062 | goto out_ro; | |
1063 | } | |
1064 | return err; | |
1065 | } else if (err != -EIO) { | |
801c135c AB |
1066 | /* |
1067 | * If this is not %-EIO, we have no idea what to do. Scheduling | |
1068 | * this physical eraseblock for erasure again would cause | |
1069 | * errors again and again. Well, lets switch to RO mode. | |
1070 | */ | |
784c1454 | 1071 | goto out_ro; |
801c135c AB |
1072 | } |
1073 | ||
1074 | /* It is %-EIO, the PEB went bad */ | |
1075 | ||
1076 | if (!ubi->bad_allowed) { | |
1077 | ubi_err("bad physical eraseblock %d detected", pnum); | |
784c1454 AB |
1078 | goto out_ro; |
1079 | } | |
801c135c | 1080 | |
784c1454 AB |
1081 | spin_lock(&ubi->volumes_lock); |
1082 | need = ubi->beb_rsvd_level - ubi->beb_rsvd_pebs + 1; | |
1083 | if (need > 0) { | |
1084 | need = ubi->avail_pebs >= need ? need : ubi->avail_pebs; | |
1085 | ubi->avail_pebs -= need; | |
1086 | ubi->rsvd_pebs += need; | |
1087 | ubi->beb_rsvd_pebs += need; | |
1088 | if (need > 0) | |
1089 | ubi_msg("reserve more %d PEBs", need); | |
1090 | } | |
801c135c | 1091 | |
784c1454 | 1092 | if (ubi->beb_rsvd_pebs == 0) { |
801c135c | 1093 | spin_unlock(&ubi->volumes_lock); |
784c1454 AB |
1094 | ubi_err("no reserved physical eraseblocks"); |
1095 | goto out_ro; | |
1096 | } | |
801c135c | 1097 | |
784c1454 AB |
1098 | spin_unlock(&ubi->volumes_lock); |
1099 | ubi_msg("mark PEB %d as bad", pnum); | |
801c135c | 1100 | |
784c1454 AB |
1101 | err = ubi_io_mark_bad(ubi, pnum); |
1102 | if (err) | |
1103 | goto out_ro; | |
1104 | ||
1105 | spin_lock(&ubi->volumes_lock); | |
1106 | ubi->beb_rsvd_pebs -= 1; | |
1107 | ubi->bad_peb_count += 1; | |
1108 | ubi->good_peb_count -= 1; | |
1109 | ubi_calculate_reserved(ubi); | |
1110 | if (ubi->beb_rsvd_pebs == 0) | |
1111 | ubi_warn("last PEB from the reserved pool was used"); | |
1112 | spin_unlock(&ubi->volumes_lock); | |
1113 | ||
1114 | return err; | |
801c135c | 1115 | |
784c1454 AB |
1116 | out_ro: |
1117 | ubi_ro_mode(ubi); | |
801c135c AB |
1118 | return err; |
1119 | } | |
1120 | ||
1121 | /** | |
1122 | * ubi_wl_put_peb - return a physical eraseblock to the wear-leveling | |
1123 | * unit. | |
1124 | * @ubi: UBI device description object | |
1125 | * @pnum: physical eraseblock to return | |
1126 | * @torture: if this physical eraseblock has to be tortured | |
1127 | * | |
1128 | * This function is called to return physical eraseblock @pnum to the pool of | |
1129 | * free physical eraseblocks. The @torture flag has to be set if an I/O error | |
1130 | * occurred to this @pnum and it has to be tested. This function returns zero | |
1131 | * in case of success and a negative error code in case of failure. | |
1132 | */ | |
1133 | int ubi_wl_put_peb(struct ubi_device *ubi, int pnum, int torture) | |
1134 | { | |
1135 | int err; | |
1136 | struct ubi_wl_entry *e; | |
1137 | ||
1138 | dbg_wl("PEB %d", pnum); | |
1139 | ubi_assert(pnum >= 0); | |
1140 | ubi_assert(pnum < ubi->peb_count); | |
1141 | ||
1142 | spin_lock(&ubi->wl_lock); | |
1143 | ||
1144 | e = ubi->lookuptbl[pnum]; | |
1145 | if (e == ubi->move_from) { | |
1146 | /* | |
1147 | * User is putting the physical eraseblock which was selected to | |
1148 | * be moved. It will be scheduled for erasure in the | |
1149 | * wear-leveling worker. | |
1150 | */ | |
1151 | dbg_wl("PEB %d is being moved", pnum); | |
1152 | ubi_assert(!ubi->move_from_put); | |
1153 | ubi->move_from_put = 1; | |
1154 | spin_unlock(&ubi->wl_lock); | |
1155 | return 0; | |
1156 | } else if (e == ubi->move_to) { | |
1157 | /* | |
1158 | * User is putting the physical eraseblock which was selected | |
1159 | * as the target the data is moved to. It may happen if the EBA | |
1160 | * unit already re-mapped the LEB but the WL unit did has not | |
1161 | * put the PEB to the "used" tree. | |
1162 | */ | |
1163 | dbg_wl("PEB %d is the target of data moving", pnum); | |
1164 | ubi_assert(!ubi->move_to_put); | |
1165 | ubi->move_to_put = 1; | |
1166 | spin_unlock(&ubi->wl_lock); | |
1167 | return 0; | |
1168 | } else { | |
5abde384 AB |
1169 | if (in_wl_tree(e, &ubi->used)) { |
1170 | paranoid_check_in_wl_tree(e, &ubi->used); | |
1171 | rb_erase(&e->rb, &ubi->used); | |
1172 | } else if (in_wl_tree(e, &ubi->scrub)) { | |
1173 | paranoid_check_in_wl_tree(e, &ubi->scrub); | |
1174 | rb_erase(&e->rb, &ubi->scrub); | |
1175 | } else | |
801c135c AB |
1176 | prot_tree_del(ubi, e->pnum); |
1177 | } | |
1178 | spin_unlock(&ubi->wl_lock); | |
1179 | ||
1180 | err = schedule_erase(ubi, e, torture); | |
1181 | if (err) { | |
1182 | spin_lock(&ubi->wl_lock); | |
5abde384 | 1183 | wl_tree_add(e, &ubi->used); |
801c135c AB |
1184 | spin_unlock(&ubi->wl_lock); |
1185 | } | |
1186 | ||
1187 | return err; | |
1188 | } | |
1189 | ||
1190 | /** | |
1191 | * ubi_wl_scrub_peb - schedule a physical eraseblock for scrubbing. | |
1192 | * @ubi: UBI device description object | |
1193 | * @pnum: the physical eraseblock to schedule | |
1194 | * | |
1195 | * If a bit-flip in a physical eraseblock is detected, this physical eraseblock | |
1196 | * needs scrubbing. This function schedules a physical eraseblock for | |
1197 | * scrubbing which is done in background. This function returns zero in case of | |
1198 | * success and a negative error code in case of failure. | |
1199 | */ | |
1200 | int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum) | |
1201 | { | |
1202 | struct ubi_wl_entry *e; | |
1203 | ||
1204 | ubi_msg("schedule PEB %d for scrubbing", pnum); | |
1205 | ||
1206 | retry: | |
1207 | spin_lock(&ubi->wl_lock); | |
1208 | e = ubi->lookuptbl[pnum]; | |
1209 | if (e == ubi->move_from || in_wl_tree(e, &ubi->scrub)) { | |
1210 | spin_unlock(&ubi->wl_lock); | |
1211 | return 0; | |
1212 | } | |
1213 | ||
1214 | if (e == ubi->move_to) { | |
1215 | /* | |
1216 | * This physical eraseblock was used to move data to. The data | |
1217 | * was moved but the PEB was not yet inserted to the proper | |
1218 | * tree. We should just wait a little and let the WL worker | |
1219 | * proceed. | |
1220 | */ | |
1221 | spin_unlock(&ubi->wl_lock); | |
1222 | dbg_wl("the PEB %d is not in proper tree, retry", pnum); | |
1223 | yield(); | |
1224 | goto retry; | |
1225 | } | |
1226 | ||
5abde384 AB |
1227 | if (in_wl_tree(e, &ubi->used)) { |
1228 | paranoid_check_in_wl_tree(e, &ubi->used); | |
1229 | rb_erase(&e->rb, &ubi->used); | |
1230 | } else | |
801c135c AB |
1231 | prot_tree_del(ubi, pnum); |
1232 | ||
5abde384 | 1233 | wl_tree_add(e, &ubi->scrub); |
801c135c AB |
1234 | spin_unlock(&ubi->wl_lock); |
1235 | ||
1236 | /* | |
1237 | * Technically scrubbing is the same as wear-leveling, so it is done | |
1238 | * by the WL worker. | |
1239 | */ | |
1240 | return ensure_wear_leveling(ubi); | |
1241 | } | |
1242 | ||
1243 | /** | |
1244 | * ubi_wl_flush - flush all pending works. | |
1245 | * @ubi: UBI device description object | |
1246 | * | |
1247 | * This function returns zero in case of success and a negative error code in | |
1248 | * case of failure. | |
1249 | */ | |
1250 | int ubi_wl_flush(struct ubi_device *ubi) | |
1251 | { | |
1252 | int err, pending_count; | |
1253 | ||
1254 | pending_count = ubi->works_count; | |
1255 | ||
1256 | dbg_wl("flush (%d pending works)", pending_count); | |
1257 | ||
1258 | /* | |
1259 | * Erase while the pending works queue is not empty, but not more then | |
1260 | * the number of currently pending works. | |
1261 | */ | |
1262 | while (pending_count-- > 0) { | |
1263 | err = do_work(ubi); | |
1264 | if (err) | |
1265 | return err; | |
1266 | } | |
1267 | ||
1268 | return 0; | |
1269 | } | |
1270 | ||
1271 | /** | |
1272 | * tree_destroy - destroy an RB-tree. | |
1273 | * @root: the root of the tree to destroy | |
1274 | */ | |
1275 | static void tree_destroy(struct rb_root *root) | |
1276 | { | |
1277 | struct rb_node *rb; | |
1278 | struct ubi_wl_entry *e; | |
1279 | ||
1280 | rb = root->rb_node; | |
1281 | while (rb) { | |
1282 | if (rb->rb_left) | |
1283 | rb = rb->rb_left; | |
1284 | else if (rb->rb_right) | |
1285 | rb = rb->rb_right; | |
1286 | else { | |
1287 | e = rb_entry(rb, struct ubi_wl_entry, rb); | |
1288 | ||
1289 | rb = rb_parent(rb); | |
1290 | if (rb) { | |
1291 | if (rb->rb_left == &e->rb) | |
1292 | rb->rb_left = NULL; | |
1293 | else | |
1294 | rb->rb_right = NULL; | |
1295 | } | |
1296 | ||
1297 | kmem_cache_free(wl_entries_slab, e); | |
1298 | } | |
1299 | } | |
1300 | } | |
1301 | ||
1302 | /** | |
1303 | * ubi_thread - UBI background thread. | |
1304 | * @u: the UBI device description object pointer | |
1305 | */ | |
1306 | static int ubi_thread(void *u) | |
1307 | { | |
1308 | int failures = 0; | |
1309 | struct ubi_device *ubi = u; | |
1310 | ||
1311 | ubi_msg("background thread \"%s\" started, PID %d", | |
1312 | ubi->bgt_name, current->pid); | |
1313 | ||
83144186 | 1314 | set_freezable(); |
801c135c AB |
1315 | for (;;) { |
1316 | int err; | |
1317 | ||
1318 | if (kthread_should_stop()) | |
1319 | goto out; | |
1320 | ||
1321 | if (try_to_freeze()) | |
1322 | continue; | |
1323 | ||
1324 | spin_lock(&ubi->wl_lock); | |
1325 | if (list_empty(&ubi->works) || ubi->ro_mode || | |
1326 | !ubi->thread_enabled) { | |
1327 | set_current_state(TASK_INTERRUPTIBLE); | |
1328 | spin_unlock(&ubi->wl_lock); | |
1329 | schedule(); | |
1330 | continue; | |
1331 | } | |
1332 | spin_unlock(&ubi->wl_lock); | |
1333 | ||
1334 | err = do_work(ubi); | |
1335 | if (err) { | |
1336 | ubi_err("%s: work failed with error code %d", | |
1337 | ubi->bgt_name, err); | |
1338 | if (failures++ > WL_MAX_FAILURES) { | |
1339 | /* | |
1340 | * Too many failures, disable the thread and | |
1341 | * switch to read-only mode. | |
1342 | */ | |
1343 | ubi_msg("%s: %d consecutive failures", | |
1344 | ubi->bgt_name, WL_MAX_FAILURES); | |
1345 | ubi_ro_mode(ubi); | |
1346 | break; | |
1347 | } | |
1348 | } else | |
1349 | failures = 0; | |
1350 | ||
1351 | cond_resched(); | |
1352 | } | |
1353 | ||
1354 | out: | |
1355 | dbg_wl("background thread \"%s\" is killed", ubi->bgt_name); | |
1356 | return 0; | |
1357 | } | |
1358 | ||
1359 | /** | |
1360 | * cancel_pending - cancel all pending works. | |
1361 | * @ubi: UBI device description object | |
1362 | */ | |
1363 | static void cancel_pending(struct ubi_device *ubi) | |
1364 | { | |
1365 | while (!list_empty(&ubi->works)) { | |
1366 | struct ubi_work *wrk; | |
1367 | ||
1368 | wrk = list_entry(ubi->works.next, struct ubi_work, list); | |
1369 | list_del(&wrk->list); | |
1370 | wrk->func(ubi, wrk, 1); | |
1371 | ubi->works_count -= 1; | |
1372 | ubi_assert(ubi->works_count >= 0); | |
1373 | } | |
1374 | } | |
1375 | ||
1376 | /** | |
1377 | * ubi_wl_init_scan - initialize the wear-leveling unit using scanning | |
1378 | * information. | |
1379 | * @ubi: UBI device description object | |
1380 | * @si: scanning information | |
1381 | * | |
1382 | * This function returns zero in case of success, and a negative error code in | |
1383 | * case of failure. | |
1384 | */ | |
1385 | int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si) | |
1386 | { | |
1387 | int err; | |
1388 | struct rb_node *rb1, *rb2; | |
1389 | struct ubi_scan_volume *sv; | |
1390 | struct ubi_scan_leb *seb, *tmp; | |
1391 | struct ubi_wl_entry *e; | |
1392 | ||
1393 | ||
1394 | ubi->used = ubi->free = ubi->scrub = RB_ROOT; | |
1395 | ubi->prot.pnum = ubi->prot.aec = RB_ROOT; | |
1396 | spin_lock_init(&ubi->wl_lock); | |
1397 | ubi->max_ec = si->max_ec; | |
1398 | INIT_LIST_HEAD(&ubi->works); | |
1399 | ||
1400 | sprintf(ubi->bgt_name, UBI_BGT_NAME_PATTERN, ubi->ubi_num); | |
1401 | ||
1402 | ubi->bgt_thread = kthread_create(ubi_thread, ubi, ubi->bgt_name); | |
1403 | if (IS_ERR(ubi->bgt_thread)) { | |
1404 | err = PTR_ERR(ubi->bgt_thread); | |
1405 | ubi_err("cannot spawn \"%s\", error %d", ubi->bgt_name, | |
1406 | err); | |
1407 | return err; | |
1408 | } | |
1409 | ||
1410 | if (ubi_devices_cnt == 0) { | |
1411 | wl_entries_slab = kmem_cache_create("ubi_wl_entry_slab", | |
1412 | sizeof(struct ubi_wl_entry), | |
20c2df83 | 1413 | 0, 0, NULL); |
801c135c AB |
1414 | if (!wl_entries_slab) |
1415 | return -ENOMEM; | |
1416 | } | |
1417 | ||
1418 | err = -ENOMEM; | |
1419 | ubi->lookuptbl = kzalloc(ubi->peb_count * sizeof(void *), GFP_KERNEL); | |
1420 | if (!ubi->lookuptbl) | |
1421 | goto out_free; | |
1422 | ||
1423 | list_for_each_entry_safe(seb, tmp, &si->erase, u.list) { | |
1424 | cond_resched(); | |
1425 | ||
1426 | e = kmem_cache_alloc(wl_entries_slab, GFP_KERNEL); | |
1427 | if (!e) | |
1428 | goto out_free; | |
1429 | ||
1430 | e->pnum = seb->pnum; | |
1431 | e->ec = seb->ec; | |
1432 | ubi->lookuptbl[e->pnum] = e; | |
1433 | if (schedule_erase(ubi, e, 0)) { | |
1434 | kmem_cache_free(wl_entries_slab, e); | |
1435 | goto out_free; | |
1436 | } | |
1437 | } | |
1438 | ||
1439 | list_for_each_entry(seb, &si->free, u.list) { | |
1440 | cond_resched(); | |
1441 | ||
1442 | e = kmem_cache_alloc(wl_entries_slab, GFP_KERNEL); | |
1443 | if (!e) | |
1444 | goto out_free; | |
1445 | ||
1446 | e->pnum = seb->pnum; | |
1447 | e->ec = seb->ec; | |
1448 | ubi_assert(e->ec >= 0); | |
5abde384 | 1449 | wl_tree_add(e, &ubi->free); |
801c135c AB |
1450 | ubi->lookuptbl[e->pnum] = e; |
1451 | } | |
1452 | ||
1453 | list_for_each_entry(seb, &si->corr, u.list) { | |
1454 | cond_resched(); | |
1455 | ||
1456 | e = kmem_cache_alloc(wl_entries_slab, GFP_KERNEL); | |
1457 | if (!e) | |
1458 | goto out_free; | |
1459 | ||
1460 | e->pnum = seb->pnum; | |
1461 | e->ec = seb->ec; | |
1462 | ubi->lookuptbl[e->pnum] = e; | |
1463 | if (schedule_erase(ubi, e, 0)) { | |
1464 | kmem_cache_free(wl_entries_slab, e); | |
1465 | goto out_free; | |
1466 | } | |
1467 | } | |
1468 | ||
1469 | ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) { | |
1470 | ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) { | |
1471 | cond_resched(); | |
1472 | ||
1473 | e = kmem_cache_alloc(wl_entries_slab, GFP_KERNEL); | |
1474 | if (!e) | |
1475 | goto out_free; | |
1476 | ||
1477 | e->pnum = seb->pnum; | |
1478 | e->ec = seb->ec; | |
1479 | ubi->lookuptbl[e->pnum] = e; | |
1480 | if (!seb->scrub) { | |
1481 | dbg_wl("add PEB %d EC %d to the used tree", | |
1482 | e->pnum, e->ec); | |
5abde384 | 1483 | wl_tree_add(e, &ubi->used); |
801c135c AB |
1484 | } else { |
1485 | dbg_wl("add PEB %d EC %d to the scrub tree", | |
1486 | e->pnum, e->ec); | |
5abde384 | 1487 | wl_tree_add(e, &ubi->scrub); |
801c135c AB |
1488 | } |
1489 | } | |
1490 | } | |
1491 | ||
5abde384 | 1492 | if (ubi->avail_pebs < WL_RESERVED_PEBS) { |
801c135c AB |
1493 | ubi_err("no enough physical eraseblocks (%d, need %d)", |
1494 | ubi->avail_pebs, WL_RESERVED_PEBS); | |
1495 | goto out_free; | |
1496 | } | |
1497 | ubi->avail_pebs -= WL_RESERVED_PEBS; | |
1498 | ubi->rsvd_pebs += WL_RESERVED_PEBS; | |
1499 | ||
1500 | /* Schedule wear-leveling if needed */ | |
1501 | err = ensure_wear_leveling(ubi); | |
1502 | if (err) | |
1503 | goto out_free; | |
1504 | ||
1505 | return 0; | |
1506 | ||
1507 | out_free: | |
1508 | cancel_pending(ubi); | |
1509 | tree_destroy(&ubi->used); | |
1510 | tree_destroy(&ubi->free); | |
1511 | tree_destroy(&ubi->scrub); | |
1512 | kfree(ubi->lookuptbl); | |
1513 | if (ubi_devices_cnt == 0) | |
1514 | kmem_cache_destroy(wl_entries_slab); | |
1515 | return err; | |
1516 | } | |
1517 | ||
1518 | /** | |
1519 | * protection_trees_destroy - destroy the protection RB-trees. | |
1520 | * @ubi: UBI device description object | |
1521 | */ | |
1522 | static void protection_trees_destroy(struct ubi_device *ubi) | |
1523 | { | |
1524 | struct rb_node *rb; | |
1525 | struct ubi_wl_prot_entry *pe; | |
1526 | ||
1527 | rb = ubi->prot.aec.rb_node; | |
1528 | while (rb) { | |
1529 | if (rb->rb_left) | |
1530 | rb = rb->rb_left; | |
1531 | else if (rb->rb_right) | |
1532 | rb = rb->rb_right; | |
1533 | else { | |
1534 | pe = rb_entry(rb, struct ubi_wl_prot_entry, rb_aec); | |
1535 | ||
1536 | rb = rb_parent(rb); | |
1537 | if (rb) { | |
1538 | if (rb->rb_left == &pe->rb_aec) | |
1539 | rb->rb_left = NULL; | |
1540 | else | |
1541 | rb->rb_right = NULL; | |
1542 | } | |
1543 | ||
1544 | kmem_cache_free(wl_entries_slab, pe->e); | |
1545 | kfree(pe); | |
1546 | } | |
1547 | } | |
1548 | } | |
1549 | ||
1550 | /** | |
1551 | * ubi_wl_close - close the wear-leveling unit. | |
1552 | * @ubi: UBI device description object | |
1553 | */ | |
1554 | void ubi_wl_close(struct ubi_device *ubi) | |
1555 | { | |
1556 | dbg_wl("disable \"%s\"", ubi->bgt_name); | |
1557 | if (ubi->bgt_thread) | |
1558 | kthread_stop(ubi->bgt_thread); | |
1559 | ||
1560 | dbg_wl("close the UBI wear-leveling unit"); | |
1561 | ||
1562 | cancel_pending(ubi); | |
1563 | protection_trees_destroy(ubi); | |
1564 | tree_destroy(&ubi->used); | |
1565 | tree_destroy(&ubi->free); | |
1566 | tree_destroy(&ubi->scrub); | |
1567 | kfree(ubi->lookuptbl); | |
1568 | if (ubi_devices_cnt == 1) | |
1569 | kmem_cache_destroy(wl_entries_slab); | |
1570 | } | |
1571 | ||
1572 | #ifdef CONFIG_MTD_UBI_DEBUG_PARANOID | |
1573 | ||
1574 | /** | |
1575 | * paranoid_check_ec - make sure that the erase counter of a physical eraseblock | |
1576 | * is correct. | |
1577 | * @ubi: UBI device description object | |
1578 | * @pnum: the physical eraseblock number to check | |
1579 | * @ec: the erase counter to check | |
1580 | * | |
1581 | * This function returns zero if the erase counter of physical eraseblock @pnum | |
1582 | * is equivalent to @ec, %1 if not, and a negative error code if an error | |
1583 | * occurred. | |
1584 | */ | |
e88d6e10 | 1585 | static int paranoid_check_ec(struct ubi_device *ubi, int pnum, int ec) |
801c135c AB |
1586 | { |
1587 | int err; | |
1588 | long long read_ec; | |
1589 | struct ubi_ec_hdr *ec_hdr; | |
1590 | ||
33818bbb | 1591 | ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS); |
801c135c AB |
1592 | if (!ec_hdr) |
1593 | return -ENOMEM; | |
1594 | ||
1595 | err = ubi_io_read_ec_hdr(ubi, pnum, ec_hdr, 0); | |
1596 | if (err && err != UBI_IO_BITFLIPS) { | |
1597 | /* The header does not have to exist */ | |
1598 | err = 0; | |
1599 | goto out_free; | |
1600 | } | |
1601 | ||
3261ebd7 | 1602 | read_ec = be64_to_cpu(ec_hdr->ec); |
801c135c AB |
1603 | if (ec != read_ec) { |
1604 | ubi_err("paranoid check failed for PEB %d", pnum); | |
1605 | ubi_err("read EC is %lld, should be %d", read_ec, ec); | |
1606 | ubi_dbg_dump_stack(); | |
1607 | err = 1; | |
1608 | } else | |
1609 | err = 0; | |
1610 | ||
1611 | out_free: | |
1612 | kfree(ec_hdr); | |
1613 | return err; | |
1614 | } | |
1615 | ||
1616 | /** | |
1617 | * paranoid_check_in_wl_tree - make sure that a wear-leveling entry is present | |
1618 | * in a WL RB-tree. | |
1619 | * @e: the wear-leveling entry to check | |
1620 | * @root: the root of the tree | |
1621 | * | |
1622 | * This function returns zero if @e is in the @root RB-tree and %1 if it | |
1623 | * is not. | |
1624 | */ | |
1625 | static int paranoid_check_in_wl_tree(struct ubi_wl_entry *e, | |
1626 | struct rb_root *root) | |
1627 | { | |
1628 | if (in_wl_tree(e, root)) | |
1629 | return 0; | |
1630 | ||
1631 | ubi_err("paranoid check failed for PEB %d, EC %d, RB-tree %p ", | |
1632 | e->pnum, e->ec, root); | |
1633 | ubi_dbg_dump_stack(); | |
1634 | return 1; | |
1635 | } | |
1636 | ||
1637 | #endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */ |