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Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001/*
Artem Bityutskiyd99383b2011-05-18 14:47:34 +03002 * @ubi: UBI device description object
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04003 * Copyright (c) International Business Machines Corp., 2006
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13 * the GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 * Authors: Artem Bityutskiy (Битюцкий Артём), Thomas Gleixner
20 */
21
22/*
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +030023 * UBI wear-leveling sub-system.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +040024 *
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +030025 * This sub-system is responsible for wear-leveling. It works in terms of
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +080026 * physical eraseblocks and erase counters and knows nothing about logical
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +030027 * eraseblocks, volumes, etc. From this sub-system's perspective all physical
28 * eraseblocks are of two types - used and free. Used physical eraseblocks are
29 * those that were "get" by the 'ubi_wl_get_peb()' function, and free physical
30 * eraseblocks are those that were put by the 'ubi_wl_put_peb()' function.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +040031 *
32 * Physical eraseblocks returned by 'ubi_wl_get_peb()' have only erase counter
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +030033 * header. The rest of the physical eraseblock contains only %0xFF bytes.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +040034 *
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +030035 * When physical eraseblocks are returned to the WL sub-system by means of the
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +040036 * 'ubi_wl_put_peb()' function, they are scheduled for erasure. The erasure is
37 * done asynchronously in context of the per-UBI device background thread,
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +030038 * which is also managed by the WL sub-system.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +040039 *
40 * The wear-leveling is ensured by means of moving the contents of used
41 * physical eraseblocks with low erase counter to free physical eraseblocks
42 * with high erase counter.
43 *
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +030044 * If the WL sub-system fails to erase a physical eraseblock, it marks it as
45 * bad.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +040046 *
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +030047 * This sub-system is also responsible for scrubbing. If a bit-flip is detected
48 * in a physical eraseblock, it has to be moved. Technically this is the same
49 * as moving it for wear-leveling reasons.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +040050 *
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +030051 * As it was said, for the UBI sub-system all physical eraseblocks are either
52 * "free" or "used". Free eraseblock are kept in the @wl->free RB-tree, while
Artem Bityutskiyb86a2c52009-05-24 14:13:34 +030053 * used eraseblocks are kept in @wl->used, @wl->erroneous, or @wl->scrub
54 * RB-trees, as well as (temporarily) in the @wl->pq queue.
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +080055 *
56 * When the WL sub-system returns a physical eraseblock, the physical
57 * eraseblock is protected from being moved for some "time". For this reason,
58 * the physical eraseblock is not directly moved from the @wl->free tree to the
59 * @wl->used tree. There is a protection queue in between where this
60 * physical eraseblock is temporarily stored (@wl->pq).
61 *
62 * All this protection stuff is needed because:
63 * o we don't want to move physical eraseblocks just after we have given them
64 * to the user; instead, we first want to let users fill them up with data;
65 *
66 * o there is a chance that the user will put the physical eraseblock very
Artem Bityutskiy44156262012-05-14 19:49:35 +030067 * soon, so it makes sense not to move it for some time, but wait.
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +080068 *
69 * Physical eraseblocks stay protected only for limited time. But the "time" is
70 * measured in erase cycles in this case. This is implemented with help of the
71 * protection queue. Eraseblocks are put to the tail of this queue when they
72 * are returned by the 'ubi_wl_get_peb()', and eraseblocks are removed from the
73 * head of the queue on each erase operation (for any eraseblock). So the
74 * length of the queue defines how may (global) erase cycles PEBs are protected.
75 *
76 * To put it differently, each physical eraseblock has 2 main states: free and
77 * used. The former state corresponds to the @wl->free tree. The latter state
78 * is split up on several sub-states:
79 * o the WL movement is allowed (@wl->used tree);
Artem Bityutskiy815bc5f2009-06-08 19:28:18 +030080 * o the WL movement is disallowed (@wl->erroneous) because the PEB is
Artem Bityutskiyb86a2c52009-05-24 14:13:34 +030081 * erroneous - e.g., there was a read error;
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +080082 * o the WL movement is temporarily prohibited (@wl->pq queue);
83 * o scrubbing is needed (@wl->scrub tree).
84 *
85 * Depending on the sub-state, wear-leveling entries of the used physical
86 * eraseblocks may be kept in one of those structures.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +040087 *
88 * Note, in this implementation, we keep a small in-RAM object for each physical
89 * eraseblock. This is surely not a scalable solution. But it appears to be good
90 * enough for moderately large flashes and it is simple. In future, one may
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +030091 * re-work this sub-system and make it more scalable.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +040092 *
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +030093 * At the moment this sub-system does not utilize the sequence number, which
94 * was introduced relatively recently. But it would be wise to do this because
95 * the sequence number of a logical eraseblock characterizes how old is it. For
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +040096 * example, when we move a PEB with low erase counter, and we need to pick the
97 * target PEB, we pick a PEB with the highest EC if our PEB is "old" and we
98 * pick target PEB with an average EC if our PEB is not very "old". This is a
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +030099 * room for future re-works of the WL sub-system.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400100 */
101
102#include <linux/slab.h>
103#include <linux/crc32.h>
104#include <linux/freezer.h>
105#include <linux/kthread.h>
106#include "ubi.h"
107
108/* Number of physical eraseblocks reserved for wear-leveling purposes */
109#define WL_RESERVED_PEBS 1
110
111/*
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400112 * Maximum difference between two erase counters. If this threshold is
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +0300113 * exceeded, the WL sub-system starts moving data from used physical
114 * eraseblocks with low erase counter to free physical eraseblocks with high
115 * erase counter.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400116 */
117#define UBI_WL_THRESHOLD CONFIG_MTD_UBI_WL_THRESHOLD
118
119/*
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +0300120 * When a physical eraseblock is moved, the WL sub-system has to pick the target
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400121 * physical eraseblock to move to. The simplest way would be just to pick the
122 * one with the highest erase counter. But in certain workloads this could lead
123 * to an unlimited wear of one or few physical eraseblock. Indeed, imagine a
124 * situation when the picked physical eraseblock is constantly erased after the
125 * data is written to it. So, we have a constant which limits the highest erase
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +0300126 * counter of the free physical eraseblock to pick. Namely, the WL sub-system
Frederik Schwarzer025dfda2008-10-16 19:02:37 +0200127 * does not pick eraseblocks with erase counter greater than the lowest erase
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400128 * counter plus %WL_FREE_MAX_DIFF.
129 */
130#define WL_FREE_MAX_DIFF (2*UBI_WL_THRESHOLD)
131
132/*
133 * Maximum number of consecutive background thread failures which is enough to
134 * switch to read-only mode.
135 */
136#define WL_MAX_FAILURES 32
137
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +0300138static int self_check_ec(struct ubi_device *ubi, int pnum, int ec);
139static int self_check_in_wl_tree(const struct ubi_device *ubi,
140 struct ubi_wl_entry *e, struct rb_root *root);
141static int self_check_in_pq(const struct ubi_device *ubi,
142 struct ubi_wl_entry *e);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400143
Richard Weinberger8199b902012-09-26 17:51:48 +0200144#ifdef CONFIG_MTD_UBI_FASTMAP
145/**
146 * update_fastmap_work_fn - calls ubi_update_fastmap from a work queue
147 * @wrk: the work description object
148 */
149static void update_fastmap_work_fn(struct work_struct *wrk)
150{
151 struct ubi_device *ubi = container_of(wrk, struct ubi_device, fm_work);
152 ubi_update_fastmap(ubi);
153}
154
155/**
156 * ubi_ubi_is_fm_block - returns 1 if a PEB is currently used in a fastmap.
157 * @ubi: UBI device description object
158 * @pnum: the to be checked PEB
159 */
160static int ubi_is_fm_block(struct ubi_device *ubi, int pnum)
161{
162 int i;
163
164 if (!ubi->fm)
165 return 0;
166
167 for (i = 0; i < ubi->fm->used_blocks; i++)
168 if (ubi->fm->e[i]->pnum == pnum)
169 return 1;
170
171 return 0;
172}
173#else
174static int ubi_is_fm_block(struct ubi_device *ubi, int pnum)
175{
176 return 0;
177}
178#endif
179
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400180/**
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400181 * wl_tree_add - add a wear-leveling entry to a WL RB-tree.
182 * @e: the wear-leveling entry to add
183 * @root: the root of the tree
184 *
185 * Note, we use (erase counter, physical eraseblock number) pairs as keys in
186 * the @ubi->used and @ubi->free RB-trees.
187 */
188static void wl_tree_add(struct ubi_wl_entry *e, struct rb_root *root)
189{
190 struct rb_node **p, *parent = NULL;
191
192 p = &root->rb_node;
193 while (*p) {
194 struct ubi_wl_entry *e1;
195
196 parent = *p;
Xiaochuan-Xu23553b22008-12-09 19:44:12 +0800197 e1 = rb_entry(parent, struct ubi_wl_entry, u.rb);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400198
199 if (e->ec < e1->ec)
200 p = &(*p)->rb_left;
201 else if (e->ec > e1->ec)
202 p = &(*p)->rb_right;
203 else {
204 ubi_assert(e->pnum != e1->pnum);
205 if (e->pnum < e1->pnum)
206 p = &(*p)->rb_left;
207 else
208 p = &(*p)->rb_right;
209 }
210 }
211
Xiaochuan-Xu23553b22008-12-09 19:44:12 +0800212 rb_link_node(&e->u.rb, parent, p);
213 rb_insert_color(&e->u.rb, root);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400214}
215
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400216/**
217 * do_work - do one pending work.
218 * @ubi: UBI device description object
219 *
220 * This function returns zero in case of success and a negative error code in
221 * case of failure.
222 */
223static int do_work(struct ubi_device *ubi)
224{
225 int err;
226 struct ubi_work *wrk;
227
Artem Bityutskiy43f9b252007-12-18 15:06:55 +0200228 cond_resched();
229
Artem Bityutskiy593dd332007-12-18 15:54:35 +0200230 /*
231 * @ubi->work_sem is used to synchronize with the workers. Workers take
232 * it in read mode, so many of them may be doing works at a time. But
233 * the queue flush code has to be sure the whole queue of works is
234 * done, and it takes the mutex in write mode.
235 */
236 down_read(&ubi->work_sem);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400237 spin_lock(&ubi->wl_lock);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400238 if (list_empty(&ubi->works)) {
239 spin_unlock(&ubi->wl_lock);
Artem Bityutskiy593dd332007-12-18 15:54:35 +0200240 up_read(&ubi->work_sem);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400241 return 0;
242 }
243
244 wrk = list_entry(ubi->works.next, struct ubi_work, list);
245 list_del(&wrk->list);
Artem Bityutskiy16f557e2007-12-19 16:03:17 +0200246 ubi->works_count -= 1;
247 ubi_assert(ubi->works_count >= 0);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400248 spin_unlock(&ubi->wl_lock);
249
250 /*
251 * Call the worker function. Do not touch the work structure
252 * after this call as it will have been freed or reused by that
253 * time by the worker function.
254 */
255 err = wrk->func(ubi, wrk, 0);
256 if (err)
257 ubi_err("work failed with error code %d", err);
Artem Bityutskiy593dd332007-12-18 15:54:35 +0200258 up_read(&ubi->work_sem);
Artem Bityutskiy16f557e2007-12-19 16:03:17 +0200259
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400260 return err;
261}
262
263/**
264 * produce_free_peb - produce a free physical eraseblock.
265 * @ubi: UBI device description object
266 *
267 * This function tries to make a free PEB by means of synchronous execution of
268 * pending works. This may be needed if, for example the background thread is
269 * disabled. Returns zero in case of success and a negative error code in case
270 * of failure.
271 */
272static int produce_free_peb(struct ubi_device *ubi)
273{
274 int err;
275
Artem Bityutskiy5abde382007-09-13 14:48:20 +0300276 while (!ubi->free.rb_node) {
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400277 spin_unlock(&ubi->wl_lock);
278
279 dbg_wl("do one work synchronously");
280 err = do_work(ubi);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400281
282 spin_lock(&ubi->wl_lock);
Richard Weinberger8199b902012-09-26 17:51:48 +0200283 if (err)
284 return err;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400285 }
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400286
287 return 0;
288}
289
290/**
291 * in_wl_tree - check if wear-leveling entry is present in a WL RB-tree.
292 * @e: the wear-leveling entry to check
293 * @root: the root of the tree
294 *
295 * This function returns non-zero if @e is in the @root RB-tree and zero if it
296 * is not.
297 */
298static int in_wl_tree(struct ubi_wl_entry *e, struct rb_root *root)
299{
300 struct rb_node *p;
301
302 p = root->rb_node;
303 while (p) {
304 struct ubi_wl_entry *e1;
305
Xiaochuan-Xu23553b22008-12-09 19:44:12 +0800306 e1 = rb_entry(p, struct ubi_wl_entry, u.rb);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400307
308 if (e->pnum == e1->pnum) {
309 ubi_assert(e == e1);
310 return 1;
311 }
312
313 if (e->ec < e1->ec)
314 p = p->rb_left;
315 else if (e->ec > e1->ec)
316 p = p->rb_right;
317 else {
318 ubi_assert(e->pnum != e1->pnum);
319 if (e->pnum < e1->pnum)
320 p = p->rb_left;
321 else
322 p = p->rb_right;
323 }
324 }
325
326 return 0;
327}
328
329/**
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800330 * prot_queue_add - add physical eraseblock to the protection queue.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400331 * @ubi: UBI device description object
332 * @e: the physical eraseblock to add
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400333 *
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800334 * This function adds @e to the tail of the protection queue @ubi->pq, where
335 * @e will stay for %UBI_PROT_QUEUE_LEN erase operations and will be
336 * temporarily protected from the wear-leveling worker. Note, @wl->lock has to
337 * be locked.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400338 */
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800339static void prot_queue_add(struct ubi_device *ubi, struct ubi_wl_entry *e)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400340{
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800341 int pq_tail = ubi->pq_head - 1;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400342
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800343 if (pq_tail < 0)
344 pq_tail = UBI_PROT_QUEUE_LEN - 1;
345 ubi_assert(pq_tail >= 0 && pq_tail < UBI_PROT_QUEUE_LEN);
346 list_add_tail(&e->u.list, &ubi->pq[pq_tail]);
347 dbg_wl("added PEB %d EC %d to the protection queue", e->pnum, e->ec);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400348}
349
350/**
351 * find_wl_entry - find wear-leveling entry closest to certain erase counter.
Richard Weinberger8199b902012-09-26 17:51:48 +0200352 * @ubi: UBI device description object
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400353 * @root: the RB-tree where to look for
Artem Bityutskiyadd82872012-03-07 18:56:29 +0200354 * @diff: maximum possible difference from the smallest erase counter
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400355 *
356 * This function looks for a wear leveling entry with erase counter closest to
Artem Bityutskiyadd82872012-03-07 18:56:29 +0200357 * min + @diff, where min is the smallest erase counter.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400358 */
Richard Weinberger8199b902012-09-26 17:51:48 +0200359static struct ubi_wl_entry *find_wl_entry(struct ubi_device *ubi,
360 struct rb_root *root, int diff)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400361{
362 struct rb_node *p;
Richard Weinberger8199b902012-09-26 17:51:48 +0200363 struct ubi_wl_entry *e, *prev_e = NULL;
Artem Bityutskiyadd82872012-03-07 18:56:29 +0200364 int max;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400365
Xiaochuan-Xu23553b22008-12-09 19:44:12 +0800366 e = rb_entry(rb_first(root), struct ubi_wl_entry, u.rb);
Artem Bityutskiyadd82872012-03-07 18:56:29 +0200367 max = e->ec + diff;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400368
369 p = root->rb_node;
370 while (p) {
371 struct ubi_wl_entry *e1;
372
Xiaochuan-Xu23553b22008-12-09 19:44:12 +0800373 e1 = rb_entry(p, struct ubi_wl_entry, u.rb);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400374 if (e1->ec >= max)
375 p = p->rb_left;
376 else {
377 p = p->rb_right;
Richard Weinberger8199b902012-09-26 17:51:48 +0200378 prev_e = e;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400379 e = e1;
380 }
381 }
382
Richard Weinberger8199b902012-09-26 17:51:48 +0200383 /* If no fastmap has been written and this WL entry can be used
384 * as anchor PEB, hold it back and return the second best WL entry
385 * such that fastmap can use the anchor PEB later. */
386 if (prev_e && !ubi->fm_disabled &&
387 !ubi->fm && e->pnum < UBI_FM_MAX_START)
388 return prev_e;
389
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400390 return e;
391}
392
393/**
Richard Weinberger8199b902012-09-26 17:51:48 +0200394 * find_mean_wl_entry - find wear-leveling entry with medium erase counter.
395 * @ubi: UBI device description object
396 * @root: the RB-tree where to look for
397 *
398 * This function looks for a wear leveling entry with medium erase counter,
399 * but not greater or equivalent than the lowest erase counter plus
400 * %WL_FREE_MAX_DIFF/2.
401 */
402static struct ubi_wl_entry *find_mean_wl_entry(struct ubi_device *ubi,
403 struct rb_root *root)
404{
405 struct ubi_wl_entry *e, *first, *last;
406
407 first = rb_entry(rb_first(root), struct ubi_wl_entry, u.rb);
408 last = rb_entry(rb_last(root), struct ubi_wl_entry, u.rb);
409
410 if (last->ec - first->ec < WL_FREE_MAX_DIFF) {
411 e = rb_entry(root->rb_node, struct ubi_wl_entry, u.rb);
412
413#ifdef CONFIG_MTD_UBI_FASTMAP
414 /* If no fastmap has been written and this WL entry can be used
415 * as anchor PEB, hold it back and return the second best
416 * WL entry such that fastmap can use the anchor PEB later. */
417 if (e && !ubi->fm_disabled && !ubi->fm &&
418 e->pnum < UBI_FM_MAX_START)
419 e = rb_entry(rb_next(root->rb_node),
420 struct ubi_wl_entry, u.rb);
421#endif
422 } else
423 e = find_wl_entry(ubi, root, WL_FREE_MAX_DIFF/2);
424
425 return e;
426}
427
428#ifdef CONFIG_MTD_UBI_FASTMAP
429/**
430 * find_anchor_wl_entry - find wear-leveling entry to used as anchor PEB.
431 * @root: the RB-tree where to look for
432 */
433static struct ubi_wl_entry *find_anchor_wl_entry(struct rb_root *root)
434{
435 struct rb_node *p;
436 struct ubi_wl_entry *e, *victim = NULL;
437 int max_ec = UBI_MAX_ERASECOUNTER;
438
439 ubi_rb_for_each_entry(p, e, root, u.rb) {
440 if (e->pnum < UBI_FM_MAX_START && e->ec < max_ec) {
441 victim = e;
442 max_ec = e->ec;
443 }
444 }
445
446 return victim;
447}
448
449static int anchor_pebs_avalible(struct rb_root *root)
450{
451 struct rb_node *p;
452 struct ubi_wl_entry *e;
453
454 ubi_rb_for_each_entry(p, e, root, u.rb)
455 if (e->pnum < UBI_FM_MAX_START)
456 return 1;
457
458 return 0;
459}
460
461/**
462 * ubi_wl_get_fm_peb - find a physical erase block with a given maximal number.
463 * @ubi: UBI device description object
464 * @anchor: This PEB will be used as anchor PEB by fastmap
465 *
466 * The function returns a physical erase block with a given maximal number
467 * and removes it from the wl subsystem.
468 * Must be called with wl_lock held!
469 */
470struct ubi_wl_entry *ubi_wl_get_fm_peb(struct ubi_device *ubi, int anchor)
471{
472 struct ubi_wl_entry *e = NULL;
473
474 if (!ubi->free.rb_node || (ubi->free_count - ubi->beb_rsvd_pebs < 1))
475 goto out;
476
477 if (anchor)
478 e = find_anchor_wl_entry(&ubi->free);
479 else
480 e = find_mean_wl_entry(ubi, &ubi->free);
481
482 if (!e)
483 goto out;
484
485 self_check_in_wl_tree(ubi, e, &ubi->free);
486
487 /* remove it from the free list,
488 * the wl subsystem does no longer know this erase block */
489 rb_erase(&e->u.rb, &ubi->free);
490 ubi->free_count--;
491out:
492 return e;
493}
494#endif
495
496/**
497 * __wl_get_peb - get a physical eraseblock.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400498 * @ubi: UBI device description object
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400499 *
500 * This function returns a physical eraseblock in case of success and a
501 * negative error code in case of failure. Might sleep.
502 */
Richard Weinberger8199b902012-09-26 17:51:48 +0200503static int __wl_get_peb(struct ubi_device *ubi)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400504{
Artem Bityutskiy7eb3aa652012-03-07 19:08:36 +0200505 int err;
Richard Weinberger8199b902012-09-26 17:51:48 +0200506 struct ubi_wl_entry *e;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400507
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400508retry:
Artem Bityutskiy5abde382007-09-13 14:48:20 +0300509 if (!ubi->free.rb_node) {
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400510 if (ubi->works_count == 0) {
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400511 ubi_err("no free eraseblocks");
Richard Weinberger8199b902012-09-26 17:51:48 +0200512 ubi_assert(list_empty(&ubi->works));
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400513 return -ENOSPC;
514 }
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400515
516 err = produce_free_peb(ubi);
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800517 if (err < 0)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400518 return err;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400519 goto retry;
520 }
521
Richard Weinberger8199b902012-09-26 17:51:48 +0200522 e = find_mean_wl_entry(ubi, &ubi->free);
523 if (!e) {
524 ubi_err("no free eraseblocks");
525 return -ENOSPC;
526 }
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400527
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +0300528 self_check_in_wl_tree(ubi, e, &ubi->free);
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800529
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400530 /*
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800531 * Move the physical eraseblock to the protection queue where it will
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400532 * be protected from being moved for some time.
533 */
Xiaochuan-Xu23553b22008-12-09 19:44:12 +0800534 rb_erase(&e->u.rb, &ubi->free);
Richard Weinberger8199b902012-09-26 17:51:48 +0200535 ubi->free_count--;
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800536 dbg_wl("PEB %d EC %d", e->pnum, e->ec);
Richard Weinberger8199b902012-09-26 17:51:48 +0200537#ifndef CONFIG_MTD_UBI_FASTMAP
538 /* We have to enqueue e only if fastmap is disabled,
539 * is fastmap enabled prot_queue_add() will be called by
540 * ubi_wl_get_peb() after removing e from the pool. */
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800541 prot_queue_add(ubi, e);
Richard Weinberger8199b902012-09-26 17:51:48 +0200542#endif
Artem Bityutskiy97d61042012-05-16 19:29:04 +0300543 err = ubi_self_check_all_ff(ubi, e->pnum, ubi->vid_hdr_aloffset,
544 ubi->peb_size - ubi->vid_hdr_aloffset);
Artem Bityutskiy40a71a82009-06-28 19:16:55 +0300545 if (err) {
Artem Bityutskiy13987882009-06-29 15:58:36 +0300546 ubi_err("new PEB %d does not contain all 0xFF bytes", e->pnum);
Artem Bityutskiyadbf05e2010-01-20 10:28:58 +0200547 return err;
Artem Bityutskiy40a71a82009-06-28 19:16:55 +0300548 }
549
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400550 return e->pnum;
551}
552
Richard Weinberger8199b902012-09-26 17:51:48 +0200553#ifdef CONFIG_MTD_UBI_FASTMAP
554/**
555 * return_unused_pool_pebs - returns unused PEB to the free tree.
556 * @ubi: UBI device description object
557 * @pool: fastmap pool description object
558 */
559static void return_unused_pool_pebs(struct ubi_device *ubi,
560 struct ubi_fm_pool *pool)
561{
562 int i;
563 struct ubi_wl_entry *e;
564
565 for (i = pool->used; i < pool->size; i++) {
566 e = ubi->lookuptbl[pool->pebs[i]];
567 wl_tree_add(e, &ubi->free);
568 ubi->free_count++;
569 }
570}
571
572/**
573 * refill_wl_pool - refills all the fastmap pool used by the
574 * WL sub-system.
575 * @ubi: UBI device description object
576 */
577static void refill_wl_pool(struct ubi_device *ubi)
578{
579 struct ubi_wl_entry *e;
580 struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
581
582 return_unused_pool_pebs(ubi, pool);
583
584 for (pool->size = 0; pool->size < pool->max_size; pool->size++) {
585 if (!ubi->free.rb_node ||
586 (ubi->free_count - ubi->beb_rsvd_pebs < 5))
587 break;
588
589 e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
590 self_check_in_wl_tree(ubi, e, &ubi->free);
591 rb_erase(&e->u.rb, &ubi->free);
592 ubi->free_count--;
593
594 pool->pebs[pool->size] = e->pnum;
595 }
596 pool->used = 0;
597}
598
599/**
600 * refill_wl_user_pool - refills all the fastmap pool used by ubi_wl_get_peb.
601 * @ubi: UBI device description object
602 */
603static void refill_wl_user_pool(struct ubi_device *ubi)
604{
605 struct ubi_fm_pool *pool = &ubi->fm_pool;
606
607 return_unused_pool_pebs(ubi, pool);
608
609 for (pool->size = 0; pool->size < pool->max_size; pool->size++) {
610 if (!ubi->free.rb_node ||
611 (ubi->free_count - ubi->beb_rsvd_pebs < 1))
612 break;
613
614 pool->pebs[pool->size] = __wl_get_peb(ubi);
615 if (pool->pebs[pool->size] < 0)
616 break;
617 }
618 pool->used = 0;
619}
620
621/**
622 * ubi_refill_pools - refills all fastmap PEB pools.
623 * @ubi: UBI device description object
624 */
625void ubi_refill_pools(struct ubi_device *ubi)
626{
627 spin_lock(&ubi->wl_lock);
628 refill_wl_pool(ubi);
629 refill_wl_user_pool(ubi);
630 spin_unlock(&ubi->wl_lock);
631}
632
633/* ubi_wl_get_peb - works exaclty like __wl_get_peb but keeps track of
634 * the fastmap pool.
635 */
636int ubi_wl_get_peb(struct ubi_device *ubi)
637{
638 int ret;
639 struct ubi_fm_pool *pool = &ubi->fm_pool;
640 struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
641
642 if (!pool->size || !wl_pool->size || pool->used == pool->size ||
643 wl_pool->used == wl_pool->size)
644 ubi_update_fastmap(ubi);
645
646 /* we got not a single free PEB */
647 if (!pool->size)
648 ret = -ENOSPC;
649 else {
650 spin_lock(&ubi->wl_lock);
651 ret = pool->pebs[pool->used++];
652 prot_queue_add(ubi, ubi->lookuptbl[ret]);
653 spin_unlock(&ubi->wl_lock);
654 }
655
656 return ret;
657}
658
659/* get_peb_for_wl - returns a PEB to be used internally by the WL sub-system.
660 *
661 * @ubi: UBI device description object
662 */
663static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
664{
665 struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
666 int pnum;
667
668 if (pool->used == pool->size || !pool->size) {
669 /* We cannot update the fastmap here because this
670 * function is called in atomic context.
671 * Let's fail here and refill/update it as soon as possible. */
672 schedule_work(&ubi->fm_work);
673 return NULL;
674 } else {
675 pnum = pool->pebs[pool->used++];
676 return ubi->lookuptbl[pnum];
677 }
678}
679#else
680static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
681{
Richard Weinbergered4b7022012-12-03 20:57:46 +0100682 struct ubi_wl_entry *e;
683
684 e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
685 self_check_in_wl_tree(ubi, e, &ubi->free);
686 rb_erase(&e->u.rb, &ubi->free);
687
688 return e;
Richard Weinberger8199b902012-09-26 17:51:48 +0200689}
690
691int ubi_wl_get_peb(struct ubi_device *ubi)
692{
693 int peb;
694
695 spin_lock(&ubi->wl_lock);
696 peb = __wl_get_peb(ubi);
697 spin_unlock(&ubi->wl_lock);
698
699 return peb;
700}
701#endif
702
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400703/**
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800704 * prot_queue_del - remove a physical eraseblock from the protection queue.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400705 * @ubi: UBI device description object
706 * @pnum: the physical eraseblock to remove
Artem Bityutskiy43f9b252007-12-18 15:06:55 +0200707 *
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800708 * This function deletes PEB @pnum from the protection queue and returns zero
709 * in case of success and %-ENODEV if the PEB was not found.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400710 */
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800711static int prot_queue_del(struct ubi_device *ubi, int pnum)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400712{
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800713 struct ubi_wl_entry *e;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400714
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800715 e = ubi->lookuptbl[pnum];
716 if (!e)
717 return -ENODEV;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400718
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +0300719 if (self_check_in_pq(ubi, e))
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800720 return -ENODEV;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400721
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800722 list_del(&e->u.list);
723 dbg_wl("deleted PEB %d from the protection queue", e->pnum);
Artem Bityutskiy43f9b252007-12-18 15:06:55 +0200724 return 0;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400725}
726
727/**
728 * sync_erase - synchronously erase a physical eraseblock.
729 * @ubi: UBI device description object
730 * @e: the the physical eraseblock to erase
731 * @torture: if the physical eraseblock has to be tortured
732 *
733 * This function returns zero in case of success and a negative error code in
734 * case of failure.
735 */
Artem Bityutskiy9c9ec142008-07-18 13:19:52 +0300736static int sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
737 int torture)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400738{
739 int err;
740 struct ubi_ec_hdr *ec_hdr;
741 unsigned long long ec = e->ec;
742
743 dbg_wl("erase PEB %d, old EC %llu", e->pnum, ec);
744
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +0300745 err = self_check_ec(ubi, e->pnum, e->ec);
Artem Bityutskiyadbf05e2010-01-20 10:28:58 +0200746 if (err)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400747 return -EINVAL;
748
Artem Bityutskiy33818bb2007-08-28 21:29:32 +0300749 ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400750 if (!ec_hdr)
751 return -ENOMEM;
752
753 err = ubi_io_sync_erase(ubi, e->pnum, torture);
754 if (err < 0)
755 goto out_free;
756
757 ec += err;
758 if (ec > UBI_MAX_ERASECOUNTER) {
759 /*
760 * Erase counter overflow. Upgrade UBI and use 64-bit
761 * erase counters internally.
762 */
763 ubi_err("erase counter overflow at PEB %d, EC %llu",
764 e->pnum, ec);
765 err = -EINVAL;
766 goto out_free;
767 }
768
769 dbg_wl("erased PEB %d, new EC %llu", e->pnum, ec);
770
Christoph Hellwig3261ebd2007-05-21 17:41:46 +0300771 ec_hdr->ec = cpu_to_be64(ec);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400772
773 err = ubi_io_write_ec_hdr(ubi, e->pnum, ec_hdr);
774 if (err)
775 goto out_free;
776
777 e->ec = ec;
778 spin_lock(&ubi->wl_lock);
779 if (e->ec > ubi->max_ec)
780 ubi->max_ec = e->ec;
781 spin_unlock(&ubi->wl_lock);
782
783out_free:
784 kfree(ec_hdr);
785 return err;
786}
787
788/**
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800789 * serve_prot_queue - check if it is time to stop protecting PEBs.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400790 * @ubi: UBI device description object
791 *
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800792 * This function is called after each erase operation and removes PEBs from the
793 * tail of the protection queue. These PEBs have been protected for long enough
794 * and should be moved to the used tree.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400795 */
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800796static void serve_prot_queue(struct ubi_device *ubi)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400797{
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800798 struct ubi_wl_entry *e, *tmp;
799 int count;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400800
801 /*
802 * There may be several protected physical eraseblock to remove,
803 * process them all.
804 */
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800805repeat:
806 count = 0;
807 spin_lock(&ubi->wl_lock);
808 list_for_each_entry_safe(e, tmp, &ubi->pq[ubi->pq_head], u.list) {
809 dbg_wl("PEB %d EC %d protection over, move to used tree",
810 e->pnum, e->ec);
811
812 list_del(&e->u.list);
813 wl_tree_add(e, &ubi->used);
814 if (count++ > 32) {
815 /*
816 * Let's be nice and avoid holding the spinlock for
817 * too long.
818 */
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400819 spin_unlock(&ubi->wl_lock);
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800820 cond_resched();
821 goto repeat;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400822 }
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400823 }
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800824
825 ubi->pq_head += 1;
826 if (ubi->pq_head == UBI_PROT_QUEUE_LEN)
827 ubi->pq_head = 0;
828 ubi_assert(ubi->pq_head >= 0 && ubi->pq_head < UBI_PROT_QUEUE_LEN);
829 spin_unlock(&ubi->wl_lock);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400830}
831
832/**
Richard Weinberger8199b902012-09-26 17:51:48 +0200833 * __schedule_ubi_work - schedule a work.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400834 * @ubi: UBI device description object
835 * @wrk: the work to schedule
836 *
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +0800837 * This function adds a work defined by @wrk to the tail of the pending works
Richard Weinberger8199b902012-09-26 17:51:48 +0200838 * list. Can only be used of ubi->work_sem is already held in read mode!
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400839 */
Richard Weinberger8199b902012-09-26 17:51:48 +0200840static void __schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400841{
842 spin_lock(&ubi->wl_lock);
843 list_add_tail(&wrk->list, &ubi->works);
844 ubi_assert(ubi->works_count >= 0);
845 ubi->works_count += 1;
Artem Bityutskiy27a0f2a2011-05-18 16:03:23 +0300846 if (ubi->thread_enabled && !ubi_dbg_is_bgt_disabled(ubi))
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400847 wake_up_process(ubi->bgt_thread);
848 spin_unlock(&ubi->wl_lock);
849}
850
Richard Weinberger8199b902012-09-26 17:51:48 +0200851/**
852 * schedule_ubi_work - schedule a work.
853 * @ubi: UBI device description object
854 * @wrk: the work to schedule
855 *
856 * This function adds a work defined by @wrk to the tail of the pending works
857 * list.
858 */
859static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
860{
861 down_read(&ubi->work_sem);
862 __schedule_ubi_work(ubi, wrk);
863 up_read(&ubi->work_sem);
864}
865
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400866static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
867 int cancel);
868
Richard Weinberger8199b902012-09-26 17:51:48 +0200869#ifdef CONFIG_MTD_UBI_FASTMAP
870/**
871 * ubi_is_erase_work - checks whether a work is erase work.
872 * @wrk: The work object to be checked
873 */
874int ubi_is_erase_work(struct ubi_work *wrk)
875{
876 return wrk->func == erase_worker;
877}
878#endif
879
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400880/**
881 * schedule_erase - schedule an erase work.
882 * @ubi: UBI device description object
883 * @e: the WL entry of the physical eraseblock to erase
Joel Reardond36e59e2012-05-18 15:40:24 +0200884 * @vol_id: the volume ID that last used this PEB
885 * @lnum: the last used logical eraseblock number for the PEB
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400886 * @torture: if the physical eraseblock has to be tortured
887 *
888 * This function returns zero in case of success and a %-ENOMEM in case of
889 * failure.
890 */
891static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
Joel Reardond36e59e2012-05-18 15:40:24 +0200892 int vol_id, int lnum, int torture)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400893{
894 struct ubi_work *wl_wrk;
895
Richard Weinberger8199b902012-09-26 17:51:48 +0200896 ubi_assert(e);
897 ubi_assert(!ubi_is_fm_block(ubi, e->pnum));
898
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400899 dbg_wl("schedule erasure of PEB %d, EC %d, torture %d",
900 e->pnum, e->ec, torture);
901
Artem Bityutskiy33818bb2007-08-28 21:29:32 +0300902 wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400903 if (!wl_wrk)
904 return -ENOMEM;
905
906 wl_wrk->func = &erase_worker;
907 wl_wrk->e = e;
Joel Reardond36e59e2012-05-18 15:40:24 +0200908 wl_wrk->vol_id = vol_id;
909 wl_wrk->lnum = lnum;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400910 wl_wrk->torture = torture;
911
912 schedule_ubi_work(ubi, wl_wrk);
913 return 0;
914}
915
916/**
Richard Weinberger8199b902012-09-26 17:51:48 +0200917 * do_sync_erase - run the erase worker synchronously.
918 * @ubi: UBI device description object
919 * @e: the WL entry of the physical eraseblock to erase
920 * @vol_id: the volume ID that last used this PEB
921 * @lnum: the last used logical eraseblock number for the PEB
922 * @torture: if the physical eraseblock has to be tortured
923 *
924 */
925static int do_sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
926 int vol_id, int lnum, int torture)
927{
928 struct ubi_work *wl_wrk;
929
930 dbg_wl("sync erase of PEB %i", e->pnum);
931
932 wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
933 if (!wl_wrk)
934 return -ENOMEM;
935
936 wl_wrk->e = e;
937 wl_wrk->vol_id = vol_id;
938 wl_wrk->lnum = lnum;
939 wl_wrk->torture = torture;
940
941 return erase_worker(ubi, wl_wrk, 0);
942}
943
944#ifdef CONFIG_MTD_UBI_FASTMAP
945/**
946 * ubi_wl_put_fm_peb - returns a PEB used in a fastmap to the wear-leveling
947 * sub-system.
948 * see: ubi_wl_put_peb()
949 *
950 * @ubi: UBI device description object
951 * @fm_e: physical eraseblock to return
952 * @lnum: the last used logical eraseblock number for the PEB
953 * @torture: if this physical eraseblock has to be tortured
954 */
955int ubi_wl_put_fm_peb(struct ubi_device *ubi, struct ubi_wl_entry *fm_e,
956 int lnum, int torture)
957{
958 struct ubi_wl_entry *e;
959 int vol_id, pnum = fm_e->pnum;
960
961 dbg_wl("PEB %d", pnum);
962
963 ubi_assert(pnum >= 0);
964 ubi_assert(pnum < ubi->peb_count);
965
966 spin_lock(&ubi->wl_lock);
967 e = ubi->lookuptbl[pnum];
968
969 /* This can happen if we recovered from a fastmap the very
970 * first time and writing now a new one. In this case the wl system
971 * has never seen any PEB used by the original fastmap.
972 */
973 if (!e) {
974 e = fm_e;
975 ubi_assert(e->ec >= 0);
976 ubi->lookuptbl[pnum] = e;
977 } else {
978 e->ec = fm_e->ec;
979 kfree(fm_e);
980 }
981
982 spin_unlock(&ubi->wl_lock);
983
984 vol_id = lnum ? UBI_FM_DATA_VOLUME_ID : UBI_FM_SB_VOLUME_ID;
985 return schedule_erase(ubi, e, vol_id, lnum, torture);
986}
987#endif
988
989/**
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +0400990 * wear_leveling_worker - wear-leveling worker function.
991 * @ubi: UBI device description object
992 * @wrk: the work object
993 * @cancel: non-zero if the worker has to free memory and exit
994 *
995 * This function copies a more worn out physical eraseblock to a less worn out
996 * one. Returns zero in case of success and a negative error code in case of
997 * failure.
998 */
999static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
1000 int cancel)
1001{
Artem Bityutskiyb86a2c52009-05-24 14:13:34 +03001002 int err, scrubbing = 0, torture = 0, protect = 0, erroneous = 0;
Artem Bityutskiy9c259a52009-06-08 12:49:08 +03001003 int vol_id = -1, uninitialized_var(lnum);
Richard Weinberger8199b902012-09-26 17:51:48 +02001004#ifdef CONFIG_MTD_UBI_FASTMAP
1005 int anchor = wrk->anchor;
1006#endif
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001007 struct ubi_wl_entry *e1, *e2;
1008 struct ubi_vid_hdr *vid_hdr;
1009
1010 kfree(wrk);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001011 if (cancel)
1012 return 0;
1013
Artem Bityutskiy33818bb2007-08-28 21:29:32 +03001014 vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001015 if (!vid_hdr)
1016 return -ENOMEM;
1017
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001018 mutex_lock(&ubi->move_mutex);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001019 spin_lock(&ubi->wl_lock);
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001020 ubi_assert(!ubi->move_from && !ubi->move_to);
1021 ubi_assert(!ubi->move_to_put);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001022
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001023 if (!ubi->free.rb_node ||
Artem Bityutskiy5abde382007-09-13 14:48:20 +03001024 (!ubi->used.rb_node && !ubi->scrub.rb_node)) {
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001025 /*
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001026 * No free physical eraseblocks? Well, they must be waiting in
1027 * the queue to be erased. Cancel movement - it will be
1028 * triggered again when a free physical eraseblock appears.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001029 *
1030 * No used physical eraseblocks? They must be temporarily
1031 * protected from being moved. They will be moved to the
1032 * @ubi->used tree later and the wear-leveling will be
1033 * triggered again.
1034 */
1035 dbg_wl("cancel WL, a list is empty: free %d, used %d",
Artem Bityutskiy5abde382007-09-13 14:48:20 +03001036 !ubi->free.rb_node, !ubi->used.rb_node);
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001037 goto out_cancel;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001038 }
1039
Richard Weinberger8199b902012-09-26 17:51:48 +02001040#ifdef CONFIG_MTD_UBI_FASTMAP
1041 /* Check whether we need to produce an anchor PEB */
1042 if (!anchor)
1043 anchor = !anchor_pebs_avalible(&ubi->free);
1044
1045 if (anchor) {
1046 e1 = find_anchor_wl_entry(&ubi->used);
1047 if (!e1)
1048 goto out_cancel;
1049 e2 = get_peb_for_wl(ubi);
1050 if (!e2)
1051 goto out_cancel;
1052
1053 self_check_in_wl_tree(ubi, e1, &ubi->used);
1054 rb_erase(&e1->u.rb, &ubi->used);
1055 dbg_wl("anchor-move PEB %d to PEB %d", e1->pnum, e2->pnum);
1056 } else if (!ubi->scrub.rb_node) {
1057#else
Artem Bityutskiy5abde382007-09-13 14:48:20 +03001058 if (!ubi->scrub.rb_node) {
Richard Weinberger8199b902012-09-26 17:51:48 +02001059#endif
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001060 /*
1061 * Now pick the least worn-out used physical eraseblock and a
1062 * highly worn-out free physical eraseblock. If the erase
1063 * counters differ much enough, start wear-leveling.
1064 */
Xiaochuan-Xu23553b22008-12-09 19:44:12 +08001065 e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
Richard Weinberger8199b902012-09-26 17:51:48 +02001066 e2 = get_peb_for_wl(ubi);
1067 if (!e2)
1068 goto out_cancel;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001069
1070 if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD)) {
1071 dbg_wl("no WL needed: min used EC %d, max free EC %d",
1072 e1->ec, e2->ec);
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001073 goto out_cancel;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001074 }
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +03001075 self_check_in_wl_tree(ubi, e1, &ubi->used);
Xiaochuan-Xu23553b22008-12-09 19:44:12 +08001076 rb_erase(&e1->u.rb, &ubi->used);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001077 dbg_wl("move PEB %d EC %d to PEB %d EC %d",
1078 e1->pnum, e1->ec, e2->pnum, e2->ec);
1079 } else {
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001080 /* Perform scrubbing */
1081 scrubbing = 1;
Xiaochuan-Xu23553b22008-12-09 19:44:12 +08001082 e1 = rb_entry(rb_first(&ubi->scrub), struct ubi_wl_entry, u.rb);
Richard Weinberger8199b902012-09-26 17:51:48 +02001083 e2 = get_peb_for_wl(ubi);
1084 if (!e2)
1085 goto out_cancel;
1086
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +03001087 self_check_in_wl_tree(ubi, e1, &ubi->scrub);
Xiaochuan-Xu23553b22008-12-09 19:44:12 +08001088 rb_erase(&e1->u.rb, &ubi->scrub);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001089 dbg_wl("scrub PEB %d to PEB %d", e1->pnum, e2->pnum);
1090 }
1091
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001092 ubi->move_from = e1;
1093 ubi->move_to = e2;
1094 spin_unlock(&ubi->wl_lock);
1095
1096 /*
1097 * Now we are going to copy physical eraseblock @e1->pnum to @e2->pnum.
1098 * We so far do not know which logical eraseblock our physical
1099 * eraseblock (@e1) belongs to. We have to read the volume identifier
1100 * header first.
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001101 *
1102 * Note, we are protected from this PEB being unmapped and erased. The
1103 * 'ubi_wl_put_peb()' would wait for moving to be finished if the PEB
1104 * which is being moved was unmapped.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001105 */
1106
1107 err = ubi_io_read_vid_hdr(ubi, e1->pnum, vid_hdr, 0);
1108 if (err && err != UBI_IO_BITFLIPS) {
Artem Bityutskiy74d82d22010-09-03 02:11:20 +03001109 if (err == UBI_IO_FF) {
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001110 /*
1111 * We are trying to move PEB without a VID header. UBI
1112 * always write VID headers shortly after the PEB was
Artem Bityutskiy87960c02009-05-24 11:58:58 +03001113 * given, so we have a situation when it has not yet
1114 * had a chance to write it, because it was preempted.
1115 * So add this PEB to the protection queue so far,
Artem Bityutskiy815bc5f2009-06-08 19:28:18 +03001116 * because presumably more data will be written there
1117 * (including the missing VID header), and then we'll
Artem Bityutskiy87960c02009-05-24 11:58:58 +03001118 * move it.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001119 */
1120 dbg_wl("PEB %d has no VID header", e1->pnum);
Artem Bityutskiy87960c02009-05-24 11:58:58 +03001121 protect = 1;
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001122 goto out_not_moved;
Artem Bityutskiy92e1a7d2010-09-03 14:22:17 +03001123 } else if (err == UBI_IO_FF_BITFLIPS) {
1124 /*
1125 * The same situation as %UBI_IO_FF, but bit-flips were
1126 * detected. It is better to schedule this PEB for
1127 * scrubbing.
1128 */
1129 dbg_wl("PEB %d has no VID header but has bit-flips",
1130 e1->pnum);
1131 scrubbing = 1;
1132 goto out_not_moved;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001133 }
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001134
1135 ubi_err("error %d while reading VID header from PEB %d",
1136 err, e1->pnum);
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001137 goto out_error;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001138 }
1139
Artem Bityutskiy9c259a52009-06-08 12:49:08 +03001140 vol_id = be32_to_cpu(vid_hdr->vol_id);
1141 lnum = be32_to_cpu(vid_hdr->lnum);
1142
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001143 err = ubi_eba_copy_leb(ubi, e1->pnum, e2->pnum, vid_hdr);
1144 if (err) {
Artem Bityutskiy87960c02009-05-24 11:58:58 +03001145 if (err == MOVE_CANCEL_RACE) {
1146 /*
1147 * The LEB has not been moved because the volume is
1148 * being deleted or the PEB has been put meanwhile. We
1149 * should prevent this PEB from being selected for
1150 * wear-leveling movement again, so put it to the
1151 * protection queue.
1152 */
1153 protect = 1;
1154 goto out_not_moved;
1155 }
Bhavesh Parekhe801e122011-11-30 17:43:42 +05301156 if (err == MOVE_RETRY) {
1157 scrubbing = 1;
1158 goto out_not_moved;
1159 }
Artem Bityutskiycc831462012-03-09 10:31:18 +02001160 if (err == MOVE_TARGET_BITFLIPS || err == MOVE_TARGET_WR_ERR ||
Artem Bityutskiyb86a2c52009-05-24 14:13:34 +03001161 err == MOVE_TARGET_RD_ERR) {
Artem Bityutskiy9c259a52009-06-08 12:49:08 +03001162 /*
1163 * Target PEB had bit-flips or write error - torture it.
1164 */
Artem Bityutskiy6fa6f5b2008-12-05 13:37:02 +02001165 torture = 1;
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001166 goto out_not_moved;
Artem Bityutskiy6fa6f5b2008-12-05 13:37:02 +02001167 }
Artem Bityutskiy87960c02009-05-24 11:58:58 +03001168
Artem Bityutskiyb86a2c52009-05-24 14:13:34 +03001169 if (err == MOVE_SOURCE_RD_ERR) {
1170 /*
1171 * An error happened while reading the source PEB. Do
1172 * not switch to R/O mode in this case, and give the
1173 * upper layers a possibility to recover from this,
1174 * e.g. by unmapping corresponding LEB. Instead, just
Artem Bityutskiy815bc5f2009-06-08 19:28:18 +03001175 * put this PEB to the @ubi->erroneous list to prevent
1176 * UBI from trying to move it over and over again.
Artem Bityutskiyb86a2c52009-05-24 14:13:34 +03001177 */
1178 if (ubi->erroneous_peb_count > ubi->max_erroneous) {
1179 ubi_err("too many erroneous eraseblocks (%d)",
1180 ubi->erroneous_peb_count);
1181 goto out_error;
1182 }
1183 erroneous = 1;
1184 goto out_not_moved;
1185 }
1186
Artem Bityutskiy90bf0262009-05-23 16:04:17 +03001187 if (err < 0)
1188 goto out_error;
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001189
Artem Bityutskiy87960c02009-05-24 11:58:58 +03001190 ubi_assert(0);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001191 }
1192
Artem Bityutskiy6a8f4832008-12-05 12:23:48 +02001193 /* The PEB has been successfully moved */
Artem Bityutskiy6a8f4832008-12-05 12:23:48 +02001194 if (scrubbing)
Artem Bityutskiy9c259a52009-06-08 12:49:08 +03001195 ubi_msg("scrubbed PEB %d (LEB %d:%d), data moved to PEB %d",
1196 e1->pnum, vol_id, lnum, e2->pnum);
1197 ubi_free_vid_hdr(ubi, vid_hdr);
Artem Bityutskiy8c1e6ee2008-07-18 12:20:23 +03001198
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001199 spin_lock(&ubi->wl_lock);
Artem Bityutskiy3c98b0a2008-12-05 12:42:45 +02001200 if (!ubi->move_to_put) {
Artem Bityutskiy5abde382007-09-13 14:48:20 +03001201 wl_tree_add(e2, &ubi->used);
Artem Bityutskiy3c98b0a2008-12-05 12:42:45 +02001202 e2 = NULL;
1203 }
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001204 ubi->move_from = ubi->move_to = NULL;
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001205 ubi->move_to_put = ubi->wl_scheduled = 0;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001206 spin_unlock(&ubi->wl_lock);
1207
Richard Weinberger8199b902012-09-26 17:51:48 +02001208 err = do_sync_erase(ubi, e1, vol_id, lnum, 0);
Artem Bityutskiy3c98b0a2008-12-05 12:42:45 +02001209 if (err) {
Artem Bityutskiy87960c02009-05-24 11:58:58 +03001210 kmem_cache_free(ubi_wl_entry_slab, e1);
Artem Bityutskiy21d08bb2009-06-08 19:28:18 +03001211 if (e2)
1212 kmem_cache_free(ubi_wl_entry_slab, e2);
Artem Bityutskiy87960c02009-05-24 11:58:58 +03001213 goto out_ro;
Artem Bityutskiy3c98b0a2008-12-05 12:42:45 +02001214 }
Artem Bityutskiy6a8f4832008-12-05 12:23:48 +02001215
Artem Bityutskiy3c98b0a2008-12-05 12:42:45 +02001216 if (e2) {
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001217 /*
1218 * Well, the target PEB was put meanwhile, schedule it for
1219 * erasure.
1220 */
Artem Bityutskiy9c259a52009-06-08 12:49:08 +03001221 dbg_wl("PEB %d (LEB %d:%d) was put meanwhile, erase",
1222 e2->pnum, vol_id, lnum);
Richard Weinberger8199b902012-09-26 17:51:48 +02001223 err = do_sync_erase(ubi, e2, vol_id, lnum, 0);
Artem Bityutskiy87960c02009-05-24 11:58:58 +03001224 if (err) {
1225 kmem_cache_free(ubi_wl_entry_slab, e2);
1226 goto out_ro;
1227 }
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001228 }
1229
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001230 dbg_wl("done");
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001231 mutex_unlock(&ubi->move_mutex);
1232 return 0;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001233
1234 /*
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001235 * For some reasons the LEB was not moved, might be an error, might be
1236 * something else. @e1 was not changed, so return it back. @e2 might
Artem Bityutskiy6fa6f5b2008-12-05 13:37:02 +02001237 * have been changed, schedule it for erasure.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001238 */
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001239out_not_moved:
Artem Bityutskiy9c259a52009-06-08 12:49:08 +03001240 if (vol_id != -1)
1241 dbg_wl("cancel moving PEB %d (LEB %d:%d) to PEB %d (%d)",
1242 e1->pnum, vol_id, lnum, e2->pnum, err);
1243 else
1244 dbg_wl("cancel moving PEB %d to PEB %d (%d)",
1245 e1->pnum, e2->pnum, err);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001246 spin_lock(&ubi->wl_lock);
Artem Bityutskiy87960c02009-05-24 11:58:58 +03001247 if (protect)
1248 prot_queue_add(ubi, e1);
Artem Bityutskiyb86a2c52009-05-24 14:13:34 +03001249 else if (erroneous) {
1250 wl_tree_add(e1, &ubi->erroneous);
1251 ubi->erroneous_peb_count += 1;
1252 } else if (scrubbing)
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001253 wl_tree_add(e1, &ubi->scrub);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001254 else
Artem Bityutskiy5abde382007-09-13 14:48:20 +03001255 wl_tree_add(e1, &ubi->used);
Artem Bityutskiy6fa6f5b2008-12-05 13:37:02 +02001256 ubi_assert(!ubi->move_to_put);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001257 ubi->move_from = ubi->move_to = NULL;
Artem Bityutskiy6fa6f5b2008-12-05 13:37:02 +02001258 ubi->wl_scheduled = 0;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001259 spin_unlock(&ubi->wl_lock);
1260
Artem Bityutskiy87960c02009-05-24 11:58:58 +03001261 ubi_free_vid_hdr(ubi, vid_hdr);
Richard Weinberger8199b902012-09-26 17:51:48 +02001262 err = do_sync_erase(ubi, e2, vol_id, lnum, torture);
Artem Bityutskiy87960c02009-05-24 11:58:58 +03001263 if (err) {
1264 kmem_cache_free(ubi_wl_entry_slab, e2);
1265 goto out_ro;
1266 }
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001267 mutex_unlock(&ubi->move_mutex);
1268 return 0;
1269
1270out_error:
Artem Bityutskiy9c259a52009-06-08 12:49:08 +03001271 if (vol_id != -1)
1272 ubi_err("error %d while moving PEB %d to PEB %d",
1273 err, e1->pnum, e2->pnum);
1274 else
1275 ubi_err("error %d while moving PEB %d (LEB %d:%d) to PEB %d",
1276 err, e1->pnum, vol_id, lnum, e2->pnum);
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001277 spin_lock(&ubi->wl_lock);
1278 ubi->move_from = ubi->move_to = NULL;
1279 ubi->move_to_put = ubi->wl_scheduled = 0;
1280 spin_unlock(&ubi->wl_lock);
1281
Artem Bityutskiy87960c02009-05-24 11:58:58 +03001282 ubi_free_vid_hdr(ubi, vid_hdr);
1283 kmem_cache_free(ubi_wl_entry_slab, e1);
1284 kmem_cache_free(ubi_wl_entry_slab, e2);
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001285
Artem Bityutskiy87960c02009-05-24 11:58:58 +03001286out_ro:
1287 ubi_ro_mode(ubi);
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001288 mutex_unlock(&ubi->move_mutex);
Artem Bityutskiy87960c02009-05-24 11:58:58 +03001289 ubi_assert(err != 0);
1290 return err < 0 ? err : -EIO;
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001291
1292out_cancel:
1293 ubi->wl_scheduled = 0;
1294 spin_unlock(&ubi->wl_lock);
1295 mutex_unlock(&ubi->move_mutex);
1296 ubi_free_vid_hdr(ubi, vid_hdr);
1297 return 0;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001298}
1299
1300/**
1301 * ensure_wear_leveling - schedule wear-leveling if it is needed.
1302 * @ubi: UBI device description object
Richard Weinberger8199b902012-09-26 17:51:48 +02001303 * @nested: set to non-zero if this function is called from UBI worker
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001304 *
1305 * This function checks if it is time to start wear-leveling and schedules it
1306 * if yes. This function returns zero in case of success and a negative error
1307 * code in case of failure.
1308 */
Richard Weinberger8199b902012-09-26 17:51:48 +02001309static int ensure_wear_leveling(struct ubi_device *ubi, int nested)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001310{
1311 int err = 0;
1312 struct ubi_wl_entry *e1;
1313 struct ubi_wl_entry *e2;
1314 struct ubi_work *wrk;
1315
1316 spin_lock(&ubi->wl_lock);
1317 if (ubi->wl_scheduled)
1318 /* Wear-leveling is already in the work queue */
1319 goto out_unlock;
1320
1321 /*
1322 * If the ubi->scrub tree is not empty, scrubbing is needed, and the
1323 * the WL worker has to be scheduled anyway.
1324 */
Artem Bityutskiy5abde382007-09-13 14:48:20 +03001325 if (!ubi->scrub.rb_node) {
1326 if (!ubi->used.rb_node || !ubi->free.rb_node)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001327 /* No physical eraseblocks - no deal */
1328 goto out_unlock;
1329
1330 /*
1331 * We schedule wear-leveling only if the difference between the
1332 * lowest erase counter of used physical eraseblocks and a high
Frederik Schwarzer025dfda2008-10-16 19:02:37 +02001333 * erase counter of free physical eraseblocks is greater than
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001334 * %UBI_WL_THRESHOLD.
1335 */
Xiaochuan-Xu23553b22008-12-09 19:44:12 +08001336 e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
Richard Weinberger8199b902012-09-26 17:51:48 +02001337 e2 = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001338
1339 if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD))
1340 goto out_unlock;
1341 dbg_wl("schedule wear-leveling");
1342 } else
1343 dbg_wl("schedule scrubbing");
1344
1345 ubi->wl_scheduled = 1;
1346 spin_unlock(&ubi->wl_lock);
1347
Artem Bityutskiy33818bb2007-08-28 21:29:32 +03001348 wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001349 if (!wrk) {
1350 err = -ENOMEM;
1351 goto out_cancel;
1352 }
1353
Richard Weinberger8199b902012-09-26 17:51:48 +02001354 wrk->anchor = 0;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001355 wrk->func = &wear_leveling_worker;
Richard Weinberger8199b902012-09-26 17:51:48 +02001356 if (nested)
1357 __schedule_ubi_work(ubi, wrk);
1358 else
1359 schedule_ubi_work(ubi, wrk);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001360 return err;
1361
1362out_cancel:
1363 spin_lock(&ubi->wl_lock);
1364 ubi->wl_scheduled = 0;
1365out_unlock:
1366 spin_unlock(&ubi->wl_lock);
1367 return err;
1368}
1369
Richard Weinberger8199b902012-09-26 17:51:48 +02001370#ifdef CONFIG_MTD_UBI_FASTMAP
1371/**
1372 * ubi_ensure_anchor_pebs - schedule wear-leveling to produce an anchor PEB.
1373 * @ubi: UBI device description object
1374 */
1375int ubi_ensure_anchor_pebs(struct ubi_device *ubi)
1376{
1377 struct ubi_work *wrk;
1378
1379 spin_lock(&ubi->wl_lock);
1380 if (ubi->wl_scheduled) {
1381 spin_unlock(&ubi->wl_lock);
1382 return 0;
1383 }
1384 ubi->wl_scheduled = 1;
1385 spin_unlock(&ubi->wl_lock);
1386
1387 wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
1388 if (!wrk) {
1389 spin_lock(&ubi->wl_lock);
1390 ubi->wl_scheduled = 0;
1391 spin_unlock(&ubi->wl_lock);
1392 return -ENOMEM;
1393 }
1394
1395 wrk->anchor = 1;
1396 wrk->func = &wear_leveling_worker;
1397 schedule_ubi_work(ubi, wrk);
1398 return 0;
1399}
1400#endif
1401
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001402/**
1403 * erase_worker - physical eraseblock erase worker function.
1404 * @ubi: UBI device description object
1405 * @wl_wrk: the work object
1406 * @cancel: non-zero if the worker has to free memory and exit
1407 *
1408 * This function erases a physical eraseblock and perform torture testing if
1409 * needed. It also takes care about marking the physical eraseblock bad if
1410 * needed. Returns zero in case of success and a negative error code in case of
1411 * failure.
1412 */
1413static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
1414 int cancel)
1415{
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001416 struct ubi_wl_entry *e = wl_wrk->e;
Shmulik Ladkani37f758a2012-07-04 11:06:01 +03001417 int pnum = e->pnum;
Joel Reardond36e59e2012-05-18 15:40:24 +02001418 int vol_id = wl_wrk->vol_id;
1419 int lnum = wl_wrk->lnum;
Shmulik Ladkani37f758a2012-07-04 11:06:01 +03001420 int err, available_consumed = 0;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001421
1422 if (cancel) {
1423 dbg_wl("cancel erasure of PEB %d EC %d", pnum, e->ec);
1424 kfree(wl_wrk);
Artem Bityutskiy06b68ba2007-12-16 12:49:01 +02001425 kmem_cache_free(ubi_wl_entry_slab, e);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001426 return 0;
1427 }
1428
Joel Reardond36e59e2012-05-18 15:40:24 +02001429 dbg_wl("erase PEB %d EC %d LEB %d:%d",
1430 pnum, e->ec, wl_wrk->vol_id, wl_wrk->lnum);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001431
Richard Weinberger8199b902012-09-26 17:51:48 +02001432 ubi_assert(!ubi_is_fm_block(ubi, e->pnum));
1433
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001434 err = sync_erase(ubi, e, wl_wrk->torture);
1435 if (!err) {
1436 /* Fine, we've erased it successfully */
1437 kfree(wl_wrk);
1438
1439 spin_lock(&ubi->wl_lock);
Artem Bityutskiy5abde382007-09-13 14:48:20 +03001440 wl_tree_add(e, &ubi->free);
Richard Weinberger8199b902012-09-26 17:51:48 +02001441 ubi->free_count++;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001442 spin_unlock(&ubi->wl_lock);
1443
1444 /*
Artem Bityutskiy9c9ec142008-07-18 13:19:52 +03001445 * One more erase operation has happened, take care about
1446 * protected physical eraseblocks.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001447 */
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08001448 serve_prot_queue(ubi);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001449
1450 /* And take care about wear-leveling */
Richard Weinberger8199b902012-09-26 17:51:48 +02001451 err = ensure_wear_leveling(ubi, 1);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001452 return err;
1453 }
1454
Artem Bityutskiy8d2d4012007-07-22 22:32:51 +03001455 ubi_err("failed to erase PEB %d, error %d", pnum, err);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001456 kfree(wl_wrk);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001457
Artem Bityutskiy784c1452007-07-18 13:42:10 +03001458 if (err == -EINTR || err == -ENOMEM || err == -EAGAIN ||
1459 err == -EBUSY) {
1460 int err1;
1461
1462 /* Re-schedule the LEB for erasure */
Joel Reardond36e59e2012-05-18 15:40:24 +02001463 err1 = schedule_erase(ubi, e, vol_id, lnum, 0);
Artem Bityutskiy784c1452007-07-18 13:42:10 +03001464 if (err1) {
1465 err = err1;
1466 goto out_ro;
1467 }
1468 return err;
Artem Bityutskiye57e0d82012-01-05 10:47:18 +02001469 }
1470
1471 kmem_cache_free(ubi_wl_entry_slab, e);
1472 if (err != -EIO)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001473 /*
1474 * If this is not %-EIO, we have no idea what to do. Scheduling
1475 * this physical eraseblock for erasure again would cause
Artem Bityutskiy815bc5f2009-06-08 19:28:18 +03001476 * errors again and again. Well, lets switch to R/O mode.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001477 */
Artem Bityutskiy784c1452007-07-18 13:42:10 +03001478 goto out_ro;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001479
1480 /* It is %-EIO, the PEB went bad */
1481
1482 if (!ubi->bad_allowed) {
1483 ubi_err("bad physical eraseblock %d detected", pnum);
Artem Bityutskiy784c1452007-07-18 13:42:10 +03001484 goto out_ro;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001485 }
1486
Artem Bityutskiy784c1452007-07-18 13:42:10 +03001487 spin_lock(&ubi->volumes_lock);
Artem Bityutskiy784c1452007-07-18 13:42:10 +03001488 if (ubi->beb_rsvd_pebs == 0) {
Shmulik Ladkani37f758a2012-07-04 11:06:01 +03001489 if (ubi->avail_pebs == 0) {
1490 spin_unlock(&ubi->volumes_lock);
1491 ubi_err("no reserved/available physical eraseblocks");
1492 goto out_ro;
1493 }
1494 ubi->avail_pebs -= 1;
1495 available_consumed = 1;
Artem Bityutskiy784c1452007-07-18 13:42:10 +03001496 }
Artem Bityutskiy784c1452007-07-18 13:42:10 +03001497 spin_unlock(&ubi->volumes_lock);
Artem Bityutskiy784c1452007-07-18 13:42:10 +03001498
Artem Bityutskiy52b605d2009-06-08 16:52:48 +03001499 ubi_msg("mark PEB %d as bad", pnum);
Artem Bityutskiy784c1452007-07-18 13:42:10 +03001500 err = ubi_io_mark_bad(ubi, pnum);
1501 if (err)
1502 goto out_ro;
1503
1504 spin_lock(&ubi->volumes_lock);
Shmulik Ladkani37f758a2012-07-04 11:06:01 +03001505 if (ubi->beb_rsvd_pebs > 0) {
1506 if (available_consumed) {
1507 /*
1508 * The amount of reserved PEBs increased since we last
1509 * checked.
1510 */
1511 ubi->avail_pebs += 1;
1512 available_consumed = 0;
1513 }
1514 ubi->beb_rsvd_pebs -= 1;
1515 }
Artem Bityutskiy784c1452007-07-18 13:42:10 +03001516 ubi->bad_peb_count += 1;
1517 ubi->good_peb_count -= 1;
1518 ubi_calculate_reserved(ubi);
Shmulik Ladkani37f758a2012-07-04 11:06:01 +03001519 if (available_consumed)
1520 ubi_warn("no PEBs in the reserved pool, used an available PEB");
1521 else if (ubi->beb_rsvd_pebs)
Artem Bityutskiy52b605d2009-06-08 16:52:48 +03001522 ubi_msg("%d PEBs left in the reserve", ubi->beb_rsvd_pebs);
1523 else
Shmulik Ladkani37f758a2012-07-04 11:06:01 +03001524 ubi_warn("last PEB from the reserve was used");
Artem Bityutskiy784c1452007-07-18 13:42:10 +03001525 spin_unlock(&ubi->volumes_lock);
1526
1527 return err;
1528
1529out_ro:
Shmulik Ladkani37f758a2012-07-04 11:06:01 +03001530 if (available_consumed) {
1531 spin_lock(&ubi->volumes_lock);
1532 ubi->avail_pebs += 1;
1533 spin_unlock(&ubi->volumes_lock);
1534 }
Artem Bityutskiy784c1452007-07-18 13:42:10 +03001535 ubi_ro_mode(ubi);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001536 return err;
1537}
1538
1539/**
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +03001540 * ubi_wl_put_peb - return a PEB to the wear-leveling sub-system.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001541 * @ubi: UBI device description object
Joel Reardond36e59e2012-05-18 15:40:24 +02001542 * @vol_id: the volume ID that last used this PEB
1543 * @lnum: the last used logical eraseblock number for the PEB
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001544 * @pnum: physical eraseblock to return
1545 * @torture: if this physical eraseblock has to be tortured
1546 *
1547 * This function is called to return physical eraseblock @pnum to the pool of
1548 * free physical eraseblocks. The @torture flag has to be set if an I/O error
1549 * occurred to this @pnum and it has to be tested. This function returns zero
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001550 * in case of success, and a negative error code in case of failure.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001551 */
Joel Reardond36e59e2012-05-18 15:40:24 +02001552int ubi_wl_put_peb(struct ubi_device *ubi, int vol_id, int lnum,
1553 int pnum, int torture)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001554{
1555 int err;
1556 struct ubi_wl_entry *e;
1557
1558 dbg_wl("PEB %d", pnum);
1559 ubi_assert(pnum >= 0);
1560 ubi_assert(pnum < ubi->peb_count);
1561
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001562retry:
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001563 spin_lock(&ubi->wl_lock);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001564 e = ubi->lookuptbl[pnum];
1565 if (e == ubi->move_from) {
1566 /*
1567 * User is putting the physical eraseblock which was selected to
1568 * be moved. It will be scheduled for erasure in the
1569 * wear-leveling worker.
1570 */
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001571 dbg_wl("PEB %d is being moved, wait", pnum);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001572 spin_unlock(&ubi->wl_lock);
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001573
1574 /* Wait for the WL worker by taking the @ubi->move_mutex */
1575 mutex_lock(&ubi->move_mutex);
1576 mutex_unlock(&ubi->move_mutex);
1577 goto retry;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001578 } else if (e == ubi->move_to) {
1579 /*
1580 * User is putting the physical eraseblock which was selected
1581 * as the target the data is moved to. It may happen if the EBA
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +03001582 * sub-system already re-mapped the LEB in 'ubi_eba_copy_leb()'
1583 * but the WL sub-system has not put the PEB to the "used" tree
1584 * yet, but it is about to do this. So we just set a flag which
1585 * will tell the WL worker that the PEB is not needed anymore
1586 * and should be scheduled for erasure.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001587 */
1588 dbg_wl("PEB %d is the target of data moving", pnum);
1589 ubi_assert(!ubi->move_to_put);
1590 ubi->move_to_put = 1;
1591 spin_unlock(&ubi->wl_lock);
1592 return 0;
1593 } else {
Artem Bityutskiy5abde382007-09-13 14:48:20 +03001594 if (in_wl_tree(e, &ubi->used)) {
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +03001595 self_check_in_wl_tree(ubi, e, &ubi->used);
Xiaochuan-Xu23553b22008-12-09 19:44:12 +08001596 rb_erase(&e->u.rb, &ubi->used);
Artem Bityutskiy5abde382007-09-13 14:48:20 +03001597 } else if (in_wl_tree(e, &ubi->scrub)) {
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +03001598 self_check_in_wl_tree(ubi, e, &ubi->scrub);
Xiaochuan-Xu23553b22008-12-09 19:44:12 +08001599 rb_erase(&e->u.rb, &ubi->scrub);
Artem Bityutskiyb86a2c52009-05-24 14:13:34 +03001600 } else if (in_wl_tree(e, &ubi->erroneous)) {
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +03001601 self_check_in_wl_tree(ubi, e, &ubi->erroneous);
Artem Bityutskiyb86a2c52009-05-24 14:13:34 +03001602 rb_erase(&e->u.rb, &ubi->erroneous);
1603 ubi->erroneous_peb_count -= 1;
1604 ubi_assert(ubi->erroneous_peb_count >= 0);
Artem Bityutskiy815bc5f2009-06-08 19:28:18 +03001605 /* Erroneous PEBs should be tortured */
Artem Bityutskiyb86a2c52009-05-24 14:13:34 +03001606 torture = 1;
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001607 } else {
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08001608 err = prot_queue_del(ubi, e->pnum);
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001609 if (err) {
1610 ubi_err("PEB %d not found", pnum);
1611 ubi_ro_mode(ubi);
1612 spin_unlock(&ubi->wl_lock);
1613 return err;
1614 }
1615 }
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001616 }
1617 spin_unlock(&ubi->wl_lock);
1618
Joel Reardond36e59e2012-05-18 15:40:24 +02001619 err = schedule_erase(ubi, e, vol_id, lnum, torture);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001620 if (err) {
1621 spin_lock(&ubi->wl_lock);
Artem Bityutskiy5abde382007-09-13 14:48:20 +03001622 wl_tree_add(e, &ubi->used);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001623 spin_unlock(&ubi->wl_lock);
1624 }
1625
1626 return err;
1627}
1628
1629/**
1630 * ubi_wl_scrub_peb - schedule a physical eraseblock for scrubbing.
1631 * @ubi: UBI device description object
1632 * @pnum: the physical eraseblock to schedule
1633 *
1634 * If a bit-flip in a physical eraseblock is detected, this physical eraseblock
1635 * needs scrubbing. This function schedules a physical eraseblock for
1636 * scrubbing which is done in background. This function returns zero in case of
1637 * success and a negative error code in case of failure.
1638 */
1639int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum)
1640{
1641 struct ubi_wl_entry *e;
1642
Artem Bityutskiy719bb842012-08-27 17:14:58 +03001643 ubi_msg("schedule PEB %d for scrubbing", pnum);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001644
1645retry:
1646 spin_lock(&ubi->wl_lock);
1647 e = ubi->lookuptbl[pnum];
Artem Bityutskiyd3f6e6c2010-08-29 23:34:44 +03001648 if (e == ubi->move_from || in_wl_tree(e, &ubi->scrub) ||
1649 in_wl_tree(e, &ubi->erroneous)) {
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001650 spin_unlock(&ubi->wl_lock);
1651 return 0;
1652 }
1653
1654 if (e == ubi->move_to) {
1655 /*
1656 * This physical eraseblock was used to move data to. The data
1657 * was moved but the PEB was not yet inserted to the proper
1658 * tree. We should just wait a little and let the WL worker
1659 * proceed.
1660 */
1661 spin_unlock(&ubi->wl_lock);
1662 dbg_wl("the PEB %d is not in proper tree, retry", pnum);
1663 yield();
1664 goto retry;
1665 }
1666
Artem Bityutskiy5abde382007-09-13 14:48:20 +03001667 if (in_wl_tree(e, &ubi->used)) {
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +03001668 self_check_in_wl_tree(ubi, e, &ubi->used);
Xiaochuan-Xu23553b22008-12-09 19:44:12 +08001669 rb_erase(&e->u.rb, &ubi->used);
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001670 } else {
1671 int err;
1672
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08001673 err = prot_queue_del(ubi, e->pnum);
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001674 if (err) {
1675 ubi_err("PEB %d not found", pnum);
1676 ubi_ro_mode(ubi);
1677 spin_unlock(&ubi->wl_lock);
1678 return err;
1679 }
1680 }
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001681
Artem Bityutskiy5abde382007-09-13 14:48:20 +03001682 wl_tree_add(e, &ubi->scrub);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001683 spin_unlock(&ubi->wl_lock);
1684
1685 /*
1686 * Technically scrubbing is the same as wear-leveling, so it is done
1687 * by the WL worker.
1688 */
Richard Weinberger8199b902012-09-26 17:51:48 +02001689 return ensure_wear_leveling(ubi, 0);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001690}
1691
1692/**
1693 * ubi_wl_flush - flush all pending works.
1694 * @ubi: UBI device description object
Joel Reardon62f384552012-05-20 21:27:11 +02001695 * @vol_id: the volume id to flush for
1696 * @lnum: the logical eraseblock number to flush for
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001697 *
Joel Reardon62f384552012-05-20 21:27:11 +02001698 * This function executes all pending works for a particular volume id /
1699 * logical eraseblock number pair. If either value is set to %UBI_ALL, then it
1700 * acts as a wildcard for all of the corresponding volume numbers or logical
1701 * eraseblock numbers. It returns zero in case of success and a negative error
1702 * code in case of failure.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001703 */
Joel Reardon62f384552012-05-20 21:27:11 +02001704int ubi_wl_flush(struct ubi_device *ubi, int vol_id, int lnum)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001705{
Joel Reardon62f384552012-05-20 21:27:11 +02001706 int err = 0;
1707 int found = 1;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001708
1709 /*
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08001710 * Erase while the pending works queue is not empty, but not more than
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001711 * the number of currently pending works.
1712 */
Joel Reardon62f384552012-05-20 21:27:11 +02001713 dbg_wl("flush pending work for LEB %d:%d (%d pending works)",
1714 vol_id, lnum, ubi->works_count);
Artem Bityutskiy593dd332007-12-18 15:54:35 +02001715
Joel Reardon62f384552012-05-20 21:27:11 +02001716 while (found) {
1717 struct ubi_work *wrk;
1718 found = 0;
Artem Bityutskiy593dd332007-12-18 15:54:35 +02001719
Artem Bityutskiy12027f12012-06-07 15:15:30 +03001720 down_read(&ubi->work_sem);
Joel Reardon62f384552012-05-20 21:27:11 +02001721 spin_lock(&ubi->wl_lock);
1722 list_for_each_entry(wrk, &ubi->works, list) {
1723 if ((vol_id == UBI_ALL || wrk->vol_id == vol_id) &&
1724 (lnum == UBI_ALL || wrk->lnum == lnum)) {
1725 list_del(&wrk->list);
1726 ubi->works_count -= 1;
1727 ubi_assert(ubi->works_count >= 0);
1728 spin_unlock(&ubi->wl_lock);
1729
1730 err = wrk->func(ubi, wrk, 0);
Artem Bityutskiy12027f12012-06-07 15:15:30 +03001731 if (err) {
1732 up_read(&ubi->work_sem);
1733 return err;
1734 }
1735
Joel Reardon62f384552012-05-20 21:27:11 +02001736 spin_lock(&ubi->wl_lock);
1737 found = 1;
1738 break;
1739 }
1740 }
1741 spin_unlock(&ubi->wl_lock);
Artem Bityutskiy12027f12012-06-07 15:15:30 +03001742 up_read(&ubi->work_sem);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001743 }
1744
Artem Bityutskiy12027f12012-06-07 15:15:30 +03001745 /*
1746 * Make sure all the works which have been done in parallel are
1747 * finished.
1748 */
1749 down_write(&ubi->work_sem);
Joel Reardon62f384552012-05-20 21:27:11 +02001750 up_write(&ubi->work_sem);
Artem Bityutskiy12027f12012-06-07 15:15:30 +03001751
Joel Reardon62f384552012-05-20 21:27:11 +02001752 return err;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001753}
1754
1755/**
1756 * tree_destroy - destroy an RB-tree.
1757 * @root: the root of the tree to destroy
1758 */
1759static void tree_destroy(struct rb_root *root)
1760{
1761 struct rb_node *rb;
1762 struct ubi_wl_entry *e;
1763
1764 rb = root->rb_node;
1765 while (rb) {
1766 if (rb->rb_left)
1767 rb = rb->rb_left;
1768 else if (rb->rb_right)
1769 rb = rb->rb_right;
1770 else {
Xiaochuan-Xu23553b22008-12-09 19:44:12 +08001771 e = rb_entry(rb, struct ubi_wl_entry, u.rb);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001772
1773 rb = rb_parent(rb);
1774 if (rb) {
Xiaochuan-Xu23553b22008-12-09 19:44:12 +08001775 if (rb->rb_left == &e->u.rb)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001776 rb->rb_left = NULL;
1777 else
1778 rb->rb_right = NULL;
1779 }
1780
Artem Bityutskiy06b68ba2007-12-16 12:49:01 +02001781 kmem_cache_free(ubi_wl_entry_slab, e);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001782 }
1783 }
1784}
1785
1786/**
1787 * ubi_thread - UBI background thread.
1788 * @u: the UBI device description object pointer
1789 */
Artem Bityutskiycdfa7882007-12-17 20:33:20 +02001790int ubi_thread(void *u)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001791{
1792 int failures = 0;
1793 struct ubi_device *ubi = u;
1794
1795 ubi_msg("background thread \"%s\" started, PID %d",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07001796 ubi->bgt_name, task_pid_nr(current));
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001797
Rafael J. Wysocki83144182007-07-17 04:03:35 -07001798 set_freezable();
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001799 for (;;) {
1800 int err;
1801
1802 if (kthread_should_stop())
Kyungmin Parkcadb40c2008-05-22 10:32:18 +09001803 break;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001804
1805 if (try_to_freeze())
1806 continue;
1807
1808 spin_lock(&ubi->wl_lock);
1809 if (list_empty(&ubi->works) || ubi->ro_mode ||
Artem Bityutskiy27a0f2a2011-05-18 16:03:23 +03001810 !ubi->thread_enabled || ubi_dbg_is_bgt_disabled(ubi)) {
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001811 set_current_state(TASK_INTERRUPTIBLE);
1812 spin_unlock(&ubi->wl_lock);
1813 schedule();
1814 continue;
1815 }
1816 spin_unlock(&ubi->wl_lock);
1817
1818 err = do_work(ubi);
1819 if (err) {
1820 ubi_err("%s: work failed with error code %d",
1821 ubi->bgt_name, err);
1822 if (failures++ > WL_MAX_FAILURES) {
1823 /*
1824 * Too many failures, disable the thread and
1825 * switch to read-only mode.
1826 */
1827 ubi_msg("%s: %d consecutive failures",
1828 ubi->bgt_name, WL_MAX_FAILURES);
1829 ubi_ro_mode(ubi);
Vitaliy Gusev2ad49882008-11-05 18:27:18 +03001830 ubi->thread_enabled = 0;
1831 continue;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001832 }
1833 } else
1834 failures = 0;
1835
1836 cond_resched();
1837 }
1838
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001839 dbg_wl("background thread \"%s\" is killed", ubi->bgt_name);
1840 return 0;
1841}
1842
1843/**
1844 * cancel_pending - cancel all pending works.
1845 * @ubi: UBI device description object
1846 */
1847static void cancel_pending(struct ubi_device *ubi)
1848{
1849 while (!list_empty(&ubi->works)) {
1850 struct ubi_work *wrk;
1851
1852 wrk = list_entry(ubi->works.next, struct ubi_work, list);
1853 list_del(&wrk->list);
1854 wrk->func(ubi, wrk, 1);
1855 ubi->works_count -= 1;
1856 ubi_assert(ubi->works_count >= 0);
1857 }
1858}
1859
1860/**
Artem Bityutskiy41e0cd92012-05-17 21:05:33 +03001861 * ubi_wl_init - initialize the WL sub-system using attaching information.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001862 * @ubi: UBI device description object
Artem Bityutskiya4e60422012-05-17 13:09:08 +03001863 * @ai: attaching information
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001864 *
1865 * This function returns zero in case of success, and a negative error code in
1866 * case of failure.
1867 */
Artem Bityutskiy41e0cd92012-05-17 21:05:33 +03001868int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001869{
Richard Weinberger8199b902012-09-26 17:51:48 +02001870 int err, i, reserved_pebs, found_pebs = 0;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001871 struct rb_node *rb1, *rb2;
Artem Bityutskiy517af482012-05-17 14:38:34 +03001872 struct ubi_ainf_volume *av;
Artem Bityutskiy2c5ec5c2012-05-17 08:26:24 +03001873 struct ubi_ainf_peb *aeb, *tmp;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001874 struct ubi_wl_entry *e;
1875
Artem Bityutskiyb86a2c52009-05-24 14:13:34 +03001876 ubi->used = ubi->erroneous = ubi->free = ubi->scrub = RB_ROOT;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001877 spin_lock_init(&ubi->wl_lock);
Artem Bityutskiy43f9b252007-12-18 15:06:55 +02001878 mutex_init(&ubi->move_mutex);
Artem Bityutskiy593dd332007-12-18 15:54:35 +02001879 init_rwsem(&ubi->work_sem);
Artem Bityutskiya4e60422012-05-17 13:09:08 +03001880 ubi->max_ec = ai->max_ec;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001881 INIT_LIST_HEAD(&ubi->works);
Richard Weinberger8199b902012-09-26 17:51:48 +02001882#ifdef CONFIG_MTD_UBI_FASTMAP
1883 INIT_WORK(&ubi->fm_work, update_fastmap_work_fn);
1884#endif
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001885
1886 sprintf(ubi->bgt_name, UBI_BGT_NAME_PATTERN, ubi->ubi_num);
1887
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001888 err = -ENOMEM;
1889 ubi->lookuptbl = kzalloc(ubi->peb_count * sizeof(void *), GFP_KERNEL);
1890 if (!ubi->lookuptbl)
Artem Bityutskiycdfa7882007-12-17 20:33:20 +02001891 return err;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001892
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08001893 for (i = 0; i < UBI_PROT_QUEUE_LEN; i++)
1894 INIT_LIST_HEAD(&ubi->pq[i]);
1895 ubi->pq_head = 0;
1896
Artem Bityutskiya4e60422012-05-17 13:09:08 +03001897 list_for_each_entry_safe(aeb, tmp, &ai->erase, u.list) {
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001898 cond_resched();
1899
Artem Bityutskiy06b68ba2007-12-16 12:49:01 +02001900 e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001901 if (!e)
1902 goto out_free;
1903
Artem Bityutskiy2c5ec5c2012-05-17 08:26:24 +03001904 e->pnum = aeb->pnum;
1905 e->ec = aeb->ec;
Richard Weinberger8199b902012-09-26 17:51:48 +02001906 ubi_assert(!ubi_is_fm_block(ubi, e->pnum));
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001907 ubi->lookuptbl[e->pnum] = e;
Joel Reardond36e59e2012-05-18 15:40:24 +02001908 if (schedule_erase(ubi, e, aeb->vol_id, aeb->lnum, 0)) {
Artem Bityutskiy06b68ba2007-12-16 12:49:01 +02001909 kmem_cache_free(ubi_wl_entry_slab, e);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001910 goto out_free;
1911 }
Richard Weinberger8199b902012-09-26 17:51:48 +02001912
1913 found_pebs++;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001914 }
1915
Richard Weinberger8199b902012-09-26 17:51:48 +02001916 ubi->free_count = 0;
Artem Bityutskiya4e60422012-05-17 13:09:08 +03001917 list_for_each_entry(aeb, &ai->free, u.list) {
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001918 cond_resched();
1919
Artem Bityutskiy06b68ba2007-12-16 12:49:01 +02001920 e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001921 if (!e)
1922 goto out_free;
1923
Artem Bityutskiy2c5ec5c2012-05-17 08:26:24 +03001924 e->pnum = aeb->pnum;
1925 e->ec = aeb->ec;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001926 ubi_assert(e->ec >= 0);
Richard Weinberger8199b902012-09-26 17:51:48 +02001927 ubi_assert(!ubi_is_fm_block(ubi, e->pnum));
1928
Artem Bityutskiy5abde382007-09-13 14:48:20 +03001929 wl_tree_add(e, &ubi->free);
Richard Weinberger8199b902012-09-26 17:51:48 +02001930 ubi->free_count++;
1931
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001932 ubi->lookuptbl[e->pnum] = e;
Richard Weinberger8199b902012-09-26 17:51:48 +02001933
1934 found_pebs++;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001935 }
1936
Artem Bityutskiy517af482012-05-17 14:38:34 +03001937 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
1938 ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) {
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001939 cond_resched();
1940
Artem Bityutskiy06b68ba2007-12-16 12:49:01 +02001941 e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001942 if (!e)
1943 goto out_free;
1944
Artem Bityutskiy2c5ec5c2012-05-17 08:26:24 +03001945 e->pnum = aeb->pnum;
1946 e->ec = aeb->ec;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001947 ubi->lookuptbl[e->pnum] = e;
Richard Weinberger8199b902012-09-26 17:51:48 +02001948
Artem Bityutskiy2c5ec5c2012-05-17 08:26:24 +03001949 if (!aeb->scrub) {
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001950 dbg_wl("add PEB %d EC %d to the used tree",
1951 e->pnum, e->ec);
Artem Bityutskiy5abde382007-09-13 14:48:20 +03001952 wl_tree_add(e, &ubi->used);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001953 } else {
1954 dbg_wl("add PEB %d EC %d to the scrub tree",
1955 e->pnum, e->ec);
Artem Bityutskiy5abde382007-09-13 14:48:20 +03001956 wl_tree_add(e, &ubi->scrub);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001957 }
Richard Weinberger8199b902012-09-26 17:51:48 +02001958
1959 found_pebs++;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001960 }
1961 }
1962
Richard Weinberger8199b902012-09-26 17:51:48 +02001963 dbg_wl("found %i PEBs", found_pebs);
1964
1965 if (ubi->fm)
1966 ubi_assert(ubi->good_peb_count == \
1967 found_pebs + ubi->fm->used_blocks);
1968 else
1969 ubi_assert(ubi->good_peb_count == found_pebs);
1970
1971 reserved_pebs = WL_RESERVED_PEBS;
1972#ifdef CONFIG_MTD_UBI_FASTMAP
1973 /* Reserve enough LEBs to store two fastmaps. */
1974 reserved_pebs += (ubi->fm_size / ubi->leb_size) * 2;
1975#endif
1976
1977 if (ubi->avail_pebs < reserved_pebs) {
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001978 ubi_err("no enough physical eraseblocks (%d, need %d)",
Richard Weinberger8199b902012-09-26 17:51:48 +02001979 ubi->avail_pebs, reserved_pebs);
Artem Bityutskiy5fc01ab2010-09-03 23:08:15 +03001980 if (ubi->corr_peb_count)
1981 ubi_err("%d PEBs are corrupted and not used",
1982 ubi->corr_peb_count);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001983 goto out_free;
1984 }
Richard Weinberger8199b902012-09-26 17:51:48 +02001985 ubi->avail_pebs -= reserved_pebs;
1986 ubi->rsvd_pebs += reserved_pebs;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001987
1988 /* Schedule wear-leveling if needed */
Richard Weinberger8199b902012-09-26 17:51:48 +02001989 err = ensure_wear_leveling(ubi, 0);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04001990 if (err)
1991 goto out_free;
1992
1993 return 0;
1994
1995out_free:
1996 cancel_pending(ubi);
1997 tree_destroy(&ubi->used);
1998 tree_destroy(&ubi->free);
1999 tree_destroy(&ubi->scrub);
2000 kfree(ubi->lookuptbl);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002001 return err;
2002}
2003
2004/**
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08002005 * protection_queue_destroy - destroy the protection queue.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002006 * @ubi: UBI device description object
2007 */
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08002008static void protection_queue_destroy(struct ubi_device *ubi)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002009{
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08002010 int i;
2011 struct ubi_wl_entry *e, *tmp;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002012
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08002013 for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i) {
2014 list_for_each_entry_safe(e, tmp, &ubi->pq[i], u.list) {
2015 list_del(&e->u.list);
2016 kmem_cache_free(ubi_wl_entry_slab, e);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002017 }
2018 }
2019}
2020
2021/**
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +03002022 * ubi_wl_close - close the wear-leveling sub-system.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002023 * @ubi: UBI device description object
2024 */
2025void ubi_wl_close(struct ubi_device *ubi)
2026{
Artem Bityutskiy85c6e6e2008-07-16 10:25:56 +03002027 dbg_wl("close the WL sub-system");
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002028 cancel_pending(ubi);
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08002029 protection_queue_destroy(ubi);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002030 tree_destroy(&ubi->used);
Artem Bityutskiyb86a2c52009-05-24 14:13:34 +03002031 tree_destroy(&ubi->erroneous);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002032 tree_destroy(&ubi->free);
2033 tree_destroy(&ubi->scrub);
2034 kfree(ubi->lookuptbl);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002035}
2036
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002037/**
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +03002038 * self_check_ec - make sure that the erase counter of a PEB is correct.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002039 * @ubi: UBI device description object
2040 * @pnum: the physical eraseblock number to check
2041 * @ec: the erase counter to check
2042 *
2043 * This function returns zero if the erase counter of physical eraseblock @pnum
Artem Bityutskiyfeddbb32011-03-28 10:12:25 +03002044 * is equivalent to @ec, and a negative error code if not or if an error
2045 * occurred.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002046 */
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +03002047static int self_check_ec(struct ubi_device *ubi, int pnum, int ec)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002048{
2049 int err;
2050 long long read_ec;
2051 struct ubi_ec_hdr *ec_hdr;
2052
Artem Bityutskiy2a734bb2011-05-18 14:53:05 +03002053 if (!ubi->dbg->chk_gen)
Artem Bityutskiy92d124f2011-03-14 18:17:40 +02002054 return 0;
2055
Artem Bityutskiy33818bb2007-08-28 21:29:32 +03002056 ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002057 if (!ec_hdr)
2058 return -ENOMEM;
2059
2060 err = ubi_io_read_ec_hdr(ubi, pnum, ec_hdr, 0);
2061 if (err && err != UBI_IO_BITFLIPS) {
2062 /* The header does not have to exist */
2063 err = 0;
2064 goto out_free;
2065 }
2066
Christoph Hellwig3261ebd2007-05-21 17:41:46 +03002067 read_ec = be64_to_cpu(ec_hdr->ec);
Richard Weinberger8199b902012-09-26 17:51:48 +02002068 if (ec != read_ec && read_ec - ec > 1) {
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +03002069 ubi_err("self-check failed for PEB %d", pnum);
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002070 ubi_err("read EC is %lld, should be %d", read_ec, ec);
Artem Bityutskiy25886a32012-04-24 06:59:49 +03002071 dump_stack();
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002072 err = 1;
2073 } else
2074 err = 0;
2075
2076out_free:
2077 kfree(ec_hdr);
2078 return err;
2079}
2080
2081/**
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +03002082 * self_check_in_wl_tree - check that wear-leveling entry is in WL RB-tree.
Artem Bityutskiyd99383b2011-05-18 14:47:34 +03002083 * @ubi: UBI device description object
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002084 * @e: the wear-leveling entry to check
2085 * @root: the root of the tree
2086 *
Artem Bityutskiyadbf05e2010-01-20 10:28:58 +02002087 * This function returns zero if @e is in the @root RB-tree and %-EINVAL if it
2088 * is not.
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002089 */
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +03002090static int self_check_in_wl_tree(const struct ubi_device *ubi,
2091 struct ubi_wl_entry *e, struct rb_root *root)
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002092{
Artem Bityutskiy2a734bb2011-05-18 14:53:05 +03002093 if (!ubi->dbg->chk_gen)
Artem Bityutskiy92d124f2011-03-14 18:17:40 +02002094 return 0;
2095
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002096 if (in_wl_tree(e, root))
2097 return 0;
2098
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +03002099 ubi_err("self-check failed for PEB %d, EC %d, RB-tree %p ",
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002100 e->pnum, e->ec, root);
Artem Bityutskiy25886a32012-04-24 06:59:49 +03002101 dump_stack();
Artem Bityutskiyadbf05e2010-01-20 10:28:58 +02002102 return -EINVAL;
Artem B. Bityutskiy801c1352006-06-27 12:22:22 +04002103}
2104
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08002105/**
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +03002106 * self_check_in_pq - check if wear-leveling entry is in the protection
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08002107 * queue.
2108 * @ubi: UBI device description object
2109 * @e: the wear-leveling entry to check
2110 *
Artem Bityutskiyadbf05e2010-01-20 10:28:58 +02002111 * This function returns zero if @e is in @ubi->pq and %-EINVAL if it is not.
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08002112 */
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +03002113static int self_check_in_pq(const struct ubi_device *ubi,
2114 struct ubi_wl_entry *e)
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08002115{
2116 struct ubi_wl_entry *p;
2117 int i;
2118
Artem Bityutskiy2a734bb2011-05-18 14:53:05 +03002119 if (!ubi->dbg->chk_gen)
Artem Bityutskiy92d124f2011-03-14 18:17:40 +02002120 return 0;
2121
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08002122 for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i)
2123 list_for_each_entry(p, &ubi->pq[i], u.list)
2124 if (p == e)
2125 return 0;
2126
Artem Bityutskiy7bf523a2012-05-16 18:29:54 +03002127 ubi_err("self-check failed for PEB %d, EC %d, Protect queue",
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08002128 e->pnum, e->ec);
Artem Bityutskiy25886a32012-04-24 06:59:49 +03002129 dump_stack();
Artem Bityutskiyadbf05e2010-01-20 10:28:58 +02002130 return -EINVAL;
Xiaochuan-Xu7b6c32d2008-12-15 21:07:41 +08002131}