83848324daa27772907d567a4af7cc09a348d7e7
2 * Copyright (c) International Business Machines Corp., 2006
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
12 * the GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 * Authors: Artem Bityutskiy (Битюцкий Артём), Thomas Gleixner
22 * UBI wear-leveling sub-system.
24 * This sub-system is responsible for wear-leveling. It works in terms of
25 * physical eraseblocks and erase counters and knows nothing about logical
26 * eraseblocks, volumes, etc. From this sub-system's perspective all physical
27 * eraseblocks are of two types - used and free. Used physical eraseblocks are
28 * those that were "get" by the 'ubi_wl_get_peb()' function, and free physical
29 * eraseblocks are those that were put by the 'ubi_wl_put_peb()' function.
31 * Physical eraseblocks returned by 'ubi_wl_get_peb()' have only erase counter
32 * header. The rest of the physical eraseblock contains only %0xFF bytes.
34 * When physical eraseblocks are returned to the WL sub-system by means of the
35 * 'ubi_wl_put_peb()' function, they are scheduled for erasure. The erasure is
36 * done asynchronously in context of the per-UBI device background thread,
37 * which is also managed by the WL sub-system.
39 * The wear-leveling is ensured by means of moving the contents of used
40 * physical eraseblocks with low erase counter to free physical eraseblocks
41 * with high erase counter.
43 * If the WL sub-system fails to erase a physical eraseblock, it marks it as
46 * This sub-system is also responsible for scrubbing. If a bit-flip is detected
47 * in a physical eraseblock, it has to be moved. Technically this is the same
48 * as moving it for wear-leveling reasons.
50 * As it was said, for the UBI sub-system all physical eraseblocks are either
51 * "free" or "used". Free eraseblock are kept in the @wl->free RB-tree, while
52 * used eraseblocks are kept in @wl->used, @wl->erroneous, or @wl->scrub
53 * RB-trees, as well as (temporarily) in the @wl->pq queue.
55 * When the WL sub-system returns a physical eraseblock, the physical
56 * eraseblock is protected from being moved for some "time". For this reason,
57 * the physical eraseblock is not directly moved from the @wl->free tree to the
58 * @wl->used tree. There is a protection queue in between where this
59 * physical eraseblock is temporarily stored (@wl->pq).
61 * All this protection stuff is needed because:
62 * o we don't want to move physical eraseblocks just after we have given them
63 * to the user; instead, we first want to let users fill them up with data;
65 * o there is a chance that the user will put the physical eraseblock very
66 * soon, so it makes sense not to move it for some time, but wait.
68 * Physical eraseblocks stay protected only for limited time. But the "time" is
69 * measured in erase cycles in this case. This is implemented with help of the
70 * protection queue. Eraseblocks are put to the tail of this queue when they
71 * are returned by the 'ubi_wl_get_peb()', and eraseblocks are removed from the
72 * head of the queue on each erase operation (for any eraseblock). So the
73 * length of the queue defines how may (global) erase cycles PEBs are protected.
75 * To put it differently, each physical eraseblock has 2 main states: free and
76 * used. The former state corresponds to the @wl->free tree. The latter state
77 * is split up on several sub-states:
78 * o the WL movement is allowed (@wl->used tree);
79 * o the WL movement is disallowed (@wl->erroneous) because the PEB is
80 * erroneous - e.g., there was a read error;
81 * o the WL movement is temporarily prohibited (@wl->pq queue);
82 * o scrubbing is needed (@wl->scrub tree).
84 * Depending on the sub-state, wear-leveling entries of the used physical
85 * eraseblocks may be kept in one of those structures.
87 * Note, in this implementation, we keep a small in-RAM object for each physical
88 * eraseblock. This is surely not a scalable solution. But it appears to be good
89 * enough for moderately large flashes and it is simple. In future, one may
90 * re-work this sub-system and make it more scalable.
92 * At the moment this sub-system does not utilize the sequence number, which
93 * was introduced relatively recently. But it would be wise to do this because
94 * the sequence number of a logical eraseblock characterizes how old is it. For
95 * example, when we move a PEB with low erase counter, and we need to pick the
96 * target PEB, we pick a PEB with the highest EC if our PEB is "old" and we
97 * pick target PEB with an average EC if our PEB is not very "old". This is a
98 * room for future re-works of the WL sub-system.
101 #include <linux/slab.h>
102 #include <linux/crc32.h>
103 #include <linux/freezer.h>
104 #include <linux/kthread.h>
107 /* Number of physical eraseblocks reserved for wear-leveling purposes */
108 #define WL_RESERVED_PEBS 1
111 * Maximum difference between two erase counters. If this threshold is
112 * exceeded, the WL sub-system starts moving data from used physical
113 * eraseblocks with low erase counter to free physical eraseblocks with high
116 #define UBI_WL_THRESHOLD CONFIG_MTD_UBI_WL_THRESHOLD
119 * When a physical eraseblock is moved, the WL sub-system has to pick the target
120 * physical eraseblock to move to. The simplest way would be just to pick the
121 * one with the highest erase counter. But in certain workloads this could lead
122 * to an unlimited wear of one or few physical eraseblock. Indeed, imagine a
123 * situation when the picked physical eraseblock is constantly erased after the
124 * data is written to it. So, we have a constant which limits the highest erase
125 * counter of the free physical eraseblock to pick. Namely, the WL sub-system
126 * does not pick eraseblocks with erase counter greater than the lowest erase
127 * counter plus %WL_FREE_MAX_DIFF.
129 #define WL_FREE_MAX_DIFF (2*UBI_WL_THRESHOLD)
132 * Maximum number of consecutive background thread failures which is enough to
133 * switch to read-only mode.
135 #define WL_MAX_FAILURES 32
137 static int self_check_ec(struct ubi_device
*ubi
, int pnum
, int ec
);
138 static int self_check_in_wl_tree(const struct ubi_device
*ubi
,
139 struct ubi_wl_entry
*e
, struct rb_root
*root
);
140 static int self_check_in_pq(const struct ubi_device
*ubi
,
141 struct ubi_wl_entry
*e
);
143 #ifdef CONFIG_MTD_UBI_FASTMAP
145 * update_fastmap_work_fn - calls ubi_update_fastmap from a work queue
146 * @wrk: the work description object
148 static void update_fastmap_work_fn(struct work_struct
*wrk
)
150 struct ubi_device
*ubi
= container_of(wrk
, struct ubi_device
, fm_work
);
151 ubi_update_fastmap(ubi
);
152 spin_lock(&ubi
->wl_lock
);
153 ubi
->fm_work_scheduled
= 0;
154 spin_unlock(&ubi
->wl_lock
);
158 * ubi_ubi_is_fm_block - returns 1 if a PEB is currently used in a fastmap.
159 * @ubi: UBI device description object
160 * @pnum: the to be checked PEB
162 static int ubi_is_fm_block(struct ubi_device
*ubi
, int pnum
)
169 for (i
= 0; i
< ubi
->fm
->used_blocks
; i
++)
170 if (ubi
->fm
->e
[i
]->pnum
== pnum
)
176 static int ubi_is_fm_block(struct ubi_device
*ubi
, int pnum
)
183 * wl_tree_add - add a wear-leveling entry to a WL RB-tree.
184 * @e: the wear-leveling entry to add
185 * @root: the root of the tree
187 * Note, we use (erase counter, physical eraseblock number) pairs as keys in
188 * the @ubi->used and @ubi->free RB-trees.
190 static void wl_tree_add(struct ubi_wl_entry
*e
, struct rb_root
*root
)
192 struct rb_node
**p
, *parent
= NULL
;
196 struct ubi_wl_entry
*e1
;
199 e1
= rb_entry(parent
, struct ubi_wl_entry
, u
.rb
);
203 else if (e
->ec
> e1
->ec
)
206 ubi_assert(e
->pnum
!= e1
->pnum
);
207 if (e
->pnum
< e1
->pnum
)
214 rb_link_node(&e
->u
.rb
, parent
, p
);
215 rb_insert_color(&e
->u
.rb
, root
);
219 * wl_tree_destroy - destroy a wear-leveling entry.
220 * @ubi: UBI device description object
221 * @e: the wear-leveling entry to add
223 * This function destroys a wear leveling entry and removes
224 * the reference from the lookup table.
226 static void wl_entry_destroy(struct ubi_device
*ubi
, struct ubi_wl_entry
*e
)
228 ubi
->lookuptbl
[e
->pnum
] = NULL
;
229 kmem_cache_free(ubi_wl_entry_slab
, e
);
233 * do_work - do one pending work.
234 * @ubi: UBI device description object
236 * This function returns zero in case of success and a negative error code in
239 static int do_work(struct ubi_device
*ubi
)
242 struct ubi_work
*wrk
;
247 * @ubi->work_sem is used to synchronize with the workers. Workers take
248 * it in read mode, so many of them may be doing works at a time. But
249 * the queue flush code has to be sure the whole queue of works is
250 * done, and it takes the mutex in write mode.
252 down_read(&ubi
->work_sem
);
253 spin_lock(&ubi
->wl_lock
);
254 if (list_empty(&ubi
->works
)) {
255 spin_unlock(&ubi
->wl_lock
);
256 up_read(&ubi
->work_sem
);
260 wrk
= list_entry(ubi
->works
.next
, struct ubi_work
, list
);
261 list_del(&wrk
->list
);
262 ubi
->works_count
-= 1;
263 ubi_assert(ubi
->works_count
>= 0);
264 spin_unlock(&ubi
->wl_lock
);
267 * Call the worker function. Do not touch the work structure
268 * after this call as it will have been freed or reused by that
269 * time by the worker function.
271 err
= wrk
->func(ubi
, wrk
, 0);
273 ubi_err(ubi
, "work failed with error code %d", err
);
274 up_read(&ubi
->work_sem
);
280 * produce_free_peb - produce a free physical eraseblock.
281 * @ubi: UBI device description object
283 * This function tries to make a free PEB by means of synchronous execution of
284 * pending works. This may be needed if, for example the background thread is
285 * disabled. Returns zero in case of success and a negative error code in case
288 static int produce_free_peb(struct ubi_device
*ubi
)
292 while (!ubi
->free
.rb_node
&& ubi
->works_count
) {
293 spin_unlock(&ubi
->wl_lock
);
295 dbg_wl("do one work synchronously");
298 spin_lock(&ubi
->wl_lock
);
307 * in_wl_tree - check if wear-leveling entry is present in a WL RB-tree.
308 * @e: the wear-leveling entry to check
309 * @root: the root of the tree
311 * This function returns non-zero if @e is in the @root RB-tree and zero if it
314 static int in_wl_tree(struct ubi_wl_entry
*e
, struct rb_root
*root
)
320 struct ubi_wl_entry
*e1
;
322 e1
= rb_entry(p
, struct ubi_wl_entry
, u
.rb
);
324 if (e
->pnum
== e1
->pnum
) {
331 else if (e
->ec
> e1
->ec
)
334 ubi_assert(e
->pnum
!= e1
->pnum
);
335 if (e
->pnum
< e1
->pnum
)
346 * prot_queue_add - add physical eraseblock to the protection queue.
347 * @ubi: UBI device description object
348 * @e: the physical eraseblock to add
350 * This function adds @e to the tail of the protection queue @ubi->pq, where
351 * @e will stay for %UBI_PROT_QUEUE_LEN erase operations and will be
352 * temporarily protected from the wear-leveling worker. Note, @wl->lock has to
355 static void prot_queue_add(struct ubi_device
*ubi
, struct ubi_wl_entry
*e
)
357 int pq_tail
= ubi
->pq_head
- 1;
360 pq_tail
= UBI_PROT_QUEUE_LEN
- 1;
361 ubi_assert(pq_tail
>= 0 && pq_tail
< UBI_PROT_QUEUE_LEN
);
362 list_add_tail(&e
->u
.list
, &ubi
->pq
[pq_tail
]);
363 dbg_wl("added PEB %d EC %d to the protection queue", e
->pnum
, e
->ec
);
367 * find_wl_entry - find wear-leveling entry closest to certain erase counter.
368 * @ubi: UBI device description object
369 * @root: the RB-tree where to look for
370 * @diff: maximum possible difference from the smallest erase counter
372 * This function looks for a wear leveling entry with erase counter closest to
373 * min + @diff, where min is the smallest erase counter.
375 static struct ubi_wl_entry
*find_wl_entry(struct ubi_device
*ubi
,
376 struct rb_root
*root
, int diff
)
379 struct ubi_wl_entry
*e
, *prev_e
= NULL
;
382 e
= rb_entry(rb_first(root
), struct ubi_wl_entry
, u
.rb
);
387 struct ubi_wl_entry
*e1
;
389 e1
= rb_entry(p
, struct ubi_wl_entry
, u
.rb
);
399 /* If no fastmap has been written and this WL entry can be used
400 * as anchor PEB, hold it back and return the second best WL entry
401 * such that fastmap can use the anchor PEB later. */
402 if (prev_e
&& !ubi
->fm_disabled
&&
403 !ubi
->fm
&& e
->pnum
< UBI_FM_MAX_START
)
410 * find_mean_wl_entry - find wear-leveling entry with medium erase counter.
411 * @ubi: UBI device description object
412 * @root: the RB-tree where to look for
414 * This function looks for a wear leveling entry with medium erase counter,
415 * but not greater or equivalent than the lowest erase counter plus
416 * %WL_FREE_MAX_DIFF/2.
418 static struct ubi_wl_entry
*find_mean_wl_entry(struct ubi_device
*ubi
,
419 struct rb_root
*root
)
421 struct ubi_wl_entry
*e
, *first
, *last
;
423 first
= rb_entry(rb_first(root
), struct ubi_wl_entry
, u
.rb
);
424 last
= rb_entry(rb_last(root
), struct ubi_wl_entry
, u
.rb
);
426 if (last
->ec
- first
->ec
< WL_FREE_MAX_DIFF
) {
427 e
= rb_entry(root
->rb_node
, struct ubi_wl_entry
, u
.rb
);
429 #ifdef CONFIG_MTD_UBI_FASTMAP
430 /* If no fastmap has been written and this WL entry can be used
431 * as anchor PEB, hold it back and return the second best
432 * WL entry such that fastmap can use the anchor PEB later. */
433 if (e
&& !ubi
->fm_disabled
&& !ubi
->fm
&&
434 e
->pnum
< UBI_FM_MAX_START
)
435 e
= rb_entry(rb_next(root
->rb_node
),
436 struct ubi_wl_entry
, u
.rb
);
439 e
= find_wl_entry(ubi
, root
, WL_FREE_MAX_DIFF
/2);
444 #ifdef CONFIG_MTD_UBI_FASTMAP
446 * find_anchor_wl_entry - find wear-leveling entry to used as anchor PEB.
447 * @root: the RB-tree where to look for
449 static struct ubi_wl_entry
*find_anchor_wl_entry(struct rb_root
*root
)
452 struct ubi_wl_entry
*e
, *victim
= NULL
;
453 int max_ec
= UBI_MAX_ERASECOUNTER
;
455 ubi_rb_for_each_entry(p
, e
, root
, u
.rb
) {
456 if (e
->pnum
< UBI_FM_MAX_START
&& e
->ec
< max_ec
) {
465 static int anchor_pebs_avalible(struct rb_root
*root
)
468 struct ubi_wl_entry
*e
;
470 ubi_rb_for_each_entry(p
, e
, root
, u
.rb
)
471 if (e
->pnum
< UBI_FM_MAX_START
)
478 * ubi_wl_get_fm_peb - find a physical erase block with a given maximal number.
479 * @ubi: UBI device description object
480 * @anchor: This PEB will be used as anchor PEB by fastmap
482 * The function returns a physical erase block with a given maximal number
483 * and removes it from the wl subsystem.
484 * Must be called with wl_lock held!
486 struct ubi_wl_entry
*ubi_wl_get_fm_peb(struct ubi_device
*ubi
, int anchor
)
488 struct ubi_wl_entry
*e
= NULL
;
490 if (!ubi
->free
.rb_node
|| (ubi
->free_count
- ubi
->beb_rsvd_pebs
< 1))
494 e
= find_anchor_wl_entry(&ubi
->free
);
496 e
= find_mean_wl_entry(ubi
, &ubi
->free
);
501 self_check_in_wl_tree(ubi
, e
, &ubi
->free
);
503 /* remove it from the free list,
504 * the wl subsystem does no longer know this erase block */
505 rb_erase(&e
->u
.rb
, &ubi
->free
);
513 * wl_get_wle - get a mean wl entry to be used by wl_get_peb() or
514 * refill_wl_user_pool().
515 * @ubi: UBI device description object
517 * This function returns a a wear leveling entry in case of success and
518 * NULL in case of failure.
520 static struct ubi_wl_entry
*wl_get_wle(struct ubi_device
*ubi
)
522 struct ubi_wl_entry
*e
;
524 e
= find_mean_wl_entry(ubi
, &ubi
->free
);
526 ubi_err(ubi
, "no free eraseblocks");
530 self_check_in_wl_tree(ubi
, e
, &ubi
->free
);
533 * Move the physical eraseblock to the protection queue where it will
534 * be protected from being moved for some time.
536 rb_erase(&e
->u
.rb
, &ubi
->free
);
538 dbg_wl("PEB %d EC %d", e
->pnum
, e
->ec
);
544 * wl_get_peb - get a physical eraseblock.
545 * @ubi: UBI device description object
547 * This function returns a physical eraseblock in case of success and a
548 * negative error code in case of failure.
549 * It is the low level component of ubi_wl_get_peb() in the non-fastmap
552 static int wl_get_peb(struct ubi_device
*ubi
)
555 struct ubi_wl_entry
*e
;
558 if (!ubi
->free
.rb_node
) {
559 if (ubi
->works_count
== 0) {
560 ubi_err(ubi
, "no free eraseblocks");
561 ubi_assert(list_empty(&ubi
->works
));
565 err
= produce_free_peb(ubi
);
572 prot_queue_add(ubi
, e
);
577 #ifdef CONFIG_MTD_UBI_FASTMAP
579 * return_unused_pool_pebs - returns unused PEB to the free tree.
580 * @ubi: UBI device description object
581 * @pool: fastmap pool description object
583 static void return_unused_pool_pebs(struct ubi_device
*ubi
,
584 struct ubi_fm_pool
*pool
)
587 struct ubi_wl_entry
*e
;
589 for (i
= pool
->used
; i
< pool
->size
; i
++) {
590 e
= ubi
->lookuptbl
[pool
->pebs
[i
]];
591 wl_tree_add(e
, &ubi
->free
);
597 * ubi_refill_pools - refills all fastmap PEB pools.
598 * @ubi: UBI device description object
600 void ubi_refill_pools(struct ubi_device
*ubi
)
602 struct ubi_fm_pool
*wl_pool
= &ubi
->fm_wl_pool
;
603 struct ubi_fm_pool
*pool
= &ubi
->fm_pool
;
604 struct ubi_wl_entry
*e
;
607 spin_lock(&ubi
->wl_lock
);
609 return_unused_pool_pebs(ubi
, wl_pool
);
610 return_unused_pool_pebs(ubi
, pool
);
617 if (pool
->size
< pool
->max_size
) {
618 if (!ubi
->free
.rb_node
||
619 (ubi
->free_count
- ubi
->beb_rsvd_pebs
< 5))
626 pool
->pebs
[pool
->size
] = e
->pnum
;
631 if (wl_pool
->size
< wl_pool
->max_size
) {
632 if (!ubi
->free
.rb_node
||
633 (ubi
->free_count
- ubi
->beb_rsvd_pebs
< 5))
636 e
= find_wl_entry(ubi
, &ubi
->free
, WL_FREE_MAX_DIFF
);
637 self_check_in_wl_tree(ubi
, e
, &ubi
->free
);
638 rb_erase(&e
->u
.rb
, &ubi
->free
);
641 wl_pool
->pebs
[wl_pool
->size
] = e
->pnum
;
653 spin_unlock(&ubi
->wl_lock
);
656 /* ubi_wl_get_peb - works exaclty like __wl_get_peb but keeps track of
658 * Returns with ubi->fm_eba_sem held in read mode!
660 int ubi_wl_get_peb(struct ubi_device
*ubi
)
662 int ret
, retried
= 0;
663 struct ubi_fm_pool
*pool
= &ubi
->fm_pool
;
664 struct ubi_fm_pool
*wl_pool
= &ubi
->fm_wl_pool
;
667 down_read(&ubi
->fm_eba_sem
);
668 spin_lock(&ubi
->wl_lock
);
669 /* We check here also for the WL pool because at this point we can
670 * refill the WL pool synchronous. */
671 if (pool
->used
== pool
->size
|| wl_pool
->used
== wl_pool
->size
) {
672 spin_unlock(&ubi
->wl_lock
);
673 up_read(&ubi
->fm_eba_sem
);
674 ret
= ubi_update_fastmap(ubi
);
676 ubi_msg(ubi
, "Unable to write a new fastmap: %i", ret
);
677 down_read(&ubi
->fm_eba_sem
);
680 down_read(&ubi
->fm_eba_sem
);
681 spin_lock(&ubi
->wl_lock
);
684 if (pool
->used
== pool
->size
) {
685 spin_unlock(&ubi
->wl_lock
);
687 ubi_err(ubi
, "Unable to get a free PEB from user WL pool");
692 up_read(&ubi
->fm_eba_sem
);
696 ubi_assert(pool
->used
< pool
->size
);
697 ret
= pool
->pebs
[pool
->used
++];
698 prot_queue_add(ubi
, ubi
->lookuptbl
[ret
]);
699 spin_unlock(&ubi
->wl_lock
);
704 /* get_peb_for_wl - returns a PEB to be used internally by the WL sub-system.
706 * @ubi: UBI device description object
708 static struct ubi_wl_entry
*get_peb_for_wl(struct ubi_device
*ubi
)
710 struct ubi_fm_pool
*pool
= &ubi
->fm_wl_pool
;
713 if (pool
->used
== pool
->size
) {
714 /* We cannot update the fastmap here because this
715 * function is called in atomic context.
716 * Let's fail here and refill/update it as soon as possible. */
717 if (!ubi
->fm_work_scheduled
) {
718 ubi
->fm_work_scheduled
= 1;
719 schedule_work(&ubi
->fm_work
);
723 pnum
= pool
->pebs
[pool
->used
++];
724 return ubi
->lookuptbl
[pnum
];
728 static struct ubi_wl_entry
*get_peb_for_wl(struct ubi_device
*ubi
)
730 struct ubi_wl_entry
*e
;
732 e
= find_wl_entry(ubi
, &ubi
->free
, WL_FREE_MAX_DIFF
);
733 self_check_in_wl_tree(ubi
, e
, &ubi
->free
);
735 ubi_assert(ubi
->free_count
>= 0);
736 rb_erase(&e
->u
.rb
, &ubi
->free
);
741 int ubi_wl_get_peb(struct ubi_device
*ubi
)
745 spin_lock(&ubi
->wl_lock
);
746 peb
= wl_get_peb(ubi
);
747 spin_unlock(&ubi
->wl_lock
);
748 down_read(&ubi
->fm_eba_sem
);
753 err
= ubi_self_check_all_ff(ubi
, peb
, ubi
->vid_hdr_aloffset
,
754 ubi
->peb_size
- ubi
->vid_hdr_aloffset
);
756 ubi_err(ubi
, "new PEB %d does not contain all 0xFF bytes",
766 * prot_queue_del - remove a physical eraseblock from the protection queue.
767 * @ubi: UBI device description object
768 * @pnum: the physical eraseblock to remove
770 * This function deletes PEB @pnum from the protection queue and returns zero
771 * in case of success and %-ENODEV if the PEB was not found.
773 static int prot_queue_del(struct ubi_device
*ubi
, int pnum
)
775 struct ubi_wl_entry
*e
;
777 e
= ubi
->lookuptbl
[pnum
];
781 if (self_check_in_pq(ubi
, e
))
784 list_del(&e
->u
.list
);
785 dbg_wl("deleted PEB %d from the protection queue", e
->pnum
);
790 * sync_erase - synchronously erase a physical eraseblock.
791 * @ubi: UBI device description object
792 * @e: the the physical eraseblock to erase
793 * @torture: if the physical eraseblock has to be tortured
795 * This function returns zero in case of success and a negative error code in
798 static int sync_erase(struct ubi_device
*ubi
, struct ubi_wl_entry
*e
,
802 struct ubi_ec_hdr
*ec_hdr
;
803 unsigned long long ec
= e
->ec
;
805 dbg_wl("erase PEB %d, old EC %llu", e
->pnum
, ec
);
807 err
= self_check_ec(ubi
, e
->pnum
, e
->ec
);
811 ec_hdr
= kzalloc(ubi
->ec_hdr_alsize
, GFP_NOFS
);
815 err
= ubi_io_sync_erase(ubi
, e
->pnum
, torture
);
820 if (ec
> UBI_MAX_ERASECOUNTER
) {
822 * Erase counter overflow. Upgrade UBI and use 64-bit
823 * erase counters internally.
825 ubi_err(ubi
, "erase counter overflow at PEB %d, EC %llu",
831 dbg_wl("erased PEB %d, new EC %llu", e
->pnum
, ec
);
833 ec_hdr
->ec
= cpu_to_be64(ec
);
835 err
= ubi_io_write_ec_hdr(ubi
, e
->pnum
, ec_hdr
);
840 spin_lock(&ubi
->wl_lock
);
841 if (e
->ec
> ubi
->max_ec
)
843 spin_unlock(&ubi
->wl_lock
);
851 * serve_prot_queue - check if it is time to stop protecting PEBs.
852 * @ubi: UBI device description object
854 * This function is called after each erase operation and removes PEBs from the
855 * tail of the protection queue. These PEBs have been protected for long enough
856 * and should be moved to the used tree.
858 static void serve_prot_queue(struct ubi_device
*ubi
)
860 struct ubi_wl_entry
*e
, *tmp
;
864 * There may be several protected physical eraseblock to remove,
869 spin_lock(&ubi
->wl_lock
);
870 list_for_each_entry_safe(e
, tmp
, &ubi
->pq
[ubi
->pq_head
], u
.list
) {
871 dbg_wl("PEB %d EC %d protection over, move to used tree",
874 list_del(&e
->u
.list
);
875 wl_tree_add(e
, &ubi
->used
);
878 * Let's be nice and avoid holding the spinlock for
881 spin_unlock(&ubi
->wl_lock
);
888 if (ubi
->pq_head
== UBI_PROT_QUEUE_LEN
)
890 ubi_assert(ubi
->pq_head
>= 0 && ubi
->pq_head
< UBI_PROT_QUEUE_LEN
);
891 spin_unlock(&ubi
->wl_lock
);
895 * __schedule_ubi_work - schedule a work.
896 * @ubi: UBI device description object
897 * @wrk: the work to schedule
899 * This function adds a work defined by @wrk to the tail of the pending works
900 * list. Can only be used if ubi->work_sem is already held in read mode!
902 static void __schedule_ubi_work(struct ubi_device
*ubi
, struct ubi_work
*wrk
)
904 spin_lock(&ubi
->wl_lock
);
905 list_add_tail(&wrk
->list
, &ubi
->works
);
906 ubi_assert(ubi
->works_count
>= 0);
907 ubi
->works_count
+= 1;
908 if (ubi
->thread_enabled
&& !ubi_dbg_is_bgt_disabled(ubi
))
909 wake_up_process(ubi
->bgt_thread
);
910 spin_unlock(&ubi
->wl_lock
);
914 * schedule_ubi_work - schedule a work.
915 * @ubi: UBI device description object
916 * @wrk: the work to schedule
918 * This function adds a work defined by @wrk to the tail of the pending works
921 static void schedule_ubi_work(struct ubi_device
*ubi
, struct ubi_work
*wrk
)
923 down_read(&ubi
->work_sem
);
924 __schedule_ubi_work(ubi
, wrk
);
925 up_read(&ubi
->work_sem
);
928 static int erase_worker(struct ubi_device
*ubi
, struct ubi_work
*wl_wrk
,
931 #ifdef CONFIG_MTD_UBI_FASTMAP
933 * ubi_is_erase_work - checks whether a work is erase work.
934 * @wrk: The work object to be checked
936 int ubi_is_erase_work(struct ubi_work
*wrk
)
938 return wrk
->func
== erase_worker
;
943 * schedule_erase - schedule an erase work.
944 * @ubi: UBI device description object
945 * @e: the WL entry of the physical eraseblock to erase
946 * @vol_id: the volume ID that last used this PEB
947 * @lnum: the last used logical eraseblock number for the PEB
948 * @torture: if the physical eraseblock has to be tortured
950 * This function returns zero in case of success and a %-ENOMEM in case of
953 static int schedule_erase(struct ubi_device
*ubi
, struct ubi_wl_entry
*e
,
954 int vol_id
, int lnum
, int torture
)
956 struct ubi_work
*wl_wrk
;
959 ubi_assert(!ubi_is_fm_block(ubi
, e
->pnum
));
961 dbg_wl("schedule erasure of PEB %d, EC %d, torture %d",
962 e
->pnum
, e
->ec
, torture
);
964 wl_wrk
= kmalloc(sizeof(struct ubi_work
), GFP_NOFS
);
968 wl_wrk
->func
= &erase_worker
;
970 wl_wrk
->vol_id
= vol_id
;
972 wl_wrk
->torture
= torture
;
974 schedule_ubi_work(ubi
, wl_wrk
);
979 * do_sync_erase - run the erase worker synchronously.
980 * @ubi: UBI device description object
981 * @e: the WL entry of the physical eraseblock to erase
982 * @vol_id: the volume ID that last used this PEB
983 * @lnum: the last used logical eraseblock number for the PEB
984 * @torture: if the physical eraseblock has to be tortured
987 static int do_sync_erase(struct ubi_device
*ubi
, struct ubi_wl_entry
*e
,
988 int vol_id
, int lnum
, int torture
)
990 struct ubi_work
*wl_wrk
;
992 dbg_wl("sync erase of PEB %i", e
->pnum
);
994 wl_wrk
= kmalloc(sizeof(struct ubi_work
), GFP_NOFS
);
999 wl_wrk
->vol_id
= vol_id
;
1000 wl_wrk
->lnum
= lnum
;
1001 wl_wrk
->torture
= torture
;
1003 return erase_worker(ubi
, wl_wrk
, 0);
1006 #ifdef CONFIG_MTD_UBI_FASTMAP
1008 * ubi_wl_put_fm_peb - returns a PEB used in a fastmap to the wear-leveling
1010 * see: ubi_wl_put_peb()
1012 * @ubi: UBI device description object
1013 * @fm_e: physical eraseblock to return
1014 * @lnum: the last used logical eraseblock number for the PEB
1015 * @torture: if this physical eraseblock has to be tortured
1017 int ubi_wl_put_fm_peb(struct ubi_device
*ubi
, struct ubi_wl_entry
*fm_e
,
1018 int lnum
, int torture
)
1020 struct ubi_wl_entry
*e
;
1021 int vol_id
, pnum
= fm_e
->pnum
;
1023 dbg_wl("PEB %d", pnum
);
1025 ubi_assert(pnum
>= 0);
1026 ubi_assert(pnum
< ubi
->peb_count
);
1028 spin_lock(&ubi
->wl_lock
);
1029 e
= ubi
->lookuptbl
[pnum
];
1031 /* This can happen if we recovered from a fastmap the very
1032 * first time and writing now a new one. In this case the wl system
1033 * has never seen any PEB used by the original fastmap.
1037 ubi_assert(e
->ec
>= 0);
1038 ubi
->lookuptbl
[pnum
] = e
;
1041 spin_unlock(&ubi
->wl_lock
);
1043 vol_id
= lnum
? UBI_FM_DATA_VOLUME_ID
: UBI_FM_SB_VOLUME_ID
;
1044 return schedule_erase(ubi
, e
, vol_id
, lnum
, torture
);
1049 * wear_leveling_worker - wear-leveling worker function.
1050 * @ubi: UBI device description object
1051 * @wrk: the work object
1052 * @shutdown: non-zero if the worker has to free memory and exit
1053 * because the WL-subsystem is shutting down
1055 * This function copies a more worn out physical eraseblock to a less worn out
1056 * one. Returns zero in case of success and a negative error code in case of
1059 static int wear_leveling_worker(struct ubi_device
*ubi
, struct ubi_work
*wrk
,
1062 int err
, scrubbing
= 0, torture
= 0, protect
= 0, erroneous
= 0;
1063 int vol_id
= -1, lnum
= -1;
1064 #ifdef CONFIG_MTD_UBI_FASTMAP
1065 int anchor
= wrk
->anchor
;
1067 struct ubi_wl_entry
*e1
, *e2
;
1068 struct ubi_vid_hdr
*vid_hdr
;
1074 vid_hdr
= ubi_zalloc_vid_hdr(ubi
, GFP_NOFS
);
1078 mutex_lock(&ubi
->move_mutex
);
1079 spin_lock(&ubi
->wl_lock
);
1080 ubi_assert(!ubi
->move_from
&& !ubi
->move_to
);
1081 ubi_assert(!ubi
->move_to_put
);
1083 if (!ubi
->free
.rb_node
||
1084 (!ubi
->used
.rb_node
&& !ubi
->scrub
.rb_node
)) {
1086 * No free physical eraseblocks? Well, they must be waiting in
1087 * the queue to be erased. Cancel movement - it will be
1088 * triggered again when a free physical eraseblock appears.
1090 * No used physical eraseblocks? They must be temporarily
1091 * protected from being moved. They will be moved to the
1092 * @ubi->used tree later and the wear-leveling will be
1095 dbg_wl("cancel WL, a list is empty: free %d, used %d",
1096 !ubi
->free
.rb_node
, !ubi
->used
.rb_node
);
1100 #ifdef CONFIG_MTD_UBI_FASTMAP
1101 /* Check whether we need to produce an anchor PEB */
1103 anchor
= !anchor_pebs_avalible(&ubi
->free
);
1106 e1
= find_anchor_wl_entry(&ubi
->used
);
1109 e2
= get_peb_for_wl(ubi
);
1113 self_check_in_wl_tree(ubi
, e1
, &ubi
->used
);
1114 rb_erase(&e1
->u
.rb
, &ubi
->used
);
1115 dbg_wl("anchor-move PEB %d to PEB %d", e1
->pnum
, e2
->pnum
);
1116 } else if (!ubi
->scrub
.rb_node
) {
1118 if (!ubi
->scrub
.rb_node
) {
1121 * Now pick the least worn-out used physical eraseblock and a
1122 * highly worn-out free physical eraseblock. If the erase
1123 * counters differ much enough, start wear-leveling.
1125 e1
= rb_entry(rb_first(&ubi
->used
), struct ubi_wl_entry
, u
.rb
);
1126 e2
= get_peb_for_wl(ubi
);
1130 if (!(e2
->ec
- e1
->ec
>= UBI_WL_THRESHOLD
)) {
1131 dbg_wl("no WL needed: min used EC %d, max free EC %d",
1134 /* Give the unused PEB back */
1135 wl_tree_add(e2
, &ubi
->free
);
1139 self_check_in_wl_tree(ubi
, e1
, &ubi
->used
);
1140 rb_erase(&e1
->u
.rb
, &ubi
->used
);
1141 dbg_wl("move PEB %d EC %d to PEB %d EC %d",
1142 e1
->pnum
, e1
->ec
, e2
->pnum
, e2
->ec
);
1144 /* Perform scrubbing */
1146 e1
= rb_entry(rb_first(&ubi
->scrub
), struct ubi_wl_entry
, u
.rb
);
1147 e2
= get_peb_for_wl(ubi
);
1151 self_check_in_wl_tree(ubi
, e1
, &ubi
->scrub
);
1152 rb_erase(&e1
->u
.rb
, &ubi
->scrub
);
1153 dbg_wl("scrub PEB %d to PEB %d", e1
->pnum
, e2
->pnum
);
1156 ubi
->move_from
= e1
;
1158 spin_unlock(&ubi
->wl_lock
);
1161 * Now we are going to copy physical eraseblock @e1->pnum to @e2->pnum.
1162 * We so far do not know which logical eraseblock our physical
1163 * eraseblock (@e1) belongs to. We have to read the volume identifier
1166 * Note, we are protected from this PEB being unmapped and erased. The
1167 * 'ubi_wl_put_peb()' would wait for moving to be finished if the PEB
1168 * which is being moved was unmapped.
1171 err
= ubi_io_read_vid_hdr(ubi
, e1
->pnum
, vid_hdr
, 0);
1172 if (err
&& err
!= UBI_IO_BITFLIPS
) {
1173 if (err
== UBI_IO_FF
) {
1175 * We are trying to move PEB without a VID header. UBI
1176 * always write VID headers shortly after the PEB was
1177 * given, so we have a situation when it has not yet
1178 * had a chance to write it, because it was preempted.
1179 * So add this PEB to the protection queue so far,
1180 * because presumably more data will be written there
1181 * (including the missing VID header), and then we'll
1184 dbg_wl("PEB %d has no VID header", e1
->pnum
);
1187 } else if (err
== UBI_IO_FF_BITFLIPS
) {
1189 * The same situation as %UBI_IO_FF, but bit-flips were
1190 * detected. It is better to schedule this PEB for
1193 dbg_wl("PEB %d has no VID header but has bit-flips",
1199 ubi_err(ubi
, "error %d while reading VID header from PEB %d",
1204 vol_id
= be32_to_cpu(vid_hdr
->vol_id
);
1205 lnum
= be32_to_cpu(vid_hdr
->lnum
);
1207 err
= ubi_eba_copy_leb(ubi
, e1
->pnum
, e2
->pnum
, vid_hdr
);
1209 if (err
== MOVE_CANCEL_RACE
) {
1211 * The LEB has not been moved because the volume is
1212 * being deleted or the PEB has been put meanwhile. We
1213 * should prevent this PEB from being selected for
1214 * wear-leveling movement again, so put it to the
1220 if (err
== MOVE_RETRY
) {
1224 if (err
== MOVE_TARGET_BITFLIPS
|| err
== MOVE_TARGET_WR_ERR
||
1225 err
== MOVE_TARGET_RD_ERR
) {
1227 * Target PEB had bit-flips or write error - torture it.
1233 if (err
== MOVE_SOURCE_RD_ERR
) {
1235 * An error happened while reading the source PEB. Do
1236 * not switch to R/O mode in this case, and give the
1237 * upper layers a possibility to recover from this,
1238 * e.g. by unmapping corresponding LEB. Instead, just
1239 * put this PEB to the @ubi->erroneous list to prevent
1240 * UBI from trying to move it over and over again.
1242 if (ubi
->erroneous_peb_count
> ubi
->max_erroneous
) {
1243 ubi_err(ubi
, "too many erroneous eraseblocks (%d)",
1244 ubi
->erroneous_peb_count
);
1257 /* The PEB has been successfully moved */
1259 ubi_msg(ubi
, "scrubbed PEB %d (LEB %d:%d), data moved to PEB %d",
1260 e1
->pnum
, vol_id
, lnum
, e2
->pnum
);
1261 ubi_free_vid_hdr(ubi
, vid_hdr
);
1263 spin_lock(&ubi
->wl_lock
);
1264 if (!ubi
->move_to_put
) {
1265 wl_tree_add(e2
, &ubi
->used
);
1268 ubi
->move_from
= ubi
->move_to
= NULL
;
1269 ubi
->move_to_put
= ubi
->wl_scheduled
= 0;
1270 spin_unlock(&ubi
->wl_lock
);
1272 err
= do_sync_erase(ubi
, e1
, vol_id
, lnum
, 0);
1275 wl_entry_destroy(ubi
, e2
);
1281 * Well, the target PEB was put meanwhile, schedule it for
1284 dbg_wl("PEB %d (LEB %d:%d) was put meanwhile, erase",
1285 e2
->pnum
, vol_id
, lnum
);
1286 err
= do_sync_erase(ubi
, e2
, vol_id
, lnum
, 0);
1292 mutex_unlock(&ubi
->move_mutex
);
1296 * For some reasons the LEB was not moved, might be an error, might be
1297 * something else. @e1 was not changed, so return it back. @e2 might
1298 * have been changed, schedule it for erasure.
1302 dbg_wl("cancel moving PEB %d (LEB %d:%d) to PEB %d (%d)",
1303 e1
->pnum
, vol_id
, lnum
, e2
->pnum
, err
);
1305 dbg_wl("cancel moving PEB %d to PEB %d (%d)",
1306 e1
->pnum
, e2
->pnum
, err
);
1307 spin_lock(&ubi
->wl_lock
);
1309 prot_queue_add(ubi
, e1
);
1310 else if (erroneous
) {
1311 wl_tree_add(e1
, &ubi
->erroneous
);
1312 ubi
->erroneous_peb_count
+= 1;
1313 } else if (scrubbing
)
1314 wl_tree_add(e1
, &ubi
->scrub
);
1316 wl_tree_add(e1
, &ubi
->used
);
1317 ubi_assert(!ubi
->move_to_put
);
1318 ubi
->move_from
= ubi
->move_to
= NULL
;
1319 ubi
->wl_scheduled
= 0;
1320 spin_unlock(&ubi
->wl_lock
);
1322 ubi_free_vid_hdr(ubi
, vid_hdr
);
1323 err
= do_sync_erase(ubi
, e2
, vol_id
, lnum
, torture
);
1327 mutex_unlock(&ubi
->move_mutex
);
1332 ubi_err(ubi
, "error %d while moving PEB %d to PEB %d",
1333 err
, e1
->pnum
, e2
->pnum
);
1335 ubi_err(ubi
, "error %d while moving PEB %d (LEB %d:%d) to PEB %d",
1336 err
, e1
->pnum
, vol_id
, lnum
, e2
->pnum
);
1337 spin_lock(&ubi
->wl_lock
);
1338 ubi
->move_from
= ubi
->move_to
= NULL
;
1339 ubi
->move_to_put
= ubi
->wl_scheduled
= 0;
1340 spin_unlock(&ubi
->wl_lock
);
1342 ubi_free_vid_hdr(ubi
, vid_hdr
);
1343 wl_entry_destroy(ubi
, e1
);
1344 wl_entry_destroy(ubi
, e2
);
1348 mutex_unlock(&ubi
->move_mutex
);
1349 ubi_assert(err
!= 0);
1350 return err
< 0 ? err
: -EIO
;
1353 ubi
->wl_scheduled
= 0;
1354 spin_unlock(&ubi
->wl_lock
);
1355 mutex_unlock(&ubi
->move_mutex
);
1356 ubi_free_vid_hdr(ubi
, vid_hdr
);
1361 * ensure_wear_leveling - schedule wear-leveling if it is needed.
1362 * @ubi: UBI device description object
1363 * @nested: set to non-zero if this function is called from UBI worker
1365 * This function checks if it is time to start wear-leveling and schedules it
1366 * if yes. This function returns zero in case of success and a negative error
1367 * code in case of failure.
1369 static int ensure_wear_leveling(struct ubi_device
*ubi
, int nested
)
1372 struct ubi_wl_entry
*e1
;
1373 struct ubi_wl_entry
*e2
;
1374 struct ubi_work
*wrk
;
1376 spin_lock(&ubi
->wl_lock
);
1377 if (ubi
->wl_scheduled
)
1378 /* Wear-leveling is already in the work queue */
1382 * If the ubi->scrub tree is not empty, scrubbing is needed, and the
1383 * the WL worker has to be scheduled anyway.
1385 if (!ubi
->scrub
.rb_node
) {
1386 if (!ubi
->used
.rb_node
|| !ubi
->free
.rb_node
)
1387 /* No physical eraseblocks - no deal */
1391 * We schedule wear-leveling only if the difference between the
1392 * lowest erase counter of used physical eraseblocks and a high
1393 * erase counter of free physical eraseblocks is greater than
1394 * %UBI_WL_THRESHOLD.
1396 e1
= rb_entry(rb_first(&ubi
->used
), struct ubi_wl_entry
, u
.rb
);
1397 e2
= find_wl_entry(ubi
, &ubi
->free
, WL_FREE_MAX_DIFF
);
1399 if (!(e2
->ec
- e1
->ec
>= UBI_WL_THRESHOLD
))
1401 dbg_wl("schedule wear-leveling");
1403 dbg_wl("schedule scrubbing");
1405 ubi
->wl_scheduled
= 1;
1406 spin_unlock(&ubi
->wl_lock
);
1408 wrk
= kmalloc(sizeof(struct ubi_work
), GFP_NOFS
);
1415 wrk
->func
= &wear_leveling_worker
;
1417 __schedule_ubi_work(ubi
, wrk
);
1419 schedule_ubi_work(ubi
, wrk
);
1423 spin_lock(&ubi
->wl_lock
);
1424 ubi
->wl_scheduled
= 0;
1426 spin_unlock(&ubi
->wl_lock
);
1430 #ifdef CONFIG_MTD_UBI_FASTMAP
1432 * ubi_ensure_anchor_pebs - schedule wear-leveling to produce an anchor PEB.
1433 * @ubi: UBI device description object
1435 int ubi_ensure_anchor_pebs(struct ubi_device
*ubi
)
1437 struct ubi_work
*wrk
;
1439 spin_lock(&ubi
->wl_lock
);
1440 if (ubi
->wl_scheduled
) {
1441 spin_unlock(&ubi
->wl_lock
);
1444 ubi
->wl_scheduled
= 1;
1445 spin_unlock(&ubi
->wl_lock
);
1447 wrk
= kmalloc(sizeof(struct ubi_work
), GFP_NOFS
);
1449 spin_lock(&ubi
->wl_lock
);
1450 ubi
->wl_scheduled
= 0;
1451 spin_unlock(&ubi
->wl_lock
);
1456 wrk
->func
= &wear_leveling_worker
;
1457 schedule_ubi_work(ubi
, wrk
);
1463 * erase_worker - physical eraseblock erase worker function.
1464 * @ubi: UBI device description object
1465 * @wl_wrk: the work object
1466 * @shutdown: non-zero if the worker has to free memory and exit
1467 * because the WL sub-system is shutting down
1469 * This function erases a physical eraseblock and perform torture testing if
1470 * needed. It also takes care about marking the physical eraseblock bad if
1471 * needed. Returns zero in case of success and a negative error code in case of
1474 static int erase_worker(struct ubi_device
*ubi
, struct ubi_work
*wl_wrk
,
1477 struct ubi_wl_entry
*e
= wl_wrk
->e
;
1479 int vol_id
= wl_wrk
->vol_id
;
1480 int lnum
= wl_wrk
->lnum
;
1481 int err
, available_consumed
= 0;
1484 dbg_wl("cancel erasure of PEB %d EC %d", pnum
, e
->ec
);
1486 wl_entry_destroy(ubi
, e
);
1490 dbg_wl("erase PEB %d EC %d LEB %d:%d",
1491 pnum
, e
->ec
, wl_wrk
->vol_id
, wl_wrk
->lnum
);
1493 ubi_assert(!ubi_is_fm_block(ubi
, e
->pnum
));
1495 err
= sync_erase(ubi
, e
, wl_wrk
->torture
);
1497 /* Fine, we've erased it successfully */
1500 spin_lock(&ubi
->wl_lock
);
1501 wl_tree_add(e
, &ubi
->free
);
1503 spin_unlock(&ubi
->wl_lock
);
1506 * One more erase operation has happened, take care about
1507 * protected physical eraseblocks.
1509 serve_prot_queue(ubi
);
1511 /* And take care about wear-leveling */
1512 err
= ensure_wear_leveling(ubi
, 1);
1516 ubi_err(ubi
, "failed to erase PEB %d, error %d", pnum
, err
);
1519 if (err
== -EINTR
|| err
== -ENOMEM
|| err
== -EAGAIN
||
1523 /* Re-schedule the LEB for erasure */
1524 err1
= schedule_erase(ubi
, e
, vol_id
, lnum
, 0);
1532 wl_entry_destroy(ubi
, e
);
1535 * If this is not %-EIO, we have no idea what to do. Scheduling
1536 * this physical eraseblock for erasure again would cause
1537 * errors again and again. Well, lets switch to R/O mode.
1541 /* It is %-EIO, the PEB went bad */
1543 if (!ubi
->bad_allowed
) {
1544 ubi_err(ubi
, "bad physical eraseblock %d detected", pnum
);
1548 spin_lock(&ubi
->volumes_lock
);
1549 if (ubi
->beb_rsvd_pebs
== 0) {
1550 if (ubi
->avail_pebs
== 0) {
1551 spin_unlock(&ubi
->volumes_lock
);
1552 ubi_err(ubi
, "no reserved/available physical eraseblocks");
1555 ubi
->avail_pebs
-= 1;
1556 available_consumed
= 1;
1558 spin_unlock(&ubi
->volumes_lock
);
1560 ubi_msg(ubi
, "mark PEB %d as bad", pnum
);
1561 err
= ubi_io_mark_bad(ubi
, pnum
);
1565 spin_lock(&ubi
->volumes_lock
);
1566 if (ubi
->beb_rsvd_pebs
> 0) {
1567 if (available_consumed
) {
1569 * The amount of reserved PEBs increased since we last
1572 ubi
->avail_pebs
+= 1;
1573 available_consumed
= 0;
1575 ubi
->beb_rsvd_pebs
-= 1;
1577 ubi
->bad_peb_count
+= 1;
1578 ubi
->good_peb_count
-= 1;
1579 ubi_calculate_reserved(ubi
);
1580 if (available_consumed
)
1581 ubi_warn(ubi
, "no PEBs in the reserved pool, used an available PEB");
1582 else if (ubi
->beb_rsvd_pebs
)
1583 ubi_msg(ubi
, "%d PEBs left in the reserve",
1584 ubi
->beb_rsvd_pebs
);
1586 ubi_warn(ubi
, "last PEB from the reserve was used");
1587 spin_unlock(&ubi
->volumes_lock
);
1592 if (available_consumed
) {
1593 spin_lock(&ubi
->volumes_lock
);
1594 ubi
->avail_pebs
+= 1;
1595 spin_unlock(&ubi
->volumes_lock
);
1602 * ubi_wl_put_peb - return a PEB to the wear-leveling sub-system.
1603 * @ubi: UBI device description object
1604 * @vol_id: the volume ID that last used this PEB
1605 * @lnum: the last used logical eraseblock number for the PEB
1606 * @pnum: physical eraseblock to return
1607 * @torture: if this physical eraseblock has to be tortured
1609 * This function is called to return physical eraseblock @pnum to the pool of
1610 * free physical eraseblocks. The @torture flag has to be set if an I/O error
1611 * occurred to this @pnum and it has to be tested. This function returns zero
1612 * in case of success, and a negative error code in case of failure.
1614 int ubi_wl_put_peb(struct ubi_device
*ubi
, int vol_id
, int lnum
,
1615 int pnum
, int torture
)
1618 struct ubi_wl_entry
*e
;
1620 dbg_wl("PEB %d", pnum
);
1621 ubi_assert(pnum
>= 0);
1622 ubi_assert(pnum
< ubi
->peb_count
);
1624 down_read(&ubi
->fm_protect
);
1627 spin_lock(&ubi
->wl_lock
);
1628 e
= ubi
->lookuptbl
[pnum
];
1629 if (e
== ubi
->move_from
) {
1631 * User is putting the physical eraseblock which was selected to
1632 * be moved. It will be scheduled for erasure in the
1633 * wear-leveling worker.
1635 dbg_wl("PEB %d is being moved, wait", pnum
);
1636 spin_unlock(&ubi
->wl_lock
);
1638 /* Wait for the WL worker by taking the @ubi->move_mutex */
1639 mutex_lock(&ubi
->move_mutex
);
1640 mutex_unlock(&ubi
->move_mutex
);
1642 } else if (e
== ubi
->move_to
) {
1644 * User is putting the physical eraseblock which was selected
1645 * as the target the data is moved to. It may happen if the EBA
1646 * sub-system already re-mapped the LEB in 'ubi_eba_copy_leb()'
1647 * but the WL sub-system has not put the PEB to the "used" tree
1648 * yet, but it is about to do this. So we just set a flag which
1649 * will tell the WL worker that the PEB is not needed anymore
1650 * and should be scheduled for erasure.
1652 dbg_wl("PEB %d is the target of data moving", pnum
);
1653 ubi_assert(!ubi
->move_to_put
);
1654 ubi
->move_to_put
= 1;
1655 spin_unlock(&ubi
->wl_lock
);
1656 up_read(&ubi
->fm_protect
);
1659 if (in_wl_tree(e
, &ubi
->used
)) {
1660 self_check_in_wl_tree(ubi
, e
, &ubi
->used
);
1661 rb_erase(&e
->u
.rb
, &ubi
->used
);
1662 } else if (in_wl_tree(e
, &ubi
->scrub
)) {
1663 self_check_in_wl_tree(ubi
, e
, &ubi
->scrub
);
1664 rb_erase(&e
->u
.rb
, &ubi
->scrub
);
1665 } else if (in_wl_tree(e
, &ubi
->erroneous
)) {
1666 self_check_in_wl_tree(ubi
, e
, &ubi
->erroneous
);
1667 rb_erase(&e
->u
.rb
, &ubi
->erroneous
);
1668 ubi
->erroneous_peb_count
-= 1;
1669 ubi_assert(ubi
->erroneous_peb_count
>= 0);
1670 /* Erroneous PEBs should be tortured */
1673 err
= prot_queue_del(ubi
, e
->pnum
);
1675 ubi_err(ubi
, "PEB %d not found", pnum
);
1677 spin_unlock(&ubi
->wl_lock
);
1678 up_read(&ubi
->fm_protect
);
1683 spin_unlock(&ubi
->wl_lock
);
1685 err
= schedule_erase(ubi
, e
, vol_id
, lnum
, torture
);
1687 spin_lock(&ubi
->wl_lock
);
1688 wl_tree_add(e
, &ubi
->used
);
1689 spin_unlock(&ubi
->wl_lock
);
1692 up_read(&ubi
->fm_protect
);
1697 * ubi_wl_scrub_peb - schedule a physical eraseblock for scrubbing.
1698 * @ubi: UBI device description object
1699 * @pnum: the physical eraseblock to schedule
1701 * If a bit-flip in a physical eraseblock is detected, this physical eraseblock
1702 * needs scrubbing. This function schedules a physical eraseblock for
1703 * scrubbing which is done in background. This function returns zero in case of
1704 * success and a negative error code in case of failure.
1706 int ubi_wl_scrub_peb(struct ubi_device
*ubi
, int pnum
)
1708 struct ubi_wl_entry
*e
;
1710 ubi_msg(ubi
, "schedule PEB %d for scrubbing", pnum
);
1713 spin_lock(&ubi
->wl_lock
);
1714 e
= ubi
->lookuptbl
[pnum
];
1715 if (e
== ubi
->move_from
|| in_wl_tree(e
, &ubi
->scrub
) ||
1716 in_wl_tree(e
, &ubi
->erroneous
)) {
1717 spin_unlock(&ubi
->wl_lock
);
1721 if (e
== ubi
->move_to
) {
1723 * This physical eraseblock was used to move data to. The data
1724 * was moved but the PEB was not yet inserted to the proper
1725 * tree. We should just wait a little and let the WL worker
1728 spin_unlock(&ubi
->wl_lock
);
1729 dbg_wl("the PEB %d is not in proper tree, retry", pnum
);
1734 if (in_wl_tree(e
, &ubi
->used
)) {
1735 self_check_in_wl_tree(ubi
, e
, &ubi
->used
);
1736 rb_erase(&e
->u
.rb
, &ubi
->used
);
1740 err
= prot_queue_del(ubi
, e
->pnum
);
1742 ubi_err(ubi
, "PEB %d not found", pnum
);
1744 spin_unlock(&ubi
->wl_lock
);
1749 wl_tree_add(e
, &ubi
->scrub
);
1750 spin_unlock(&ubi
->wl_lock
);
1753 * Technically scrubbing is the same as wear-leveling, so it is done
1756 return ensure_wear_leveling(ubi
, 0);
1760 * ubi_wl_flush - flush all pending works.
1761 * @ubi: UBI device description object
1762 * @vol_id: the volume id to flush for
1763 * @lnum: the logical eraseblock number to flush for
1765 * This function executes all pending works for a particular volume id /
1766 * logical eraseblock number pair. If either value is set to %UBI_ALL, then it
1767 * acts as a wildcard for all of the corresponding volume numbers or logical
1768 * eraseblock numbers. It returns zero in case of success and a negative error
1769 * code in case of failure.
1771 int ubi_wl_flush(struct ubi_device
*ubi
, int vol_id
, int lnum
)
1777 * Erase while the pending works queue is not empty, but not more than
1778 * the number of currently pending works.
1780 dbg_wl("flush pending work for LEB %d:%d (%d pending works)",
1781 vol_id
, lnum
, ubi
->works_count
);
1784 struct ubi_work
*wrk
, *tmp
;
1787 down_read(&ubi
->work_sem
);
1788 spin_lock(&ubi
->wl_lock
);
1789 list_for_each_entry_safe(wrk
, tmp
, &ubi
->works
, list
) {
1790 if ((vol_id
== UBI_ALL
|| wrk
->vol_id
== vol_id
) &&
1791 (lnum
== UBI_ALL
|| wrk
->lnum
== lnum
)) {
1792 list_del(&wrk
->list
);
1793 ubi
->works_count
-= 1;
1794 ubi_assert(ubi
->works_count
>= 0);
1795 spin_unlock(&ubi
->wl_lock
);
1797 err
= wrk
->func(ubi
, wrk
, 0);
1799 up_read(&ubi
->work_sem
);
1803 spin_lock(&ubi
->wl_lock
);
1808 spin_unlock(&ubi
->wl_lock
);
1809 up_read(&ubi
->work_sem
);
1813 * Make sure all the works which have been done in parallel are
1816 down_write(&ubi
->work_sem
);
1817 up_write(&ubi
->work_sem
);
1823 * tree_destroy - destroy an RB-tree.
1824 * @ubi: UBI device description object
1825 * @root: the root of the tree to destroy
1827 static void tree_destroy(struct ubi_device
*ubi
, struct rb_root
*root
)
1830 struct ubi_wl_entry
*e
;
1836 else if (rb
->rb_right
)
1839 e
= rb_entry(rb
, struct ubi_wl_entry
, u
.rb
);
1843 if (rb
->rb_left
== &e
->u
.rb
)
1846 rb
->rb_right
= NULL
;
1849 wl_entry_destroy(ubi
, e
);
1855 * ubi_thread - UBI background thread.
1856 * @u: the UBI device description object pointer
1858 int ubi_thread(void *u
)
1861 struct ubi_device
*ubi
= u
;
1863 ubi_msg(ubi
, "background thread \"%s\" started, PID %d",
1864 ubi
->bgt_name
, task_pid_nr(current
));
1870 if (kthread_should_stop())
1873 if (try_to_freeze())
1876 spin_lock(&ubi
->wl_lock
);
1877 if (list_empty(&ubi
->works
) || ubi
->ro_mode
||
1878 !ubi
->thread_enabled
|| ubi_dbg_is_bgt_disabled(ubi
)) {
1879 set_current_state(TASK_INTERRUPTIBLE
);
1880 spin_unlock(&ubi
->wl_lock
);
1884 spin_unlock(&ubi
->wl_lock
);
1888 ubi_err(ubi
, "%s: work failed with error code %d",
1889 ubi
->bgt_name
, err
);
1890 if (failures
++ > WL_MAX_FAILURES
) {
1892 * Too many failures, disable the thread and
1893 * switch to read-only mode.
1895 ubi_msg(ubi
, "%s: %d consecutive failures",
1896 ubi
->bgt_name
, WL_MAX_FAILURES
);
1898 ubi
->thread_enabled
= 0;
1907 dbg_wl("background thread \"%s\" is killed", ubi
->bgt_name
);
1912 * shutdown_work - shutdown all pending works.
1913 * @ubi: UBI device description object
1915 static void shutdown_work(struct ubi_device
*ubi
)
1917 #ifdef CONFIG_MTD_UBI_FASTMAP
1918 flush_work(&ubi
->fm_work
);
1920 while (!list_empty(&ubi
->works
)) {
1921 struct ubi_work
*wrk
;
1923 wrk
= list_entry(ubi
->works
.next
, struct ubi_work
, list
);
1924 list_del(&wrk
->list
);
1925 wrk
->func(ubi
, wrk
, 1);
1926 ubi
->works_count
-= 1;
1927 ubi_assert(ubi
->works_count
>= 0);
1932 * ubi_wl_init - initialize the WL sub-system using attaching information.
1933 * @ubi: UBI device description object
1934 * @ai: attaching information
1936 * This function returns zero in case of success, and a negative error code in
1939 int ubi_wl_init(struct ubi_device
*ubi
, struct ubi_attach_info
*ai
)
1941 int err
, i
, reserved_pebs
, found_pebs
= 0;
1942 struct rb_node
*rb1
, *rb2
;
1943 struct ubi_ainf_volume
*av
;
1944 struct ubi_ainf_peb
*aeb
, *tmp
;
1945 struct ubi_wl_entry
*e
;
1947 ubi
->used
= ubi
->erroneous
= ubi
->free
= ubi
->scrub
= RB_ROOT
;
1948 spin_lock_init(&ubi
->wl_lock
);
1949 mutex_init(&ubi
->move_mutex
);
1950 init_rwsem(&ubi
->work_sem
);
1951 ubi
->max_ec
= ai
->max_ec
;
1952 INIT_LIST_HEAD(&ubi
->works
);
1953 #ifdef CONFIG_MTD_UBI_FASTMAP
1954 INIT_WORK(&ubi
->fm_work
, update_fastmap_work_fn
);
1957 sprintf(ubi
->bgt_name
, UBI_BGT_NAME_PATTERN
, ubi
->ubi_num
);
1960 ubi
->lookuptbl
= kzalloc(ubi
->peb_count
* sizeof(void *), GFP_KERNEL
);
1961 if (!ubi
->lookuptbl
)
1964 for (i
= 0; i
< UBI_PROT_QUEUE_LEN
; i
++)
1965 INIT_LIST_HEAD(&ubi
->pq
[i
]);
1968 list_for_each_entry_safe(aeb
, tmp
, &ai
->erase
, u
.list
) {
1971 e
= kmem_cache_alloc(ubi_wl_entry_slab
, GFP_KERNEL
);
1975 e
->pnum
= aeb
->pnum
;
1977 ubi_assert(!ubi_is_fm_block(ubi
, e
->pnum
));
1978 ubi
->lookuptbl
[e
->pnum
] = e
;
1979 if (schedule_erase(ubi
, e
, aeb
->vol_id
, aeb
->lnum
, 0)) {
1980 wl_entry_destroy(ubi
, e
);
1987 ubi
->free_count
= 0;
1988 list_for_each_entry(aeb
, &ai
->free
, u
.list
) {
1991 e
= kmem_cache_alloc(ubi_wl_entry_slab
, GFP_KERNEL
);
1995 e
->pnum
= aeb
->pnum
;
1997 ubi_assert(e
->ec
>= 0);
1998 ubi_assert(!ubi_is_fm_block(ubi
, e
->pnum
));
2000 wl_tree_add(e
, &ubi
->free
);
2003 ubi
->lookuptbl
[e
->pnum
] = e
;
2008 ubi_rb_for_each_entry(rb1
, av
, &ai
->volumes
, rb
) {
2009 ubi_rb_for_each_entry(rb2
, aeb
, &av
->root
, u
.rb
) {
2012 e
= kmem_cache_alloc(ubi_wl_entry_slab
, GFP_KERNEL
);
2016 e
->pnum
= aeb
->pnum
;
2018 ubi
->lookuptbl
[e
->pnum
] = e
;
2021 dbg_wl("add PEB %d EC %d to the used tree",
2023 wl_tree_add(e
, &ubi
->used
);
2025 dbg_wl("add PEB %d EC %d to the scrub tree",
2027 wl_tree_add(e
, &ubi
->scrub
);
2034 dbg_wl("found %i PEBs", found_pebs
);
2037 ubi_assert(ubi
->good_peb_count
== \
2038 found_pebs
+ ubi
->fm
->used_blocks
);
2040 for (i
= 0; i
< ubi
->fm
->used_blocks
; i
++) {
2042 ubi
->lookuptbl
[e
->pnum
] = e
;
2046 ubi_assert(ubi
->good_peb_count
== found_pebs
);
2048 reserved_pebs
= WL_RESERVED_PEBS
;
2049 #ifdef CONFIG_MTD_UBI_FASTMAP
2050 /* Reserve enough LEBs to store two fastmaps. */
2051 reserved_pebs
+= (ubi
->fm_size
/ ubi
->leb_size
) * 2;
2054 if (ubi
->avail_pebs
< reserved_pebs
) {
2055 ubi_err(ubi
, "no enough physical eraseblocks (%d, need %d)",
2056 ubi
->avail_pebs
, reserved_pebs
);
2057 if (ubi
->corr_peb_count
)
2058 ubi_err(ubi
, "%d PEBs are corrupted and not used",
2059 ubi
->corr_peb_count
);
2062 ubi
->avail_pebs
-= reserved_pebs
;
2063 ubi
->rsvd_pebs
+= reserved_pebs
;
2065 /* Schedule wear-leveling if needed */
2066 err
= ensure_wear_leveling(ubi
, 0);
2074 tree_destroy(ubi
, &ubi
->used
);
2075 tree_destroy(ubi
, &ubi
->free
);
2076 tree_destroy(ubi
, &ubi
->scrub
);
2077 kfree(ubi
->lookuptbl
);
2082 * protection_queue_destroy - destroy the protection queue.
2083 * @ubi: UBI device description object
2085 static void protection_queue_destroy(struct ubi_device
*ubi
)
2088 struct ubi_wl_entry
*e
, *tmp
;
2090 for (i
= 0; i
< UBI_PROT_QUEUE_LEN
; ++i
) {
2091 list_for_each_entry_safe(e
, tmp
, &ubi
->pq
[i
], u
.list
) {
2092 list_del(&e
->u
.list
);
2093 wl_entry_destroy(ubi
, e
);
2098 static void ubi_fastmap_close(struct ubi_device
*ubi
)
2100 #ifdef CONFIG_MTD_UBI_FASTMAP
2103 flush_work(&ubi
->fm_work
);
2104 return_unused_pool_pebs(ubi
, &ubi
->fm_pool
);
2105 return_unused_pool_pebs(ubi
, &ubi
->fm_wl_pool
);
2108 for (i
= 0; i
< ubi
->fm
->used_blocks
; i
++)
2109 kfree(ubi
->fm
->e
[i
]);
2116 * ubi_wl_close - close the wear-leveling sub-system.
2117 * @ubi: UBI device description object
2119 void ubi_wl_close(struct ubi_device
*ubi
)
2121 dbg_wl("close the WL sub-system");
2122 ubi_fastmap_close(ubi
);
2124 protection_queue_destroy(ubi
);
2125 tree_destroy(ubi
, &ubi
->used
);
2126 tree_destroy(ubi
, &ubi
->erroneous
);
2127 tree_destroy(ubi
, &ubi
->free
);
2128 tree_destroy(ubi
, &ubi
->scrub
);
2129 kfree(ubi
->lookuptbl
);
2133 * self_check_ec - make sure that the erase counter of a PEB is correct.
2134 * @ubi: UBI device description object
2135 * @pnum: the physical eraseblock number to check
2136 * @ec: the erase counter to check
2138 * This function returns zero if the erase counter of physical eraseblock @pnum
2139 * is equivalent to @ec, and a negative error code if not or if an error
2142 static int self_check_ec(struct ubi_device
*ubi
, int pnum
, int ec
)
2146 struct ubi_ec_hdr
*ec_hdr
;
2148 if (!ubi_dbg_chk_gen(ubi
))
2151 ec_hdr
= kzalloc(ubi
->ec_hdr_alsize
, GFP_NOFS
);
2155 err
= ubi_io_read_ec_hdr(ubi
, pnum
, ec_hdr
, 0);
2156 if (err
&& err
!= UBI_IO_BITFLIPS
) {
2157 /* The header does not have to exist */
2162 read_ec
= be64_to_cpu(ec_hdr
->ec
);
2163 if (ec
!= read_ec
&& read_ec
- ec
> 1) {
2164 ubi_err(ubi
, "self-check failed for PEB %d", pnum
);
2165 ubi_err(ubi
, "read EC is %lld, should be %d", read_ec
, ec
);
2177 * self_check_in_wl_tree - check that wear-leveling entry is in WL RB-tree.
2178 * @ubi: UBI device description object
2179 * @e: the wear-leveling entry to check
2180 * @root: the root of the tree
2182 * This function returns zero if @e is in the @root RB-tree and %-EINVAL if it
2185 static int self_check_in_wl_tree(const struct ubi_device
*ubi
,
2186 struct ubi_wl_entry
*e
, struct rb_root
*root
)
2188 if (!ubi_dbg_chk_gen(ubi
))
2191 if (in_wl_tree(e
, root
))
2194 ubi_err(ubi
, "self-check failed for PEB %d, EC %d, RB-tree %p ",
2195 e
->pnum
, e
->ec
, root
);
2201 * self_check_in_pq - check if wear-leveling entry is in the protection
2203 * @ubi: UBI device description object
2204 * @e: the wear-leveling entry to check
2206 * This function returns zero if @e is in @ubi->pq and %-EINVAL if it is not.
2208 static int self_check_in_pq(const struct ubi_device
*ubi
,
2209 struct ubi_wl_entry
*e
)
2211 struct ubi_wl_entry
*p
;
2214 if (!ubi_dbg_chk_gen(ubi
))
2217 for (i
= 0; i
< UBI_PROT_QUEUE_LEN
; ++i
)
2218 list_for_each_entry(p
, &ubi
->pq
[i
], u
.list
)
2222 ubi_err(ubi
, "self-check failed for PEB %d, EC %d, Protect queue",
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