2 * Copyright (c) International Business Machines Corp., 2006
4 * SPDX-License-Identifier: GPL-2.0+
6 * Authors: Artem Bityutskiy (Битюцкий Артём), Thomas Gleixner
10 * UBI wear-leveling sub-system.
12 * This sub-system is responsible for wear-leveling. It works in terms of
13 * physical eraseblocks and erase counters and knows nothing about logical
14 * eraseblocks, volumes, etc. From this sub-system's perspective all physical
15 * eraseblocks are of two types - used and free. Used physical eraseblocks are
16 * those that were "get" by the 'ubi_wl_get_peb()' function, and free physical
17 * eraseblocks are those that were put by the 'ubi_wl_put_peb()' function.
19 * Physical eraseblocks returned by 'ubi_wl_get_peb()' have only erase counter
20 * header. The rest of the physical eraseblock contains only %0xFF bytes.
22 * When physical eraseblocks are returned to the WL sub-system by means of the
23 * 'ubi_wl_put_peb()' function, they are scheduled for erasure. The erasure is
24 * done asynchronously in context of the per-UBI device background thread,
25 * which is also managed by the WL sub-system.
27 * The wear-leveling is ensured by means of moving the contents of used
28 * physical eraseblocks with low erase counter to free physical eraseblocks
29 * with high erase counter.
31 * If the WL sub-system fails to erase a physical eraseblock, it marks it as
34 * This sub-system is also responsible for scrubbing. If a bit-flip is detected
35 * in a physical eraseblock, it has to be moved. Technically this is the same
36 * as moving it for wear-leveling reasons.
38 * As it was said, for the UBI sub-system all physical eraseblocks are either
39 * "free" or "used". Free eraseblock are kept in the @wl->free RB-tree, while
40 * used eraseblocks are kept in @wl->used, @wl->erroneous, or @wl->scrub
41 * RB-trees, as well as (temporarily) in the @wl->pq queue.
43 * When the WL sub-system returns a physical eraseblock, the physical
44 * eraseblock is protected from being moved for some "time". For this reason,
45 * the physical eraseblock is not directly moved from the @wl->free tree to the
46 * @wl->used tree. There is a protection queue in between where this
47 * physical eraseblock is temporarily stored (@wl->pq).
49 * All this protection stuff is needed because:
50 * o we don't want to move physical eraseblocks just after we have given them
51 * to the user; instead, we first want to let users fill them up with data;
53 * o there is a chance that the user will put the physical eraseblock very
54 * soon, so it makes sense not to move it for some time, but wait.
56 * Physical eraseblocks stay protected only for limited time. But the "time" is
57 * measured in erase cycles in this case. This is implemented with help of the
58 * protection queue. Eraseblocks are put to the tail of this queue when they
59 * are returned by the 'ubi_wl_get_peb()', and eraseblocks are removed from the
60 * head of the queue on each erase operation (for any eraseblock). So the
61 * length of the queue defines how may (global) erase cycles PEBs are protected.
63 * To put it differently, each physical eraseblock has 2 main states: free and
64 * used. The former state corresponds to the @wl->free tree. The latter state
65 * is split up on several sub-states:
66 * o the WL movement is allowed (@wl->used tree);
67 * o the WL movement is disallowed (@wl->erroneous) because the PEB is
68 * erroneous - e.g., there was a read error;
69 * o the WL movement is temporarily prohibited (@wl->pq queue);
70 * o scrubbing is needed (@wl->scrub tree).
72 * Depending on the sub-state, wear-leveling entries of the used physical
73 * eraseblocks may be kept in one of those structures.
75 * Note, in this implementation, we keep a small in-RAM object for each physical
76 * eraseblock. This is surely not a scalable solution. But it appears to be good
77 * enough for moderately large flashes and it is simple. In future, one may
78 * re-work this sub-system and make it more scalable.
80 * At the moment this sub-system does not utilize the sequence number, which
81 * was introduced relatively recently. But it would be wise to do this because
82 * the sequence number of a logical eraseblock characterizes how old is it. For
83 * example, when we move a PEB with low erase counter, and we need to pick the
84 * target PEB, we pick a PEB with the highest EC if our PEB is "old" and we
85 * pick target PEB with an average EC if our PEB is not very "old". This is a
86 * room for future re-works of the WL sub-system.
90 #include <linux/slab.h>
91 #include <linux/crc32.h>
92 #include <linux/freezer.h>
93 #include <linux/kthread.h>
95 #include <ubi_uboot.h>
101 /* Number of physical eraseblocks reserved for wear-leveling purposes */
102 #define WL_RESERVED_PEBS 1
105 * Maximum difference between two erase counters. If this threshold is
106 * exceeded, the WL sub-system starts moving data from used physical
107 * eraseblocks with low erase counter to free physical eraseblocks with high
110 #define UBI_WL_THRESHOLD CONFIG_MTD_UBI_WL_THRESHOLD
113 * When a physical eraseblock is moved, the WL sub-system has to pick the target
114 * physical eraseblock to move to. The simplest way would be just to pick the
115 * one with the highest erase counter. But in certain workloads this could lead
116 * to an unlimited wear of one or few physical eraseblock. Indeed, imagine a
117 * situation when the picked physical eraseblock is constantly erased after the
118 * data is written to it. So, we have a constant which limits the highest erase
119 * counter of the free physical eraseblock to pick. Namely, the WL sub-system
120 * does not pick eraseblocks with erase counter greater than the lowest erase
121 * counter plus %WL_FREE_MAX_DIFF.
123 #define WL_FREE_MAX_DIFF (2*UBI_WL_THRESHOLD)
126 * Maximum number of consecutive background thread failures which is enough to
127 * switch to read-only mode.
129 #define WL_MAX_FAILURES 32
131 static int self_check_ec(struct ubi_device *ubi, int pnum, int ec);
132 static int self_check_in_wl_tree(const struct ubi_device *ubi,
133 struct ubi_wl_entry *e, struct rb_root *root);
134 static int self_check_in_pq(const struct ubi_device *ubi,
135 struct ubi_wl_entry *e);
138 * wl_tree_add - add a wear-leveling entry to a WL RB-tree.
139 * @e: the wear-leveling entry to add
140 * @root: the root of the tree
142 * Note, we use (erase counter, physical eraseblock number) pairs as keys in
143 * the @ubi->used and @ubi->free RB-trees.
145 static void wl_tree_add(struct ubi_wl_entry *e, struct rb_root *root)
147 struct rb_node **p, *parent = NULL;
151 struct ubi_wl_entry *e1;
154 e1 = rb_entry(parent, struct ubi_wl_entry, u.rb);
158 else if (e->ec > e1->ec)
161 ubi_assert(e->pnum != e1->pnum);
162 if (e->pnum < e1->pnum)
169 rb_link_node(&e->u.rb, parent, p);
170 rb_insert_color(&e->u.rb, root);
174 * wl_tree_destroy - destroy a wear-leveling entry.
175 * @ubi: UBI device description object
176 * @e: the wear-leveling entry to add
178 * This function destroys a wear leveling entry and removes
179 * the reference from the lookup table.
181 static void wl_entry_destroy(struct ubi_device *ubi, struct ubi_wl_entry *e)
183 ubi->lookuptbl[e->pnum] = NULL;
184 kmem_cache_free(ubi_wl_entry_slab, e);
188 * do_work - do one pending work.
189 * @ubi: UBI device description object
191 * This function returns zero in case of success and a negative error code in
195 static int do_work(struct ubi_device *ubi)
197 int do_work(struct ubi_device *ubi)
201 struct ubi_work *wrk;
206 * @ubi->work_sem is used to synchronize with the workers. Workers take
207 * it in read mode, so many of them may be doing works at a time. But
208 * the queue flush code has to be sure the whole queue of works is
209 * done, and it takes the mutex in write mode.
211 down_read(&ubi->work_sem);
212 spin_lock(&ubi->wl_lock);
213 if (list_empty(&ubi->works)) {
214 spin_unlock(&ubi->wl_lock);
215 up_read(&ubi->work_sem);
219 wrk = list_entry(ubi->works.next, struct ubi_work, list);
220 list_del(&wrk->list);
221 ubi->works_count -= 1;
222 ubi_assert(ubi->works_count >= 0);
223 spin_unlock(&ubi->wl_lock);
226 * Call the worker function. Do not touch the work structure
227 * after this call as it will have been freed or reused by that
228 * time by the worker function.
230 err = wrk->func(ubi, wrk, 0);
232 ubi_err(ubi, "work failed with error code %d", err);
233 up_read(&ubi->work_sem);
239 * in_wl_tree - check if wear-leveling entry is present in a WL RB-tree.
240 * @e: the wear-leveling entry to check
241 * @root: the root of the tree
243 * This function returns non-zero if @e is in the @root RB-tree and zero if it
246 static int in_wl_tree(struct ubi_wl_entry *e, struct rb_root *root)
252 struct ubi_wl_entry *e1;
254 e1 = rb_entry(p, struct ubi_wl_entry, u.rb);
256 if (e->pnum == e1->pnum) {
263 else if (e->ec > e1->ec)
266 ubi_assert(e->pnum != e1->pnum);
267 if (e->pnum < e1->pnum)
278 * prot_queue_add - add physical eraseblock to the protection queue.
279 * @ubi: UBI device description object
280 * @e: the physical eraseblock to add
282 * This function adds @e to the tail of the protection queue @ubi->pq, where
283 * @e will stay for %UBI_PROT_QUEUE_LEN erase operations and will be
284 * temporarily protected from the wear-leveling worker. Note, @wl->lock has to
287 static void prot_queue_add(struct ubi_device *ubi, struct ubi_wl_entry *e)
289 int pq_tail = ubi->pq_head - 1;
292 pq_tail = UBI_PROT_QUEUE_LEN - 1;
293 ubi_assert(pq_tail >= 0 && pq_tail < UBI_PROT_QUEUE_LEN);
294 list_add_tail(&e->u.list, &ubi->pq[pq_tail]);
295 dbg_wl("added PEB %d EC %d to the protection queue", e->pnum, e->ec);
299 * find_wl_entry - find wear-leveling entry closest to certain erase counter.
300 * @ubi: UBI device description object
301 * @root: the RB-tree where to look for
302 * @diff: maximum possible difference from the smallest erase counter
304 * This function looks for a wear leveling entry with erase counter closest to
305 * min + @diff, where min is the smallest erase counter.
307 static struct ubi_wl_entry *find_wl_entry(struct ubi_device *ubi,
308 struct rb_root *root, int diff)
311 struct ubi_wl_entry *e, *prev_e = NULL;
314 e = rb_entry(rb_first(root), struct ubi_wl_entry, u.rb);
319 struct ubi_wl_entry *e1;
321 e1 = rb_entry(p, struct ubi_wl_entry, u.rb);
331 /* If no fastmap has been written and this WL entry can be used
332 * as anchor PEB, hold it back and return the second best WL entry
333 * such that fastmap can use the anchor PEB later. */
334 if (prev_e && !ubi->fm_disabled &&
335 !ubi->fm && e->pnum < UBI_FM_MAX_START)
342 * find_mean_wl_entry - find wear-leveling entry with medium erase counter.
343 * @ubi: UBI device description object
344 * @root: the RB-tree where to look for
346 * This function looks for a wear leveling entry with medium erase counter,
347 * but not greater or equivalent than the lowest erase counter plus
348 * %WL_FREE_MAX_DIFF/2.
350 static struct ubi_wl_entry *find_mean_wl_entry(struct ubi_device *ubi,
351 struct rb_root *root)
353 struct ubi_wl_entry *e, *first, *last;
355 first = rb_entry(rb_first(root), struct ubi_wl_entry, u.rb);
356 last = rb_entry(rb_last(root), struct ubi_wl_entry, u.rb);
358 if (last->ec - first->ec < WL_FREE_MAX_DIFF) {
359 e = rb_entry(root->rb_node, struct ubi_wl_entry, u.rb);
361 /* If no fastmap has been written and this WL entry can be used
362 * as anchor PEB, hold it back and return the second best
363 * WL entry such that fastmap can use the anchor PEB later. */
364 e = may_reserve_for_fm(ubi, e, root);
366 e = find_wl_entry(ubi, root, WL_FREE_MAX_DIFF/2);
372 * wl_get_wle - get a mean wl entry to be used by ubi_wl_get_peb() or
373 * refill_wl_user_pool().
374 * @ubi: UBI device description object
376 * This function returns a a wear leveling entry in case of success and
377 * NULL in case of failure.
379 static struct ubi_wl_entry *wl_get_wle(struct ubi_device *ubi)
381 struct ubi_wl_entry *e;
383 e = find_mean_wl_entry(ubi, &ubi->free);
385 ubi_err(ubi, "no free eraseblocks");
389 self_check_in_wl_tree(ubi, e, &ubi->free);
392 * Move the physical eraseblock to the protection queue where it will
393 * be protected from being moved for some time.
395 rb_erase(&e->u.rb, &ubi->free);
397 dbg_wl("PEB %d EC %d", e->pnum, e->ec);
403 * prot_queue_del - remove a physical eraseblock from the protection queue.
404 * @ubi: UBI device description object
405 * @pnum: the physical eraseblock to remove
407 * This function deletes PEB @pnum from the protection queue and returns zero
408 * in case of success and %-ENODEV if the PEB was not found.
410 static int prot_queue_del(struct ubi_device *ubi, int pnum)
412 struct ubi_wl_entry *e;
414 e = ubi->lookuptbl[pnum];
418 if (self_check_in_pq(ubi, e))
421 list_del(&e->u.list);
422 dbg_wl("deleted PEB %d from the protection queue", e->pnum);
427 * sync_erase - synchronously erase a physical eraseblock.
428 * @ubi: UBI device description object
429 * @e: the the physical eraseblock to erase
430 * @torture: if the physical eraseblock has to be tortured
432 * This function returns zero in case of success and a negative error code in
435 static int sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
439 struct ubi_ec_hdr *ec_hdr;
440 unsigned long long ec = e->ec;
442 dbg_wl("erase PEB %d, old EC %llu", e->pnum, ec);
444 err = self_check_ec(ubi, e->pnum, e->ec);
448 ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
452 err = ubi_io_sync_erase(ubi, e->pnum, torture);
457 if (ec > UBI_MAX_ERASECOUNTER) {
459 * Erase counter overflow. Upgrade UBI and use 64-bit
460 * erase counters internally.
462 ubi_err(ubi, "erase counter overflow at PEB %d, EC %llu",
468 dbg_wl("erased PEB %d, new EC %llu", e->pnum, ec);
470 ec_hdr->ec = cpu_to_be64(ec);
472 err = ubi_io_write_ec_hdr(ubi, e->pnum, ec_hdr);
477 spin_lock(&ubi->wl_lock);
478 if (e->ec > ubi->max_ec)
480 spin_unlock(&ubi->wl_lock);
488 * serve_prot_queue - check if it is time to stop protecting PEBs.
489 * @ubi: UBI device description object
491 * This function is called after each erase operation and removes PEBs from the
492 * tail of the protection queue. These PEBs have been protected for long enough
493 * and should be moved to the used tree.
495 static void serve_prot_queue(struct ubi_device *ubi)
497 struct ubi_wl_entry *e, *tmp;
501 * There may be several protected physical eraseblock to remove,
506 spin_lock(&ubi->wl_lock);
507 list_for_each_entry_safe(e, tmp, &ubi->pq[ubi->pq_head], u.list) {
508 dbg_wl("PEB %d EC %d protection over, move to used tree",
511 list_del(&e->u.list);
512 wl_tree_add(e, &ubi->used);
515 * Let's be nice and avoid holding the spinlock for
518 spin_unlock(&ubi->wl_lock);
525 if (ubi->pq_head == UBI_PROT_QUEUE_LEN)
527 ubi_assert(ubi->pq_head >= 0 && ubi->pq_head < UBI_PROT_QUEUE_LEN);
528 spin_unlock(&ubi->wl_lock);
532 * __schedule_ubi_work - schedule a work.
533 * @ubi: UBI device description object
534 * @wrk: the work to schedule
536 * This function adds a work defined by @wrk to the tail of the pending works
537 * list. Can only be used if ubi->work_sem is already held in read mode!
539 static void __schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
541 spin_lock(&ubi->wl_lock);
542 list_add_tail(&wrk->list, &ubi->works);
543 ubi_assert(ubi->works_count >= 0);
544 ubi->works_count += 1;
546 if (ubi->thread_enabled && !ubi_dbg_is_bgt_disabled(ubi))
547 wake_up_process(ubi->bgt_thread);
551 * U-Boot special: We have no bgt_thread in U-Boot!
552 * So just call do_work() here directly.
556 ubi_err(ubi, "%s: work failed with error code %d",
560 spin_unlock(&ubi->wl_lock);
564 * schedule_ubi_work - schedule a work.
565 * @ubi: UBI device description object
566 * @wrk: the work to schedule
568 * This function adds a work defined by @wrk to the tail of the pending works
571 static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
573 down_read(&ubi->work_sem);
574 __schedule_ubi_work(ubi, wrk);
575 up_read(&ubi->work_sem);
578 static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
582 * schedule_erase - schedule an erase work.
583 * @ubi: UBI device description object
584 * @e: the WL entry of the physical eraseblock to erase
585 * @vol_id: the volume ID that last used this PEB
586 * @lnum: the last used logical eraseblock number for the PEB
587 * @torture: if the physical eraseblock has to be tortured
589 * This function returns zero in case of success and a %-ENOMEM in case of
592 static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
593 int vol_id, int lnum, int torture)
595 struct ubi_work *wl_wrk;
599 dbg_wl("schedule erasure of PEB %d, EC %d, torture %d",
600 e->pnum, e->ec, torture);
602 wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
606 wl_wrk->func = &erase_worker;
608 wl_wrk->vol_id = vol_id;
610 wl_wrk->torture = torture;
612 schedule_ubi_work(ubi, wl_wrk);
617 * do_sync_erase - run the erase worker synchronously.
618 * @ubi: UBI device description object
619 * @e: the WL entry of the physical eraseblock to erase
620 * @vol_id: the volume ID that last used this PEB
621 * @lnum: the last used logical eraseblock number for the PEB
622 * @torture: if the physical eraseblock has to be tortured
625 static int do_sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
626 int vol_id, int lnum, int torture)
628 struct ubi_work *wl_wrk;
630 dbg_wl("sync erase of PEB %i", e->pnum);
632 wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
637 wl_wrk->vol_id = vol_id;
639 wl_wrk->torture = torture;
641 return erase_worker(ubi, wl_wrk, 0);
645 * wear_leveling_worker - wear-leveling worker function.
646 * @ubi: UBI device description object
647 * @wrk: the work object
648 * @shutdown: non-zero if the worker has to free memory and exit
649 * because the WL-subsystem is shutting down
651 * This function copies a more worn out physical eraseblock to a less worn out
652 * one. Returns zero in case of success and a negative error code in case of
655 static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
658 int err, scrubbing = 0, torture = 0, protect = 0, erroneous = 0;
659 int vol_id = -1, lnum = -1;
660 #ifdef CONFIG_MTD_UBI_FASTMAP
661 int anchor = wrk->anchor;
663 struct ubi_wl_entry *e1, *e2;
664 struct ubi_vid_hdr *vid_hdr;
670 vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
674 mutex_lock(&ubi->move_mutex);
675 spin_lock(&ubi->wl_lock);
676 ubi_assert(!ubi->move_from && !ubi->move_to);
677 ubi_assert(!ubi->move_to_put);
679 if (!ubi->free.rb_node ||
680 (!ubi->used.rb_node && !ubi->scrub.rb_node)) {
682 * No free physical eraseblocks? Well, they must be waiting in
683 * the queue to be erased. Cancel movement - it will be
684 * triggered again when a free physical eraseblock appears.
686 * No used physical eraseblocks? They must be temporarily
687 * protected from being moved. They will be moved to the
688 * @ubi->used tree later and the wear-leveling will be
691 dbg_wl("cancel WL, a list is empty: free %d, used %d",
692 !ubi->free.rb_node, !ubi->used.rb_node);
696 #ifdef CONFIG_MTD_UBI_FASTMAP
697 /* Check whether we need to produce an anchor PEB */
699 anchor = !anchor_pebs_avalible(&ubi->free);
702 e1 = find_anchor_wl_entry(&ubi->used);
705 e2 = get_peb_for_wl(ubi);
709 self_check_in_wl_tree(ubi, e1, &ubi->used);
710 rb_erase(&e1->u.rb, &ubi->used);
711 dbg_wl("anchor-move PEB %d to PEB %d", e1->pnum, e2->pnum);
712 } else if (!ubi->scrub.rb_node) {
714 if (!ubi->scrub.rb_node) {
717 * Now pick the least worn-out used physical eraseblock and a
718 * highly worn-out free physical eraseblock. If the erase
719 * counters differ much enough, start wear-leveling.
721 e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
722 e2 = get_peb_for_wl(ubi);
726 if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD)) {
727 dbg_wl("no WL needed: min used EC %d, max free EC %d",
730 /* Give the unused PEB back */
731 wl_tree_add(e2, &ubi->free);
735 self_check_in_wl_tree(ubi, e1, &ubi->used);
736 rb_erase(&e1->u.rb, &ubi->used);
737 dbg_wl("move PEB %d EC %d to PEB %d EC %d",
738 e1->pnum, e1->ec, e2->pnum, e2->ec);
740 /* Perform scrubbing */
742 e1 = rb_entry(rb_first(&ubi->scrub), struct ubi_wl_entry, u.rb);
743 e2 = get_peb_for_wl(ubi);
747 self_check_in_wl_tree(ubi, e1, &ubi->scrub);
748 rb_erase(&e1->u.rb, &ubi->scrub);
749 dbg_wl("scrub PEB %d to PEB %d", e1->pnum, e2->pnum);
754 spin_unlock(&ubi->wl_lock);
757 * Now we are going to copy physical eraseblock @e1->pnum to @e2->pnum.
758 * We so far do not know which logical eraseblock our physical
759 * eraseblock (@e1) belongs to. We have to read the volume identifier
762 * Note, we are protected from this PEB being unmapped and erased. The
763 * 'ubi_wl_put_peb()' would wait for moving to be finished if the PEB
764 * which is being moved was unmapped.
767 err = ubi_io_read_vid_hdr(ubi, e1->pnum, vid_hdr, 0);
768 if (err && err != UBI_IO_BITFLIPS) {
769 if (err == UBI_IO_FF) {
771 * We are trying to move PEB without a VID header. UBI
772 * always write VID headers shortly after the PEB was
773 * given, so we have a situation when it has not yet
774 * had a chance to write it, because it was preempted.
775 * So add this PEB to the protection queue so far,
776 * because presumably more data will be written there
777 * (including the missing VID header), and then we'll
780 dbg_wl("PEB %d has no VID header", e1->pnum);
783 } else if (err == UBI_IO_FF_BITFLIPS) {
785 * The same situation as %UBI_IO_FF, but bit-flips were
786 * detected. It is better to schedule this PEB for
789 dbg_wl("PEB %d has no VID header but has bit-flips",
795 ubi_err(ubi, "error %d while reading VID header from PEB %d",
800 vol_id = be32_to_cpu(vid_hdr->vol_id);
801 lnum = be32_to_cpu(vid_hdr->lnum);
803 err = ubi_eba_copy_leb(ubi, e1->pnum, e2->pnum, vid_hdr);
805 if (err == MOVE_CANCEL_RACE) {
807 * The LEB has not been moved because the volume is
808 * being deleted or the PEB has been put meanwhile. We
809 * should prevent this PEB from being selected for
810 * wear-leveling movement again, so put it to the
816 if (err == MOVE_RETRY) {
820 if (err == MOVE_TARGET_BITFLIPS || err == MOVE_TARGET_WR_ERR ||
821 err == MOVE_TARGET_RD_ERR) {
823 * Target PEB had bit-flips or write error - torture it.
829 if (err == MOVE_SOURCE_RD_ERR) {
831 * An error happened while reading the source PEB. Do
832 * not switch to R/O mode in this case, and give the
833 * upper layers a possibility to recover from this,
834 * e.g. by unmapping corresponding LEB. Instead, just
835 * put this PEB to the @ubi->erroneous list to prevent
836 * UBI from trying to move it over and over again.
838 if (ubi->erroneous_peb_count > ubi->max_erroneous) {
839 ubi_err(ubi, "too many erroneous eraseblocks (%d)",
840 ubi->erroneous_peb_count);
853 /* The PEB has been successfully moved */
855 ubi_msg(ubi, "scrubbed PEB %d (LEB %d:%d), data moved to PEB %d",
856 e1->pnum, vol_id, lnum, e2->pnum);
857 ubi_free_vid_hdr(ubi, vid_hdr);
859 spin_lock(&ubi->wl_lock);
860 if (!ubi->move_to_put) {
861 wl_tree_add(e2, &ubi->used);
864 ubi->move_from = ubi->move_to = NULL;
865 ubi->move_to_put = ubi->wl_scheduled = 0;
866 spin_unlock(&ubi->wl_lock);
868 err = do_sync_erase(ubi, e1, vol_id, lnum, 0);
871 wl_entry_destroy(ubi, e2);
877 * Well, the target PEB was put meanwhile, schedule it for
880 dbg_wl("PEB %d (LEB %d:%d) was put meanwhile, erase",
881 e2->pnum, vol_id, lnum);
882 err = do_sync_erase(ubi, e2, vol_id, lnum, 0);
888 mutex_unlock(&ubi->move_mutex);
892 * For some reasons the LEB was not moved, might be an error, might be
893 * something else. @e1 was not changed, so return it back. @e2 might
894 * have been changed, schedule it for erasure.
898 dbg_wl("cancel moving PEB %d (LEB %d:%d) to PEB %d (%d)",
899 e1->pnum, vol_id, lnum, e2->pnum, err);
901 dbg_wl("cancel moving PEB %d to PEB %d (%d)",
902 e1->pnum, e2->pnum, err);
903 spin_lock(&ubi->wl_lock);
905 prot_queue_add(ubi, e1);
906 else if (erroneous) {
907 wl_tree_add(e1, &ubi->erroneous);
908 ubi->erroneous_peb_count += 1;
909 } else if (scrubbing)
910 wl_tree_add(e1, &ubi->scrub);
912 wl_tree_add(e1, &ubi->used);
913 ubi_assert(!ubi->move_to_put);
914 ubi->move_from = ubi->move_to = NULL;
915 ubi->wl_scheduled = 0;
916 spin_unlock(&ubi->wl_lock);
918 ubi_free_vid_hdr(ubi, vid_hdr);
919 err = do_sync_erase(ubi, e2, vol_id, lnum, torture);
923 mutex_unlock(&ubi->move_mutex);
928 ubi_err(ubi, "error %d while moving PEB %d to PEB %d",
929 err, e1->pnum, e2->pnum);
931 ubi_err(ubi, "error %d while moving PEB %d (LEB %d:%d) to PEB %d",
932 err, e1->pnum, vol_id, lnum, e2->pnum);
933 spin_lock(&ubi->wl_lock);
934 ubi->move_from = ubi->move_to = NULL;
935 ubi->move_to_put = ubi->wl_scheduled = 0;
936 spin_unlock(&ubi->wl_lock);
938 ubi_free_vid_hdr(ubi, vid_hdr);
939 wl_entry_destroy(ubi, e1);
940 wl_entry_destroy(ubi, e2);
944 mutex_unlock(&ubi->move_mutex);
945 ubi_assert(err != 0);
946 return err < 0 ? err : -EIO;
949 ubi->wl_scheduled = 0;
950 spin_unlock(&ubi->wl_lock);
951 mutex_unlock(&ubi->move_mutex);
952 ubi_free_vid_hdr(ubi, vid_hdr);
957 * ensure_wear_leveling - schedule wear-leveling if it is needed.
958 * @ubi: UBI device description object
959 * @nested: set to non-zero if this function is called from UBI worker
961 * This function checks if it is time to start wear-leveling and schedules it
962 * if yes. This function returns zero in case of success and a negative error
963 * code in case of failure.
965 static int ensure_wear_leveling(struct ubi_device *ubi, int nested)
968 struct ubi_wl_entry *e1;
969 struct ubi_wl_entry *e2;
970 struct ubi_work *wrk;
972 spin_lock(&ubi->wl_lock);
973 if (ubi->wl_scheduled)
974 /* Wear-leveling is already in the work queue */
978 * If the ubi->scrub tree is not empty, scrubbing is needed, and the
979 * the WL worker has to be scheduled anyway.
981 if (!ubi->scrub.rb_node) {
982 if (!ubi->used.rb_node || !ubi->free.rb_node)
983 /* No physical eraseblocks - no deal */
987 * We schedule wear-leveling only if the difference between the
988 * lowest erase counter of used physical eraseblocks and a high
989 * erase counter of free physical eraseblocks is greater than
992 e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
993 e2 = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
995 if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD))
997 dbg_wl("schedule wear-leveling");
999 dbg_wl("schedule scrubbing");
1001 ubi->wl_scheduled = 1;
1002 spin_unlock(&ubi->wl_lock);
1004 wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
1011 wrk->func = &wear_leveling_worker;
1013 __schedule_ubi_work(ubi, wrk);
1015 schedule_ubi_work(ubi, wrk);
1019 spin_lock(&ubi->wl_lock);
1020 ubi->wl_scheduled = 0;
1022 spin_unlock(&ubi->wl_lock);
1027 * erase_worker - physical eraseblock erase worker function.
1028 * @ubi: UBI device description object
1029 * @wl_wrk: the work object
1030 * @shutdown: non-zero if the worker has to free memory and exit
1031 * because the WL sub-system is shutting down
1033 * This function erases a physical eraseblock and perform torture testing if
1034 * needed. It also takes care about marking the physical eraseblock bad if
1035 * needed. Returns zero in case of success and a negative error code in case of
1038 static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
1041 struct ubi_wl_entry *e = wl_wrk->e;
1043 int vol_id = wl_wrk->vol_id;
1044 int lnum = wl_wrk->lnum;
1045 int err, available_consumed = 0;
1048 dbg_wl("cancel erasure of PEB %d EC %d", pnum, e->ec);
1050 wl_entry_destroy(ubi, e);
1054 dbg_wl("erase PEB %d EC %d LEB %d:%d",
1055 pnum, e->ec, wl_wrk->vol_id, wl_wrk->lnum);
1057 err = sync_erase(ubi, e, wl_wrk->torture);
1059 /* Fine, we've erased it successfully */
1062 spin_lock(&ubi->wl_lock);
1063 wl_tree_add(e, &ubi->free);
1065 spin_unlock(&ubi->wl_lock);
1068 * One more erase operation has happened, take care about
1069 * protected physical eraseblocks.
1071 serve_prot_queue(ubi);
1073 /* And take care about wear-leveling */
1074 err = ensure_wear_leveling(ubi, 1);
1078 ubi_err(ubi, "failed to erase PEB %d, error %d", pnum, err);
1081 if (err == -EINTR || err == -ENOMEM || err == -EAGAIN ||
1085 /* Re-schedule the LEB for erasure */
1086 err1 = schedule_erase(ubi, e, vol_id, lnum, 0);
1094 wl_entry_destroy(ubi, e);
1097 * If this is not %-EIO, we have no idea what to do. Scheduling
1098 * this physical eraseblock for erasure again would cause
1099 * errors again and again. Well, lets switch to R/O mode.
1103 /* It is %-EIO, the PEB went bad */
1105 if (!ubi->bad_allowed) {
1106 ubi_err(ubi, "bad physical eraseblock %d detected", pnum);
1110 spin_lock(&ubi->volumes_lock);
1111 if (ubi->beb_rsvd_pebs == 0) {
1112 if (ubi->avail_pebs == 0) {
1113 spin_unlock(&ubi->volumes_lock);
1114 ubi_err(ubi, "no reserved/available physical eraseblocks");
1117 ubi->avail_pebs -= 1;
1118 available_consumed = 1;
1120 spin_unlock(&ubi->volumes_lock);
1122 ubi_msg(ubi, "mark PEB %d as bad", pnum);
1123 err = ubi_io_mark_bad(ubi, pnum);
1127 spin_lock(&ubi->volumes_lock);
1128 if (ubi->beb_rsvd_pebs > 0) {
1129 if (available_consumed) {
1131 * The amount of reserved PEBs increased since we last
1134 ubi->avail_pebs += 1;
1135 available_consumed = 0;
1137 ubi->beb_rsvd_pebs -= 1;
1139 ubi->bad_peb_count += 1;
1140 ubi->good_peb_count -= 1;
1141 ubi_calculate_reserved(ubi);
1142 if (available_consumed)
1143 ubi_warn(ubi, "no PEBs in the reserved pool, used an available PEB");
1144 else if (ubi->beb_rsvd_pebs)
1145 ubi_msg(ubi, "%d PEBs left in the reserve",
1146 ubi->beb_rsvd_pebs);
1148 ubi_warn(ubi, "last PEB from the reserve was used");
1149 spin_unlock(&ubi->volumes_lock);
1154 if (available_consumed) {
1155 spin_lock(&ubi->volumes_lock);
1156 ubi->avail_pebs += 1;
1157 spin_unlock(&ubi->volumes_lock);
1164 * ubi_wl_put_peb - return a PEB to the wear-leveling sub-system.
1165 * @ubi: UBI device description object
1166 * @vol_id: the volume ID that last used this PEB
1167 * @lnum: the last used logical eraseblock number for the PEB
1168 * @pnum: physical eraseblock to return
1169 * @torture: if this physical eraseblock has to be tortured
1171 * This function is called to return physical eraseblock @pnum to the pool of
1172 * free physical eraseblocks. The @torture flag has to be set if an I/O error
1173 * occurred to this @pnum and it has to be tested. This function returns zero
1174 * in case of success, and a negative error code in case of failure.
1176 int ubi_wl_put_peb(struct ubi_device *ubi, int vol_id, int lnum,
1177 int pnum, int torture)
1180 struct ubi_wl_entry *e;
1182 dbg_wl("PEB %d", pnum);
1183 ubi_assert(pnum >= 0);
1184 ubi_assert(pnum < ubi->peb_count);
1186 down_read(&ubi->fm_protect);
1189 spin_lock(&ubi->wl_lock);
1190 e = ubi->lookuptbl[pnum];
1191 if (e == ubi->move_from) {
1193 * User is putting the physical eraseblock which was selected to
1194 * be moved. It will be scheduled for erasure in the
1195 * wear-leveling worker.
1197 dbg_wl("PEB %d is being moved, wait", pnum);
1198 spin_unlock(&ubi->wl_lock);
1200 /* Wait for the WL worker by taking the @ubi->move_mutex */
1201 mutex_lock(&ubi->move_mutex);
1202 mutex_unlock(&ubi->move_mutex);
1204 } else if (e == ubi->move_to) {
1206 * User is putting the physical eraseblock which was selected
1207 * as the target the data is moved to. It may happen if the EBA
1208 * sub-system already re-mapped the LEB in 'ubi_eba_copy_leb()'
1209 * but the WL sub-system has not put the PEB to the "used" tree
1210 * yet, but it is about to do this. So we just set a flag which
1211 * will tell the WL worker that the PEB is not needed anymore
1212 * and should be scheduled for erasure.
1214 dbg_wl("PEB %d is the target of data moving", pnum);
1215 ubi_assert(!ubi->move_to_put);
1216 ubi->move_to_put = 1;
1217 spin_unlock(&ubi->wl_lock);
1218 up_read(&ubi->fm_protect);
1221 if (in_wl_tree(e, &ubi->used)) {
1222 self_check_in_wl_tree(ubi, e, &ubi->used);
1223 rb_erase(&e->u.rb, &ubi->used);
1224 } else if (in_wl_tree(e, &ubi->scrub)) {
1225 self_check_in_wl_tree(ubi, e, &ubi->scrub);
1226 rb_erase(&e->u.rb, &ubi->scrub);
1227 } else if (in_wl_tree(e, &ubi->erroneous)) {
1228 self_check_in_wl_tree(ubi, e, &ubi->erroneous);
1229 rb_erase(&e->u.rb, &ubi->erroneous);
1230 ubi->erroneous_peb_count -= 1;
1231 ubi_assert(ubi->erroneous_peb_count >= 0);
1232 /* Erroneous PEBs should be tortured */
1235 err = prot_queue_del(ubi, e->pnum);
1237 ubi_err(ubi, "PEB %d not found", pnum);
1239 spin_unlock(&ubi->wl_lock);
1240 up_read(&ubi->fm_protect);
1245 spin_unlock(&ubi->wl_lock);
1247 err = schedule_erase(ubi, e, vol_id, lnum, torture);
1249 spin_lock(&ubi->wl_lock);
1250 wl_tree_add(e, &ubi->used);
1251 spin_unlock(&ubi->wl_lock);
1254 up_read(&ubi->fm_protect);
1259 * ubi_wl_scrub_peb - schedule a physical eraseblock for scrubbing.
1260 * @ubi: UBI device description object
1261 * @pnum: the physical eraseblock to schedule
1263 * If a bit-flip in a physical eraseblock is detected, this physical eraseblock
1264 * needs scrubbing. This function schedules a physical eraseblock for
1265 * scrubbing which is done in background. This function returns zero in case of
1266 * success and a negative error code in case of failure.
1268 int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum)
1270 struct ubi_wl_entry *e;
1272 ubi_msg(ubi, "schedule PEB %d for scrubbing", pnum);
1275 spin_lock(&ubi->wl_lock);
1276 e = ubi->lookuptbl[pnum];
1277 if (e == ubi->move_from || in_wl_tree(e, &ubi->scrub) ||
1278 in_wl_tree(e, &ubi->erroneous)) {
1279 spin_unlock(&ubi->wl_lock);
1283 if (e == ubi->move_to) {
1285 * This physical eraseblock was used to move data to. The data
1286 * was moved but the PEB was not yet inserted to the proper
1287 * tree. We should just wait a little and let the WL worker
1290 spin_unlock(&ubi->wl_lock);
1291 dbg_wl("the PEB %d is not in proper tree, retry", pnum);
1296 if (in_wl_tree(e, &ubi->used)) {
1297 self_check_in_wl_tree(ubi, e, &ubi->used);
1298 rb_erase(&e->u.rb, &ubi->used);
1302 err = prot_queue_del(ubi, e->pnum);
1304 ubi_err(ubi, "PEB %d not found", pnum);
1306 spin_unlock(&ubi->wl_lock);
1311 wl_tree_add(e, &ubi->scrub);
1312 spin_unlock(&ubi->wl_lock);
1315 * Technically scrubbing is the same as wear-leveling, so it is done
1318 return ensure_wear_leveling(ubi, 0);
1322 * ubi_wl_flush - flush all pending works.
1323 * @ubi: UBI device description object
1324 * @vol_id: the volume id to flush for
1325 * @lnum: the logical eraseblock number to flush for
1327 * This function executes all pending works for a particular volume id /
1328 * logical eraseblock number pair. If either value is set to %UBI_ALL, then it
1329 * acts as a wildcard for all of the corresponding volume numbers or logical
1330 * eraseblock numbers. It returns zero in case of success and a negative error
1331 * code in case of failure.
1333 int ubi_wl_flush(struct ubi_device *ubi, int vol_id, int lnum)
1339 * Erase while the pending works queue is not empty, but not more than
1340 * the number of currently pending works.
1342 dbg_wl("flush pending work for LEB %d:%d (%d pending works)",
1343 vol_id, lnum, ubi->works_count);
1346 struct ubi_work *wrk, *tmp;
1349 down_read(&ubi->work_sem);
1350 spin_lock(&ubi->wl_lock);
1351 list_for_each_entry_safe(wrk, tmp, &ubi->works, list) {
1352 if ((vol_id == UBI_ALL || wrk->vol_id == vol_id) &&
1353 (lnum == UBI_ALL || wrk->lnum == lnum)) {
1354 list_del(&wrk->list);
1355 ubi->works_count -= 1;
1356 ubi_assert(ubi->works_count >= 0);
1357 spin_unlock(&ubi->wl_lock);
1359 err = wrk->func(ubi, wrk, 0);
1361 up_read(&ubi->work_sem);
1365 spin_lock(&ubi->wl_lock);
1370 spin_unlock(&ubi->wl_lock);
1371 up_read(&ubi->work_sem);
1375 * Make sure all the works which have been done in parallel are
1378 down_write(&ubi->work_sem);
1379 up_write(&ubi->work_sem);
1385 * tree_destroy - destroy an RB-tree.
1386 * @ubi: UBI device description object
1387 * @root: the root of the tree to destroy
1389 static void tree_destroy(struct ubi_device *ubi, struct rb_root *root)
1392 struct ubi_wl_entry *e;
1398 else if (rb->rb_right)
1401 e = rb_entry(rb, struct ubi_wl_entry, u.rb);
1405 if (rb->rb_left == &e->u.rb)
1408 rb->rb_right = NULL;
1411 wl_entry_destroy(ubi, e);
1417 * ubi_thread - UBI background thread.
1418 * @u: the UBI device description object pointer
1420 int ubi_thread(void *u)
1423 struct ubi_device *ubi = u;
1425 ubi_msg(ubi, "background thread \"%s\" started, PID %d",
1426 ubi->bgt_name, task_pid_nr(current));
1432 if (kthread_should_stop())
1435 if (try_to_freeze())
1438 spin_lock(&ubi->wl_lock);
1439 if (list_empty(&ubi->works) || ubi->ro_mode ||
1440 !ubi->thread_enabled || ubi_dbg_is_bgt_disabled(ubi)) {
1441 set_current_state(TASK_INTERRUPTIBLE);
1442 spin_unlock(&ubi->wl_lock);
1446 spin_unlock(&ubi->wl_lock);
1450 ubi_err(ubi, "%s: work failed with error code %d",
1451 ubi->bgt_name, err);
1452 if (failures++ > WL_MAX_FAILURES) {
1454 * Too many failures, disable the thread and
1455 * switch to read-only mode.
1457 ubi_msg(ubi, "%s: %d consecutive failures",
1458 ubi->bgt_name, WL_MAX_FAILURES);
1460 ubi->thread_enabled = 0;
1469 dbg_wl("background thread \"%s\" is killed", ubi->bgt_name);
1474 * shutdown_work - shutdown all pending works.
1475 * @ubi: UBI device description object
1477 static void shutdown_work(struct ubi_device *ubi)
1479 #ifdef CONFIG_MTD_UBI_FASTMAP
1481 flush_work(&ubi->fm_work);
1483 /* in U-Boot, we have all work done */
1486 while (!list_empty(&ubi->works)) {
1487 struct ubi_work *wrk;
1489 wrk = list_entry(ubi->works.next, struct ubi_work, list);
1490 list_del(&wrk->list);
1491 wrk->func(ubi, wrk, 1);
1492 ubi->works_count -= 1;
1493 ubi_assert(ubi->works_count >= 0);
1498 * ubi_wl_init - initialize the WL sub-system using attaching information.
1499 * @ubi: UBI device description object
1500 * @ai: attaching information
1502 * This function returns zero in case of success, and a negative error code in
1505 int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
1507 int err, i, reserved_pebs, found_pebs = 0;
1508 struct rb_node *rb1, *rb2;
1509 struct ubi_ainf_volume *av;
1510 struct ubi_ainf_peb *aeb, *tmp;
1511 struct ubi_wl_entry *e;
1513 ubi->used = ubi->erroneous = ubi->free = ubi->scrub = RB_ROOT;
1514 spin_lock_init(&ubi->wl_lock);
1515 mutex_init(&ubi->move_mutex);
1516 init_rwsem(&ubi->work_sem);
1517 ubi->max_ec = ai->max_ec;
1518 INIT_LIST_HEAD(&ubi->works);
1520 sprintf(ubi->bgt_name, UBI_BGT_NAME_PATTERN, ubi->ubi_num);
1523 ubi->lookuptbl = kzalloc(ubi->peb_count * sizeof(void *), GFP_KERNEL);
1524 if (!ubi->lookuptbl)
1527 for (i = 0; i < UBI_PROT_QUEUE_LEN; i++)
1528 INIT_LIST_HEAD(&ubi->pq[i]);
1531 list_for_each_entry_safe(aeb, tmp, &ai->erase, u.list) {
1534 e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
1538 e->pnum = aeb->pnum;
1540 ubi->lookuptbl[e->pnum] = e;
1541 if (schedule_erase(ubi, e, aeb->vol_id, aeb->lnum, 0)) {
1542 wl_entry_destroy(ubi, e);
1549 ubi->free_count = 0;
1550 list_for_each_entry(aeb, &ai->free, u.list) {
1553 e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
1557 e->pnum = aeb->pnum;
1559 ubi_assert(e->ec >= 0);
1561 wl_tree_add(e, &ubi->free);
1564 ubi->lookuptbl[e->pnum] = e;
1569 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
1570 ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) {
1573 e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
1577 e->pnum = aeb->pnum;
1579 ubi->lookuptbl[e->pnum] = e;
1582 dbg_wl("add PEB %d EC %d to the used tree",
1584 wl_tree_add(e, &ubi->used);
1586 dbg_wl("add PEB %d EC %d to the scrub tree",
1588 wl_tree_add(e, &ubi->scrub);
1595 dbg_wl("found %i PEBs", found_pebs);
1598 ubi_assert(ubi->good_peb_count ==
1599 found_pebs + ubi->fm->used_blocks);
1601 for (i = 0; i < ubi->fm->used_blocks; i++) {
1603 ubi->lookuptbl[e->pnum] = e;
1607 ubi_assert(ubi->good_peb_count == found_pebs);
1609 reserved_pebs = WL_RESERVED_PEBS;
1610 ubi_fastmap_init(ubi, &reserved_pebs);
1612 if (ubi->avail_pebs < reserved_pebs) {
1613 ubi_err(ubi, "no enough physical eraseblocks (%d, need %d)",
1614 ubi->avail_pebs, reserved_pebs);
1615 if (ubi->corr_peb_count)
1616 ubi_err(ubi, "%d PEBs are corrupted and not used",
1617 ubi->corr_peb_count);
1620 ubi->avail_pebs -= reserved_pebs;
1621 ubi->rsvd_pebs += reserved_pebs;
1623 /* Schedule wear-leveling if needed */
1624 err = ensure_wear_leveling(ubi, 0);
1632 tree_destroy(ubi, &ubi->used);
1633 tree_destroy(ubi, &ubi->free);
1634 tree_destroy(ubi, &ubi->scrub);
1635 kfree(ubi->lookuptbl);
1640 * protection_queue_destroy - destroy the protection queue.
1641 * @ubi: UBI device description object
1643 static void protection_queue_destroy(struct ubi_device *ubi)
1646 struct ubi_wl_entry *e, *tmp;
1648 for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i) {
1649 list_for_each_entry_safe(e, tmp, &ubi->pq[i], u.list) {
1650 list_del(&e->u.list);
1651 wl_entry_destroy(ubi, e);
1657 * ubi_wl_close - close the wear-leveling sub-system.
1658 * @ubi: UBI device description object
1660 void ubi_wl_close(struct ubi_device *ubi)
1662 dbg_wl("close the WL sub-system");
1663 ubi_fastmap_close(ubi);
1665 protection_queue_destroy(ubi);
1666 tree_destroy(ubi, &ubi->used);
1667 tree_destroy(ubi, &ubi->erroneous);
1668 tree_destroy(ubi, &ubi->free);
1669 tree_destroy(ubi, &ubi->scrub);
1670 kfree(ubi->lookuptbl);
1674 * self_check_ec - make sure that the erase counter of a PEB is correct.
1675 * @ubi: UBI device description object
1676 * @pnum: the physical eraseblock number to check
1677 * @ec: the erase counter to check
1679 * This function returns zero if the erase counter of physical eraseblock @pnum
1680 * is equivalent to @ec, and a negative error code if not or if an error
1683 static int self_check_ec(struct ubi_device *ubi, int pnum, int ec)
1687 struct ubi_ec_hdr *ec_hdr;
1689 if (!ubi_dbg_chk_gen(ubi))
1692 ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
1696 err = ubi_io_read_ec_hdr(ubi, pnum, ec_hdr, 0);
1697 if (err && err != UBI_IO_BITFLIPS) {
1698 /* The header does not have to exist */
1703 read_ec = be64_to_cpu(ec_hdr->ec);
1704 if (ec != read_ec && read_ec - ec > 1) {
1705 ubi_err(ubi, "self-check failed for PEB %d", pnum);
1706 ubi_err(ubi, "read EC is %lld, should be %d", read_ec, ec);
1718 * self_check_in_wl_tree - check that wear-leveling entry is in WL RB-tree.
1719 * @ubi: UBI device description object
1720 * @e: the wear-leveling entry to check
1721 * @root: the root of the tree
1723 * This function returns zero if @e is in the @root RB-tree and %-EINVAL if it
1726 static int self_check_in_wl_tree(const struct ubi_device *ubi,
1727 struct ubi_wl_entry *e, struct rb_root *root)
1729 if (!ubi_dbg_chk_gen(ubi))
1732 if (in_wl_tree(e, root))
1735 ubi_err(ubi, "self-check failed for PEB %d, EC %d, RB-tree %p ",
1736 e->pnum, e->ec, root);
1742 * self_check_in_pq - check if wear-leveling entry is in the protection
1744 * @ubi: UBI device description object
1745 * @e: the wear-leveling entry to check
1747 * This function returns zero if @e is in @ubi->pq and %-EINVAL if it is not.
1749 static int self_check_in_pq(const struct ubi_device *ubi,
1750 struct ubi_wl_entry *e)
1752 struct ubi_wl_entry *p;
1755 if (!ubi_dbg_chk_gen(ubi))
1758 for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i)
1759 list_for_each_entry(p, &ubi->pq[i], u.list)
1763 ubi_err(ubi, "self-check failed for PEB %d, EC %d, Protect queue",
1768 #ifndef CONFIG_MTD_UBI_FASTMAP
1769 static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
1771 struct ubi_wl_entry *e;
1773 e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
1774 self_check_in_wl_tree(ubi, e, &ubi->free);
1776 ubi_assert(ubi->free_count >= 0);
1777 rb_erase(&e->u.rb, &ubi->free);
1783 * produce_free_peb - produce a free physical eraseblock.
1784 * @ubi: UBI device description object
1786 * This function tries to make a free PEB by means of synchronous execution of
1787 * pending works. This may be needed if, for example the background thread is
1788 * disabled. Returns zero in case of success and a negative error code in case
1791 static int produce_free_peb(struct ubi_device *ubi)
1795 while (!ubi->free.rb_node && ubi->works_count) {
1796 spin_unlock(&ubi->wl_lock);
1798 dbg_wl("do one work synchronously");
1801 spin_lock(&ubi->wl_lock);
1810 * ubi_wl_get_peb - get a physical eraseblock.
1811 * @ubi: UBI device description object
1813 * This function returns a physical eraseblock in case of success and a
1814 * negative error code in case of failure.
1815 * Returns with ubi->fm_eba_sem held in read mode!
1817 int ubi_wl_get_peb(struct ubi_device *ubi)
1820 struct ubi_wl_entry *e;
1823 down_read(&ubi->fm_eba_sem);
1824 spin_lock(&ubi->wl_lock);
1825 if (!ubi->free.rb_node) {
1826 if (ubi->works_count == 0) {
1827 ubi_err(ubi, "no free eraseblocks");
1828 ubi_assert(list_empty(&ubi->works));
1829 spin_unlock(&ubi->wl_lock);
1833 err = produce_free_peb(ubi);
1835 spin_unlock(&ubi->wl_lock);
1838 spin_unlock(&ubi->wl_lock);
1839 up_read(&ubi->fm_eba_sem);
1843 e = wl_get_wle(ubi);
1844 prot_queue_add(ubi, e);
1845 spin_unlock(&ubi->wl_lock);
1847 err = ubi_self_check_all_ff(ubi, e->pnum, ubi->vid_hdr_aloffset,
1848 ubi->peb_size - ubi->vid_hdr_aloffset);
1850 ubi_err(ubi, "new PEB %d does not contain all 0xFF bytes", e->pnum);
1857 #include "fastmap-wl.c"