1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991001011021031041051061071081091101111121131141151161171181191201211221231241251261271281291301311321331341351361371381391401411421431441451461471481491501511521531541551561571581591601611621631641651661671681691701711721731741751761771781791801811821831841851861871881891901911921931941951961971981992002012022032042052062072082092102112122132142152162172182192202212222232242252262272282292302312322332342352362372382392402412422432442452462472482492502512522532542552562572582592602612622632642652662672682692702712722732742752762772782792802812822832842852862872882892902912922932942952962972982993003013023033043053063073083093103113123133143153163173183193203213223233243253263273283293303313323333343353363373383393403413423433443453463473483493503513523533543553563573583593603613623633643653663673683693703713723733743753763773783793803813823833843853863873883893903913923933943953963973983994004014024034044054064074084094104114124134144154164174184194204214224234244254264274284294304314324334344354364374384394404414424434444454464474484494504514524534544554564574584594604614624634644654664674684694704714724734744754764774784794804814824834844854864874884894904914924934944954964974984995005015025035045055065075085095105115125135145155165175185195205215225235245255265275285295305315325335345355365375385395405415425435445455465475485495505515525535545555565575585595605615625635645655665675685695705715725735745755765775785795805815825835845855865875885895905915925935945955965975985996006016026036046056066076086096106116126136146156166176186196206216226236246256266276286296306316326336346356366376386396406416426436446456466476486496506516526536546556566576586596606616626636646656666676686696706716726736746756766776786796806816826836846856866876886896906916926936946956966976986997007017027037047057067077087097107117127137147157167177187197207217227237247257267277287297307317327337347357367377387397407417427437447457467477487497507517527537547557567577587597607617627637647657667677687697707717727737747757767777787797807817827837847857867877887897907917927937947957967977987998008018028038048058068078088098108118128138148158168178188198208218228238248258268278288298308318328338348358368378388398408418428438448458468478488498508518528538548558568578588598608618628638648658668678688698708718728738748758768778788798808818828838848858868878888898908918928938948958968978988999009019029039049059069079089099109119129139149159169179189199209219229239249259269279289299309319329339349359369379389399409419429439449459469479489499509519529539549559569579589599609619629639649659669679689699709719729739749759769779789799809819829839849859869879889899909919929939949959969979989991000100110021003100410051006100710081009101010111012101310141015101610171018101910201021102210231024102510261027102810291030103110321033103410351036103710381039104010411042104310441045104610471048104910501051105210531054105510561057105810591060106110621063106410651066106710681069107010711072107310741075107610771078107910801081108210831084108510861087108810891090109110921093109410951096109710981099110011011102110311041105110611071108110911101111111211131114111511161117111811191120112111221123112411251126112711281129113011311132113311341135113611371138113911401141114211431144114511461147114811491150115111521153115411551156115711581159116011611162116311641165116611671168116911701171117211731174117511761177117811791180118111821183118411851186118711881189119011911192119311941195119611971198119912001201120212031204120512061207120812091210121112121213121412151216121712181219122012211222122312241225122612271228122912301231123212331234123512361237123812391240124112421243124412451246124712481249125012511252125312541255125612571258125912601261126212631264126512661267126812691270127112721273127412751276127712781279128012811282128312841285128612871288128912901291129212931294129512961297129812991300130113021303130413051306130713081309131013111312131313141315131613171318131913201321132213231324132513261327132813291330133113321333133413351336133713381339134013411342134313441345134613471348134913501351135213531354135513561357135813591360136113621363136413651366136713681369137013711372137313741375137613771378137913801381138213831384138513861387138813891390139113921393139413951396139713981399140014011402140314041405140614071408140914101411141214131414141514161417141814191420142114221423142414251426142714281429143014311432143314341435143614371438143914401441144214431444144514461447144814491450145114521453145414551456145714581459146014611462146314641465146614671468146914701471147214731474147514761477147814791480148114821483148414851486148714881489149014911492149314941495149614971498149915001501150215031504150515061507150815091510151115121513151415151516151715181519152015211522152315241525152615271528152915301531153215331534153515361537153815391540154115421543154415451546154715481549155015511552155315541555155615571558155915601561156215631564156515661567156815691570157115721573157415751576157715781579158015811582158315841585158615871588158915901591159215931594159515961597159815991600160116021603160416051606160716081609161016111612161316141615161616171618161916201621162216231624162516261627162816291630163116321633163416351636163716381639164016411642164316441645164616471648164916501651165216531654165516561657165816591660166116621663166416651666166716681669167016711672167316741675167616771678167916801681168216831684168516861687168816891690169116921693169416951696169716981699170017011702170317041705170617071708170917101711171217131714171517161717171817191720172117221723172417251726172717281729173017311732173317341735173617371738173917401741174217431744174517461747174817491750175117521753175417551756175717581759176017611762176317641765176617671768176917701771177217731774177517761777177817791780178117821783178417851786178717881789179017911792179317941795179617971798179918001801180218031804180518061807180818091810181118121813181418151816181718181819182018211822182318241825182618271828182918301831183218331834183518361837183818391840184118421843184418451846184718481849185018511852185318541855185618571858185918601861186218631864186518661867186818691870187118721873187418751876187718781879188018811882188318841885188618871888188918901891189218931894189518961897189818991900190119021903190419051906190719081909191019111912191319141915191619171918191919201921192219231924192519261927192819291930193119321933193419351936193719381939 |
- /*
- * Copyright (c) International Business Machines Corp., 2006
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
- * the GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- *
- * Authors: Artem Bityutskiy (Битюцкий Артём), Thomas Gleixner
- */
- /*
- * UBI wear-leveling sub-system.
- *
- * This sub-system is responsible for wear-leveling. It works in terms of
- * physical eraseblocks and erase counters and knows nothing about logical
- * eraseblocks, volumes, etc. From this sub-system's perspective all physical
- * eraseblocks are of two types - used and free. Used physical eraseblocks are
- * those that were "get" by the 'ubi_wl_get_peb()' function, and free physical
- * eraseblocks are those that were put by the 'ubi_wl_put_peb()' function.
- *
- * Physical eraseblocks returned by 'ubi_wl_get_peb()' have only erase counter
- * header. The rest of the physical eraseblock contains only %0xFF bytes.
- *
- * When physical eraseblocks are returned to the WL sub-system by means of the
- * 'ubi_wl_put_peb()' function, they are scheduled for erasure. The erasure is
- * done asynchronously in context of the per-UBI device background thread,
- * which is also managed by the WL sub-system.
- *
- * The wear-leveling is ensured by means of moving the contents of used
- * physical eraseblocks with low erase counter to free physical eraseblocks
- * with high erase counter.
- *
- * If the WL sub-system fails to erase a physical eraseblock, it marks it as
- * bad.
- *
- * This sub-system is also responsible for scrubbing. If a bit-flip is detected
- * in a physical eraseblock, it has to be moved. Technically this is the same
- * as moving it for wear-leveling reasons.
- *
- * As it was said, for the UBI sub-system all physical eraseblocks are either
- * "free" or "used". Free eraseblock are kept in the @wl->free RB-tree, while
- * used eraseblocks are kept in @wl->used, @wl->erroneous, or @wl->scrub
- * RB-trees, as well as (temporarily) in the @wl->pq queue.
- *
- * When the WL sub-system returns a physical eraseblock, the physical
- * eraseblock is protected from being moved for some "time". For this reason,
- * the physical eraseblock is not directly moved from the @wl->free tree to the
- * @wl->used tree. There is a protection queue in between where this
- * physical eraseblock is temporarily stored (@wl->pq).
- *
- * All this protection stuff is needed because:
- * o we don't want to move physical eraseblocks just after we have given them
- * to the user; instead, we first want to let users fill them up with data;
- *
- * o there is a chance that the user will put the physical eraseblock very
- * soon, so it makes sense not to move it for some time, but wait.
- *
- * Physical eraseblocks stay protected only for limited time. But the "time" is
- * measured in erase cycles in this case. This is implemented with help of the
- * protection queue. Eraseblocks are put to the tail of this queue when they
- * are returned by the 'ubi_wl_get_peb()', and eraseblocks are removed from the
- * head of the queue on each erase operation (for any eraseblock). So the
- * length of the queue defines how may (global) erase cycles PEBs are protected.
- *
- * To put it differently, each physical eraseblock has 2 main states: free and
- * used. The former state corresponds to the @wl->free tree. The latter state
- * is split up on several sub-states:
- * o the WL movement is allowed (@wl->used tree);
- * o the WL movement is disallowed (@wl->erroneous) because the PEB is
- * erroneous - e.g., there was a read error;
- * o the WL movement is temporarily prohibited (@wl->pq queue);
- * o scrubbing is needed (@wl->scrub tree).
- *
- * Depending on the sub-state, wear-leveling entries of the used physical
- * eraseblocks may be kept in one of those structures.
- *
- * Note, in this implementation, we keep a small in-RAM object for each physical
- * eraseblock. This is surely not a scalable solution. But it appears to be good
- * enough for moderately large flashes and it is simple. In future, one may
- * re-work this sub-system and make it more scalable.
- *
- * At the moment this sub-system does not utilize the sequence number, which
- * was introduced relatively recently. But it would be wise to do this because
- * the sequence number of a logical eraseblock characterizes how old is it. For
- * example, when we move a PEB with low erase counter, and we need to pick the
- * target PEB, we pick a PEB with the highest EC if our PEB is "old" and we
- * pick target PEB with an average EC if our PEB is not very "old". This is a
- * room for future re-works of the WL sub-system.
- */
- #include <linux/slab.h>
- #include <linux/crc32.h>
- #include <linux/freezer.h>
- #include <linux/kthread.h>
- #include "ubi.h"
- #include "wl.h"
- /* Number of physical eraseblocks reserved for wear-leveling purposes */
- #define WL_RESERVED_PEBS 1
- /*
- * Maximum difference between two erase counters. If this threshold is
- * exceeded, the WL sub-system starts moving data from used physical
- * eraseblocks with low erase counter to free physical eraseblocks with high
- * erase counter.
- */
- #define UBI_WL_THRESHOLD CONFIG_MTD_UBI_WL_THRESHOLD
- /*
- * When a physical eraseblock is moved, the WL sub-system has to pick the target
- * physical eraseblock to move to. The simplest way would be just to pick the
- * one with the highest erase counter. But in certain workloads this could lead
- * to an unlimited wear of one or few physical eraseblock. Indeed, imagine a
- * situation when the picked physical eraseblock is constantly erased after the
- * data is written to it. So, we have a constant which limits the highest erase
- * counter of the free physical eraseblock to pick. Namely, the WL sub-system
- * does not pick eraseblocks with erase counter greater than the lowest erase
- * counter plus %WL_FREE_MAX_DIFF.
- */
- #define WL_FREE_MAX_DIFF (2*UBI_WL_THRESHOLD)
- /*
- * Maximum number of consecutive background thread failures which is enough to
- * switch to read-only mode.
- */
- #define WL_MAX_FAILURES 32
- static int self_check_ec(struct ubi_device *ubi, int pnum, int ec);
- static int self_check_in_wl_tree(const struct ubi_device *ubi,
- struct ubi_wl_entry *e, struct rb_root *root);
- static int self_check_in_pq(const struct ubi_device *ubi,
- struct ubi_wl_entry *e);
- /**
- * wl_tree_add - add a wear-leveling entry to a WL RB-tree.
- * @e: the wear-leveling entry to add
- * @root: the root of the tree
- *
- * Note, we use (erase counter, physical eraseblock number) pairs as keys in
- * the @ubi->used and @ubi->free RB-trees.
- */
- static void wl_tree_add(struct ubi_wl_entry *e, struct rb_root *root)
- {
- struct rb_node **p, *parent = NULL;
- p = &root->rb_node;
- while (*p) {
- struct ubi_wl_entry *e1;
- parent = *p;
- e1 = rb_entry(parent, struct ubi_wl_entry, u.rb);
- if (e->ec < e1->ec)
- p = &(*p)->rb_left;
- else if (e->ec > e1->ec)
- p = &(*p)->rb_right;
- else {
- ubi_assert(e->pnum != e1->pnum);
- if (e->pnum < e1->pnum)
- p = &(*p)->rb_left;
- else
- p = &(*p)->rb_right;
- }
- }
- rb_link_node(&e->u.rb, parent, p);
- rb_insert_color(&e->u.rb, root);
- }
- /**
- * wl_tree_destroy - destroy a wear-leveling entry.
- * @ubi: UBI device description object
- * @e: the wear-leveling entry to add
- *
- * This function destroys a wear leveling entry and removes
- * the reference from the lookup table.
- */
- static void wl_entry_destroy(struct ubi_device *ubi, struct ubi_wl_entry *e)
- {
- ubi->lookuptbl[e->pnum] = NULL;
- kmem_cache_free(ubi_wl_entry_slab, e);
- }
- /**
- * do_work - do one pending work.
- * @ubi: UBI device description object
- *
- * This function returns zero in case of success and a negative error code in
- * case of failure.
- */
- static int do_work(struct ubi_device *ubi)
- {
- int err;
- struct ubi_work *wrk;
- cond_resched();
- /*
- * @ubi->work_sem is used to synchronize with the workers. Workers take
- * it in read mode, so many of them may be doing works at a time. But
- * the queue flush code has to be sure the whole queue of works is
- * done, and it takes the mutex in write mode.
- */
- down_read(&ubi->work_sem);
- spin_lock(&ubi->wl_lock);
- if (list_empty(&ubi->works)) {
- spin_unlock(&ubi->wl_lock);
- up_read(&ubi->work_sem);
- return 0;
- }
- wrk = list_entry(ubi->works.next, struct ubi_work, list);
- list_del(&wrk->list);
- ubi->works_count -= 1;
- ubi_assert(ubi->works_count >= 0);
- spin_unlock(&ubi->wl_lock);
- /*
- * Call the worker function. Do not touch the work structure
- * after this call as it will have been freed or reused by that
- * time by the worker function.
- */
- err = wrk->func(ubi, wrk, 0);
- if (err)
- ubi_err(ubi, "work failed with error code %d", err);
- up_read(&ubi->work_sem);
- return err;
- }
- /**
- * in_wl_tree - check if wear-leveling entry is present in a WL RB-tree.
- * @e: the wear-leveling entry to check
- * @root: the root of the tree
- *
- * This function returns non-zero if @e is in the @root RB-tree and zero if it
- * is not.
- */
- static int in_wl_tree(struct ubi_wl_entry *e, struct rb_root *root)
- {
- struct rb_node *p;
- p = root->rb_node;
- while (p) {
- struct ubi_wl_entry *e1;
- e1 = rb_entry(p, struct ubi_wl_entry, u.rb);
- if (e->pnum == e1->pnum) {
- ubi_assert(e == e1);
- return 1;
- }
- if (e->ec < e1->ec)
- p = p->rb_left;
- else if (e->ec > e1->ec)
- p = p->rb_right;
- else {
- ubi_assert(e->pnum != e1->pnum);
- if (e->pnum < e1->pnum)
- p = p->rb_left;
- else
- p = p->rb_right;
- }
- }
- return 0;
- }
- /**
- * prot_queue_add - add physical eraseblock to the protection queue.
- * @ubi: UBI device description object
- * @e: the physical eraseblock to add
- *
- * This function adds @e to the tail of the protection queue @ubi->pq, where
- * @e will stay for %UBI_PROT_QUEUE_LEN erase operations and will be
- * temporarily protected from the wear-leveling worker. Note, @wl->lock has to
- * be locked.
- */
- static void prot_queue_add(struct ubi_device *ubi, struct ubi_wl_entry *e)
- {
- int pq_tail = ubi->pq_head - 1;
- if (pq_tail < 0)
- pq_tail = UBI_PROT_QUEUE_LEN - 1;
- ubi_assert(pq_tail >= 0 && pq_tail < UBI_PROT_QUEUE_LEN);
- list_add_tail(&e->u.list, &ubi->pq[pq_tail]);
- dbg_wl("added PEB %d EC %d to the protection queue", e->pnum, e->ec);
- }
- /**
- * find_wl_entry - find wear-leveling entry closest to certain erase counter.
- * @ubi: UBI device description object
- * @root: the RB-tree where to look for
- * @diff: maximum possible difference from the smallest erase counter
- *
- * This function looks for a wear leveling entry with erase counter closest to
- * min + @diff, where min is the smallest erase counter.
- */
- static struct ubi_wl_entry *find_wl_entry(struct ubi_device *ubi,
- struct rb_root *root, int diff)
- {
- struct rb_node *p;
- struct ubi_wl_entry *e, *prev_e = NULL;
- int max;
- e = rb_entry(rb_first(root), struct ubi_wl_entry, u.rb);
- max = e->ec + diff;
- p = root->rb_node;
- while (p) {
- struct ubi_wl_entry *e1;
- e1 = rb_entry(p, struct ubi_wl_entry, u.rb);
- if (e1->ec >= max)
- p = p->rb_left;
- else {
- p = p->rb_right;
- prev_e = e;
- e = e1;
- }
- }
- /* If no fastmap has been written and this WL entry can be used
- * as anchor PEB, hold it back and return the second best WL entry
- * such that fastmap can use the anchor PEB later. */
- if (prev_e && !ubi->fm_disabled &&
- !ubi->fm && e->pnum < UBI_FM_MAX_START)
- return prev_e;
- return e;
- }
- /**
- * find_mean_wl_entry - find wear-leveling entry with medium erase counter.
- * @ubi: UBI device description object
- * @root: the RB-tree where to look for
- *
- * This function looks for a wear leveling entry with medium erase counter,
- * but not greater or equivalent than the lowest erase counter plus
- * %WL_FREE_MAX_DIFF/2.
- */
- static struct ubi_wl_entry *find_mean_wl_entry(struct ubi_device *ubi,
- struct rb_root *root)
- {
- struct ubi_wl_entry *e, *first, *last;
- first = rb_entry(rb_first(root), struct ubi_wl_entry, u.rb);
- last = rb_entry(rb_last(root), struct ubi_wl_entry, u.rb);
- if (last->ec - first->ec < WL_FREE_MAX_DIFF) {
- e = rb_entry(root->rb_node, struct ubi_wl_entry, u.rb);
- /* If no fastmap has been written and this WL entry can be used
- * as anchor PEB, hold it back and return the second best
- * WL entry such that fastmap can use the anchor PEB later. */
- e = may_reserve_for_fm(ubi, e, root);
- } else
- e = find_wl_entry(ubi, root, WL_FREE_MAX_DIFF/2);
- return e;
- }
- /**
- * wl_get_wle - get a mean wl entry to be used by ubi_wl_get_peb() or
- * refill_wl_user_pool().
- * @ubi: UBI device description object
- *
- * This function returns a a wear leveling entry in case of success and
- * NULL in case of failure.
- */
- static struct ubi_wl_entry *wl_get_wle(struct ubi_device *ubi)
- {
- struct ubi_wl_entry *e;
- e = find_mean_wl_entry(ubi, &ubi->free);
- if (!e) {
- ubi_err(ubi, "no free eraseblocks");
- return NULL;
- }
- self_check_in_wl_tree(ubi, e, &ubi->free);
- /*
- * Move the physical eraseblock to the protection queue where it will
- * be protected from being moved for some time.
- */
- rb_erase(&e->u.rb, &ubi->free);
- ubi->free_count--;
- dbg_wl("PEB %d EC %d", e->pnum, e->ec);
- return e;
- }
- /**
- * prot_queue_del - remove a physical eraseblock from the protection queue.
- * @ubi: UBI device description object
- * @pnum: the physical eraseblock to remove
- *
- * This function deletes PEB @pnum from the protection queue and returns zero
- * in case of success and %-ENODEV if the PEB was not found.
- */
- static int prot_queue_del(struct ubi_device *ubi, int pnum)
- {
- struct ubi_wl_entry *e;
- e = ubi->lookuptbl[pnum];
- if (!e)
- return -ENODEV;
- if (self_check_in_pq(ubi, e))
- return -ENODEV;
- list_del(&e->u.list);
- dbg_wl("deleted PEB %d from the protection queue", e->pnum);
- return 0;
- }
- /**
- * sync_erase - synchronously erase a physical eraseblock.
- * @ubi: UBI device description object
- * @e: the the physical eraseblock to erase
- * @torture: if the physical eraseblock has to be tortured
- *
- * This function returns zero in case of success and a negative error code in
- * case of failure.
- */
- static int sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
- int torture)
- {
- int err;
- struct ubi_ec_hdr *ec_hdr;
- unsigned long long ec = e->ec;
- dbg_wl("erase PEB %d, old EC %llu", e->pnum, ec);
- err = self_check_ec(ubi, e->pnum, e->ec);
- if (err)
- return -EINVAL;
- ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
- if (!ec_hdr)
- return -ENOMEM;
- err = ubi_io_sync_erase(ubi, e->pnum, torture);
- if (err < 0)
- goto out_free;
- ec += err;
- if (ec > UBI_MAX_ERASECOUNTER) {
- /*
- * Erase counter overflow. Upgrade UBI and use 64-bit
- * erase counters internally.
- */
- ubi_err(ubi, "erase counter overflow at PEB %d, EC %llu",
- e->pnum, ec);
- err = -EINVAL;
- goto out_free;
- }
- dbg_wl("erased PEB %d, new EC %llu", e->pnum, ec);
- ec_hdr->ec = cpu_to_be64(ec);
- err = ubi_io_write_ec_hdr(ubi, e->pnum, ec_hdr);
- if (err)
- goto out_free;
- e->ec = ec;
- spin_lock(&ubi->wl_lock);
- if (e->ec > ubi->max_ec)
- ubi->max_ec = e->ec;
- spin_unlock(&ubi->wl_lock);
- out_free:
- kfree(ec_hdr);
- return err;
- }
- /**
- * serve_prot_queue - check if it is time to stop protecting PEBs.
- * @ubi: UBI device description object
- *
- * This function is called after each erase operation and removes PEBs from the
- * tail of the protection queue. These PEBs have been protected for long enough
- * and should be moved to the used tree.
- */
- static void serve_prot_queue(struct ubi_device *ubi)
- {
- struct ubi_wl_entry *e, *tmp;
- int count;
- /*
- * There may be several protected physical eraseblock to remove,
- * process them all.
- */
- repeat:
- count = 0;
- spin_lock(&ubi->wl_lock);
- list_for_each_entry_safe(e, tmp, &ubi->pq[ubi->pq_head], u.list) {
- dbg_wl("PEB %d EC %d protection over, move to used tree",
- e->pnum, e->ec);
- list_del(&e->u.list);
- wl_tree_add(e, &ubi->used);
- if (count++ > 32) {
- /*
- * Let's be nice and avoid holding the spinlock for
- * too long.
- */
- spin_unlock(&ubi->wl_lock);
- cond_resched();
- goto repeat;
- }
- }
- ubi->pq_head += 1;
- if (ubi->pq_head == UBI_PROT_QUEUE_LEN)
- ubi->pq_head = 0;
- ubi_assert(ubi->pq_head >= 0 && ubi->pq_head < UBI_PROT_QUEUE_LEN);
- spin_unlock(&ubi->wl_lock);
- }
- /**
- * __schedule_ubi_work - schedule a work.
- * @ubi: UBI device description object
- * @wrk: the work to schedule
- *
- * This function adds a work defined by @wrk to the tail of the pending works
- * list. Can only be used if ubi->work_sem is already held in read mode!
- */
- static void __schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
- {
- spin_lock(&ubi->wl_lock);
- list_add_tail(&wrk->list, &ubi->works);
- ubi_assert(ubi->works_count >= 0);
- ubi->works_count += 1;
- if (ubi->thread_enabled && !ubi_dbg_is_bgt_disabled(ubi))
- wake_up_process(ubi->bgt_thread);
- spin_unlock(&ubi->wl_lock);
- }
- /**
- * schedule_ubi_work - schedule a work.
- * @ubi: UBI device description object
- * @wrk: the work to schedule
- *
- * This function adds a work defined by @wrk to the tail of the pending works
- * list.
- */
- static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
- {
- down_read(&ubi->work_sem);
- __schedule_ubi_work(ubi, wrk);
- up_read(&ubi->work_sem);
- }
- static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
- int shutdown);
- /**
- * schedule_erase - schedule an erase work.
- * @ubi: UBI device description object
- * @e: the WL entry of the physical eraseblock to erase
- * @vol_id: the volume ID that last used this PEB
- * @lnum: the last used logical eraseblock number for the PEB
- * @torture: if the physical eraseblock has to be tortured
- *
- * This function returns zero in case of success and a %-ENOMEM in case of
- * failure.
- */
- static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
- int vol_id, int lnum, int torture, bool nested)
- {
- struct ubi_work *wl_wrk;
- ubi_assert(e);
- dbg_wl("schedule erasure of PEB %d, EC %d, torture %d",
- e->pnum, e->ec, torture);
- wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
- if (!wl_wrk)
- return -ENOMEM;
- wl_wrk->func = &erase_worker;
- wl_wrk->e = e;
- wl_wrk->vol_id = vol_id;
- wl_wrk->lnum = lnum;
- wl_wrk->torture = torture;
- if (nested)
- __schedule_ubi_work(ubi, wl_wrk);
- else
- schedule_ubi_work(ubi, wl_wrk);
- return 0;
- }
- static int __erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk);
- /**
- * do_sync_erase - run the erase worker synchronously.
- * @ubi: UBI device description object
- * @e: the WL entry of the physical eraseblock to erase
- * @vol_id: the volume ID that last used this PEB
- * @lnum: the last used logical eraseblock number for the PEB
- * @torture: if the physical eraseblock has to be tortured
- *
- */
- static int do_sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
- int vol_id, int lnum, int torture)
- {
- struct ubi_work wl_wrk;
- dbg_wl("sync erase of PEB %i", e->pnum);
- wl_wrk.e = e;
- wl_wrk.vol_id = vol_id;
- wl_wrk.lnum = lnum;
- wl_wrk.torture = torture;
- return __erase_worker(ubi, &wl_wrk);
- }
- /**
- * wear_leveling_worker - wear-leveling worker function.
- * @ubi: UBI device description object
- * @wrk: the work object
- * @shutdown: non-zero if the worker has to free memory and exit
- * because the WL-subsystem is shutting down
- *
- * This function copies a more worn out physical eraseblock to a less worn out
- * one. Returns zero in case of success and a negative error code in case of
- * failure.
- */
- static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
- int shutdown)
- {
- int err, scrubbing = 0, torture = 0, protect = 0, erroneous = 0;
- int erase = 0, keep = 0, vol_id = -1, lnum = -1;
- #ifdef CONFIG_MTD_UBI_FASTMAP
- int anchor = wrk->anchor;
- #endif
- struct ubi_wl_entry *e1, *e2;
- struct ubi_vid_hdr *vid_hdr;
- kfree(wrk);
- if (shutdown)
- return 0;
- vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
- if (!vid_hdr)
- return -ENOMEM;
- down_read(&ubi->fm_eba_sem);
- mutex_lock(&ubi->move_mutex);
- spin_lock(&ubi->wl_lock);
- ubi_assert(!ubi->move_from && !ubi->move_to);
- ubi_assert(!ubi->move_to_put);
- if (!ubi->free.rb_node ||
- (!ubi->used.rb_node && !ubi->scrub.rb_node)) {
- /*
- * No free physical eraseblocks? Well, they must be waiting in
- * the queue to be erased. Cancel movement - it will be
- * triggered again when a free physical eraseblock appears.
- *
- * No used physical eraseblocks? They must be temporarily
- * protected from being moved. They will be moved to the
- * @ubi->used tree later and the wear-leveling will be
- * triggered again.
- */
- dbg_wl("cancel WL, a list is empty: free %d, used %d",
- !ubi->free.rb_node, !ubi->used.rb_node);
- goto out_cancel;
- }
- #ifdef CONFIG_MTD_UBI_FASTMAP
- /* Check whether we need to produce an anchor PEB */
- if (!anchor)
- anchor = !anchor_pebs_avalible(&ubi->free);
- if (anchor) {
- e1 = find_anchor_wl_entry(&ubi->used);
- if (!e1)
- goto out_cancel;
- e2 = get_peb_for_wl(ubi);
- if (!e2)
- goto out_cancel;
- self_check_in_wl_tree(ubi, e1, &ubi->used);
- rb_erase(&e1->u.rb, &ubi->used);
- dbg_wl("anchor-move PEB %d to PEB %d", e1->pnum, e2->pnum);
- } else if (!ubi->scrub.rb_node) {
- #else
- if (!ubi->scrub.rb_node) {
- #endif
- /*
- * Now pick the least worn-out used physical eraseblock and a
- * highly worn-out free physical eraseblock. If the erase
- * counters differ much enough, start wear-leveling.
- */
- e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
- e2 = get_peb_for_wl(ubi);
- if (!e2)
- goto out_cancel;
- if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD)) {
- dbg_wl("no WL needed: min used EC %d, max free EC %d",
- e1->ec, e2->ec);
- /* Give the unused PEB back */
- wl_tree_add(e2, &ubi->free);
- ubi->free_count++;
- goto out_cancel;
- }
- self_check_in_wl_tree(ubi, e1, &ubi->used);
- rb_erase(&e1->u.rb, &ubi->used);
- dbg_wl("move PEB %d EC %d to PEB %d EC %d",
- e1->pnum, e1->ec, e2->pnum, e2->ec);
- } else {
- /* Perform scrubbing */
- scrubbing = 1;
- e1 = rb_entry(rb_first(&ubi->scrub), struct ubi_wl_entry, u.rb);
- e2 = get_peb_for_wl(ubi);
- if (!e2)
- goto out_cancel;
- self_check_in_wl_tree(ubi, e1, &ubi->scrub);
- rb_erase(&e1->u.rb, &ubi->scrub);
- dbg_wl("scrub PEB %d to PEB %d", e1->pnum, e2->pnum);
- }
- ubi->move_from = e1;
- ubi->move_to = e2;
- spin_unlock(&ubi->wl_lock);
- /*
- * Now we are going to copy physical eraseblock @e1->pnum to @e2->pnum.
- * We so far do not know which logical eraseblock our physical
- * eraseblock (@e1) belongs to. We have to read the volume identifier
- * header first.
- *
- * Note, we are protected from this PEB being unmapped and erased. The
- * 'ubi_wl_put_peb()' would wait for moving to be finished if the PEB
- * which is being moved was unmapped.
- */
- err = ubi_io_read_vid_hdr(ubi, e1->pnum, vid_hdr, 0);
- if (err && err != UBI_IO_BITFLIPS) {
- if (err == UBI_IO_FF) {
- /*
- * We are trying to move PEB without a VID header. UBI
- * always write VID headers shortly after the PEB was
- * given, so we have a situation when it has not yet
- * had a chance to write it, because it was preempted.
- * So add this PEB to the protection queue so far,
- * because presumably more data will be written there
- * (including the missing VID header), and then we'll
- * move it.
- */
- dbg_wl("PEB %d has no VID header", e1->pnum);
- protect = 1;
- goto out_not_moved;
- } else if (err == UBI_IO_FF_BITFLIPS) {
- /*
- * The same situation as %UBI_IO_FF, but bit-flips were
- * detected. It is better to schedule this PEB for
- * scrubbing.
- */
- dbg_wl("PEB %d has no VID header but has bit-flips",
- e1->pnum);
- scrubbing = 1;
- goto out_not_moved;
- } else if (ubi->fast_attach && err == UBI_IO_BAD_HDR_EBADMSG) {
- /*
- * While a full scan would detect interrupted erasures
- * at attach time we can face them here when attached from
- * Fastmap.
- */
- dbg_wl("PEB %d has ECC errors, maybe from an interrupted erasure",
- e1->pnum);
- erase = 1;
- goto out_not_moved;
- }
- ubi_err(ubi, "error %d while reading VID header from PEB %d",
- err, e1->pnum);
- goto out_error;
- }
- vol_id = be32_to_cpu(vid_hdr->vol_id);
- lnum = be32_to_cpu(vid_hdr->lnum);
- err = ubi_eba_copy_leb(ubi, e1->pnum, e2->pnum, vid_hdr);
- if (err) {
- if (err == MOVE_CANCEL_RACE) {
- /*
- * The LEB has not been moved because the volume is
- * being deleted or the PEB has been put meanwhile. We
- * should prevent this PEB from being selected for
- * wear-leveling movement again, so put it to the
- * protection queue.
- */
- protect = 1;
- goto out_not_moved;
- }
- if (err == MOVE_RETRY) {
- scrubbing = 1;
- goto out_not_moved;
- }
- if (err == MOVE_TARGET_BITFLIPS || err == MOVE_TARGET_WR_ERR ||
- err == MOVE_TARGET_RD_ERR) {
- /*
- * Target PEB had bit-flips or write error - torture it.
- */
- torture = 1;
- keep = 1;
- goto out_not_moved;
- }
- if (err == MOVE_SOURCE_RD_ERR) {
- /*
- * An error happened while reading the source PEB. Do
- * not switch to R/O mode in this case, and give the
- * upper layers a possibility to recover from this,
- * e.g. by unmapping corresponding LEB. Instead, just
- * put this PEB to the @ubi->erroneous list to prevent
- * UBI from trying to move it over and over again.
- */
- if (ubi->erroneous_peb_count > ubi->max_erroneous) {
- ubi_err(ubi, "too many erroneous eraseblocks (%d)",
- ubi->erroneous_peb_count);
- goto out_error;
- }
- erroneous = 1;
- goto out_not_moved;
- }
- if (err < 0)
- goto out_error;
- ubi_assert(0);
- }
- /* The PEB has been successfully moved */
- if (scrubbing)
- ubi_msg(ubi, "scrubbed PEB %d (LEB %d:%d), data moved to PEB %d",
- e1->pnum, vol_id, lnum, e2->pnum);
- ubi_free_vid_hdr(ubi, vid_hdr);
- spin_lock(&ubi->wl_lock);
- if (!ubi->move_to_put) {
- wl_tree_add(e2, &ubi->used);
- e2 = NULL;
- }
- ubi->move_from = ubi->move_to = NULL;
- ubi->move_to_put = ubi->wl_scheduled = 0;
- spin_unlock(&ubi->wl_lock);
- err = do_sync_erase(ubi, e1, vol_id, lnum, 0);
- if (err) {
- if (e2)
- wl_entry_destroy(ubi, e2);
- goto out_ro;
- }
- if (e2) {
- /*
- * Well, the target PEB was put meanwhile, schedule it for
- * erasure.
- */
- dbg_wl("PEB %d (LEB %d:%d) was put meanwhile, erase",
- e2->pnum, vol_id, lnum);
- err = do_sync_erase(ubi, e2, vol_id, lnum, 0);
- if (err)
- goto out_ro;
- }
- dbg_wl("done");
- mutex_unlock(&ubi->move_mutex);
- up_read(&ubi->fm_eba_sem);
- return 0;
- /*
- * For some reasons the LEB was not moved, might be an error, might be
- * something else. @e1 was not changed, so return it back. @e2 might
- * have been changed, schedule it for erasure.
- */
- out_not_moved:
- if (vol_id != -1)
- dbg_wl("cancel moving PEB %d (LEB %d:%d) to PEB %d (%d)",
- e1->pnum, vol_id, lnum, e2->pnum, err);
- else
- dbg_wl("cancel moving PEB %d to PEB %d (%d)",
- e1->pnum, e2->pnum, err);
- spin_lock(&ubi->wl_lock);
- if (protect)
- prot_queue_add(ubi, e1);
- else if (erroneous) {
- wl_tree_add(e1, &ubi->erroneous);
- ubi->erroneous_peb_count += 1;
- } else if (scrubbing)
- wl_tree_add(e1, &ubi->scrub);
- else if (keep)
- wl_tree_add(e1, &ubi->used);
- ubi_assert(!ubi->move_to_put);
- ubi->move_from = ubi->move_to = NULL;
- ubi->wl_scheduled = 0;
- spin_unlock(&ubi->wl_lock);
- ubi_free_vid_hdr(ubi, vid_hdr);
- err = do_sync_erase(ubi, e2, vol_id, lnum, torture);
- if (err)
- goto out_ro;
- if (erase) {
- err = do_sync_erase(ubi, e1, vol_id, lnum, 1);
- if (err)
- goto out_ro;
- }
- mutex_unlock(&ubi->move_mutex);
- up_read(&ubi->fm_eba_sem);
- return 0;
- out_error:
- if (vol_id != -1)
- ubi_err(ubi, "error %d while moving PEB %d to PEB %d",
- err, e1->pnum, e2->pnum);
- else
- ubi_err(ubi, "error %d while moving PEB %d (LEB %d:%d) to PEB %d",
- err, e1->pnum, vol_id, lnum, e2->pnum);
- spin_lock(&ubi->wl_lock);
- ubi->move_from = ubi->move_to = NULL;
- ubi->move_to_put = ubi->wl_scheduled = 0;
- spin_unlock(&ubi->wl_lock);
- ubi_free_vid_hdr(ubi, vid_hdr);
- wl_entry_destroy(ubi, e1);
- wl_entry_destroy(ubi, e2);
- out_ro:
- ubi_ro_mode(ubi);
- mutex_unlock(&ubi->move_mutex);
- up_read(&ubi->fm_eba_sem);
- ubi_assert(err != 0);
- return err < 0 ? err : -EIO;
- out_cancel:
- ubi->wl_scheduled = 0;
- spin_unlock(&ubi->wl_lock);
- mutex_unlock(&ubi->move_mutex);
- up_read(&ubi->fm_eba_sem);
- ubi_free_vid_hdr(ubi, vid_hdr);
- return 0;
- }
- /**
- * ensure_wear_leveling - schedule wear-leveling if it is needed.
- * @ubi: UBI device description object
- * @nested: set to non-zero if this function is called from UBI worker
- *
- * This function checks if it is time to start wear-leveling and schedules it
- * if yes. This function returns zero in case of success and a negative error
- * code in case of failure.
- */
- static int ensure_wear_leveling(struct ubi_device *ubi, int nested)
- {
- int err = 0;
- struct ubi_wl_entry *e1;
- struct ubi_wl_entry *e2;
- struct ubi_work *wrk;
- spin_lock(&ubi->wl_lock);
- if (ubi->wl_scheduled)
- /* Wear-leveling is already in the work queue */
- goto out_unlock;
- /*
- * If the ubi->scrub tree is not empty, scrubbing is needed, and the
- * the WL worker has to be scheduled anyway.
- */
- if (!ubi->scrub.rb_node) {
- if (!ubi->used.rb_node || !ubi->free.rb_node)
- /* No physical eraseblocks - no deal */
- goto out_unlock;
- /*
- * We schedule wear-leveling only if the difference between the
- * lowest erase counter of used physical eraseblocks and a high
- * erase counter of free physical eraseblocks is greater than
- * %UBI_WL_THRESHOLD.
- */
- e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
- e2 = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
- if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD))
- goto out_unlock;
- dbg_wl("schedule wear-leveling");
- } else
- dbg_wl("schedule scrubbing");
- ubi->wl_scheduled = 1;
- spin_unlock(&ubi->wl_lock);
- wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
- if (!wrk) {
- err = -ENOMEM;
- goto out_cancel;
- }
- wrk->anchor = 0;
- wrk->func = &wear_leveling_worker;
- if (nested)
- __schedule_ubi_work(ubi, wrk);
- else
- schedule_ubi_work(ubi, wrk);
- return err;
- out_cancel:
- spin_lock(&ubi->wl_lock);
- ubi->wl_scheduled = 0;
- out_unlock:
- spin_unlock(&ubi->wl_lock);
- return err;
- }
- /**
- * __erase_worker - physical eraseblock erase worker function.
- * @ubi: UBI device description object
- * @wl_wrk: the work object
- * @shutdown: non-zero if the worker has to free memory and exit
- * because the WL sub-system is shutting down
- *
- * This function erases a physical eraseblock and perform torture testing if
- * needed. It also takes care about marking the physical eraseblock bad if
- * needed. Returns zero in case of success and a negative error code in case of
- * failure.
- */
- static int __erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk)
- {
- struct ubi_wl_entry *e = wl_wrk->e;
- int pnum = e->pnum;
- int vol_id = wl_wrk->vol_id;
- int lnum = wl_wrk->lnum;
- int err, available_consumed = 0;
- dbg_wl("erase PEB %d EC %d LEB %d:%d",
- pnum, e->ec, wl_wrk->vol_id, wl_wrk->lnum);
- err = sync_erase(ubi, e, wl_wrk->torture);
- if (!err) {
- spin_lock(&ubi->wl_lock);
- wl_tree_add(e, &ubi->free);
- ubi->free_count++;
- spin_unlock(&ubi->wl_lock);
- /*
- * One more erase operation has happened, take care about
- * protected physical eraseblocks.
- */
- serve_prot_queue(ubi);
- /* And take care about wear-leveling */
- err = ensure_wear_leveling(ubi, 1);
- return err;
- }
- ubi_err(ubi, "failed to erase PEB %d, error %d", pnum, err);
- if (err == -EINTR || err == -ENOMEM || err == -EAGAIN ||
- err == -EBUSY) {
- int err1;
- /* Re-schedule the LEB for erasure */
- err1 = schedule_erase(ubi, e, vol_id, lnum, 0, false);
- if (err1) {
- wl_entry_destroy(ubi, e);
- err = err1;
- goto out_ro;
- }
- return err;
- }
- wl_entry_destroy(ubi, e);
- if (err != -EIO)
- /*
- * If this is not %-EIO, we have no idea what to do. Scheduling
- * this physical eraseblock for erasure again would cause
- * errors again and again. Well, lets switch to R/O mode.
- */
- goto out_ro;
- /* It is %-EIO, the PEB went bad */
- if (!ubi->bad_allowed) {
- ubi_err(ubi, "bad physical eraseblock %d detected", pnum);
- goto out_ro;
- }
- spin_lock(&ubi->volumes_lock);
- if (ubi->beb_rsvd_pebs == 0) {
- if (ubi->avail_pebs == 0) {
- spin_unlock(&ubi->volumes_lock);
- ubi_err(ubi, "no reserved/available physical eraseblocks");
- goto out_ro;
- }
- ubi->avail_pebs -= 1;
- available_consumed = 1;
- }
- spin_unlock(&ubi->volumes_lock);
- ubi_msg(ubi, "mark PEB %d as bad", pnum);
- err = ubi_io_mark_bad(ubi, pnum);
- if (err)
- goto out_ro;
- spin_lock(&ubi->volumes_lock);
- if (ubi->beb_rsvd_pebs > 0) {
- if (available_consumed) {
- /*
- * The amount of reserved PEBs increased since we last
- * checked.
- */
- ubi->avail_pebs += 1;
- available_consumed = 0;
- }
- ubi->beb_rsvd_pebs -= 1;
- }
- ubi->bad_peb_count += 1;
- ubi->good_peb_count -= 1;
- ubi_calculate_reserved(ubi);
- if (available_consumed)
- ubi_warn(ubi, "no PEBs in the reserved pool, used an available PEB");
- else if (ubi->beb_rsvd_pebs)
- ubi_msg(ubi, "%d PEBs left in the reserve",
- ubi->beb_rsvd_pebs);
- else
- ubi_warn(ubi, "last PEB from the reserve was used");
- spin_unlock(&ubi->volumes_lock);
- return err;
- out_ro:
- if (available_consumed) {
- spin_lock(&ubi->volumes_lock);
- ubi->avail_pebs += 1;
- spin_unlock(&ubi->volumes_lock);
- }
- ubi_ro_mode(ubi);
- return err;
- }
- static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
- int shutdown)
- {
- int ret;
- if (shutdown) {
- struct ubi_wl_entry *e = wl_wrk->e;
- dbg_wl("cancel erasure of PEB %d EC %d", e->pnum, e->ec);
- kfree(wl_wrk);
- wl_entry_destroy(ubi, e);
- return 0;
- }
- ret = __erase_worker(ubi, wl_wrk);
- kfree(wl_wrk);
- return ret;
- }
- /**
- * ubi_wl_put_peb - return a PEB to the wear-leveling sub-system.
- * @ubi: UBI device description object
- * @vol_id: the volume ID that last used this PEB
- * @lnum: the last used logical eraseblock number for the PEB
- * @pnum: physical eraseblock to return
- * @torture: if this physical eraseblock has to be tortured
- *
- * This function is called to return physical eraseblock @pnum to the pool of
- * free physical eraseblocks. The @torture flag has to be set if an I/O error
- * occurred to this @pnum and it has to be tested. This function returns zero
- * in case of success, and a negative error code in case of failure.
- */
- int ubi_wl_put_peb(struct ubi_device *ubi, int vol_id, int lnum,
- int pnum, int torture)
- {
- int err;
- struct ubi_wl_entry *e;
- dbg_wl("PEB %d", pnum);
- ubi_assert(pnum >= 0);
- ubi_assert(pnum < ubi->peb_count);
- down_read(&ubi->fm_protect);
- retry:
- spin_lock(&ubi->wl_lock);
- e = ubi->lookuptbl[pnum];
- if (e == ubi->move_from) {
- /*
- * User is putting the physical eraseblock which was selected to
- * be moved. It will be scheduled for erasure in the
- * wear-leveling worker.
- */
- dbg_wl("PEB %d is being moved, wait", pnum);
- spin_unlock(&ubi->wl_lock);
- /* Wait for the WL worker by taking the @ubi->move_mutex */
- mutex_lock(&ubi->move_mutex);
- mutex_unlock(&ubi->move_mutex);
- goto retry;
- } else if (e == ubi->move_to) {
- /*
- * User is putting the physical eraseblock which was selected
- * as the target the data is moved to. It may happen if the EBA
- * sub-system already re-mapped the LEB in 'ubi_eba_copy_leb()'
- * but the WL sub-system has not put the PEB to the "used" tree
- * yet, but it is about to do this. So we just set a flag which
- * will tell the WL worker that the PEB is not needed anymore
- * and should be scheduled for erasure.
- */
- dbg_wl("PEB %d is the target of data moving", pnum);
- ubi_assert(!ubi->move_to_put);
- ubi->move_to_put = 1;
- spin_unlock(&ubi->wl_lock);
- up_read(&ubi->fm_protect);
- return 0;
- } else {
- if (in_wl_tree(e, &ubi->used)) {
- self_check_in_wl_tree(ubi, e, &ubi->used);
- rb_erase(&e->u.rb, &ubi->used);
- } else if (in_wl_tree(e, &ubi->scrub)) {
- self_check_in_wl_tree(ubi, e, &ubi->scrub);
- rb_erase(&e->u.rb, &ubi->scrub);
- } else if (in_wl_tree(e, &ubi->erroneous)) {
- self_check_in_wl_tree(ubi, e, &ubi->erroneous);
- rb_erase(&e->u.rb, &ubi->erroneous);
- ubi->erroneous_peb_count -= 1;
- ubi_assert(ubi->erroneous_peb_count >= 0);
- /* Erroneous PEBs should be tortured */
- torture = 1;
- } else {
- err = prot_queue_del(ubi, e->pnum);
- if (err) {
- ubi_err(ubi, "PEB %d not found", pnum);
- ubi_ro_mode(ubi);
- spin_unlock(&ubi->wl_lock);
- up_read(&ubi->fm_protect);
- return err;
- }
- }
- }
- spin_unlock(&ubi->wl_lock);
- err = schedule_erase(ubi, e, vol_id, lnum, torture, false);
- if (err) {
- spin_lock(&ubi->wl_lock);
- wl_tree_add(e, &ubi->used);
- spin_unlock(&ubi->wl_lock);
- }
- up_read(&ubi->fm_protect);
- return err;
- }
- /**
- * ubi_wl_scrub_peb - schedule a physical eraseblock for scrubbing.
- * @ubi: UBI device description object
- * @pnum: the physical eraseblock to schedule
- *
- * If a bit-flip in a physical eraseblock is detected, this physical eraseblock
- * needs scrubbing. This function schedules a physical eraseblock for
- * scrubbing which is done in background. This function returns zero in case of
- * success and a negative error code in case of failure.
- */
- int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum)
- {
- struct ubi_wl_entry *e;
- ubi_msg(ubi, "schedule PEB %d for scrubbing", pnum);
- retry:
- spin_lock(&ubi->wl_lock);
- e = ubi->lookuptbl[pnum];
- if (e == ubi->move_from || in_wl_tree(e, &ubi->scrub) ||
- in_wl_tree(e, &ubi->erroneous)) {
- spin_unlock(&ubi->wl_lock);
- return 0;
- }
- if (e == ubi->move_to) {
- /*
- * This physical eraseblock was used to move data to. The data
- * was moved but the PEB was not yet inserted to the proper
- * tree. We should just wait a little and let the WL worker
- * proceed.
- */
- spin_unlock(&ubi->wl_lock);
- dbg_wl("the PEB %d is not in proper tree, retry", pnum);
- yield();
- goto retry;
- }
- if (in_wl_tree(e, &ubi->used)) {
- self_check_in_wl_tree(ubi, e, &ubi->used);
- rb_erase(&e->u.rb, &ubi->used);
- } else {
- int err;
- err = prot_queue_del(ubi, e->pnum);
- if (err) {
- ubi_err(ubi, "PEB %d not found", pnum);
- ubi_ro_mode(ubi);
- spin_unlock(&ubi->wl_lock);
- return err;
- }
- }
- wl_tree_add(e, &ubi->scrub);
- spin_unlock(&ubi->wl_lock);
- /*
- * Technically scrubbing is the same as wear-leveling, so it is done
- * by the WL worker.
- */
- return ensure_wear_leveling(ubi, 0);
- }
- /**
- * ubi_wl_flush - flush all pending works.
- * @ubi: UBI device description object
- * @vol_id: the volume id to flush for
- * @lnum: the logical eraseblock number to flush for
- *
- * This function executes all pending works for a particular volume id /
- * logical eraseblock number pair. If either value is set to %UBI_ALL, then it
- * acts as a wildcard for all of the corresponding volume numbers or logical
- * eraseblock numbers. It returns zero in case of success and a negative error
- * code in case of failure.
- */
- int ubi_wl_flush(struct ubi_device *ubi, int vol_id, int lnum)
- {
- int err = 0;
- int found = 1;
- /*
- * Erase while the pending works queue is not empty, but not more than
- * the number of currently pending works.
- */
- dbg_wl("flush pending work for LEB %d:%d (%d pending works)",
- vol_id, lnum, ubi->works_count);
- while (found) {
- struct ubi_work *wrk, *tmp;
- found = 0;
- down_read(&ubi->work_sem);
- spin_lock(&ubi->wl_lock);
- list_for_each_entry_safe(wrk, tmp, &ubi->works, list) {
- if ((vol_id == UBI_ALL || wrk->vol_id == vol_id) &&
- (lnum == UBI_ALL || wrk->lnum == lnum)) {
- list_del(&wrk->list);
- ubi->works_count -= 1;
- ubi_assert(ubi->works_count >= 0);
- spin_unlock(&ubi->wl_lock);
- err = wrk->func(ubi, wrk, 0);
- if (err) {
- up_read(&ubi->work_sem);
- return err;
- }
- spin_lock(&ubi->wl_lock);
- found = 1;
- break;
- }
- }
- spin_unlock(&ubi->wl_lock);
- up_read(&ubi->work_sem);
- }
- /*
- * Make sure all the works which have been done in parallel are
- * finished.
- */
- down_write(&ubi->work_sem);
- up_write(&ubi->work_sem);
- return err;
- }
- /**
- * tree_destroy - destroy an RB-tree.
- * @ubi: UBI device description object
- * @root: the root of the tree to destroy
- */
- static void tree_destroy(struct ubi_device *ubi, struct rb_root *root)
- {
- struct rb_node *rb;
- struct ubi_wl_entry *e;
- rb = root->rb_node;
- while (rb) {
- if (rb->rb_left)
- rb = rb->rb_left;
- else if (rb->rb_right)
- rb = rb->rb_right;
- else {
- e = rb_entry(rb, struct ubi_wl_entry, u.rb);
- rb = rb_parent(rb);
- if (rb) {
- if (rb->rb_left == &e->u.rb)
- rb->rb_left = NULL;
- else
- rb->rb_right = NULL;
- }
- wl_entry_destroy(ubi, e);
- }
- }
- }
- /**
- * ubi_thread - UBI background thread.
- * @u: the UBI device description object pointer
- */
- int ubi_thread(void *u)
- {
- int failures = 0;
- struct ubi_device *ubi = u;
- ubi_msg(ubi, "background thread \"%s\" started, PID %d",
- ubi->bgt_name, task_pid_nr(current));
- set_freezable();
- for (;;) {
- int err;
- if (kthread_should_stop())
- break;
- if (try_to_freeze())
- continue;
- spin_lock(&ubi->wl_lock);
- if (list_empty(&ubi->works) || ubi->ro_mode ||
- !ubi->thread_enabled || ubi_dbg_is_bgt_disabled(ubi)) {
- set_current_state(TASK_INTERRUPTIBLE);
- spin_unlock(&ubi->wl_lock);
- schedule();
- continue;
- }
- spin_unlock(&ubi->wl_lock);
- err = do_work(ubi);
- if (err) {
- ubi_err(ubi, "%s: work failed with error code %d",
- ubi->bgt_name, err);
- if (failures++ > WL_MAX_FAILURES) {
- /*
- * Too many failures, disable the thread and
- * switch to read-only mode.
- */
- ubi_msg(ubi, "%s: %d consecutive failures",
- ubi->bgt_name, WL_MAX_FAILURES);
- ubi_ro_mode(ubi);
- ubi->thread_enabled = 0;
- continue;
- }
- } else
- failures = 0;
- cond_resched();
- }
- dbg_wl("background thread \"%s\" is killed", ubi->bgt_name);
- ubi->thread_enabled = 0;
- return 0;
- }
- /**
- * shutdown_work - shutdown all pending works.
- * @ubi: UBI device description object
- */
- static void shutdown_work(struct ubi_device *ubi)
- {
- while (!list_empty(&ubi->works)) {
- struct ubi_work *wrk;
- wrk = list_entry(ubi->works.next, struct ubi_work, list);
- list_del(&wrk->list);
- wrk->func(ubi, wrk, 1);
- ubi->works_count -= 1;
- ubi_assert(ubi->works_count >= 0);
- }
- }
- /**
- * erase_aeb - erase a PEB given in UBI attach info PEB
- * @ubi: UBI device description object
- * @aeb: UBI attach info PEB
- * @sync: If true, erase synchronously. Otherwise schedule for erasure
- */
- static int erase_aeb(struct ubi_device *ubi, struct ubi_ainf_peb *aeb, bool sync)
- {
- struct ubi_wl_entry *e;
- int err;
- e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
- if (!e)
- return -ENOMEM;
- e->pnum = aeb->pnum;
- e->ec = aeb->ec;
- ubi->lookuptbl[e->pnum] = e;
- if (sync) {
- err = sync_erase(ubi, e, false);
- if (err)
- goto out_free;
- wl_tree_add(e, &ubi->free);
- ubi->free_count++;
- } else {
- err = schedule_erase(ubi, e, aeb->vol_id, aeb->lnum, 0, false);
- if (err)
- goto out_free;
- }
- return 0;
- out_free:
- wl_entry_destroy(ubi, e);
- return err;
- }
- /**
- * ubi_wl_init - initialize the WL sub-system using attaching information.
- * @ubi: UBI device description object
- * @ai: attaching information
- *
- * This function returns zero in case of success, and a negative error code in
- * case of failure.
- */
- int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
- {
- int err, i, reserved_pebs, found_pebs = 0;
- struct rb_node *rb1, *rb2;
- struct ubi_ainf_volume *av;
- struct ubi_ainf_peb *aeb, *tmp;
- struct ubi_wl_entry *e;
- ubi->used = ubi->erroneous = ubi->free = ubi->scrub = RB_ROOT;
- spin_lock_init(&ubi->wl_lock);
- mutex_init(&ubi->move_mutex);
- init_rwsem(&ubi->work_sem);
- ubi->max_ec = ai->max_ec;
- INIT_LIST_HEAD(&ubi->works);
- sprintf(ubi->bgt_name, UBI_BGT_NAME_PATTERN, ubi->ubi_num);
- err = -ENOMEM;
- ubi->lookuptbl = kzalloc(ubi->peb_count * sizeof(void *), GFP_KERNEL);
- if (!ubi->lookuptbl)
- return err;
- for (i = 0; i < UBI_PROT_QUEUE_LEN; i++)
- INIT_LIST_HEAD(&ubi->pq[i]);
- ubi->pq_head = 0;
- list_for_each_entry_safe(aeb, tmp, &ai->erase, u.list) {
- cond_resched();
- err = erase_aeb(ubi, aeb, false);
- if (err)
- goto out_free;
- found_pebs++;
- }
- ubi->free_count = 0;
- list_for_each_entry(aeb, &ai->free, u.list) {
- cond_resched();
- e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
- if (!e) {
- err = -ENOMEM;
- goto out_free;
- }
- e->pnum = aeb->pnum;
- e->ec = aeb->ec;
- ubi_assert(e->ec >= 0);
- wl_tree_add(e, &ubi->free);
- ubi->free_count++;
- ubi->lookuptbl[e->pnum] = e;
- found_pebs++;
- }
- ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
- ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb) {
- cond_resched();
- e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
- if (!e) {
- err = -ENOMEM;
- goto out_free;
- }
- e->pnum = aeb->pnum;
- e->ec = aeb->ec;
- ubi->lookuptbl[e->pnum] = e;
- if (!aeb->scrub) {
- dbg_wl("add PEB %d EC %d to the used tree",
- e->pnum, e->ec);
- wl_tree_add(e, &ubi->used);
- } else {
- dbg_wl("add PEB %d EC %d to the scrub tree",
- e->pnum, e->ec);
- wl_tree_add(e, &ubi->scrub);
- }
- found_pebs++;
- }
- }
- list_for_each_entry(aeb, &ai->fastmap, u.list) {
- cond_resched();
- e = ubi_find_fm_block(ubi, aeb->pnum);
- if (e) {
- ubi_assert(!ubi->lookuptbl[e->pnum]);
- ubi->lookuptbl[e->pnum] = e;
- } else {
- bool sync = false;
- /*
- * Usually old Fastmap PEBs are scheduled for erasure
- * and we don't have to care about them but if we face
- * an power cut before scheduling them we need to
- * take care of them here.
- */
- if (ubi->lookuptbl[aeb->pnum])
- continue;
- /*
- * The fastmap update code might not find a free PEB for
- * writing the fastmap anchor to and then reuses the
- * current fastmap anchor PEB. When this PEB gets erased
- * and a power cut happens before it is written again we
- * must make sure that the fastmap attach code doesn't
- * find any outdated fastmap anchors, hence we erase the
- * outdated fastmap anchor PEBs synchronously here.
- */
- if (aeb->vol_id == UBI_FM_SB_VOLUME_ID)
- sync = true;
- err = erase_aeb(ubi, aeb, sync);
- if (err)
- goto out_free;
- }
- found_pebs++;
- }
- dbg_wl("found %i PEBs", found_pebs);
- ubi_assert(ubi->good_peb_count == found_pebs);
- reserved_pebs = WL_RESERVED_PEBS;
- ubi_fastmap_init(ubi, &reserved_pebs);
- if (ubi->avail_pebs < reserved_pebs) {
- ubi_err(ubi, "no enough physical eraseblocks (%d, need %d)",
- ubi->avail_pebs, reserved_pebs);
- if (ubi->corr_peb_count)
- ubi_err(ubi, "%d PEBs are corrupted and not used",
- ubi->corr_peb_count);
- err = -ENOSPC;
- goto out_free;
- }
- ubi->avail_pebs -= reserved_pebs;
- ubi->rsvd_pebs += reserved_pebs;
- /* Schedule wear-leveling if needed */
- err = ensure_wear_leveling(ubi, 0);
- if (err)
- goto out_free;
- return 0;
- out_free:
- shutdown_work(ubi);
- tree_destroy(ubi, &ubi->used);
- tree_destroy(ubi, &ubi->free);
- tree_destroy(ubi, &ubi->scrub);
- kfree(ubi->lookuptbl);
- return err;
- }
- /**
- * protection_queue_destroy - destroy the protection queue.
- * @ubi: UBI device description object
- */
- static void protection_queue_destroy(struct ubi_device *ubi)
- {
- int i;
- struct ubi_wl_entry *e, *tmp;
- for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i) {
- list_for_each_entry_safe(e, tmp, &ubi->pq[i], u.list) {
- list_del(&e->u.list);
- wl_entry_destroy(ubi, e);
- }
- }
- }
- /**
- * ubi_wl_close - close the wear-leveling sub-system.
- * @ubi: UBI device description object
- */
- void ubi_wl_close(struct ubi_device *ubi)
- {
- dbg_wl("close the WL sub-system");
- ubi_fastmap_close(ubi);
- shutdown_work(ubi);
- protection_queue_destroy(ubi);
- tree_destroy(ubi, &ubi->used);
- tree_destroy(ubi, &ubi->erroneous);
- tree_destroy(ubi, &ubi->free);
- tree_destroy(ubi, &ubi->scrub);
- kfree(ubi->lookuptbl);
- }
- /**
- * self_check_ec - make sure that the erase counter of a PEB is correct.
- * @ubi: UBI device description object
- * @pnum: the physical eraseblock number to check
- * @ec: the erase counter to check
- *
- * This function returns zero if the erase counter of physical eraseblock @pnum
- * is equivalent to @ec, and a negative error code if not or if an error
- * occurred.
- */
- static int self_check_ec(struct ubi_device *ubi, int pnum, int ec)
- {
- int err;
- long long read_ec;
- struct ubi_ec_hdr *ec_hdr;
- if (!ubi_dbg_chk_gen(ubi))
- return 0;
- ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
- if (!ec_hdr)
- return -ENOMEM;
- err = ubi_io_read_ec_hdr(ubi, pnum, ec_hdr, 0);
- if (err && err != UBI_IO_BITFLIPS) {
- /* The header does not have to exist */
- err = 0;
- goto out_free;
- }
- read_ec = be64_to_cpu(ec_hdr->ec);
- if (ec != read_ec && read_ec - ec > 1) {
- ubi_err(ubi, "self-check failed for PEB %d", pnum);
- ubi_err(ubi, "read EC is %lld, should be %d", read_ec, ec);
- dump_stack();
- err = 1;
- } else
- err = 0;
- out_free:
- kfree(ec_hdr);
- return err;
- }
- /**
- * self_check_in_wl_tree - check that wear-leveling entry is in WL RB-tree.
- * @ubi: UBI device description object
- * @e: the wear-leveling entry to check
- * @root: the root of the tree
- *
- * This function returns zero if @e is in the @root RB-tree and %-EINVAL if it
- * is not.
- */
- static int self_check_in_wl_tree(const struct ubi_device *ubi,
- struct ubi_wl_entry *e, struct rb_root *root)
- {
- if (!ubi_dbg_chk_gen(ubi))
- return 0;
- if (in_wl_tree(e, root))
- return 0;
- ubi_err(ubi, "self-check failed for PEB %d, EC %d, RB-tree %p ",
- e->pnum, e->ec, root);
- dump_stack();
- return -EINVAL;
- }
- /**
- * self_check_in_pq - check if wear-leveling entry is in the protection
- * queue.
- * @ubi: UBI device description object
- * @e: the wear-leveling entry to check
- *
- * This function returns zero if @e is in @ubi->pq and %-EINVAL if it is not.
- */
- static int self_check_in_pq(const struct ubi_device *ubi,
- struct ubi_wl_entry *e)
- {
- struct ubi_wl_entry *p;
- int i;
- if (!ubi_dbg_chk_gen(ubi))
- return 0;
- for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i)
- list_for_each_entry(p, &ubi->pq[i], u.list)
- if (p == e)
- return 0;
- ubi_err(ubi, "self-check failed for PEB %d, EC %d, Protect queue",
- e->pnum, e->ec);
- dump_stack();
- return -EINVAL;
- }
- #ifndef CONFIG_MTD_UBI_FASTMAP
- static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
- {
- struct ubi_wl_entry *e;
- e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
- self_check_in_wl_tree(ubi, e, &ubi->free);
- ubi->free_count--;
- ubi_assert(ubi->free_count >= 0);
- rb_erase(&e->u.rb, &ubi->free);
- return e;
- }
- /**
- * produce_free_peb - produce a free physical eraseblock.
- * @ubi: UBI device description object
- *
- * This function tries to make a free PEB by means of synchronous execution of
- * pending works. This may be needed if, for example the background thread is
- * disabled. Returns zero in case of success and a negative error code in case
- * of failure.
- */
- static int produce_free_peb(struct ubi_device *ubi)
- {
- int err;
- while (!ubi->free.rb_node && ubi->works_count) {
- spin_unlock(&ubi->wl_lock);
- dbg_wl("do one work synchronously");
- err = do_work(ubi);
- spin_lock(&ubi->wl_lock);
- if (err)
- return err;
- }
- return 0;
- }
- /**
- * ubi_wl_get_peb - get a physical eraseblock.
- * @ubi: UBI device description object
- *
- * This function returns a physical eraseblock in case of success and a
- * negative error code in case of failure.
- * Returns with ubi->fm_eba_sem held in read mode!
- */
- int ubi_wl_get_peb(struct ubi_device *ubi)
- {
- int err;
- struct ubi_wl_entry *e;
- retry:
- down_read(&ubi->fm_eba_sem);
- spin_lock(&ubi->wl_lock);
- if (!ubi->free.rb_node) {
- if (ubi->works_count == 0) {
- ubi_err(ubi, "no free eraseblocks");
- ubi_assert(list_empty(&ubi->works));
- spin_unlock(&ubi->wl_lock);
- return -ENOSPC;
- }
- err = produce_free_peb(ubi);
- if (err < 0) {
- spin_unlock(&ubi->wl_lock);
- return err;
- }
- spin_unlock(&ubi->wl_lock);
- up_read(&ubi->fm_eba_sem);
- goto retry;
- }
- e = wl_get_wle(ubi);
- prot_queue_add(ubi, e);
- spin_unlock(&ubi->wl_lock);
- err = ubi_self_check_all_ff(ubi, e->pnum, ubi->vid_hdr_aloffset,
- ubi->peb_size - ubi->vid_hdr_aloffset);
- if (err) {
- ubi_err(ubi, "new PEB %d does not contain all 0xFF bytes", e->pnum);
- return err;
- }
- return e->pnum;
- }
- #else
- #include "fastmap-wl.c"
- #endif
|