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2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 | // SPDX-License-Identifier: GPL-2.0-or-later /* * Copyright (c) International Business Machines Corp., 2006 * * 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_entry_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 * @executed: whether there is one work is executed * * This function returns zero in case of success and a negative error code in * case of failure. If @executed is not NULL and there is one work executed, * @executed is set as %1, otherwise @executed is set as %0. */ static int do_work(struct ubi_device *ubi, int *executed) { 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); if (executed) *executed = 0; return 0; } if (executed) *executed = 1; 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; } /** * in_pq - check if a wear-leveling entry is present in the protection queue. * @ubi: UBI device description object * @e: the wear-leveling entry to check * * This function returns non-zero if @e is in the protection queue and zero * if it is not. */ static inline int in_pq(const struct ubi_device *ubi, struct ubi_wl_entry *e) { struct ubi_wl_entry *p; int i; for (i = 0; i < UBI_PROT_QUEUE_LEN; ++i) list_for_each_entry(p, &ubi->pq[i], u.list) if (p == e) return 1; 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 * @pick_max: pick PEB even its erase counter beyonds 'min_ec + @diff' * * 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, int pick_max) { struct rb_node *p; struct ubi_wl_entry *e; 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) { if (pick_max) e = e1; p = p->rb_left; } else { p = p->rb_right; e = e1; } } 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 fm_anchor is not * reserved 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, 0); 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 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; } /** * ubi_sync_erase - synchronously erase a physical eraseblock. * @ubi: UBI device description object * @e: 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. */ int ubi_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 * @nested: denotes whether the work_sem is already held * * 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); } static int ensure_wear_leveling(struct ubi_device *ubi, int nested); /** * 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; struct ubi_wl_entry *e1, *e2; struct ubi_vid_io_buf *vidb; struct ubi_vid_hdr *vid_hdr; int dst_leb_clean = 0; kfree(wrk); if (shutdown) return 0; vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS); if (!vidb) return -ENOMEM; vid_hdr = ubi_get_vid_hdr(vidb); 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); #ifdef CONFIG_MTD_UBI_FASTMAP if (!next_peb_for_wl(ubi) || #else if (!ubi->free.rb_node || #endif (!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 e1 = find_anchor_wl_entry(&ubi->used); if (e1 && ubi->fm_anchor && (ubi->fm_anchor->ec - e1->ec >= UBI_WL_THRESHOLD)) { ubi->fm_do_produce_anchor = 1; /* * fm_anchor is no longer considered a good anchor. * NULL assignment also prevents multiple wear level checks * of this PEB. */ wl_tree_add(ubi->fm_anchor, &ubi->free); ubi->fm_anchor = NULL; ubi->free_count++; } if (ubi->fm_do_produce_anchor) { 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); ubi->fm_do_produce_anchor = 0; } 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, vidb, 0); if (err && err != UBI_IO_BITFLIPS) { dst_leb_clean = 1; 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, vidb); 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; dst_leb_clean = 1; goto out_not_moved; } if (err == MOVE_RETRY) { scrubbing = 1; dst_leb_clean = 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; } dst_leb_clean = 1; 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_buf(vidb); 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) { spin_lock(&ubi->wl_lock); wl_entry_destroy(ubi, e2); spin_unlock(&ubi->wl_lock); } 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); if (dst_leb_clean) { wl_tree_add(e2, &ubi->free); ubi->free_count++; } 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_buf(vidb); if (dst_leb_clean) { ensure_wear_leveling(ubi, 1); } else { 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; wl_entry_destroy(ubi, e1); wl_entry_destroy(ubi, e2); spin_unlock(&ubi->wl_lock); ubi_free_vid_buf(vidb); 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_buf(vidb); 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_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 * WL worker has to be scheduled anyway. */ if (!ubi->scrub.rb_node) { #ifdef CONFIG_MTD_UBI_FASTMAP if (!need_wear_leveling(ubi)) goto out_unlock; #else struct ubi_wl_entry *e1; struct ubi_wl_entry *e2; 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, 0); if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD)) goto out_unlock; #endif 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->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 * * 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 = ubi_sync_erase(ubi, e, wl_wrk->torture); if (!err) { spin_lock(&ubi->wl_lock); if (!ubi->fm_disabled && !ubi->fm_anchor && e->pnum < UBI_FM_MAX_START) { /* * Abort anchor production, if needed it will be * enabled again in the wear leveling started below. */ ubi->fm_anchor = e; ubi->fm_do_produce_anchor = 0; } else { 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, true); if (err1) { spin_lock(&ubi->wl_lock); wl_entry_destroy(ubi, e); spin_unlock(&ubi->wl_lock); err = err1; goto out_ro; } return err; } spin_lock(&ubi->wl_lock); wl_entry_destroy(ubi, e); spin_unlock(&ubi->wl_lock); 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) { /* * This wl entry has been removed for some errors by other * process (eg. wear leveling worker), corresponding process * (except __erase_worker, which cannot concurrent with * ubi_wl_put_peb) will set ubi ro_mode at the same time, * just ignore this wl entry. */ spin_unlock(&ubi->wl_lock); up_read(&ubi->fm_protect); return 0; } 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; } static bool scrub_possible(struct ubi_device *ubi, struct ubi_wl_entry *e) { if (in_wl_tree(e, &ubi->scrub)) return false; else if (in_wl_tree(e, &ubi->erroneous)) return false; else if (ubi->move_from == e) return false; else if (ubi->move_to == e) return false; return true; } /** * ubi_bitflip_check - Check an eraseblock for bitflips and scrub it if needed. * @ubi: UBI device description object * @pnum: the physical eraseblock to schedule * @force: don't read the block, assume bitflips happened and take action. * * This function reads the given eraseblock and checks if bitflips occured. * In case of bitflips, the eraseblock is scheduled for scrubbing. * If scrubbing is forced with @force, the eraseblock is not read, * but scheduled for scrubbing right away. * * Returns: * %EINVAL, PEB is out of range * %ENOENT, PEB is no longer used by UBI * %EBUSY, PEB cannot be checked now or a check is currently running on it * %EAGAIN, bit flips happened but scrubbing is currently not possible * %EUCLEAN, bit flips happened and PEB is scheduled for scrubbing * %0, no bit flips detected */ int ubi_bitflip_check(struct ubi_device *ubi, int pnum, int force) { int err = 0; struct ubi_wl_entry *e; if (pnum < 0 || pnum >= ubi->peb_count) { err = -EINVAL; goto out; } /* * Pause all parallel work, otherwise it can happen that the * erase worker frees a wl entry under us. */ down_write(&ubi->work_sem); /* * Make sure that the wl entry does not change state while * inspecting it. */ spin_lock(&ubi->wl_lock); e = ubi->lookuptbl[pnum]; if (!e) { spin_unlock(&ubi->wl_lock); err = -ENOENT; goto out_resume; } /* * Does it make sense to check this PEB? */ if (!scrub_possible(ubi, e)) { spin_unlock(&ubi->wl_lock); err = -EBUSY; goto out_resume; } spin_unlock(&ubi->wl_lock); if (!force) { mutex_lock(&ubi->buf_mutex); err = ubi_io_read(ubi, ubi->peb_buf, pnum, 0, ubi->peb_size); mutex_unlock(&ubi->buf_mutex); } if (force || err == UBI_IO_BITFLIPS) { /* * Okay, bit flip happened, let's figure out what we can do. */ spin_lock(&ubi->wl_lock); /* * Recheck. We released wl_lock, UBI might have killed the * wl entry under us. */ e = ubi->lookuptbl[pnum]; if (!e) { spin_unlock(&ubi->wl_lock); err = -ENOENT; goto out_resume; } /* * Need to re-check state */ if (!scrub_possible(ubi, e)) { spin_unlock(&ubi->wl_lock); err = -EBUSY; goto out_resume; } if (in_pq(ubi, e)) { prot_queue_del(ubi, e->pnum); wl_tree_add(e, &ubi->scrub); spin_unlock(&ubi->wl_lock); err = ensure_wear_leveling(ubi, 1); } else if (in_wl_tree(e, &ubi->used)) { rb_erase(&e->u.rb, &ubi->used); wl_tree_add(e, &ubi->scrub); spin_unlock(&ubi->wl_lock); err = ensure_wear_leveling(ubi, 1); } else if (in_wl_tree(e, &ubi->free)) { rb_erase(&e->u.rb, &ubi->free); ubi->free_count--; spin_unlock(&ubi->wl_lock); /* * This PEB is empty we can schedule it for * erasure right away. No wear leveling needed. */ err = schedule_erase(ubi, e, UBI_UNKNOWN, UBI_UNKNOWN, force ? 0 : 1, true); } else { spin_unlock(&ubi->wl_lock); err = -EAGAIN; } if (!err && !force) err = -EUCLEAN; } else { err = 0; } out_resume: up_write(&ubi->work_sem); out: 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); /* * Check kthread_should_stop() after we set the task * state to guarantee that we either see the stop bit * and exit or the task state is reset to runnable such * that it's not scheduled out indefinitely and detects * the stop bit at kthread_should_stop(). */ if (kthread_should_stop()) { set_current_state(TASK_RUNNING); break; } schedule(); continue; } spin_unlock(&ubi->wl_lock); err = do_work(ubi, NULL); 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 = ubi_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 = kcalloc(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; ubi->free_count = 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++; } 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; #ifdef CONFIG_MTD_UBI_FASTMAP if (!ubi->ro_mode && !ubi->fm_disabled) ubi_ensure_anchor_pebs(ubi); #endif 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) { if (!ubi_dbg_chk_gen(ubi)) return 0; if (in_pq(ubi, 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, 0); 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, NULL); 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 |