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Diffstat (limited to 'drivers/mtd/ubi/wl.c')
| -rw-r--r-- | drivers/mtd/ubi/wl.c | 1671 |
1 files changed, 1671 insertions, 0 deletions
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c new file mode 100644 index 000000000000..9ecaf77eca9e --- /dev/null +++ b/drivers/mtd/ubi/wl.c @@ -0,0 +1,1671 @@ +/* + * 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 unit. + * + * This unit 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 unit'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 unit 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 unit. + * + * 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. + * + * The 'ubi_wl_get_peb()' function accepts data type hints which help to pick + * an "optimal" physical eraseblock. For example, when it is known that the + * physical eraseblock will be "put" soon because it contains short-term data, + * the WL unit may pick a free physical eraseblock with low erase counter, and + * so forth. + * + * If the WL unit fails to erase a physical eraseblock, it marks it as bad. + * + * This unit 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 unit all physical eraseblocks are either "free" + * or "used". Free eraseblock are kept in the @wl->free RB-tree, while used + * eraseblocks are kept in a set of different RB-trees: @wl->used, + * @wl->prot.pnum, @wl->prot.aec, and @wl->scrub. + * + * 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 unit and make it more scalable. + * + * At the moment this unit 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 unit. + * + * FIXME: looks too complex, should be simplified (later). + */ + +#include <linux/slab.h> +#include <linux/crc32.h> +#include <linux/freezer.h> +#include <linux/kthread.h> +#include "ubi.h" + +/* Number of physical eraseblocks reserved for wear-leveling purposes */ +#define WL_RESERVED_PEBS 1 + +/* + * How many erase cycles are short term, unknown, and long term physical + * eraseblocks protected. + */ +#define ST_PROTECTION 16 +#define U_PROTECTION 10 +#define LT_PROTECTION 4 + +/* + * Maximum difference between two erase counters. If this threshold is + * exceeded, the WL unit 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 unit 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 unit does + * not pick eraseblocks with erase counter greater then 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 + +/** + * struct ubi_wl_entry - wear-leveling entry. + * @rb: link in the corresponding RB-tree + * @ec: erase counter + * @pnum: physical eraseblock number + * + * Each physical eraseblock has a corresponding &struct wl_entry object which + * may be kept in different RB-trees. + */ +struct ubi_wl_entry { + struct rb_node rb; + int ec; + int pnum; +}; + +/** + * struct ubi_wl_prot_entry - PEB protection entry. + * @rb_pnum: link in the @wl->prot.pnum RB-tree + * @rb_aec: link in the @wl->prot.aec RB-tree + * @abs_ec: the absolute erase counter value when the protection ends + * @e: the wear-leveling entry of the physical eraseblock under protection + * + * When the WL unit 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 one more tree in between where this physical eraseblock is + * temporarily stored (@wl->prot). + * + * 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; this is + * especially important in case of "short term" physical eraseblocks. + * + * 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 + * absolute erase counter (@wl->abs_ec). When it reaches certain value, the + * physical eraseblocks are moved from the protection trees (@wl->prot.*) to + * the @wl->used tree. + * + * Protected physical eraseblocks are searched by physical eraseblock number + * (when they are put) and by the absolute erase counter (to check if it is + * time to move them to the @wl->used tree). So there are actually 2 RB-trees + * storing the protected physical eraseblocks: @wl->prot.pnum and + * @wl->prot.aec. They are referred to as the "protection" trees. The + * first one is indexed by the physical eraseblock number. The second one is + * indexed by the absolute erase counter. Both trees store + * &struct ubi_wl_prot_entry objects. + * + * 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 temporarily prohibited (@wl->prot.pnum and + * @wl->prot.aec trees); + * 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 trees. + */ +struct ubi_wl_prot_entry { + struct rb_node rb_pnum; + struct rb_node rb_aec; + unsigned long long abs_ec; + struct ubi_wl_entry *e; +}; + +/** + * struct ubi_work - UBI work description data structure. + * @list: a link in the list of pending works + * @func: worker function + * @priv: private data of the worker function + * + * @e: physical eraseblock to erase + * @torture: if the physical eraseblock has to be tortured + * + * The @func pointer points to the worker function. If the @cancel argument is + * not zero, the worker has to free the resources and exit immediately. The + * worker has to return zero in case of success and a negative error code in + * case of failure. + */ +struct ubi_work { + struct list_head list; + int (*func)(struct ubi_device *ubi, struct ubi_work *wrk, int cancel); + /* The below fields are only relevant to erasure works */ + struct ubi_wl_entry *e; + int torture; +}; + +#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID +static int paranoid_check_ec(const struct ubi_device *ubi, int pnum, int ec); +static int paranoid_check_in_wl_tree(struct ubi_wl_entry *e, + struct rb_root *root); +#else +#define paranoid_check_ec(ubi, pnum, ec) 0 +#define paranoid_check_in_wl_tree(e, root) +#endif + +/* Slab cache for wear-leveling entries */ +static struct kmem_cache *wl_entries_slab; + +/** + * tree_empty - a helper function to check if an RB-tree is empty. + * @root: the root of the tree + * + * This function returns non-zero if the RB-tree is empty and zero if not. + */ +static inline int tree_empty(struct rb_root *root) +{ + return root->rb_node == NULL; +} + +/** + * 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, 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->rb, parent, p); + rb_insert_color(&e->rb, root); +} + + +/* + * Helper functions to add and delete wear-leveling entries from different + * trees. + */ + +static void free_tree_add(struct ubi_device *ubi, struct ubi_wl_entry *e) +{ + wl_tree_add(e, &ubi->free); +} +static inline void used_tree_add(struct ubi_device *ubi, + struct ubi_wl_entry *e) +{ + wl_tree_add(e, &ubi->used); +} +static inline void scrub_tree_add(struct ubi_device *ubi, + struct ubi_wl_entry *e) +{ + wl_tree_add(e, &ubi->scrub); +} +static inline void free_tree_del(struct ubi_device *ubi, + struct ubi_wl_entry *e) +{ + paranoid_check_in_wl_tree(e, &ubi->free); + rb_erase(&e->rb, &ubi->free); +} +static inline void used_tree_del(struct ubi_device *ubi, + struct ubi_wl_entry *e) +{ + paranoid_check_in_wl_tree(e, &ubi->used); + rb_erase(&e->rb, &ubi->used); +} +static inline void scrub_tree_del(struct ubi_device *ubi, + struct ubi_wl_entry *e) +{ + paranoid_check_in_wl_tree(e, &ubi->scrub); + rb_erase(&e->rb, &ubi->scrub); +} + +/** + * 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; + + spin_lock(&ubi->wl_lock); + + if (list_empty(&ubi->works)) { + spin_unlock(&ubi->wl_lock); + return 0; + } + + wrk = list_entry(ubi->works.next, struct ubi_work, list); + list_del(&wrk->list); + 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("work failed with error code %d", err); + + spin_lock(&ubi->wl_lock); + ubi->works_count -= 1; + ubi_assert(ubi->works_count >= 0); + spin_unlock(&ubi->wl_lock); + return err; +} + +/** + * 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; + + spin_lock(&ubi->wl_lock); + while (tree_empty(&ubi->free)) { + spin_unlock(&ubi->wl_lock); + + dbg_wl("do one work synchronously"); + err = do_work(ubi); + if (err) + return err; + + spin_lock(&ubi->wl_lock); + } + spin_unlock(&ubi->wl_lock); + + return 0; +} + +/** + * 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, 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_tree_add - add physical eraseblock to protection trees. + * @ubi: UBI device description object + * @e: the physical eraseblock to add + * @pe: protection entry object to use + * @abs_ec: absolute erase counter value when this physical eraseblock has + * to be removed from the protection trees. + * + * @wl->lock has to be locked. + */ +static void prot_tree_add(struct ubi_device *ubi, struct ubi_wl_entry *e, + struct ubi_wl_prot_entry *pe, int abs_ec) +{ + struct rb_node **p, *parent = NULL; + struct ubi_wl_prot_entry *pe1; + + pe->e = e; + pe->abs_ec = ubi->abs_ec + abs_ec; + + p = &ubi->prot.pnum.rb_node; + while (*p) { + parent = *p; + pe1 = rb_entry(parent, struct ubi_wl_prot_entry, rb_pnum); + + if (e->pnum < pe1->e->pnum) + p = &(*p)->rb_left; + else + p = &(*p)->rb_right; + } + rb_link_node(&pe->rb_pnum, parent, p); + rb_insert_color(&pe->rb_pnum, &ubi->prot.pnum); + + p = &ubi->prot.aec.rb_node; + parent = NULL; + while (*p) { + parent = *p; + pe1 = rb_entry(parent, struct ubi_wl_prot_entry, rb_aec); + + if (pe->abs_ec < pe1->abs_ec) + p = &(*p)->rb_left; + else + p = &(*p)->rb_right; + } + rb_link_node(&pe->rb_aec, parent, p); + rb_insert_color(&pe->rb_aec, &ubi->prot.aec); +} + +/** + * find_wl_entry - find wear-leveling entry closest to certain erase counter. + * @root: the RB-tree where to look for + * @max: highest possible erase counter + * + * This function looks for a wear leveling entry with erase counter closest to + * @max and less then @max. + */ +static struct ubi_wl_entry *find_wl_entry(struct rb_root *root, int max) +{ + struct rb_node *p; + struct ubi_wl_entry *e; + + e = rb_entry(rb_first(root), struct ubi_wl_entry, rb); + max += e->ec; + + p = root->rb_node; + while (p) { + struct ubi_wl_entry *e1; + + e1 = rb_entry(p, struct ubi_wl_entry, rb); + if (e1->ec >= max) + p = p->rb_left; + else { + p = p->rb_right; + e = e1; + } + } + + return e; +} + +/** + * ubi_wl_get_peb - get a physical eraseblock. + * @ubi: UBI device description object + * @dtype: type of data which will be stored in this physical eraseblock + * + * This function returns a physical eraseblock in case of success and a + * negative error code in case of failure. Might sleep. + */ +int ubi_wl_get_peb(struct ubi_device *ubi, int dtype) +{ + int err, protect, medium_ec; + struct ubi_wl_entry *e, *first, *last; + struct ubi_wl_prot_entry *pe; + + ubi_assert(dtype == UBI_LONGTERM || dtype == UBI_SHORTTERM || + dtype == UBI_UNKNOWN); + + pe = kmalloc(sizeof(struct ubi_wl_prot_entry), GFP_KERNEL); + if (!pe) + return -ENOMEM; + +retry: + spin_lock(&ubi->wl_lock); + if (tree_empty(&ubi->free)) { + if (ubi->works_count == 0) { + ubi_assert(list_empty(&ubi->works)); + ubi_err("no free eraseblocks"); + spin_unlock(&ubi->wl_lock); + kfree(pe); + return -ENOSPC; + } + spin_unlock(&ubi->wl_lock); + + err = produce_free_peb(ubi); + if (err < 0) { + kfree(pe); + return err; + } + goto retry; + } + + switch (dtype) { + case UBI_LONGTERM: + /* + * For long term data we pick a physical eraseblock + * with high erase counter. But the highest erase + * counter we can pick is bounded by the the lowest + * erase counter plus %WL_FREE_MAX_DIFF. + */ + e = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF); + protect = LT_PROTECTION; + break; + case UBI_UNKNOWN: + /* + * For unknown data we pick a physical eraseblock with + * medium erase counter. But we by no means can pick a + * physical eraseblock with erase counter greater or + * equivalent than the lowest erase counter plus + * %WL_FREE_MAX_DIFF. + */ + first = rb_entry(rb_first(&ubi->free), + struct ubi_wl_entry, rb); + last = rb_entry(rb_last(&ubi->free), + struct ubi_wl_entry, rb); + + if (last->ec - first->ec < WL_FREE_MAX_DIFF) + e = rb_entry(ubi->free.rb_node, + struct ubi_wl_entry, rb); + else { + medium_ec = (first->ec + WL_FREE_MAX_DIFF)/2; + e = find_wl_entry(&ubi->free, medium_ec); + } + protect = U_PROTECTION; + break; + case UBI_SHORTTERM: + /* + * For short term data we pick a physical eraseblock + * with the lowest erase counter as we expect it will + * be erased soon. + */ + e = rb_entry(rb_first(&ubi->free), + struct ubi_wl_entry, rb); + protect = ST_PROTECTION; + break; + default: + protect = 0; + e = NULL; + BUG(); + } + + /* + * Move the physical eraseblock to the protection trees where it will + * be protected from being moved for some time. + */ + free_tree_del(ubi, e); + prot_tree_add(ubi, e, pe, protect); + + dbg_wl("PEB %d EC %d, protection %d", e->pnum, e->ec, protect); + spin_unlock(&ubi->wl_lock); + + return e->pnum; +} + +/** + * prot_tree_del - remove a physical eraseblock from the protection trees + * @ubi: UBI device description object + * @pnum: the physical eraseblock to remove + */ +static void prot_tree_del(struct ubi_device *ubi, int pnum) +{ + struct rb_node *p; + struct ubi_wl_prot_entry *pe = NULL; + + p = ubi->prot.pnum.rb_node; + while (p) { + + pe = rb_entry(p, struct ubi_wl_prot_entry, rb_pnum); + + if (pnum == pe->e->pnum) + break; + + if (pnum < pe->e->pnum) + p = p->rb_left; + else + p = p->rb_right; + } + + ubi_assert(pe->e->pnum == pnum); + rb_erase(&pe->rb_aec, &ubi->prot.aec); + rb_erase(&pe->rb_pnum, &ubi->prot.pnum); + kfree(pe); +} + +/** + * 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 = paranoid_check_ec(ubi, e->pnum, e->ec); + if (err > 0) + return -EINVAL; + + ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL); + 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("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_ubi64(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; +} + +/** + * check_protection_over - check if it is time to stop protecting some + * physical eraseblocks. + * @ubi: UBI device description object + * + * This function is called after each erase operation, when the absolute erase + * counter is incremented, to check if some physical eraseblock have not to be + * protected any longer. These physical eraseblocks are moved from the + * protection trees to the used tree. + */ +static void check_protection_over(struct ubi_device *ubi) +{ + struct ubi_wl_prot_entry *pe; + + /* + * There may be several protected physical eraseblock to remove, + * process them all. + */ + while (1) { + spin_lock(&ubi->wl_lock); + if (tree_empty(&ubi->prot.aec)) { + spin_unlock(&ubi->wl_lock); + break; + } + + pe = rb_entry(rb_first(&ubi->prot.aec), + struct ubi_wl_prot_entry, rb_aec); + + if (pe->abs_ec > ubi->abs_ec) { + spin_unlock(&ubi->wl_lock); + break; + } + + dbg_wl("PEB %d protection over, abs_ec %llu, PEB abs_ec %llu", + pe->e->pnum, ubi->abs_ec, pe->abs_ec); + rb_erase(&pe->rb_aec, &ubi->prot.aec); + rb_erase(&pe->rb_pnum, &ubi->prot.pnum); + used_tree_add(ubi, pe->e); + spin_unlock(&ubi->wl_lock); + + kfree(pe); + cond_resched(); + } +} + +/** + * schedule_ubi_work - schedule a work. + * @ubi: UBI device description object + * @wrk: the work to schedule + * + * This function enqueues 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) +{ + 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) + wake_up_process(ubi->bgt_thread); + spin_unlock(&ubi->wl_lock); +} + +static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk, + int cancel); + +/** + * schedule_erase - schedule an erase work. + * @ubi: UBI device description object + * @e: the WL entry of the physical eraseblock to erase + * @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 torture) +{ + struct ubi_work *wl_wrk; + + dbg_wl("schedule erasure of PEB %d, EC %d, torture %d", + e->pnum, e->ec, torture); + + wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_KERNEL); + if (!wl_wrk) + return -ENOMEM; + + wl_wrk->func = &erase_worker; + wl_wrk->e = e; + wl_wrk->torture = torture; + + schedule_ubi_work(ubi, wl_wrk); + return 0; +} + +/** + * wear_leveling_worker - wear-leveling worker function. + * @ubi: UBI device description object + * @wrk: the work object + * @cancel: non-zero if the worker has to free memory and exit + * + * 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 cancel) +{ + int err, put = 0; + struct ubi_wl_entry *e1, *e2; + struct ubi_vid_hdr *vid_hdr; + + kfree(wrk); + + if (cancel) + return 0; + + vid_hdr = ubi_zalloc_vid_hdr(ubi); + if (!vid_hdr) + return -ENOMEM; + + spin_lock(&ubi->wl_lock); + + /* + * Only one WL worker at a time is supported at this implementation, so + * make sure a PEB is not being moved already. + */ + if (ubi->move_to || tree_empty(&ubi->free) || + (tree_empty(&ubi->used) && tree_empty(&ubi->scrub))) { + /* + * Only one WL worker at a time is supported at this + * implementation, so if a LEB is already being moved, cancel. + * + * No free physical eraseblocks? Well, we cancel wear-leveling + * then. 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", + tree_empty(&ubi->free), tree_empty(&ubi->used)); + ubi->wl_scheduled = 0; + spin_unlock(&ubi->wl_lock); + ubi_free_vid_hdr(ubi, vid_hdr); + return 0; + } + + if (tree_empty(&ubi->scrub)) { + /* + * 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, rb); + e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF); + + 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); + ubi->wl_scheduled = 0; + spin_unlock(&ubi->wl_lock); + ubi_free_vid_hdr(ubi, vid_hdr); + return 0; + } + used_tree_del(ubi, e1); + dbg_wl("move PEB %d EC %d to PEB %d EC %d", + e1->pnum, e1->ec, e2->pnum, e2->ec); + } else { + e1 = rb_entry(rb_first(&ubi->scrub), struct ubi_wl_entry, rb); + e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF); + scrub_tree_del(ubi, e1); + dbg_wl("scrub PEB %d to PEB %d", e1->pnum, e2->pnum); + } + + free_tree_del(ubi, e2); + ubi_assert(!ubi->move_from && !ubi->move_to); + ubi_assert(!ubi->move_to_put && !ubi->move_from_put); + 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. + */ + + err = ubi_io_read_vid_hdr(ubi, e1->pnum, vid_hdr, 0); + if (err && err != UBI_IO_BITFLIPS) { + if (err == UBI_IO_PEB_FREE) { + /* + * 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 did not have + * chance to write it down because it was preempted. + * Just re-schedule the work, so that next time it will + * likely have the VID header in place. + */ + dbg_wl("PEB %d has no VID header", e1->pnum); + err = 0; + } else { + ubi_err("error %d while reading VID header from PEB %d", + err, e1->pnum); + if (err > 0) + err = -EIO; + } + goto error; + } + + err = ubi_eba_copy_leb(ubi, e1->pnum, e2->pnum, vid_hdr); + if (err) { + if (err == UBI_IO_BITFLIPS) + err = 0; + goto error; + } + + ubi_free_vid_hdr(ubi, vid_hdr); + spin_lock(&ubi->wl_lock); + if (!ubi->move_to_put) + used_tree_add(ubi, e2); + else + put = 1; + ubi->move_from = ubi->move_to = NULL; + ubi->move_from_put = ubi->move_to_put = 0; + ubi->wl_scheduled = 0; + spin_unlock(&ubi->wl_lock); + + if (put) { + /* + * Well, the target PEB was put meanwhile, schedule it for + * erasure. + */ + dbg_wl("PEB %d was put meanwhile, erase", e2->pnum); + err = schedule_erase(ubi, e2, 0); + if (err) { + kmem_cache_free(wl_entries_slab, e2); + ubi_ro_mode(ubi); + } + } + + err = schedule_erase(ubi, e1, 0); + if (err) { + kmem_cache_free(wl_entries_slab, e1); + ubi_ro_mode(ubi); + } + + dbg_wl("done"); + return err; + + /* + * Some error occurred. @e1 was not changed, so return it back. @e2 + * might be changed, schedule it for erasure. + */ +error: + if (err) + dbg_wl("error %d occurred, cancel operation", err); + ubi_assert(err <= 0); + + ubi_free_vid_hdr(ubi, vid_hdr); + spin_lock(&ubi->wl_lock); + ubi->wl_scheduled = 0; + if (ubi->move_from_put) + put = 1; + else + used_tree_add(ubi, e1); + ubi->move_from = ubi->move_to = NULL; + ubi->move_from_put = ubi->move_to_put = 0; + spin_unlock(&ubi->wl_lock); + + if (put) { + /* + * Well, the target PEB was put meanwhile, schedule it for + * erasure. + */ + dbg_wl("PEB %d was put meanwhile, erase", e1->pnum); + err = schedule_erase(ubi, e1, 0); + if (err) { + kmem_cache_free(wl_entries_slab, e1); + ubi_ro_mode(ubi); + } + } + + err = schedule_erase(ubi, e2, 0); + if (err) { + kmem_cache_free(wl_entries_slab, e2); + ubi_ro_mode(ubi); + } + + yield(); + return err; +} + +/** + * ensure_wear_leveling - schedule wear-leveling if it is needed. + * @ubi: UBI device description object + * + * 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 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 (tree_empty(&ubi->scrub)) { + if (tree_empty(&ubi->used) || tree_empty(&ubi->free)) + /* 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 then + * %UBI_WL_THRESHOLD. + */ + e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, rb); + e2 = find_wl_entry(&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_KERNEL); + if (!wrk) { + err = -ENOMEM; + goto out_cancel; + } + + wrk->func = &wear_leveling_worker; + 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 + * @cancel: non-zero if the worker has to free memory and exit + * + * 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, + int cancel) +{ + int err; + struct ubi_wl_entry *e = wl_wrk->e; + int pnum = e->pnum; + + if (cancel) { + dbg_wl("cancel erasure of PEB %d EC %d", pnum, e->ec); + kfree(wl_wrk); + kmem_cache_free(wl_entries_slab, e); + return 0; + } + + dbg_wl("erase PEB %d EC %d", pnum, e->ec); + + err = sync_erase(ubi, e, wl_wrk->torture); + if (!err) { + /* Fine, we've erased it successfully */ + kfree(wl_wrk); + + spin_lock(&ubi->wl_lock); + ubi->abs_ec += 1; + free_tree_add(ubi, e); + spin_unlock(&ubi->wl_lock); + + /* + * One more erase operation has happened, take care about protected + * physical eraseblocks. + */ + check_protection_over(ubi); + + /* And take care about wear-leveling */ + err = ensure_wear_leveling(ubi); + return err; + } + + kfree(wl_wrk); + kmem_cache_free(wl_entries_slab, 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 RO mode. + */ + ubi_ro_mode(ubi); + return err; + } + + /* It is %-EIO, the PEB went bad */ + + if (!ubi->bad_allowed) { + ubi_err("bad physical eraseblock %d detected", pnum); + ubi_ro_mode(ubi); + err = -EIO; + } else { + int need; + + spin_lock(&ubi->volumes_lock); + need = ubi->beb_rsvd_level - ubi->beb_rsvd_pebs + 1; + if (need > 0) { + need = ubi->avail_pebs >= need ? need : ubi->avail_pebs; + ubi->avail_pebs -= need; + ubi->rsvd_pebs += need; + ubi->beb_rsvd_pebs += need; + if (need > 0) + ubi_msg("reserve more %d PEBs", need); + } + + if (ubi->beb_rsvd_pebs == 0) { + spin_unlock(&ubi->volumes_lock); + ubi_err("no reserved physical eraseblocks"); + ubi_ro_mode(ubi); + return -EIO; + } + + spin_unlock(&ubi->volumes_lock); + ubi_msg("mark PEB %d as bad", pnum); + + err = ubi_io_mark_bad(ubi, pnum); + if (err) { + ubi_ro_mode(ubi); + return err; + } + + spin_lock(&ubi->volumes_lock); + ubi->beb_rsvd_pebs -= 1; + ubi->bad_peb_count += 1; + ubi->good_peb_count -= 1; + ubi_calculate_reserved(ubi); + if (ubi->beb_rsvd_pebs == 0) + ubi_warn("last PEB from the reserved pool was used"); + spin_unlock(&ubi->volumes_lock); + } + + return err; +} + +/** + * ubi_wl_put_peb - return a physical eraseblock to the wear-leveling + * unit. + * @ubi: UBI device description object + * @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 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); + + 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", pnum); + ubi_assert(!ubi->move_from_put); + ubi->move_from_put = 1; + spin_unlock(&ubi->wl_lock); + return 0; + } 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 + * unit already re-mapped the LEB but the WL unit did has not + * put the PEB to the "used" tree. + */ + 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); + return 0; + } else { + if (in_wl_tree(e, &ubi->used)) + used_tree_del(ubi, e); + else if (in_wl_tree(e, &ubi->scrub)) + scrub_tree_del(ubi, e); + else + prot_tree_del(ubi, e->pnum); + } + spin_unlock(&ubi->wl_lock); + + err = schedule_erase(ubi, e, torture); + if (err) { + spin_lock(&ubi->wl_lock); + used_tree_add(ubi, e); + spin_unlock(&ubi->wl_lock); + } + + 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("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)) { + 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)) + used_tree_del(ubi, e); + else + prot_tree_del(ubi, pnum); + + scrub_tree_add(ubi, e); + 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); +} + +/** + * ubi_wl_flush - flush all pending works. + * @ubi: UBI device description object + * + * This function returns zero in case of success and a negative error code in + * case of failure. + */ +int ubi_wl_flush(struct ubi_device *ubi) +{ + int err, pending_count; + + pending_count = ubi->works_count; + + dbg_wl("flush (%d pending works)", pending_count); + + /* + * Erase while the pending works queue is not empty, but not more then + * the number of currently pending works. + */ + while (pending_count-- > 0) { + err = do_work(ubi); + if (err) + return err; + } + + return 0; +} + +/** + * tree_destroy - destroy an RB-tree. + * @root: the root of the tree to destroy + */ +static void tree_destroy(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, rb); + + rb = rb_parent(rb); + if (rb) { + if (rb->rb_left == &e->rb) + rb->rb_left = NULL; + else + rb->rb_right = NULL; + } + + kmem_cache_free(wl_entries_slab, e); + } + } +} + +/** + * ubi_thread - UBI background thread. + * @u: the UBI device description object pointer + */ +static int ubi_thread(void *u) +{ + int failures = 0; + struct ubi_device *ubi = u; + + ubi_msg("background thread \"%s\" started, PID %d", + ubi->bgt_name, current->pid); + + for (;;) { + int err; + + if (kthread_should_stop()) + goto out; + + if (try_to_freeze()) + continue; + + spin_lock(&ubi->wl_lock); + if (list_empty(&ubi->works) || ubi->ro_mode || + !ubi->thread_enabled) { + 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("%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("%s: %d consecutive failures", + ubi->bgt_name, WL_MAX_FAILURES); + ubi_ro_mode(ubi); + break; + } + } else + failures = 0; + + cond_resched(); + } + +out: + dbg_wl("background thread \"%s\" is killed", ubi->bgt_name); + return 0; +} + +/** + * cancel_pending - cancel all pending works. + * @ubi: UBI device description object + */ +static void cancel_pending(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); + } +} + +/** + * ubi_wl_init_scan - initialize the wear-leveling unit using scanning + * information. + * @ubi: UBI device description object + * @si: scanning information + * + * This function returns zero in case of success, and a negative error code in + * case of failure. + */ +int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si) +{ + int err; + struct rb_node *rb1, *rb2; + struct ubi_scan_volume *sv; + struct ubi_scan_leb *seb, *tmp; + struct ubi_wl_entry *e; + + + ubi->used = ubi->free = ubi->scrub = RB_ROOT; + ubi->prot.pnum = ubi->prot.aec = RB_ROOT; + spin_lock_init(&ubi->wl_lock); + ubi->max_ec = si->max_ec; + INIT_LIST_HEAD(&ubi->works); + + sprintf(ubi->bgt_name, UBI_BGT_NAME_PATTERN, ubi->ubi_num); + + ubi->bgt_thread = kthread_create(ubi_thread, ubi, ubi->bgt_name); + if (IS_ERR(ubi->bgt_thread)) { + err = PTR_ERR(ubi->bgt_thread); + ubi_err("cannot spawn \"%s\", error %d", ubi->bgt_name, + err); + return err; + } + + if (ubi_devices_cnt == 0) { + wl_entries_slab = kmem_cache_create("ubi_wl_entry_slab", + sizeof(struct ubi_wl_entry), + 0, 0, NULL, NULL); + if (!wl_entries_slab) + return -ENOMEM; + } + + err = -ENOMEM; + ubi->lookuptbl = kzalloc(ubi->peb_count * sizeof(void *), GFP_KERNEL); + if (!ubi->lookuptbl) + goto out_free; + + list_for_each_entry_safe(seb, tmp, &si->erase, u.list) { + cond_resched(); + + e = kmem_cache_alloc(wl_entries_slab, GFP_KERNEL); + if (!e) + goto out_free; + + e->pnum = seb->pnum; + e->ec = seb->ec; + ubi->lookuptbl[e->pnum] = e; + if (schedule_erase(ubi, e, 0)) { + kmem_cache_free(wl_entries_slab, e); + goto out_free; + } + } + + list_for_each_entry(seb, &si->free, u.list) { + cond_resched(); + + e = kmem_cache_alloc(wl_entries_slab, GFP_KERNEL); + if (!e) + goto out_free; + + e->pnum = seb->pnum; + e->ec = seb->ec; + ubi_assert(e->ec >= 0); + free_tree_add(ubi, e); + ubi->lookuptbl[e->pnum] = e; + } + + list_for_each_entry(seb, &si->corr, u.list) { + cond_resched(); + + e = kmem_cache_alloc(wl_entries_slab, GFP_KERNEL); + if (!e) + goto out_free; + + e->pnum = seb->pnum; + e->ec = seb->ec; + ubi->lookuptbl[e->pnum] = e; + if (schedule_erase(ubi, e, 0)) { + kmem_cache_free(wl_entries_slab, e); + goto out_free; + } + } + + ubi_rb_for_each_entry(rb1, sv, &si->volumes, rb) { + ubi_rb_for_each_entry(rb2, seb, &sv->root, u.rb) { + cond_resched(); + + e = kmem_cache_alloc(wl_entries_slab, GFP_KERNEL); + if (!e) + goto out_free; + + e->pnum = seb->pnum; + e->ec = seb->ec; + ubi->lookuptbl[e->pnum] = e; + if (!seb->scrub) { + dbg_wl("add PEB %d EC %d to the used tree", + e->pnum, e->ec); + used_tree_add(ubi, e); + } else { + dbg_wl("add PEB %d EC %d to the scrub tree", + e->pnum, e->ec); + scrub_tree_add(ubi, e); + } + } + } + + if (WL_RESERVED_PEBS > ubi->avail_pebs) { + ubi_err("no enough physical eraseblocks (%d, need %d)", + ubi->avail_pebs, WL_RESERVED_PEBS); + goto out_free; + } + ubi->avail_pebs -= WL_RESERVED_PEBS; + ubi->rsvd_pebs += WL_RESERVED_PEBS; + + /* Schedule wear-leveling if needed */ + err = ensure_wear_leveling(ubi); + if (err) + goto out_free; + + return 0; + +out_free: + cancel_pending(ubi); + tree_destroy(&ubi->used); + tree_destroy(&ubi->free); + tree_destroy(&ubi->scrub); + kfree(ubi->lookuptbl); + if (ubi_devices_cnt == 0) + kmem_cache_destroy(wl_entries_slab); + return err; +} + +/** + * protection_trees_destroy - destroy the protection RB-trees. + * @ubi: UBI device description object + */ +static void protection_trees_destroy(struct ubi_device *ubi) +{ + struct rb_node *rb; + struct ubi_wl_prot_entry *pe; + + rb = ubi->prot.aec.rb_node; + while (rb) { + if (rb->rb_left) + rb = rb->rb_left; + else if (rb->rb_right) + rb = rb->rb_right; + else { + pe = rb_entry(rb, struct ubi_wl_prot_entry, rb_aec); + + rb = rb_parent(rb); + if (rb) { + if (rb->rb_left == &pe->rb_aec) + rb->rb_left = NULL; + else + rb->rb_right = NULL; + } + + kmem_cache_free(wl_entries_slab, pe->e); + kfree(pe); + } + } +} + +/** + * ubi_wl_close - close the wear-leveling unit. + * @ubi: UBI device description object + */ +void ubi_wl_close(struct ubi_device *ubi) +{ + dbg_wl("disable \"%s\"", ubi->bgt_name); + if (ubi->bgt_thread) + kthread_stop(ubi->bgt_thread); + + dbg_wl("close the UBI wear-leveling unit"); + + cancel_pending(ubi); + protection_trees_destroy(ubi); + tree_destroy(&ubi->used); + tree_destroy(&ubi->free); + tree_destroy(&ubi->scrub); + kfree(ubi->lookuptbl); + if (ubi_devices_cnt == 1) + kmem_cache_destroy(wl_entries_slab); +} + +#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID + +/** + * paranoid_check_ec - make sure that the erase counter of a physical eraseblock + * 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, %1 if not, and a negative error code if an error + * occurred. + */ +static int paranoid_check_ec(const struct ubi_device *ubi, int pnum, int ec) +{ + int err; + long long read_ec; + struct ubi_ec_hdr *ec_hdr; + + ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL); + 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 = ubi64_to_cpu(ec_hdr->ec); + if (ec != read_ec) { + ubi_err("paranoid check failed for PEB %d", pnum); + ubi_err("read EC is %lld, should be %d", read_ec, ec); + ubi_dbg_dump_stack(); + err = 1; + } else + err = 0; + +out_free: + kfree(ec_hdr); + return err; +} + +/** + * paranoid_check_in_wl_tree - make sure that a 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 zero if @e is in the @root RB-tree and %1 if it + * is not. + */ +static int paranoid_check_in_wl_tree(struct ubi_wl_entry *e, + struct rb_root *root) +{ + if (in_wl_tree(e, root)) + return 0; + + ubi_err("paranoid check failed for PEB %d, EC %d, RB-tree %p ", + e->pnum, e->ec, root); + ubi_dbg_dump_stack(); + return 1; +} + +#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */ |