/*
* 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 */
