blob: 4611a75f12415b44aa398acd9688da5d26fc8787 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2012 Linutronix GmbH
* Copyright (c) 2014 sigma star gmbh
* Author: Richard Weinberger <richard@nod.at>
*/
/**
* update_fastmap_work_fn - calls ubi_update_fastmap from a work queue
* @wrk: the work description object
*/
static void update_fastmap_work_fn(struct work_struct *wrk)
{
struct ubi_device *ubi = container_of(wrk, struct ubi_device, fm_work);
ubi_update_fastmap(ubi);
spin_lock(&ubi->wl_lock);
ubi->fm_work_scheduled = 0;
spin_unlock(&ubi->wl_lock);
}
/**
* find_anchor_wl_entry - find wear-leveling entry to used as anchor PEB.
* @root: the RB-tree where to look for
*/
static struct ubi_wl_entry *find_anchor_wl_entry(struct rb_root *root)
{
struct rb_node *p;
struct ubi_wl_entry *e, *victim = NULL;
int max_ec = UBI_MAX_ERASECOUNTER;
ubi_rb_for_each_entry(p, e, root, u.rb) {
if (e->pnum < UBI_FM_MAX_START && e->ec < max_ec) {
victim = e;
max_ec = e->ec;
}
}
return victim;
}
static inline void return_unused_peb(struct ubi_device *ubi,
struct ubi_wl_entry *e)
{
wl_tree_add(e, &ubi->free);
ubi->free_count++;
}
/**
* return_unused_pool_pebs - returns unused PEB to the free tree.
* @ubi: UBI device description object
* @pool: fastmap pool description object
*/
static void return_unused_pool_pebs(struct ubi_device *ubi,
struct ubi_fm_pool *pool)
{
int i;
struct ubi_wl_entry *e;
for (i = pool->used; i < pool->size; i++) {
e = ubi->lookuptbl[pool->pebs[i]];
return_unused_peb(ubi, e);
}
}
/**
* ubi_wl_get_fm_peb - find a physical erase block with a given maximal number.
* @ubi: UBI device description object
* @anchor: This PEB will be used as anchor PEB by fastmap
*
* The function returns a physical erase block with a given maximal number
* and removes it from the wl subsystem.
* Must be called with wl_lock held!
*/
struct ubi_wl_entry *ubi_wl_get_fm_peb(struct ubi_device *ubi, int anchor)
{
struct ubi_wl_entry *e = NULL;
if (!ubi->free.rb_node)
goto out;
if (anchor)
e = find_anchor_wl_entry(&ubi->free);
else
e = find_mean_wl_entry(ubi, &ubi->free);
if (!e)
goto out;
self_check_in_wl_tree(ubi, e, &ubi->free);
/* remove it from the free list,
* the wl subsystem does no longer know this erase block */
rb_erase(&e->u.rb, &ubi->free);
ubi->free_count--;
out:
return e;
}
/*
* has_enough_free_count - whether ubi has enough free pebs to fill fm pools
* @ubi: UBI device description object
*
* This helper function checks whether there are enough free pebs (deducted
* by fastmap pebs) to fill fm_pool and fm_wl_pool, above rule works after
* there is at least one of free pebs is filled into fm_wl_pool.
*/
static bool has_enough_free_count(struct ubi_device *ubi)
{
int fm_used = 0; // fastmap non anchor pebs.
if (!ubi->free.rb_node)
return false;
if (ubi->fm_wl_pool.size > 0 && !(ubi->ro_mode || ubi->fm_disabled))
fm_used = ubi->fm_size / ubi->leb_size - 1;
return ubi->free_count > fm_used;
}
/**
* ubi_refill_pools - refills all fastmap PEB pools.
* @ubi: UBI device description object
*/
void ubi_refill_pools(struct ubi_device *ubi)
{
struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
struct ubi_fm_pool *pool = &ubi->fm_pool;
struct ubi_wl_entry *e;
int enough;
spin_lock(&ubi->wl_lock);
return_unused_pool_pebs(ubi, wl_pool);
return_unused_pool_pebs(ubi, pool);
wl_pool->size = 0;
pool->size = 0;
if (ubi->fm_anchor) {
wl_tree_add(ubi->fm_anchor, &ubi->free);
ubi->free_count++;
ubi->fm_anchor = NULL;
}
if (!ubi->fm_disabled)
/*
* All available PEBs are in ubi->free, now is the time to get
* the best anchor PEBs.
*/
ubi->fm_anchor = ubi_wl_get_fm_peb(ubi, 1);
for (;;) {
enough = 0;
if (pool->size < pool->max_size) {
if (!has_enough_free_count(ubi))
break;
e = wl_get_wle(ubi);
if (!e)
break;
pool->pebs[pool->size] = e->pnum;
pool->size++;
} else
enough++;
if (wl_pool->size < wl_pool->max_size) {
if (!has_enough_free_count(ubi))
break;
e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
self_check_in_wl_tree(ubi, e, &ubi->free);
rb_erase(&e->u.rb, &ubi->free);
ubi->free_count--;
wl_pool->pebs[wl_pool->size] = e->pnum;
wl_pool->size++;
} else
enough++;
if (enough == 2)
break;
}
wl_pool->used = 0;
pool->used = 0;
spin_unlock(&ubi->wl_lock);
}
/**
* 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) {
dbg_wl("do one work synchronously");
err = do_work(ubi);
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 ret, attempts = 0;
struct ubi_fm_pool *pool = &ubi->fm_pool;
struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
again:
down_read(&ubi->fm_eba_sem);
spin_lock(&ubi->wl_lock);
/* We check here also for the WL pool because at this point we can
* refill the WL pool synchronous. */
if (pool->used == pool->size || wl_pool->used == wl_pool->size) {
spin_unlock(&ubi->wl_lock);
up_read(&ubi->fm_eba_sem);
ret = ubi_update_fastmap(ubi);
if (ret) {
ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
down_read(&ubi->fm_eba_sem);
return -ENOSPC;
}
down_read(&ubi->fm_eba_sem);
spin_lock(&ubi->wl_lock);
}
if (pool->used == pool->size) {
spin_unlock(&ubi->wl_lock);
attempts++;
if (attempts == 10) {
ubi_err(ubi, "Unable to get a free PEB from user WL pool");
ret = -ENOSPC;
goto out;
}
up_read(&ubi->fm_eba_sem);
ret = produce_free_peb(ubi);
if (ret < 0) {
down_read(&ubi->fm_eba_sem);
goto out;
}
goto again;
}
ubi_assert(pool->used < pool->size);
ret = pool->pebs[pool->used++];
prot_queue_add(ubi, ubi->lookuptbl[ret]);
spin_unlock(&ubi->wl_lock);
out:
return ret;
}
/**
* next_peb_for_wl - returns next PEB to be used internally by the
* WL sub-system.
*
* @ubi: UBI device description object
*/
static struct ubi_wl_entry *next_peb_for_wl(struct ubi_device *ubi)
{
struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
int pnum;
if (pool->used == pool->size)
return NULL;
pnum = pool->pebs[pool->used];
return ubi->lookuptbl[pnum];
}
/**
* need_wear_leveling - checks whether to trigger a wear leveling work.
* UBI fetches free PEB from wl_pool, we check free PEBs from both 'wl_pool'
* and 'ubi->free', because free PEB in 'ubi->free' tree maybe moved into
* 'wl_pool' by ubi_refill_pools().
*
* @ubi: UBI device description object
*/
static bool need_wear_leveling(struct ubi_device *ubi)
{
int ec;
struct ubi_wl_entry *e;
if (!ubi->used.rb_node)
return false;
e = next_peb_for_wl(ubi);
if (!e) {
if (!ubi->free.rb_node)
return false;
e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
ec = e->ec;
} else {
ec = e->ec;
if (ubi->free.rb_node) {
e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
ec = max(ec, e->ec);
}
}
e = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
return ec - e->ec >= UBI_WL_THRESHOLD;
}
/* get_peb_for_wl - returns a PEB to be used internally by the WL sub-system.
*
* @ubi: UBI device description object
*/
static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
{
struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
int pnum;
ubi_assert(rwsem_is_locked(&ubi->fm_eba_sem));
if (pool->used == pool->size) {
/* We cannot update the fastmap here because this
* function is called in atomic context.
* Let's fail here and refill/update it as soon as possible. */
if (!ubi->fm_work_scheduled) {
ubi->fm_work_scheduled = 1;
schedule_work(&ubi->fm_work);
}
return NULL;
}
pnum = pool->pebs[pool->used++];
return ubi->lookuptbl[pnum];
}
/**
* ubi_ensure_anchor_pebs - schedule wear-leveling to produce an anchor PEB.
* @ubi: UBI device description object
*/
int ubi_ensure_anchor_pebs(struct ubi_device *ubi)
{
struct ubi_work *wrk;
struct ubi_wl_entry *anchor;
spin_lock(&ubi->wl_lock);
/* Do we already have an anchor? */
if (ubi->fm_anchor) {
spin_unlock(&ubi->wl_lock);
return 0;
}
/* See if we can find an anchor PEB on the list of free PEBs */
anchor = ubi_wl_get_fm_peb(ubi, 1);
if (anchor) {
ubi->fm_anchor = anchor;
spin_unlock(&ubi->wl_lock);
return 0;
}
ubi->fm_do_produce_anchor = 1;
/* No luck, trigger wear leveling to produce a new anchor PEB. */
if (ubi->wl_scheduled) {
spin_unlock(&ubi->wl_lock);
return 0;
}
ubi->wl_scheduled = 1;
spin_unlock(&ubi->wl_lock);
wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
if (!wrk) {
spin_lock(&ubi->wl_lock);
ubi->wl_scheduled = 0;
spin_unlock(&ubi->wl_lock);
return -ENOMEM;
}
wrk->func = &wear_leveling_worker;
__schedule_ubi_work(ubi, wrk);
return 0;
}
/**
* ubi_wl_put_fm_peb - returns a PEB used in a fastmap to the wear-leveling
* sub-system.
* see: ubi_wl_put_peb()
*
* @ubi: UBI device description object
* @fm_e: physical eraseblock to return
* @lnum: the last used logical eraseblock number for the PEB
* @torture: if this physical eraseblock has to be tortured
*/
int ubi_wl_put_fm_peb(struct ubi_device *ubi, struct ubi_wl_entry *fm_e,
int lnum, int torture)
{
struct ubi_wl_entry *e;
int vol_id, pnum = fm_e->pnum;
dbg_wl("PEB %d", pnum);
ubi_assert(pnum >= 0);
ubi_assert(pnum < ubi->peb_count);
spin_lock(&ubi->wl_lock);
e = ubi->lookuptbl[pnum];
/* This can happen if we recovered from a fastmap the very
* first time and writing now a new one. In this case the wl system
* has never seen any PEB used by the original fastmap.
*/
if (!e) {
e = fm_e;
ubi_assert(e->ec >= 0);
ubi->lookuptbl[pnum] = e;
}
spin_unlock(&ubi->wl_lock);
vol_id = lnum ? UBI_FM_DATA_VOLUME_ID : UBI_FM_SB_VOLUME_ID;
return schedule_erase(ubi, e, vol_id, lnum, torture, true);
}
/**
* ubi_is_erase_work - checks whether a work is erase work.
* @wrk: The work object to be checked
*/
int ubi_is_erase_work(struct ubi_work *wrk)
{
return wrk->func == erase_worker;
}
static void ubi_fastmap_close(struct ubi_device *ubi)
{
int i;
return_unused_pool_pebs(ubi, &ubi->fm_pool);
return_unused_pool_pebs(ubi, &ubi->fm_wl_pool);
if (ubi->fm_anchor) {
return_unused_peb(ubi, ubi->fm_anchor);
ubi->fm_anchor = NULL;
}
if (ubi->fm) {
for (i = 0; i < ubi->fm->used_blocks; i++)
kfree(ubi->fm->e[i]);
}
kfree(ubi->fm);
}
/**
* may_reserve_for_fm - tests whether a PEB shall be reserved for fastmap.
* See find_mean_wl_entry()
*
* @ubi: UBI device description object
* @e: physical eraseblock to return
* @root: RB tree to test against.
*/
static struct ubi_wl_entry *may_reserve_for_fm(struct ubi_device *ubi,
struct ubi_wl_entry *e,
struct rb_root *root) {
if (e && !ubi->fm_disabled && !ubi->fm &&
e->pnum < UBI_FM_MAX_START)
e = rb_entry(rb_next(root->rb_node),
struct ubi_wl_entry, u.rb);
return e;
}