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Commit 8199b901 authored by Richard Weinberger's avatar Richard Weinberger Committed by Artem Bityutskiy
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UBI: Add fastmap support to the WL sub-system 



To make fastmap possible the WL sub-system needs some
changes.
Mostly to support fastmaps pools.

Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
parent dac6e208

drivers/mtd/ubi/wl.c

+531 −44
Original line number Diff line number Diff line
@@ -141,6 +141,42 @@ static int self_check_in_wl_tree(const struct ubi_device *ubi, 
static int self_check_in_pq(const struct ubi_device *ubi,

			    struct ubi_wl_entry *e);



#ifdef CONFIG_MTD_UBI_FASTMAP

/**

 * 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);

}



/**

 *  ubi_ubi_is_fm_block - returns 1 if a PEB is currently used in a fastmap.

 *  @ubi: UBI device description object

 *  @pnum: the to be checked PEB

 */

static int ubi_is_fm_block(struct ubi_device *ubi, int pnum)

{

	int i;



	if (!ubi->fm)

		return 0;



	for (i = 0; i < ubi->fm->used_blocks; i++)

		if (ubi->fm->e[i]->pnum == pnum)

			return 1;



	return 0;

}

#else

static int ubi_is_fm_block(struct ubi_device *ubi, int pnum)

{

	return 0;

}

#endif



/**

 * wl_tree_add - add a wear-leveling entry to a WL RB-tree.

 * @e: the wear-leveling entry to add
@@ -237,18 +273,16 @@ static int produce_free_peb(struct ubi_device *ubi) 
{

	int err;



	spin_lock(&ubi->wl_lock);

	while (!ubi->free.rb_node) {

		spin_unlock(&ubi->wl_lock);



		dbg_wl("do one work synchronously");

		err = do_work(ubi);

		if (err)

			return err;



		spin_lock(&ubi->wl_lock);

		if (err)

			return err;

	}

	spin_unlock(&ubi->wl_lock);



	return 0;

}
@@ -315,16 +349,18 @@ static void prot_queue_add(struct ubi_device *ubi, struct ubi_wl_entry *e) 


/**

 * find_wl_entry - find wear-leveling entry closest to certain erase counter.

 * @ubi: UBI device description object

 * @root: the RB-tree where to look for

 * @diff: maximum possible difference from the smallest erase counter

 *

 * This function looks for a wear leveling entry with erase counter closest to

 * min + @diff, where min is the smallest erase counter.

 */

static struct ubi_wl_entry *find_wl_entry(struct rb_root *root, int diff)

static struct ubi_wl_entry *find_wl_entry(struct ubi_device *ubi,

					  struct rb_root *root, int diff)

{

	struct rb_node *p;

	struct ubi_wl_entry *e;

	struct ubi_wl_entry *e, *prev_e = NULL;

	int max;



	e = rb_entry(rb_first(root), struct ubi_wl_entry, u.rb);
@@ -339,35 +375,143 @@ static struct ubi_wl_entry *find_wl_entry(struct rb_root *root, int diff) 
			p = p->rb_left;

		else {

			p = p->rb_right;

			prev_e = e;

			e = e1;

		}

	}



	/* If no fastmap has been written and this WL entry can be used

	 * as anchor PEB, hold it back and return the second best WL entry

	 * such that fastmap can use the anchor PEB later. */

	if (prev_e && !ubi->fm_disabled &&

	    !ubi->fm && e->pnum < UBI_FM_MAX_START)

		return prev_e;



	return e;

}



/**

 * find_mean_wl_entry - find wear-leveling entry with medium erase counter.

 * @ubi: UBI device description object

 * @root: the RB-tree where to look for

 *

 * This function looks for a wear leveling entry with medium erase counter,

 * but not greater or equivalent than the lowest erase counter plus

 * %WL_FREE_MAX_DIFF/2.

 */

static struct ubi_wl_entry *find_mean_wl_entry(struct ubi_device *ubi,

					       struct rb_root *root)

{

	struct ubi_wl_entry *e, *first, *last;



	first = rb_entry(rb_first(root), struct ubi_wl_entry, u.rb);

	last = rb_entry(rb_last(root), struct ubi_wl_entry, u.rb);



	if (last->ec - first->ec < WL_FREE_MAX_DIFF) {

		e = rb_entry(root->rb_node, struct ubi_wl_entry, u.rb);



#ifdef CONFIG_MTD_UBI_FASTMAP

		/* If no fastmap has been written and this WL entry can be used

		 * as anchor PEB, hold it back and return the second best

		 * WL entry such that fastmap can use the anchor PEB later. */

		if (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);

#endif

	} else

		e = find_wl_entry(ubi, root, WL_FREE_MAX_DIFF/2);



	return e;

}



#ifdef CONFIG_MTD_UBI_FASTMAP

/**

 * ubi_wl_get_peb - get a physical eraseblock.

 * 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 int anchor_pebs_avalible(struct rb_root *root)

{

	struct rb_node *p;

	struct ubi_wl_entry *e;



	ubi_rb_for_each_entry(p, e, root, u.rb)

		if (e->pnum < UBI_FM_MAX_START)

			return 1;



	return 0;

}



/**

 * 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 || (ubi->free_count - ubi->beb_rsvd_pebs < 1))

		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;

}

#endif



/**

 * __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. Might sleep.

 */

int ubi_wl_get_peb(struct ubi_device *ubi)

static int __wl_get_peb(struct ubi_device *ubi)

{

	int err;

	struct ubi_wl_entry *e, *first, *last;

	struct ubi_wl_entry *e;



retry:

	spin_lock(&ubi->wl_lock);

	if (!ubi->free.rb_node) {

		if (ubi->works_count == 0) {

			ubi_assert(list_empty(&ubi->works));

			ubi_err("no free eraseblocks");

			spin_unlock(&ubi->wl_lock);

			ubi_assert(list_empty(&ubi->works));

			return -ENOSPC;

		}

		spin_unlock(&ubi->wl_lock);



		err = produce_free_peb(ubi);

		if (err < 0)
@@ -375,13 +519,11 @@ int ubi_wl_get_peb(struct ubi_device *ubi) 
		goto retry;

	}



	first = rb_entry(rb_first(&ubi->free), struct ubi_wl_entry, u.rb);

	last = rb_entry(rb_last(&ubi->free), struct ubi_wl_entry, u.rb);



	if (last->ec - first->ec < WL_FREE_MAX_DIFF)

		e = rb_entry(ubi->free.rb_node, struct ubi_wl_entry, u.rb);

	else

		e = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF/2);

	e = find_mean_wl_entry(ubi, &ubi->free);

	if (!e) {

		ubi_err("no free eraseblocks");

		return -ENOSPC;

	}



	self_check_in_wl_tree(ubi, e, &ubi->free);
@@ -390,10 +532,14 @@ int ubi_wl_get_peb(struct ubi_device *ubi) 
	 * be protected from being moved for some time.

	 */

	rb_erase(&e->u.rb, &ubi->free);

	ubi->free_count--;

	dbg_wl("PEB %d EC %d", e->pnum, e->ec);

#ifndef CONFIG_MTD_UBI_FASTMAP

	/* We have to enqueue e only if fastmap is disabled,

	 * is fastmap enabled prot_queue_add() will be called by

	 * ubi_wl_get_peb() after removing e from the pool. */

	prot_queue_add(ubi, e);

	spin_unlock(&ubi->wl_lock);



#endif

	err = ubi_self_check_all_ff(ubi, e->pnum, ubi->vid_hdr_aloffset,

				    ubi->peb_size - ubi->vid_hdr_aloffset);

	if (err) {
@@ -404,6 +550,150 @@ int ubi_wl_get_peb(struct ubi_device *ubi) 
	return e->pnum;

}



#ifdef CONFIG_MTD_UBI_FASTMAP

/**

 * 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]];

		wl_tree_add(e, &ubi->free);

		ubi->free_count++;

	}

}



/**

 * refill_wl_pool - refills all the fastmap pool used by the

 * WL sub-system.

 * @ubi: UBI device description object

 */

static void refill_wl_pool(struct ubi_device *ubi)

{

	struct ubi_wl_entry *e;

	struct ubi_fm_pool *pool = &ubi->fm_wl_pool;



	return_unused_pool_pebs(ubi, pool);



	for (pool->size = 0; pool->size < pool->max_size; pool->size++) {

		if (!ubi->free.rb_node ||

		   (ubi->free_count - ubi->beb_rsvd_pebs < 5))

			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--;



		pool->pebs[pool->size] = e->pnum;

	}

	pool->used = 0;

}



/**

 * refill_wl_user_pool - refills all the fastmap pool used by ubi_wl_get_peb.

 * @ubi: UBI device description object

 */

static void refill_wl_user_pool(struct ubi_device *ubi)

{

	struct ubi_fm_pool *pool = &ubi->fm_pool;



	return_unused_pool_pebs(ubi, pool);



	for (pool->size = 0; pool->size < pool->max_size; pool->size++) {

		if (!ubi->free.rb_node ||

		   (ubi->free_count - ubi->beb_rsvd_pebs < 1))

			break;



		pool->pebs[pool->size] = __wl_get_peb(ubi);

		if (pool->pebs[pool->size] < 0)

			break;

	}

	pool->used = 0;

}



/**

 * ubi_refill_pools - refills all fastmap PEB pools.

 * @ubi: UBI device description object

 */

void ubi_refill_pools(struct ubi_device *ubi)

{

	spin_lock(&ubi->wl_lock);

	refill_wl_pool(ubi);

	refill_wl_user_pool(ubi);

	spin_unlock(&ubi->wl_lock);

}



/* ubi_wl_get_peb - works exaclty like __wl_get_peb but keeps track of

 * the fastmap pool.

 */

int ubi_wl_get_peb(struct ubi_device *ubi)

{

	int ret;

	struct ubi_fm_pool *pool = &ubi->fm_pool;

	struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;



	if (!pool->size || !wl_pool->size || pool->used == pool->size ||

	    wl_pool->used == wl_pool->size)

		ubi_update_fastmap(ubi);



	/* we got not a single free PEB */

	if (!pool->size)

		ret = -ENOSPC;

	else {

		spin_lock(&ubi->wl_lock);

		ret = pool->pebs[pool->used++];

		prot_queue_add(ubi, ubi->lookuptbl[ret]);

		spin_unlock(&ubi->wl_lock);

	}



	return ret;

}



/* 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;



	if (pool->used == pool->size || !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. */

		schedule_work(&ubi->fm_work);

		return NULL;

	} else {

		pnum = pool->pebs[pool->used++];

		return ubi->lookuptbl[pnum];

	}

}

#else

static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)

{

	return find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);

}



int ubi_wl_get_peb(struct ubi_device *ubi)

{

	int peb;



	spin_lock(&ubi->wl_lock);

	peb = __wl_get_peb(ubi);

	spin_unlock(&ubi->wl_lock);



	return peb;

}

#endif



/**

 * prot_queue_del - remove a physical eraseblock from the protection queue.

 * @ubi: UBI device description object
@@ -534,14 +824,14 @@ static void serve_prot_queue(struct ubi_device *ubi) 
}



/**

 * schedule_ubi_work - schedule a work.

 * __schedule_ubi_work - schedule a work.

 * @ubi: UBI device description object

 * @wrk: the work to schedule

 *

 * This function adds a work defined by @wrk to the tail of the pending works

 * list.

 * list. Can only be used of ubi->work_sem is already held in read mode!

 */

static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)

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);
@@ -552,9 +842,35 @@ static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk) 
	spin_unlock(&ubi->wl_lock);

}



/**

 * schedule_ubi_work - schedule a work.

 * @ubi: UBI device description object

 * @wrk: the work to schedule

 *

 * This function adds a work defined by @wrk to the tail of the pending works

 * list.

 */

static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)

{

	down_read(&ubi->work_sem);

	__schedule_ubi_work(ubi, wrk);

	up_read(&ubi->work_sem);

}



static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,

			int cancel);



#ifdef CONFIG_MTD_UBI_FASTMAP

/**

 * 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;

}

#endif



/**

 * schedule_erase - schedule an erase work.

 * @ubi: UBI device description object
@@ -571,6 +887,9 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e, 
{

	struct ubi_work *wl_wrk;



	ubi_assert(e);

	ubi_assert(!ubi_is_fm_block(ubi, e->pnum));



	dbg_wl("schedule erasure of PEB %d, EC %d, torture %d",

	       e->pnum, e->ec, torture);
@@ -588,6 +907,79 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e, 
	return 0;

}



/**

 * do_sync_erase - run the erase worker synchronously.

 * @ubi: UBI device description object

 * @e: the WL entry of the physical eraseblock to erase

 * @vol_id: the volume ID that last used this PEB

 * @lnum: the last used logical eraseblock number for the PEB

 * @torture: if the physical eraseblock has to be tortured

 *

 */

static int do_sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,

			 int vol_id, int lnum, int torture)

{

	struct ubi_work *wl_wrk;



	dbg_wl("sync erase of PEB %i", e->pnum);



	wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);

	if (!wl_wrk)

		return -ENOMEM;



	wl_wrk->e = e;

	wl_wrk->vol_id = vol_id;

	wl_wrk->lnum = lnum;

	wl_wrk->torture = torture;



	return erase_worker(ubi, wl_wrk, 0);

}



#ifdef CONFIG_MTD_UBI_FASTMAP

/**

 * 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;

	} else {

		e->ec = fm_e->ec;

		kfree(fm_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);

}

#endif



/**

 * wear_leveling_worker - wear-leveling worker function.

 * @ubi: UBI device description object
@@ -603,6 +995,9 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk, 
{

	int err, scrubbing = 0, torture = 0, protect = 0, erroneous = 0;

	int vol_id = -1, uninitialized_var(lnum);

#ifdef CONFIG_MTD_UBI_FASTMAP

	int anchor = wrk->anchor;

#endif

	struct ubi_wl_entry *e1, *e2;

	struct ubi_vid_hdr *vid_hdr;
@@ -636,14 +1031,35 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk, 
		goto out_cancel;

	}



#ifdef CONFIG_MTD_UBI_FASTMAP

	/* Check whether we need to produce an anchor PEB */

	if (!anchor)

		anchor = !anchor_pebs_avalible(&ubi->free);



	if (anchor) {

		e1 = find_anchor_wl_entry(&ubi->used);

		if (!e1)

			goto out_cancel;

		e2 = get_peb_for_wl(ubi);

		if (!e2)

			goto out_cancel;



		self_check_in_wl_tree(ubi, e1, &ubi->used);

		rb_erase(&e1->u.rb, &ubi->used);

		dbg_wl("anchor-move PEB %d to PEB %d", e1->pnum, e2->pnum);

	} else if (!ubi->scrub.rb_node) {

#else

	if (!ubi->scrub.rb_node) {

#endif

		/*

		 * Now pick the least worn-out used physical eraseblock and a

		 * highly worn-out free physical eraseblock. If the erase

		 * counters differ much enough, start wear-leveling.

		 */

		e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);

		e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);

		e2 = get_peb_for_wl(ubi);

		if (!e2)

			goto out_cancel;



		if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD)) {

			dbg_wl("no WL needed: min used EC %d, max free EC %d",
@@ -658,14 +1074,15 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk, 
		/* Perform scrubbing */

		scrubbing = 1;

		e1 = rb_entry(rb_first(&ubi->scrub), struct ubi_wl_entry, u.rb);

		e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);

		e2 = get_peb_for_wl(ubi);

		if (!e2)

			goto out_cancel;



		self_check_in_wl_tree(ubi, e1, &ubi->scrub);

		rb_erase(&e1->u.rb, &ubi->scrub);

		dbg_wl("scrub PEB %d to PEB %d", e1->pnum, e2->pnum);

	}



	self_check_in_wl_tree(ubi, e2, &ubi->free);

	rb_erase(&e2->u.rb, &ubi->free);

	ubi->move_from = e1;

	ubi->move_to = e2;

	spin_unlock(&ubi->wl_lock);
@@ -782,7 +1199,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk, 
	ubi->move_to_put = ubi->wl_scheduled = 0;

	spin_unlock(&ubi->wl_lock);



	err = schedule_erase(ubi, e1, vol_id, lnum, 0);

	err = do_sync_erase(ubi, e1, vol_id, lnum, 0);

	if (err) {

		kmem_cache_free(ubi_wl_entry_slab, e1);

		if (e2)
@@ -797,7 +1214,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk, 
		 */

		dbg_wl("PEB %d (LEB %d:%d) was put meanwhile, erase",

		       e2->pnum, vol_id, lnum);

		err = schedule_erase(ubi, e2, vol_id, lnum, 0);

		err = do_sync_erase(ubi, e2, vol_id, lnum, 0);

		if (err) {

			kmem_cache_free(ubi_wl_entry_slab, e2);

			goto out_ro;
@@ -836,7 +1253,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk, 
	spin_unlock(&ubi->wl_lock);



	ubi_free_vid_hdr(ubi, vid_hdr);

	err = schedule_erase(ubi, e2, vol_id, lnum, torture);

	err = do_sync_erase(ubi, e2, vol_id, lnum, torture);

	if (err) {

		kmem_cache_free(ubi_wl_entry_slab, e2);

		goto out_ro;
@@ -877,12 +1294,13 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk, 
/**

 * ensure_wear_leveling - schedule wear-leveling if it is needed.

 * @ubi: UBI device description object

 * @nested: set to non-zero if this function is called from UBI worker

 *

 * This function checks if it is time to start wear-leveling and schedules it

 * if yes. This function returns zero in case of success and a negative error

 * code in case of failure.

 */

static int ensure_wear_leveling(struct ubi_device *ubi)

static int ensure_wear_leveling(struct ubi_device *ubi, int nested)

{

	int err = 0;

	struct ubi_wl_entry *e1;
@@ -910,7 +1328,7 @@ static int ensure_wear_leveling(struct ubi_device *ubi) 
		 * %UBI_WL_THRESHOLD.

		 */

		e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);

		e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);

		e2 = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);



		if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD))

			goto out_unlock;
@@ -927,7 +1345,11 @@ static int ensure_wear_leveling(struct ubi_device *ubi) 
		goto out_cancel;

	}



	wrk->anchor = 0;

	wrk->func = &wear_leveling_worker;

	if (nested)

		__schedule_ubi_work(ubi, wrk);

	else

		schedule_ubi_work(ubi, wrk);

	return err;
@@ -939,6 +1361,38 @@ static int ensure_wear_leveling(struct ubi_device *ubi) 
	return err;

}



#ifdef CONFIG_MTD_UBI_FASTMAP

/**

 * 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;



	spin_lock(&ubi->wl_lock);

	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->anchor = 1;

	wrk->func = &wear_leveling_worker;

	schedule_ubi_work(ubi, wrk);

	return 0;

}

#endif



/**

 * erase_worker - physical eraseblock erase worker function.

 * @ubi: UBI device description object
@@ -969,6 +1423,8 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk, 
	dbg_wl("erase PEB %d EC %d LEB %d:%d",

	       pnum, e->ec, wl_wrk->vol_id, wl_wrk->lnum);



	ubi_assert(!ubi_is_fm_block(ubi, e->pnum));



	err = sync_erase(ubi, e, wl_wrk->torture);

	if (!err) {

		/* Fine, we've erased it successfully */
@@ -976,6 +1432,7 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk, 


		spin_lock(&ubi->wl_lock);

		wl_tree_add(e, &ubi->free);

		ubi->free_count++;

		spin_unlock(&ubi->wl_lock);



		/*
@@ -985,7 +1442,7 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk, 
		serve_prot_queue(ubi);



		/* And take care about wear-leveling */

		err = ensure_wear_leveling(ubi);

		err = ensure_wear_leveling(ubi, 1);

		return err;

	}
@@ -1223,7 +1680,7 @@ int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum) 
	 * Technically scrubbing is the same as wear-leveling, so it is done

	 * by the WL worker.

	 */

	return ensure_wear_leveling(ubi);

	return ensure_wear_leveling(ubi, 0);

}



/**
@@ -1404,7 +1861,7 @@ static void cancel_pending(struct ubi_device *ubi) 
 */

int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)

{

	int err, i;

	int err, i, reserved_pebs, found_pebs = 0;

	struct rb_node *rb1, *rb2;

	struct ubi_ainf_volume *av;

	struct ubi_ainf_peb *aeb, *tmp;
@@ -1416,6 +1873,9 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai) 
	init_rwsem(&ubi->work_sem);

	ubi->max_ec = ai->max_ec;

	INIT_LIST_HEAD(&ubi->works);

#ifdef CONFIG_MTD_UBI_FASTMAP

	INIT_WORK(&ubi->fm_work, update_fastmap_work_fn);

#endif



	sprintf(ubi->bgt_name, UBI_BGT_NAME_PATTERN, ubi->ubi_num);
@@ -1437,13 +1897,17 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai) 


		e->pnum = aeb->pnum;

		e->ec = aeb->ec;

		ubi_assert(!ubi_is_fm_block(ubi, e->pnum));

		ubi->lookuptbl[e->pnum] = e;

		if (schedule_erase(ubi, e, aeb->vol_id, aeb->lnum, 0)) {

			kmem_cache_free(ubi_wl_entry_slab, e);

			goto out_free;

		}



		found_pebs++;

	}



	ubi->free_count = 0;

	list_for_each_entry(aeb, &ai->free, u.list) {

		cond_resched();
@@ -1454,8 +1918,14 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai) 
		e->pnum = aeb->pnum;

		e->ec = aeb->ec;

		ubi_assert(e->ec >= 0);

		ubi_assert(!ubi_is_fm_block(ubi, e->pnum));



		wl_tree_add(e, &ubi->free);

		ubi->free_count++;



		ubi->lookuptbl[e->pnum] = e;



		found_pebs++;

	}



	ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
@@ -1469,6 +1939,7 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai) 
			e->pnum = aeb->pnum;

			e->ec = aeb->ec;

			ubi->lookuptbl[e->pnum] = e;



			if (!aeb->scrub) {

				dbg_wl("add PEB %d EC %d to the used tree",

				       e->pnum, e->ec);
@@ -1478,22 +1949,38 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai) 
				       e->pnum, e->ec);

				wl_tree_add(e, &ubi->scrub);

			}



			found_pebs++;

		}

	}



	if (ubi->avail_pebs < WL_RESERVED_PEBS) {

	dbg_wl("found %i PEBs", found_pebs);



	if (ubi->fm)

		ubi_assert(ubi->good_peb_count == \

			   found_pebs + ubi->fm->used_blocks);

	else

		ubi_assert(ubi->good_peb_count == found_pebs);



	reserved_pebs = WL_RESERVED_PEBS;

#ifdef CONFIG_MTD_UBI_FASTMAP

	/* Reserve enough LEBs to store two fastmaps. */

	reserved_pebs += (ubi->fm_size / ubi->leb_size) * 2;

#endif



	if (ubi->avail_pebs < reserved_pebs) {

		ubi_err("no enough physical eraseblocks (%d, need %d)",

			ubi->avail_pebs, WL_RESERVED_PEBS);

			ubi->avail_pebs, reserved_pebs);

		if (ubi->corr_peb_count)

			ubi_err("%d PEBs are corrupted and not used",

				ubi->corr_peb_count);

		goto out_free;

	}

	ubi->avail_pebs -= WL_RESERVED_PEBS;

	ubi->rsvd_pebs += WL_RESERVED_PEBS;

	ubi->avail_pebs -= reserved_pebs;

	ubi->rsvd_pebs += reserved_pebs;



	/* Schedule wear-leveling if needed */

	err = ensure_wear_leveling(ubi);

	err = ensure_wear_leveling(ubi, 0);

	if (err)

		goto out_free;
@@ -1572,7 +2059,7 @@ static int self_check_ec(struct ubi_device *ubi, int pnum, int ec) 
	}



	read_ec = be64_to_cpu(ec_hdr->ec);

	if (ec != read_ec) {

	if (ec != read_ec && read_ec - ec > 1) {

		ubi_err("self-check failed for PEB %d", pnum);

		ubi_err("read EC is %lld, should be %d", read_ec, ec);

		dump_stack();