Commit 14072ee3 authored by Zhihao Cheng's avatar Zhihao Cheng Committed by Richard Weinberger
Browse files

ubi: fastmap: Check wl_pool for free peb before wear leveling 



UBI fetches free peb from wl_pool during wear leveling, so UBI should
check wl_pool's empty status before wear leveling. Otherwise, UBI will
miss wear leveling chances when free pebs are run out.

Signed-off-by: default avatarZhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent d09e9a2b

drivers/mtd/ubi/fastmap-wl.c

+52 −0
Original line number Diff line number Diff line
@@ -275,6 +275,58 @@ int ubi_wl_get_peb(struct ubi_device *ubi) 
	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

drivers/mtd/ubi/wl.c

+12 −2
Original line number Diff line number Diff line
@@ -670,7 +670,11 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk, 
	ubi_assert(!ubi->move_from && !ubi->move_to);

	ubi_assert(!ubi->move_to_put);



#ifdef CONFIG_MTD_UBI_FASTMAP

	if (!next_peb_for_wl(ubi) ||

#else

	if (!ubi->free.rb_node ||

#endif

	    (!ubi->used.rb_node && !ubi->scrub.rb_node)) {

		/*

		 * No free physical eraseblocks? Well, they must be waiting in
@@ -1003,8 +1007,6 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk, 
static int ensure_wear_leveling(struct ubi_device *ubi, int nested)

{

	int err = 0;

	struct ubi_wl_entry *e1;

	struct ubi_wl_entry *e2;

	struct ubi_work *wrk;



	spin_lock(&ubi->wl_lock);
@@ -1017,6 +1019,13 @@ static int ensure_wear_leveling(struct ubi_device *ubi, int nested) 
	 * the WL worker has to be scheduled anyway.

	 */

	if (!ubi->scrub.rb_node) {

#ifdef CONFIG_MTD_UBI_FASTMAP

		if (!need_wear_leveling(ubi))

			goto out_unlock;

#else

		struct ubi_wl_entry *e1;

		struct ubi_wl_entry *e2;



		if (!ubi->used.rb_node || !ubi->free.rb_node)

			/* No physical eraseblocks - no deal */

			goto out_unlock;
@@ -1032,6 +1041,7 @@ static int ensure_wear_leveling(struct ubi_device *ubi, int nested) 


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

			goto out_unlock;

#endif

		dbg_wl("schedule wear-leveling");

	} else

		dbg_wl("schedule scrubbing");

drivers/mtd/ubi/wl.h

+2 −0
Original line number Diff line number Diff line
@@ -5,6 +5,8 @@ 
static void update_fastmap_work_fn(struct work_struct *wrk);

static struct ubi_wl_entry *find_anchor_wl_entry(struct rb_root *root);

static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi);

static struct ubi_wl_entry *next_peb_for_wl(struct ubi_device *ubi);

static bool need_wear_leveling(struct ubi_device *ubi);

static void ubi_fastmap_close(struct ubi_device *ubi);

static inline void ubi_fastmap_init(struct ubi_device *ubi, int *count)

{