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
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+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
+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");
+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)
{