Messages in this thread Patch in this message | | | From | Richard Weinberger <> | Subject | [PATCH 3/7] UBI: Fastmap: Ensure that not all anchor PEBs go into a pool. | Date | Sat, 23 Jun 2012 15:03:18 +0200 |
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If we have no fastmap on flash make sure that not all anchor PEBs go into a WL pool such that at least one can be used by fastmap.
Signed-off-by: Richard Weinberger <richard@nod.at> --- drivers/mtd/ubi/wl.c | 36 +++++++++++++++++++++++++++--------- 1 files changed, 27 insertions(+), 9 deletions(-)
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c index b4d4358..8b2af8f4 100644 --- a/drivers/mtd/ubi/wl.c +++ b/drivers/mtd/ubi/wl.c @@ -342,16 +342,18 @@ 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); @@ -366,32 +368,48 @@ 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 (!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 rb_root *root) +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) + if (last->ec - first->ec < WL_FREE_MAX_DIFF) { e = rb_entry(root->rb_node, struct ubi_wl_entry, u.rb); + + /* 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 && e->pnum < UBI_FM_MAX_START) + e = rb_entry(rb_next(root->rb_node), struct ubi_wl_entry, u.rb); + } else - e = find_wl_entry(root, WL_FREE_MAX_DIFF/2); + e = find_wl_entry(ubi, root, WL_FREE_MAX_DIFF/2); return e; } @@ -452,7 +470,7 @@ struct ubi_wl_entry *ubi_wl_get_fm_peb(struct ubi_device *ubi, int max_pnum) } if (max_pnum < 0) - e = find_mean_wl_entry(&ubi->free); + e = find_mean_wl_entry(ubi, &ubi->free); else e = find_anchor_wl_entry(&ubi->free, max_pnum); @@ -494,7 +512,7 @@ retry: goto retry; } - e = find_mean_wl_entry(&ubi->free); + e = find_mean_wl_entry(ubi, &ubi->free); self_check_in_wl_tree(ubi, e, &ubi->free); @@ -547,7 +565,7 @@ static void refill_wl_pool(struct ubi_device *ubi) if (!ubi->free.rb_node) break; - e = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF); + 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); @@ -1241,7 +1259,7 @@ static int ensure_wear_leveling(struct ubi_device *ubi, int nested) * %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; -- 1.7.6.5
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