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: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

diff --git a/drivers/mtd/ubi/fastmap-wl.c b/drivers/mtd/ubi/fastmap-wl.c
index 053ab52668e8bf3c1b8f39b8430e56fbdd9161a5..0ee452275578d9e5b968a41b41e9cbbc66be794d 100644 (file)
--- a/drivers/mtd/ubi/fastmap-wl.c
+++ b/drivers/mtd/ubi/fastmap-wl.c
@@ -275,6 +275,58 @@ 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

diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index afcdacb9d0e999a9a5eb1df6a7050d3858d5b50e..55bae06cf4083f4edc247208d3a78fa8090c5495 100644 (file)
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -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 @@ out_cancel:
 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");

diff --git a/drivers/mtd/ubi/wl.h b/drivers/mtd/ubi/wl.h
index c93a53293786358148ad5cc9b8aac10a36cb8f21..5ebe374a08aed9954e385cbcdabad7d974617659 100644 (file)
--- a/drivers/mtd/ubi/wl.h
+++ b/drivers/mtd/ubi/wl.h
@@ -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)
 {