Merging upstream version 6.7.7.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

9 files changed, 164 insertions, 113 deletions

diff --git a/drivers/mtd/ubi/block.c b/drivers/mtd/ubi/block.c
index 437c5b83ff..309a42aeaa 100644
--- a/drivers/mtd/ubi/block.c
+++ b/drivers/mtd/ubi/block.c
@@ -447,13 +447,15 @@ out_unlock:
 
 static void ubiblock_cleanup(struct ubiblock *dev)
 {
+	int id = dev->gd->first_minor;
+
 	/* Stop new requests to arrive */
 	del_gendisk(dev->gd);
 	/* Finally destroy the blk queue */
 	dev_info(disk_to_dev(dev->gd), "released");
 	put_disk(dev->gd);
 	blk_mq_free_tag_set(&dev->tag_set);
-	idr_remove(&ubiblock_minor_idr, dev->gd->first_minor);
+	idr_remove(&ubiblock_minor_idr, id);
 }
 
 int ubiblock_remove(struct ubi_volume_info *vi)
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 8ee51e49fc..7d4ff1193d 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -35,7 +35,7 @@
 #define MTD_PARAM_LEN_MAX 64
 
 /* Maximum number of comma-separated items in the 'mtd=' parameter */
-#define MTD_PARAM_MAX_COUNT 5
+#define MTD_PARAM_MAX_COUNT 6
 
 /* Maximum value for the number of bad PEBs per 1024 PEBs */
 #define MAX_MTD_UBI_BEB_LIMIT 768
@@ -54,6 +54,7 @@
  * @vid_hdr_offs: VID header offset
  * @max_beb_per1024: maximum expected number of bad PEBs per 1024 PEBs
  * @enable_fm: enable fastmap when value is non-zero
+ * @need_resv_pool: reserve pool->max_size pebs when value is none-zero
  */
 struct mtd_dev_param {
 	char name[MTD_PARAM_LEN_MAX];
@@ -61,6 +62,7 @@ struct mtd_dev_param {
 	int vid_hdr_offs;
 	int max_beb_per1024;
 	int enable_fm;
+	int need_resv_pool;
 };
 
 /* Numbers of elements set in the @mtd_dev_param array */
@@ -825,6 +827,7 @@ static int autoresize(struct ubi_device *ubi, int vol_id)
  * @vid_hdr_offset: VID header offset
  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
  * @disable_fm: whether disable fastmap
+ * @need_resv_pool: whether reserve pebs to fill fm_pool
  *
  * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
  * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
@@ -840,7 +843,8 @@ static int autoresize(struct ubi_device *ubi, int vol_id)
  * @ubi_devices_mutex.
  */
 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
-		       int vid_hdr_offset, int max_beb_per1024, bool disable_fm)
+		       int vid_hdr_offset, int max_beb_per1024, bool disable_fm,
+		       bool need_resv_pool)
 {
 	struct ubi_device *ubi;
 	int i, err;
@@ -951,6 +955,7 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
 		UBI_FM_MIN_POOL_SIZE);
 
 	ubi->fm_wl_pool.max_size = ubi->fm_pool.max_size / 2;
+	ubi->fm_pool_rsv_cnt = need_resv_pool ? ubi->fm_pool.max_size : 0;
 	ubi->fm_disabled = (!fm_autoconvert || disable_fm) ? 1 : 0;
 	if (fm_debug)
 		ubi_enable_dbg_chk_fastmap(ubi);
@@ -1273,7 +1278,8 @@ static int __init ubi_init(void)
 		mutex_lock(&ubi_devices_mutex);
 		err = ubi_attach_mtd_dev(mtd, p->ubi_num,
 					 p->vid_hdr_offs, p->max_beb_per1024,
-					 p->enable_fm == 0);
+					 p->enable_fm == 0,
+					 p->need_resv_pool != 0);
 		mutex_unlock(&ubi_devices_mutex);
 		if (err < 0) {
 			pr_err("UBI error: cannot attach mtd%d\n",
@@ -1482,6 +1488,18 @@ static int ubi_mtd_param_parse(const char *val, const struct kernel_param *kp)
 	} else
 		p->enable_fm = 0;
 
+	token = tokens[5];
+	if (token) {
+		int err = kstrtoint(token, 10, &p->need_resv_pool);
+
+		if (err) {
+			pr_err("UBI error: bad value for need_resv_pool parameter: %s\n",
+				token);
+			return -EINVAL;
+		}
+	} else
+		p->need_resv_pool = 0;
+
 	mtd_devs += 1;
 	return 0;
 }
@@ -1495,6 +1513,7 @@ MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: mtd=<name|num|pa
 		      __stringify(CONFIG_MTD_UBI_BEB_LIMIT) ") if 0)\n"
 		      "Optional \"ubi_num\" parameter specifies UBI device number which have to be assigned to the newly created UBI device (assigned automatically by default)\n"
 		      "Optional \"enable_fm\" parameter determines whether to enable fastmap during attach. If the value is non-zero, fastmap is enabled. Default value is 0.\n"
+		      "Optional \"need_resv_pool\" parameter determines whether to reserve pool->max_size pebs during attach. If the value is non-zero, peb reservation is enabled. Default value is 0.\n"
 		      "\n"
 		      "Example 1: mtd=/dev/mtd0 - attach MTD device /dev/mtd0.\n"
 		      "Example 2: mtd=content,1984 mtd=4 - attach MTD device with name \"content\" using VID header offset 1984, and MTD device number 4 with default VID header offset.\n"
diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index f43430b9c1..0d8f04cf03 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -1041,7 +1041,8 @@ static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
 		 */
 		mutex_lock(&ubi_devices_mutex);
 		err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset,
-					 req.max_beb_per1024, !!req.disable_fm);
+					 req.max_beb_per1024, !!req.disable_fm,
+					 !!req.need_resv_pool);
 		mutex_unlock(&ubi_devices_mutex);
 		if (err < 0)
 			put_mtd_device(mtd);
diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index 655ff41863..8d1f0e0589 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -33,9 +33,6 @@
 #include <linux/err.h>
 #include "ubi.h"
 
-/* Number of physical eraseblocks reserved for atomic LEB change operation */
-#define EBA_RESERVED_PEBS 1
-
 /**
  * struct ubi_eba_entry - structure encoding a single LEB -> PEB association
  * @pnum: the physical eraseblock number attached to the LEB
diff --git a/drivers/mtd/ubi/fastmap-wl.c b/drivers/mtd/ubi/fastmap-wl.c
index 863f571f1a..2a9cc9413c 100644
--- a/drivers/mtd/ubi/fastmap-wl.c
+++ b/drivers/mtd/ubi/fastmap-wl.c
@@ -76,7 +76,7 @@ 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))
+	if (!ubi->free.rb_node)
 		goto out;
 
 	if (anchor)
@@ -98,43 +98,104 @@ out:
 }
 
 /*
- * has_enough_free_count - whether ubi has enough free pebs to fill fm pools
+ * wait_free_pebs_for_pool - wait until there enough free pebs
+ * @ubi: UBI device description object
+ *
+ * Wait and execute do_work until there are enough free pebs, fill pool
+ * as much as we can. This will reduce pool refilling times, which can
+ * reduce the fastmap updating frequency.
+ */
+static void wait_free_pebs_for_pool(struct ubi_device *ubi)
+{
+	struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
+	struct ubi_fm_pool *pool = &ubi->fm_pool;
+	int free, expect_free, executed;
+	/*
+	 * There are at least following free pebs which reserved by UBI:
+	 * 1. WL_RESERVED_PEBS[1]
+	 * 2. EBA_RESERVED_PEBS[1]
+	 * 3. fm pebs - 1: Twice fastmap size deducted by fastmap and fm_anchor
+	 * 4. beb_rsvd_pebs: This value should be get under lock ubi->wl_lock
+	 */
+	int reserved = WL_RESERVED_PEBS + EBA_RESERVED_PEBS +
+		       ubi->fm_size / ubi->leb_size - 1 + ubi->fm_pool_rsv_cnt;
+
+	do {
+		spin_lock(&ubi->wl_lock);
+		free = ubi->free_count;
+		free += pool->size - pool->used + wl_pool->size - wl_pool->used;
+		expect_free = reserved + ubi->beb_rsvd_pebs;
+		spin_unlock(&ubi->wl_lock);
+
+		/*
+		 * Break out if there are no works or work is executed failure,
+		 * given the fact that erase_worker will schedule itself when
+		 * -EBUSY is returned from mtd layer caused by system shutdown.
+		 */
+		if (do_work(ubi, &executed) || !executed)
+			break;
+	} while (free < expect_free);
+}
+
+/*
+ * left_free_count - returns the number of free pebs to fill fm pools
  * @ubi: UBI device description object
- * @is_wl_pool: whether UBI is filling wear leveling pool
  *
- * This helper function checks whether there are enough free pebs (deducted
- * by fastmap pebs) to fill fm_pool and fm_wl_pool, above rule works after
- * there is at least one of free pebs is filled into fm_wl_pool.
- * For wear leveling pool, UBI should also reserve free pebs for bad pebs
- * handling, because there maybe no enough free pebs for user volumes after
- * producing new bad pebs.
+ * This helper function returns the number of free pebs (deducted
+ * by fastmap pebs) to fill fm_pool and fm_wl_pool.
  */
-static bool has_enough_free_count(struct ubi_device *ubi, bool is_wl_pool)
+static int left_free_count(struct ubi_device *ubi)
 {
 	int fm_used = 0;	// fastmap non anchor pebs.
-	int beb_rsvd_pebs;
 
 	if (!ubi->free.rb_node)
-		return false;
+		return 0;
 
-	beb_rsvd_pebs = is_wl_pool ? ubi->beb_rsvd_pebs : 0;
-	if (ubi->fm_wl_pool.size > 0 && !(ubi->ro_mode || ubi->fm_disabled))
+	if (!ubi->ro_mode && !ubi->fm_disabled)
 		fm_used = ubi->fm_size / ubi->leb_size - 1;
 
-	return ubi->free_count - beb_rsvd_pebs > fm_used;
+	return ubi->free_count - fm_used;
+}
+
+/*
+ * can_fill_pools - whether free PEBs will be left after filling pools
+ * @ubi: UBI device description object
+ * @free: current number of free PEBs
+ *
+ * Return %1 if there are still left free PEBs after filling pools,
+ * otherwise %0 is returned.
+ */
+static int can_fill_pools(struct ubi_device *ubi, int free)
+{
+	struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
+	struct ubi_fm_pool *pool = &ubi->fm_pool;
+	int pool_need = pool->max_size - pool->size +
+			wl_pool->max_size - wl_pool->size;
+
+	if (free - pool_need < 1)
+		return 0;
+
+	return 1;
 }
 
 /**
- * ubi_refill_pools - refills all fastmap PEB pools.
+ * ubi_refill_pools_and_lock - refills all fastmap PEB pools and takes fm locks.
  * @ubi: UBI device description object
  */
-void ubi_refill_pools(struct ubi_device *ubi)
+void ubi_refill_pools_and_lock(struct ubi_device *ubi)
 {
 	struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
 	struct ubi_fm_pool *pool = &ubi->fm_pool;
 	struct ubi_wl_entry *e;
 	int enough;
 
+	if (!ubi->ro_mode && !ubi->fm_disabled)
+		wait_free_pebs_for_pool(ubi);
+
+	down_write(&ubi->fm_protect);
+	down_write(&ubi->work_sem);
+	down_write(&ubi->fm_eba_sem);
+
 	spin_lock(&ubi->wl_lock);
 
 	return_unused_pool_pebs(ubi, wl_pool);
@@ -159,7 +220,7 @@ void ubi_refill_pools(struct ubi_device *ubi)
 	for (;;) {
 		enough = 0;
 		if (pool->size < pool->max_size) {
-			if (!has_enough_free_count(ubi, false))
+			if (left_free_count(ubi) <= 0)
 				break;
 
 			e = wl_get_wle(ubi);
@@ -172,10 +233,13 @@ void ubi_refill_pools(struct ubi_device *ubi)
 			enough++;
 
 		if (wl_pool->size < wl_pool->max_size) {
-			if (!has_enough_free_count(ubi, true))
+			int left_free = left_free_count(ubi);
+
+			if (left_free <= 0)
 				break;
 
-			e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
+			e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF,
+					  !can_fill_pools(ubi, left_free));
 			self_check_in_wl_tree(ubi, e, &ubi->free);
 			rb_erase(&e->u.rb, &ubi->free);
 			ubi->free_count--;
@@ -210,7 +274,7 @@ static int produce_free_peb(struct ubi_device *ubi)
 
 	while (!ubi->free.rb_node && ubi->works_count) {
 		dbg_wl("do one work synchronously");
-		err = do_work(ubi);
+		err = do_work(ubi, NULL);
 
 		if (err)
 			return err;
@@ -315,12 +379,12 @@ static bool need_wear_leveling(struct ubi_device *ubi)
 	if (!e) {
 		if (!ubi->free.rb_node)
 			return false;
-		e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
+		e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF, 0);
 		ec = e->ec;
 	} else {
 		ec = e->ec;
 		if (ubi->free.rb_node) {
-			e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
+			e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF, 0);
 			ec = max(ec, e->ec);
 		}
 	}
@@ -481,7 +545,7 @@ static void ubi_fastmap_close(struct ubi_device *ubi)
 static struct ubi_wl_entry *may_reserve_for_fm(struct ubi_device *ubi,
 					   struct ubi_wl_entry *e,
 					   struct rb_root *root) {
-	if (e && !ubi->fm_disabled && !ubi->fm &&
+	if (e && !ubi->fm_disabled && !ubi->fm && !ubi->fm_anchor &&
 	    e->pnum < UBI_FM_MAX_START)
 		e = rb_entry(rb_next(root->rb_node),
 			     struct ubi_wl_entry, u.rb);
diff --git a/drivers/mtd/ubi/fastmap.c b/drivers/mtd/ubi/fastmap.c
index 28c8151a07..2a728c31e6 100644
--- a/drivers/mtd/ubi/fastmap.c
+++ b/drivers/mtd/ubi/fastmap.c
@@ -20,7 +20,7 @@ static inline unsigned long *init_seen(struct ubi_device *ubi)
 	if (!ubi_dbg_chk_fastmap(ubi))
 		return NULL;
 
-	ret = bitmap_zalloc(ubi->peb_count, GFP_KERNEL);
+	ret = bitmap_zalloc(ubi->peb_count, GFP_NOFS);
 	if (!ret)
 		return ERR_PTR(-ENOMEM);
 
@@ -105,7 +105,7 @@ static struct ubi_vid_io_buf *new_fm_vbuf(struct ubi_device *ubi, int vol_id)
 	struct ubi_vid_io_buf *new;
 	struct ubi_vid_hdr *vh;
 
-	new = ubi_alloc_vid_buf(ubi, GFP_KERNEL);
+	new = ubi_alloc_vid_buf(ubi, GFP_NOFS);
 	if (!new)
 		goto out;
 
@@ -1390,53 +1390,6 @@ out:
 }
 
 /**
- * erase_block - Manually erase a PEB.
- * @ubi: UBI device object
- * @pnum: PEB to be erased
- *
- * Returns the new EC value on success, < 0 indicates an internal error.
- */
-static int erase_block(struct ubi_device *ubi, int pnum)
-{
-	int ret;
-	struct ubi_ec_hdr *ec_hdr;
-	long long ec;
-
-	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
-	if (!ec_hdr)
-		return -ENOMEM;
-
-	ret = ubi_io_read_ec_hdr(ubi, pnum, ec_hdr, 0);
-	if (ret < 0)
-		goto out;
-	else if (ret && ret != UBI_IO_BITFLIPS) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	ret = ubi_io_sync_erase(ubi, pnum, 0);
-	if (ret < 0)
-		goto out;
-
-	ec = be64_to_cpu(ec_hdr->ec);
-	ec += ret;
-	if (ec > UBI_MAX_ERASECOUNTER) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	ec_hdr->ec = cpu_to_be64(ec);
-	ret = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr);
-	if (ret < 0)
-		goto out;
-
-	ret = ec;
-out:
-	kfree(ec_hdr);
-	return ret;
-}
-
-/**
  * invalidate_fastmap - destroys a fastmap.
  * @ubi: UBI device object
  *
@@ -1462,7 +1415,7 @@ static int invalidate_fastmap(struct ubi_device *ubi)
 	ubi->fm = NULL;
 
 	ret = -ENOMEM;
-	fm = kzalloc(sizeof(*fm), GFP_KERNEL);
+	fm = kzalloc(sizeof(*fm), GFP_NOFS);
 	if (!fm)
 		goto out;
 
@@ -1538,11 +1491,7 @@ int ubi_update_fastmap(struct ubi_device *ubi)
 	struct ubi_fastmap_layout *new_fm, *old_fm;
 	struct ubi_wl_entry *tmp_e;
 
-	down_write(&ubi->fm_protect);
-	down_write(&ubi->work_sem);
-	down_write(&ubi->fm_eba_sem);
-
-	ubi_refill_pools(ubi);
+	ubi_refill_pools_and_lock(ubi);
 
 	if (ubi->ro_mode || ubi->fm_disabled) {
 		up_write(&ubi->fm_eba_sem);
@@ -1551,7 +1500,7 @@ int ubi_update_fastmap(struct ubi_device *ubi)
 		return 0;
 	}
 
-	new_fm = kzalloc(sizeof(*new_fm), GFP_KERNEL);
+	new_fm = kzalloc(sizeof(*new_fm), GFP_NOFS);
 	if (!new_fm) {
 		up_write(&ubi->fm_eba_sem);
 		up_write(&ubi->work_sem);
@@ -1576,7 +1525,7 @@ int ubi_update_fastmap(struct ubi_device *ubi)
 
 		if (!tmp_e) {
 			if (old_fm && old_fm->e[i]) {
-				ret = erase_block(ubi, old_fm->e[i]->pnum);
+				ret = ubi_sync_erase(ubi, old_fm->e[i], 0);
 				if (ret < 0) {
 					ubi_err(ubi, "could not erase old fastmap PEB");
 
@@ -1628,7 +1577,7 @@ int ubi_update_fastmap(struct ubi_device *ubi)
 	if (old_fm) {
 		/* no fresh anchor PEB was found, reuse the old one */
 		if (!tmp_e) {
-			ret = erase_block(ubi, old_fm->e[0]->pnum);
+			ret = ubi_sync_erase(ubi, old_fm->e[0], 0);
 			if (ret < 0) {
 				ubi_err(ubi, "could not erase old anchor PEB");
 
@@ -1640,7 +1589,6 @@ int ubi_update_fastmap(struct ubi_device *ubi)
 				goto err;
 			}
 			new_fm->e[0] = old_fm->e[0];
-			new_fm->e[0]->ec = ret;
 			old_fm->e[0] = NULL;
 		} else {
 			/* we've got a new anchor PEB, return the old one */
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index c8f1bd4fa1..a5ec566df0 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -82,6 +82,9 @@ void ubi_err(const struct ubi_device *ubi, const char *fmt, ...);
 #define UBI_DFS_DIR_NAME "ubi%d"
 #define UBI_DFS_DIR_LEN  (3 + 2 + 1)
 
+/* Number of physical eraseblocks reserved for atomic LEB change operation */
+#define EBA_RESERVED_PEBS 1
+
 /*
  * Error codes returned by the I/O sub-system.
  *
@@ -491,6 +494,7 @@ struct ubi_debug_info {
  * @fast_attach: non-zero if UBI was attached by fastmap
  * @fm_anchor: The next anchor PEB to use for fastmap
  * @fm_do_produce_anchor: If true produce an anchor PEB in wl
+ * @fm_pool_rsv_cnt: Number of reserved PEBs for filling pool/wl_pool
  *
  * @used: RB-tree of used physical eraseblocks
  * @erroneous: RB-tree of erroneous used physical eraseblocks
@@ -601,6 +605,7 @@ struct ubi_device {
 	int fast_attach;
 	struct ubi_wl_entry *fm_anchor;
 	int fm_do_produce_anchor;
+	int fm_pool_rsv_cnt;
 
 	/* Wear-leveling sub-system's stuff */
 	struct rb_root used;
@@ -902,6 +907,7 @@ int self_check_eba(struct ubi_device *ubi, struct ubi_attach_info *ai_fastmap,
 		   struct ubi_attach_info *ai_scan);
 
 /* wl.c */
+int ubi_sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e, int torture);
 int ubi_wl_get_peb(struct ubi_device *ubi);
 int ubi_wl_put_peb(struct ubi_device *ubi, int vol_id, int lnum,
 		   int pnum, int torture);
@@ -914,7 +920,7 @@ struct ubi_wl_entry *ubi_wl_get_fm_peb(struct ubi_device *ubi, int anchor);
 int ubi_wl_put_fm_peb(struct ubi_device *ubi, struct ubi_wl_entry *used_e,
 		      int lnum, int torture);
 int ubi_is_erase_work(struct ubi_work *wrk);
-void ubi_refill_pools(struct ubi_device *ubi);
+void ubi_refill_pools_and_lock(struct ubi_device *ubi);
 int ubi_ensure_anchor_pebs(struct ubi_device *ubi);
 int ubi_bitflip_check(struct ubi_device *ubi, int pnum, int force_scrub);
 
@@ -938,7 +944,7 @@ int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
 /* build.c */
 int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
 		       int vid_hdr_offset, int max_beb_per1024,
-		       bool disable_fm);
+		       bool disable_fm, bool need_resv_pool);
 int ubi_detach_mtd_dev(int ubi_num, int anyway);
 struct ubi_device *ubi_get_device(int ubi_num);
 void ubi_put_device(struct ubi_device *ubi);
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index 26a214f016..a357f3d27f 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -181,11 +181,13 @@ static void wl_entry_destroy(struct ubi_device *ubi, struct ubi_wl_entry *e)
 /**
  * do_work - do one pending work.
  * @ubi: UBI device description object
+ * @executed: whether there is one work is executed
  *
  * This function returns zero in case of success and a negative error code in
- * case of failure.
+ * case of failure. If @executed is not NULL and there is one work executed,
+ * @executed is set as %1, otherwise @executed is set as %0.
  */
-static int do_work(struct ubi_device *ubi)
+static int do_work(struct ubi_device *ubi, int *executed)
 {
 	int err;
 	struct ubi_work *wrk;
@@ -203,9 +205,13 @@ static int do_work(struct ubi_device *ubi)
 	if (list_empty(&ubi->works)) {
 		spin_unlock(&ubi->wl_lock);
 		up_read(&ubi->work_sem);
+		if (executed)
+			*executed = 0;
 		return 0;
 	}
 
+	if (executed)
+		*executed = 1;
 	wrk = list_entry(ubi->works.next, struct ubi_work, list);
 	list_del(&wrk->list);
 	ubi->works_count -= 1;
@@ -311,12 +317,14 @@ static void prot_queue_add(struct ubi_device *ubi, struct ubi_wl_entry *e)
  * @ubi: UBI device description object
  * @root: the RB-tree where to look for
  * @diff: maximum possible difference from the smallest erase counter
+ * @pick_max: pick PEB even its erase counter beyonds 'min_ec + @diff'
  *
  * 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 ubi_device *ubi,
-					  struct rb_root *root, int diff)
+					  struct rb_root *root, int diff,
+					  int pick_max)
 {
 	struct rb_node *p;
 	struct ubi_wl_entry *e;
@@ -330,9 +338,11 @@ static struct ubi_wl_entry *find_wl_entry(struct ubi_device *ubi,
 		struct ubi_wl_entry *e1;
 
 		e1 = rb_entry(p, struct ubi_wl_entry, u.rb);
-		if (e1->ec >= max)
+		if (e1->ec >= max) {
+			if (pick_max)
+				e = e1;
 			p = p->rb_left;
-		else {
+		} else {
 			p = p->rb_right;
 			e = e1;
 		}
@@ -361,12 +371,15 @@ static struct ubi_wl_entry *find_mean_wl_entry(struct ubi_device *ubi,
 	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 no fastmap has been written and fm_anchor is not
+		 * reserved 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.
+		 */
 		e = may_reserve_for_fm(ubi, e, root);
 	} else
-		e = find_wl_entry(ubi, root, WL_FREE_MAX_DIFF/2);
+		e = find_wl_entry(ubi, root, WL_FREE_MAX_DIFF/2, 0);
 
 	return e;
 }
@@ -427,7 +440,7 @@ static int prot_queue_del(struct ubi_device *ubi, int pnum)
 }
 
 /**
- * sync_erase - synchronously erase a physical eraseblock.
+ * ubi_sync_erase - synchronously erase a physical eraseblock.
  * @ubi: UBI device description object
  * @e: the physical eraseblock to erase
  * @torture: if the physical eraseblock has to be tortured
@@ -435,8 +448,7 @@ static int prot_queue_del(struct ubi_device *ubi, int pnum)
  * This function returns zero in case of success and a negative error code in
  * case of failure.
  */
-static int sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
-		      int torture)
+int ubi_sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e, int torture)
 {
 	int err;
 	struct ubi_ec_hdr *ec_hdr;
@@ -1040,7 +1052,7 @@ 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, &ubi->free, WL_FREE_MAX_DIFF);
+		e2 = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF, 0);
 
 		if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD))
 			goto out_unlock;
@@ -1094,7 +1106,7 @@ 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);
 
-	err = sync_erase(ubi, e, wl_wrk->torture);
+	err = ubi_sync_erase(ubi, e, wl_wrk->torture);
 	if (!err) {
 		spin_lock(&ubi->wl_lock);
 
@@ -1686,7 +1698,7 @@ int ubi_thread(void *u)
 		}
 		spin_unlock(&ubi->wl_lock);
 
-		err = do_work(ubi);
+		err = do_work(ubi, NULL);
 		if (err) {
 			ubi_err(ubi, "%s: work failed with error code %d",
 				ubi->bgt_name, err);
@@ -1749,7 +1761,7 @@ static int erase_aeb(struct ubi_device *ubi, struct ubi_ainf_peb *aeb, bool sync
 	ubi->lookuptbl[e->pnum] = e;
 
 	if (sync) {
-		err = sync_erase(ubi, e, false);
+		err = ubi_sync_erase(ubi, e, false);
 		if (err)
 			goto out_free;
 
@@ -2071,7 +2083,7 @@ static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
 {
 	struct ubi_wl_entry *e;
 
-	e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
+	e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF, 0);
 	self_check_in_wl_tree(ubi, e, &ubi->free);
 	ubi->free_count--;
 	ubi_assert(ubi->free_count >= 0);
@@ -2097,7 +2109,7 @@ static int produce_free_peb(struct ubi_device *ubi)
 		spin_unlock(&ubi->wl_lock);
 
 		dbg_wl("do one work synchronously");
-		err = do_work(ubi);
+		err = do_work(ubi, NULL);
 
 		spin_lock(&ubi->wl_lock);
 		if (err)
diff --git a/drivers/mtd/ubi/wl.h b/drivers/mtd/ubi/wl.h
index 5ebe374a08..7b6715ef6d 100644
--- a/drivers/mtd/ubi/wl.h
+++ b/drivers/mtd/ubi/wl.h
@@ -10,8 +10,10 @@ 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)
 {
-	/* Reserve enough LEBs to store two fastmaps. */
-	*count += (ubi->fm_size / ubi->leb_size) * 2;
+	if (ubi->fm_disabled)
+		ubi->fm_pool_rsv_cnt = 0;
+	/* Reserve enough LEBs to store two fastmaps and to fill pools. */
+	*count += (ubi->fm_size / ubi->leb_size) * 2 + ubi->fm_pool_rsv_cnt;
 	INIT_WORK(&ubi->fm_work, update_fastmap_work_fn);
 }
 static struct ubi_wl_entry *may_reserve_for_fm(struct ubi_device *ubi,