1 files changed, 212 insertions, 44 deletions

diff --git a/drivers/mtd/ubi/fastmap-wl.c b/drivers/mtd/ubi/fastmap-wl.c
index 4f0bd6b4422a..e2bc1122bfd3 100644
--- a/drivers/mtd/ubi/fastmap-wl.c
+++ b/drivers/mtd/ubi/fastmap-wl.c
@@ -1,17 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2012 Linutronix GmbH
  * Copyright (c) 2014 sigma star gmbh
  * Author: Richard Weinberger <richard@nod.at>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; version 2.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
- * the GNU General Public License for more details.
- *
  */
 
 /**
@@ -48,6 +39,13 @@ static struct ubi_wl_entry *find_anchor_wl_entry(struct rb_root *root)
 	return victim;
 }
 
+static inline void return_unused_peb(struct ubi_device *ubi,
+				     struct ubi_wl_entry *e)
+{
+	wl_tree_add(e, &ubi->free);
+	ubi->free_count++;
+}
+
 /**
  * return_unused_pool_pebs - returns unused PEB to the free tree.
  * @ubi: UBI device description object
@@ -61,23 +59,10 @@ static void return_unused_pool_pebs(struct ubi_device *ubi,
 
 	for (i = pool->used; i < pool->size; i++) {
 		e = ubi->lookuptbl[pool->pebs[i]];
-		wl_tree_add(e, &ubi->free);
-		ubi->free_count++;
+		return_unused_peb(ubi, e);
 	}
 }
 
-static int anchor_pebs_avalible(struct rb_root *root)
-{
-	struct rb_node *p;
-	struct ubi_wl_entry *e;
-
-	ubi_rb_for_each_entry(p, e, root, u.rb)
-		if (e->pnum < UBI_FM_MAX_START)
-			return 1;
-
-	return 0;
-}
-
 /**
  * ubi_wl_get_fm_peb - find a physical erase block with a given maximal number.
  * @ubi: UBI device description object
@@ -91,7 +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)
@@ -112,17 +97,105 @@ out:
 	return e;
 }
 
+/*
+ * 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
+ *
+ * This helper function returns the number of free pebs (deducted
+ * by fastmap pebs) to fill fm_pool and fm_wl_pool.
+ */
+static int left_free_count(struct ubi_device *ubi)
+{
+	int fm_used = 0;	// fastmap non anchor pebs.
+
+	if (!ubi->free.rb_node)
+		return 0;
+
+	if (!ubi->ro_mode && !ubi->fm_disabled)
+		fm_used = ubi->fm_size / ubi->leb_size - 1;
+
+	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);
@@ -131,10 +204,23 @@ void ubi_refill_pools(struct ubi_device *ubi)
 	wl_pool->size = 0;
 	pool->size = 0;
 
+	if (ubi->fm_anchor) {
+		wl_tree_add(ubi->fm_anchor, &ubi->free);
+		ubi->free_count++;
+		ubi->fm_anchor = NULL;
+	}
+
+	if (!ubi->fm_disabled)
+		/*
+		 * All available PEBs are in ubi->free, now is the time to get
+		 * the best anchor PEBs.
+		 */
+		ubi->fm_anchor = ubi_wl_get_fm_peb(ubi, 1);
+
 	for (;;) {
 		enough = 0;
 		if (pool->size < pool->max_size) {
-			if (!ubi->free.rb_node)
+			if (left_free_count(ubi) <= 0)
 				break;
 
 			e = wl_get_wle(ubi);
@@ -147,11 +233,13 @@ void ubi_refill_pools(struct ubi_device *ubi)
 			enough++;
 
 		if (wl_pool->size < wl_pool->max_size) {
-			if (!ubi->free.rb_node ||
-			   (ubi->free_count - ubi->beb_rsvd_pebs < 5))
+			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--;
@@ -186,7 +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;
@@ -205,7 +293,7 @@ static int produce_free_peb(struct ubi_device *ubi)
  */
 int ubi_wl_get_peb(struct ubi_device *ubi)
 {
-	int ret, retried = 0;
+	int ret, attempts = 0;
 	struct ubi_fm_pool *pool = &ubi->fm_pool;
 	struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
 
@@ -230,12 +318,12 @@ again:
 
 	if (pool->used == pool->size) {
 		spin_unlock(&ubi->wl_lock);
-		if (retried) {
+		attempts++;
+		if (attempts == 10) {
 			ubi_err(ubi, "Unable to get a free PEB from user WL pool");
 			ret = -ENOSPC;
 			goto out;
 		}
-		retried = 1;
 		up_read(&ubi->fm_eba_sem);
 		ret = produce_free_peb(ubi);
 		if (ret < 0) {
@@ -253,6 +341,71 @@ out:
 	return ret;
 }
 
+/**
+ * next_peb_for_wl - returns next PEB to be used internally by the
+ * WL sub-system.
+ *
+ * @ubi: UBI device description object
+ * @need_fill: whether to fill wear-leveling pool when no PEBs are found
+ */
+static struct ubi_wl_entry *next_peb_for_wl(struct ubi_device *ubi,
+					    bool need_fill)
+{
+	struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
+	int pnum;
+
+	if (pool->used == pool->size) {
+		if (need_fill && !ubi->fm_work_scheduled) {
+			/*
+			 * We cannot update the fastmap here because this
+			 * function is called in atomic context.
+			 * Let's fail here and refill/update it as soon as
+			 * possible.
+			 */
+			ubi->fm_work_scheduled = 1;
+			schedule_work(&ubi->fm_work);
+		}
+		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, false);
+	if (!e) {
+		if (!ubi->free.rb_node)
+			return false;
+		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, 0);
+			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
@@ -286,8 +439,26 @@ static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
 int ubi_ensure_anchor_pebs(struct ubi_device *ubi)
 {
 	struct ubi_work *wrk;
+	struct ubi_wl_entry *anchor;
 
 	spin_lock(&ubi->wl_lock);
+
+	/* Do we already have an anchor? */
+	if (ubi->fm_anchor) {
+		spin_unlock(&ubi->wl_lock);
+		return 0;
+	}
+
+	/* See if we can find an anchor PEB on the list of free PEBs */
+	anchor = ubi_wl_get_fm_peb(ubi, 1);
+	if (anchor) {
+		ubi->fm_anchor = anchor;
+		spin_unlock(&ubi->wl_lock);
+		return 0;
+	}
+
+	ubi->fm_do_produce_anchor = 1;
+	/* No luck, trigger wear leveling to produce a new anchor PEB. */
 	if (ubi->wl_scheduled) {
 		spin_unlock(&ubi->wl_lock);
 		return 0;
@@ -303,7 +474,6 @@ int ubi_ensure_anchor_pebs(struct ubi_device *ubi)
 		return -ENOMEM;
 	}
 
-	wrk->anchor = 1;
 	wrk->func = &wear_leveling_worker;
 	__schedule_ubi_work(ubi, wrk);
 	return 0;
@@ -360,17 +530,15 @@ int ubi_is_erase_work(struct ubi_work *wrk)
 
 static void ubi_fastmap_close(struct ubi_device *ubi)
 {
-	int i;
-
-	flush_work(&ubi->fm_work);
 	return_unused_pool_pebs(ubi, &ubi->fm_pool);
 	return_unused_pool_pebs(ubi, &ubi->fm_wl_pool);
 
-	if (ubi->fm) {
-		for (i = 0; i < ubi->fm->used_blocks; i++)
-			kfree(ubi->fm->e[i]);
+	if (ubi->fm_anchor) {
+		return_unused_peb(ubi, ubi->fm_anchor);
+		ubi->fm_anchor = NULL;
 	}
-	kfree(ubi->fm);
+
+	ubi_free_fastmap(ubi);
 }
 
 /**
@@ -384,7 +552,7 @@ 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);