From 1543e317f1da31b75942316931e8f491a8920811 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Thu, 04 Jan 2024 10:08:02 +0000
Subject: [PATCH] disable FB

---
 kernel/drivers/mtd/ubi/fastmap-wl.c |   64 +++++++++++++++++++++++--------
 1 files changed, 47 insertions(+), 17 deletions(-)

diff --git a/kernel/drivers/mtd/ubi/fastmap-wl.c b/kernel/drivers/mtd/ubi/fastmap-wl.c
index e08f6b4..69592be 100644
--- a/kernel/drivers/mtd/ubi/fastmap-wl.c
+++ b/kernel/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.
- *
  */
 
 /**
@@ -106,6 +97,33 @@
 	return e;
 }
 
+/*
+ * has_enough_free_count - whether ubi has enough 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.
+ */
+static bool has_enough_free_count(struct ubi_device *ubi, bool is_wl_pool)
+{
+	int fm_used = 0;	// fastmap non anchor pebs.
+	int beb_rsvd_pebs;
+
+	if (!ubi->free.rb_node)
+		return false;
+
+	beb_rsvd_pebs = is_wl_pool ? ubi->beb_rsvd_pebs : 0;
+	if (ubi->fm_wl_pool.size > 0 && !(ubi->ro_mode || ubi->fm_disabled))
+		fm_used = ubi->fm_size / ubi->leb_size - 1;
+
+	return ubi->free_count - beb_rsvd_pebs > fm_used;
+}
+
 /**
  * ubi_refill_pools - refills all fastmap PEB pools.
  * @ubi: UBI device description object
@@ -125,10 +143,23 @@
 	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 (!has_enough_free_count(ubi, false))
 				break;
 
 			e = wl_get_wle(ubi);
@@ -141,8 +172,7 @@
 			enough++;
 
 		if (wl_pool->size < wl_pool->max_size) {
-			if (!ubi->free.rb_node ||
-			   (ubi->free_count - ubi->beb_rsvd_pebs < 5))
+			if (!has_enough_free_count(ubi, true))
 				break;
 
 			e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
@@ -199,7 +229,7 @@
  */
 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;
 
@@ -224,12 +254,12 @@
 
 	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) {
@@ -298,8 +328,8 @@
 		return 0;
 	}
 
-	/* No luck, trigger wear leveling to produce a new anchor PEB */
 	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;

--
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