1 files changed, 107 insertions, 0 deletions
diff --git a/linux-2.4.x/fs/jffs2/wear_leveling.c b/linux-2.4.x/fs/jffs2/wear_leveling.c
new file mode 100644
index 0000000..1eeb713
--- /dev/null
+++ b/linux-2.4.x/fs/jffs2/wear_leveling.c
@@ -0,0 +1,107 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright (C) 2005  Zhao Forrest <forrest.zhao@intel.com>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+
+#include "nodelist.h"
+
+void jffs2_add_to_hash_table(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint8_t flag)
+{
+	struct jffs2_blocks_bucket *hash_table;
+	uint32_t index, *current_index_p;
+
+	if (flag == 1) {
+		hash_table = c->used_blocks;
+		current_index_p = &(c->used_blocks_current_index);
+	}else if (flag == 2) {
+		hash_table = c->free_blocks;
+		current_index_p = &(c->free_blocks_current_index);
+	}else {
+		return;
+	}
+
+	index = (jeb->erase_count >> BUCKET_RANGE_BIT_LEN);
+	if (index >= HASH_SIZE) {
+		return;
+	}
+	if (index < *current_index_p) {
+		*current_index_p = index;
+	}
+	hash_table[index].number++;
+	list_add_tail(&jeb->hash_list, &(hash_table[index].chain));
+	return;
+}
+
+void jffs2_remove_from_hash_table(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint8_t flag)
+{
+	struct jffs2_blocks_bucket *hash_table;
+	uint32_t index, *current_index_p, i;
+
+	if (flag == 1) {
+		hash_table = c->used_blocks;
+		current_index_p = &(c->used_blocks_current_index);
+	}else if (flag == 2) {
+		hash_table = c->free_blocks;
+		current_index_p = &(c->free_blocks_current_index);
+	}else {
+		return;
+	}
+
+	index = (jeb->erase_count >> BUCKET_RANGE_BIT_LEN);
+	if (index >= HASH_SIZE) {
+		return;
+	}
+	hash_table[index].number--;
+	list_del(&jeb->hash_list);
+
+	if (hash_table[index].number == 0) {
+		for (i=index+1; i<HASH_SIZE; i++) {
+			if (hash_table[i].number != 0) {
+				*current_index_p = i;
+				break;
+			}
+		}
+		if (i == HASH_SIZE) {
+			*current_index_p = HASH_SIZE;
+		}
+	}
+	return;
+}
+
+struct jffs2_eraseblock *jffs2_get_free_block(struct jffs2_sb_info *c)
+{
+	struct list_head *next;
+	struct jffs2_eraseblock *jeb;
+
+	if (c->free_blocks_current_index == HASH_SIZE) {
+		return NULL;
+	}
+	next = c->free_blocks[c->free_blocks_current_index].chain.next;
+	jeb = list_entry(next, struct jffs2_eraseblock, hash_list);
+	list_del(&jeb->list);
+	jffs2_remove_from_hash_table(c, jeb, 2);
+	c->nr_free_blocks--;
+
+	return jeb;
+}
+
+struct jffs2_eraseblock *jffs2_get_used_block(struct jffs2_sb_info *c)
+{
+	struct list_head *next;
+	struct jffs2_eraseblock *jeb;
+
+	if (c->used_blocks_current_index == HASH_SIZE) {
+		return NULL;
+	}
+	next = c->used_blocks[c->used_blocks_current_index].chain.next;
+	jeb = list_entry(next, struct jffs2_eraseblock, hash_list);
+	list_del(&jeb->list);
+	jffs2_remove_from_hash_table(c, jeb, 1);
+
+	return jeb;
+}
+