f2fs: use _safe() version of list_for_each

This is calling list_del() inside a loop which is a problem when we try
move to the next item on the list.  I've converted it to use the _safe
version.  And also, as a cleanup, I've converted it to use
list_for_each_entry instead of list_for_each.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/recovery.c

@@ -173,10 +173,9 @@ static int find_fsync_dnodes(struct f2fs_sb_info *sbi, struct list_head *head)
 static void destroy_fsync_dnodes(struct f2fs_sb_info *sbi,
 					struct list_head *head)
 {
-	struct list_head *this;
-	struct fsync_inode_entry *entry;
-	list_for_each(this, head) {
-		entry = list_entry(this, struct fsync_inode_entry, list);
+	struct fsync_inode_entry *entry, *tmp;
+
+	list_for_each_entry_safe(entry, tmp, head, list) {
 		iput(entry->inode);
 		list_del(&entry->list);
 		kmem_cache_free(fsync_entry_slab, entry);