ftrace: Separate out the copying of a ftrace_hash from __ftrace_hash_move()

Most of the functionality of __ftrace_hash_move() can be reused, but not all
of it. That is, __ftrace_hash_move() is used to simply make a new hash from
an existing one, using the same size as the original. Creating a dup_hash(),
where we can specify a new size will be useful when we want to create a hash
with a default size, or simply copy the old one.
Signed-off-by: Steven Rostedt (VMWare) <rostedt@goodmis.org>

kernel/trace/ftrace.c

@@ -1372,23 +1372,15 @@ ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
 				       struct ftrace_hash *new_hash);
 
-static struct ftrace_hash *
-__ftrace_hash_move(struct ftrace_hash *src)
+static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
 {
 	struct ftrace_func_entry *entry;
-	struct hlist_node *tn;
-	struct hlist_head *hhd;
 	struct ftrace_hash *new_hash;
-	int size = src->count;
+	struct hlist_head *hhd;
+	struct hlist_node *tn;
 	int bits = 0;
 	int i;
 
-	/*
-	 * If the new source is empty, just return the empty_hash.
-	 */
-	if (ftrace_hash_empty(src))
-		return EMPTY_HASH;
-
 	/*
 	 * Make the hash size about 1/2 the # found
 	 */
@@ -1413,10 +1405,23 @@ __ftrace_hash_move(struct ftrace_hash *src)
 			__add_hash_entry(new_hash, entry);
 		}
 	}
-
 	return new_hash;
 }
 
+static struct ftrace_hash *
+__ftrace_hash_move(struct ftrace_hash *src)
+{
+	int size = src->count;
+
+	/*
+	 * If the new source is empty, just return the empty_hash.
+	 */
+	if (ftrace_hash_empty(src))
+		return EMPTY_HASH;
+
+	return dup_hash(src, size);
+}
+
 static int
 ftrace_hash_move(struct ftrace_ops *ops, int enable,
 		 struct ftrace_hash **dst, struct ftrace_hash *src)