function-graph: Fix seqfile memory leak

Every time we cat set_graph_function, we leak memory allocated
by seq_open().

Signed-off-by: Li Zefan <[e-mail]>
LKML-Reference: <[e-mail]>
Signed-off-by: Steven Rostedt <[e-mail]>

kernel/trace/ftrace.c

···
 }
 
 static int
+ftrace_graph_release(struct inode *inode, struct file *file)
+{
+	if (file->f_mode & FMODE_READ)
+		seq_release(inode, file);
+	return 0;
+}
+
+static int
 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
 {
 	struct dyn_ftrace *rec;
···
 }
 
 static const struct file_operations ftrace_graph_fops = {
-	.open = ftrace_graph_open,
-	.read = seq_read,
-	.write = ftrace_graph_write,
+	.open		= ftrace_graph_open,
+	.read		= seq_read,
+	.write		= ftrace_graph_write,
+	.release	= ftrace_graph_release,
 };
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */