[PATCH] sparse annotations for page-writeback

More to do, but its a beginning.

mm/page-writeback.c

@@ -345,7 +345,7 @@ static void wb_kupdate(unsigned long arg)
  * sysctl handler for /proc/sys/vm/dirty_writeback_centisecs
  */
 int dirty_writeback_centisecs_handler(ctl_table *table, int write,
-		struct file *file, void *buffer, size_t *length)
+		struct file *file, void __user *buffer, size_t *length)
 {
 	proc_dointvec(table, write, file, buffer, length);
 	if (dirty_writeback_centisecs) {