[PATCH] don't use REMOVE_LINKS/SET_LINKS for reparenting

There are places where kernel uses REMOVE_LINKS/SET_LINKS while changing
process's ->parent.  Use add_parent/remove_parent instead, they don't abuse
of global process list.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/exit.c

@@ -238,10 +238,10 @@ static void reparent_to_init(void)
 
 	ptrace_unlink(current);
 	/* Reparent to init */
-	REMOVE_LINKS(current);
+	remove_parent(current);
 	current->parent = child_reaper;
 	current->real_parent = child_reaper;
-	SET_LINKS(current);
+	add_parent(current);
 
 	/* Set the exit signal to SIGCHLD so we signal init on exit */
 	current->exit_signal = SIGCHLD;

kernel/ptrace.c

@@ -35,9 +35,9 @@ void __ptrace_link(task_t *child, task_t *new_parent)
 	if (child->parent == new_parent)
 		return;
 	list_add(&child->ptrace_list, &child->parent->ptrace_children);
-	REMOVE_LINKS(child);
+	remove_parent(child);
 	child->parent = new_parent;
-	SET_LINKS(child);
+	add_parent(child);
 }
 
 /*
@@ -77,9 +77,9 @@ void __ptrace_unlink(task_t *child)
 	child->ptrace = 0;
 	if (!list_empty(&child->ptrace_list)) {
 		list_del_init(&child->ptrace_list);
-		REMOVE_LINKS(child);
+		remove_parent(child);
 		child->parent = child->real_parent;
-		SET_LINKS(child);
+		add_parent(child);
 	}
 
 	ptrace_untrace(child);