[PATCH 5/8] reparent_leader: check EXIT_DEAD instead of task_detached()

[Oleg Nesterov <oleg@redhat.com>]

Change reparent_leader() to check ->exit_state instead of ->exit_signal,
this matches the similar EXIT_DEAD check in wait_consider_task() and
allows us to cleanup the do_notify_parent/task_detached logic.

task_detached() was really needed during reparenting before 9cd80bbb
"do_wait() optimization: do not place sub-threads on ->children list"
to filter out the sub-threads. After this change task_detached(p) can
only be true if p is the dead group_leader and its parent ignores
SIGCHLD, in this case the caller of do_notify_parent() is going to
reap this task and it should set EXIT_DEAD.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---

 kernel/exit.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- ptrace/kernel/exit.c~5_reparent_leader_ck_exit_dead	2011-06-22 22:47:12.000000000 +0200
+++ ptrace/kernel/exit.c	2011-06-22 22:47:12.000000000 +0200
@@ -741,7 +741,7 @@ static void reparent_leader(struct task_
 {
 	list_move_tail(&p->sibling, &p->real_parent->children);
 
-	if (task_detached(p))
+	if (p->exit_state == EXIT_DEAD)
 		return;
 	/*
 	 * If this is a threaded reparent there is no need to