tree 1d0ba868866354569d2b8854a26ff48dbdbc1a98
parent fef23e7fbb11a0a78cd61935f7056bc2b237995a
author Oleg Nesterov <oleg@tv-sign.ru> 1143591059 -0800
committer Linus Torvalds <torvalds@g5.osdl.org> 1143599800 -0800

[PATCH] simplify exec from init's subthread

I think it is enough to take tasklist_lock for reading while changing
child_reaper:

	Reparenting needs write_lock(tasklist_lock)

	Only one thread in a thread group can do exec()

	sighand->siglock garantees that get_signal_to_deliver()
	will not see a stale value of child_reaper.

This means that we can change child_reaper earlier, without calling
zap_other_threads() twice.

"child_reaper = current" is a NOOP when init does exec from main thread, we
don't care.

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