Commit c9dc05bf authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

exit: reparent: introduce find_alive_thread() 



Add the new simple helper to factor out the for_each_thread() code in
find_child_reaper() and find_new_reaper().  It can also simplify the
potential PF_EXITING -> exit_state change, plus perhaps we can change this
code to take SIGNAL_GROUP_EXIT into account.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Sterling Alexander <stalexan@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1109909c

kernel/exit.c

+19 −13
Original line number Diff line number Diff line
@@ -459,6 +459,17 @@ static void exit_mm(struct task_struct *tsk) 
	clear_thread_flag(TIF_MEMDIE);

}



static struct task_struct *find_alive_thread(struct task_struct *p)

{

	struct task_struct *t;



	for_each_thread(p, t) {

		if (!(t->flags & PF_EXITING))

			return t;

	}

	return NULL;

}



static struct task_struct *find_child_reaper(struct task_struct *father)

	__releases(&tasklist_lock)

	__acquires(&tasklist_lock)
@@ -469,9 +480,8 @@ static struct task_struct *find_child_reaper(struct task_struct *father) 
	if (likely(reaper != father))

		return reaper;



	for_each_thread(father, reaper) {

		if (reaper->flags & PF_EXITING)

			continue;

	reaper = find_alive_thread(father);

	if (reaper) {

		pid_ns->child_reaper = reaper;

		return reaper;

	}
@@ -497,16 +507,13 @@ static struct task_struct *find_child_reaper(struct task_struct *father) 
static struct task_struct *find_new_reaper(struct task_struct *father,

					   struct task_struct *child_reaper)

{

	struct task_struct *thread;

	struct task_struct *thread, *reaper;



	for_each_thread(father, thread) {

		if (thread->flags & PF_EXITING)

			continue;

	thread = find_alive_thread(father);

	if (thread)

		return thread;

	}



	if (father->signal->has_child_subreaper) {

		struct task_struct *reaper;

		/*

		 * Find the first ->is_child_subreaper ancestor in our pid_ns.

		 * We start from father to ensure we can not look into another
@@ -520,12 +527,11 @@ static struct task_struct *find_new_reaper(struct task_struct *father, 
				break;

			if (!reaper->signal->is_child_subreaper)

				continue;

			for_each_thread(reaper, thread) {

				if (!(thread->flags & PF_EXITING))

			thread = find_alive_thread(reaper);

			if (thread)

				return thread;

		}

	}

	}



	return child_reaper;

}