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Commit 2831096e authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

exit: reparent: cleanup the usage of reparent_leader() 



1. Now that reparent_leader() doesn't abuse ->sibling we can shift
   list_move_tail() from reparent_leader() to forget_original_parent()
   and turn it into a single list_splice_tail_init(). This also makes
   BUG_ON(!list_empty()) and list_for_each_entry_safe() unnecessary.

2. This also allows to shift the same_thread_group() check, it looks
   a bit more clear in the caller.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Cc: Sterling Alexander <stalexan@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roland McGrath <roland@hack.frob.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 57a05918

kernel/exit.c

+9 −13
Original line number Diff line number Diff line
@@ -529,15 +529,7 @@ static struct task_struct *find_new_reaper(struct task_struct *father) 
static void reparent_leader(struct task_struct *father, struct task_struct *p,

				struct list_head *dead)

{

	list_move_tail(&p->sibling, &p->real_parent->children);



	if (p->exit_state == EXIT_DEAD)

		return;

	/*

	 * If this is a threaded reparent there is no need to

	 * notify anyone anything has happened.

	 */

	if (same_thread_group(p->real_parent, father))

	if (unlikely(p->exit_state == EXIT_DEAD))

		return;



	/* We don't want people slaying init. */
@@ -568,7 +560,7 @@ static void forget_original_parent(struct task_struct *father) 
	exit_ptrace(father);

	reaper = find_new_reaper(father);



	list_for_each_entry_safe(p, n, &father->children, sibling) {

	list_for_each_entry(p, &father->children, sibling) {

		for_each_thread(p, t) {

			t->real_parent = reaper;

			BUG_ON((!t->ptrace) != (t->parent == father));
@@ -578,12 +570,16 @@ static void forget_original_parent(struct task_struct *father) 
				group_send_sig_info(t->pdeath_signal,

						    SEND_SIG_NOINFO, t);

		}

		/*

		 * If this is a threaded reparent there is no need to

		 * notify anyone anything has happened.

		 */

		if (!same_thread_group(reaper, father))

			reparent_leader(father, p, &dead_children);

	}

	list_splice_tail_init(&father->children, &reaper->children);

	write_unlock_irq(&tasklist_lock);



	BUG_ON(!list_empty(&father->children));



	list_for_each_entry_safe(p, n, &dead_children, ptrace_entry) {

		list_del_init(&p->ptrace_entry);

		release_task(p);