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Commit e62e6650 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

signals: unify send_sigqueue/send_group_sigqueue completely 



Suggested by Pavel Emelyanov.

send_sigqueue/send_group_sigqueue are only differ in how they lock ->siglock.
Unify them.  send_group_sigqueue() uses spin_lock() because it knows the task
can't exit, but in that case lock_task_sighand() can't fail and doesn't hurt.

Note that the "sig" argument is ignored, it is always equal to ->si_signo.

Signed-off-by: default avatarPavel Emelyanov <xemul@openvz.org>
Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4cd4b6d4

kernel/signal.c

+21 −37
Original line number Diff line number Diff line
@@ -1240,14 +1240,27 @@ void sigqueue_free(struct sigqueue *q) 
	__sigqueue_free(q);

}



static int do_send_sigqueue(int sig, struct sigqueue *q, struct task_struct *t,

static int do_send_sigqueue(struct sigqueue *q, struct task_struct *t,

				int group)

{

	int sig = q->info.si_signo;

	struct sigpending *pending;

	unsigned long flags;

	int ret;



	BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));



	ret = -1;

	if (!likely(lock_task_sighand(t, &flags)))

		goto ret;



	handle_stop_signal(sig, t);



	ret = 1;

	if (sig_ignored(t, sig))

		goto out;



	ret = 0;

	if (unlikely(!list_empty(&q->list))) {

		/*

		 * If an SI_TIMER entry is already queue just increment
@@ -1256,58 +1269,29 @@ static int do_send_sigqueue(int sig, struct sigqueue *q, struct task_struct *t, 


		BUG_ON(q->info.si_code != SI_TIMER);

		q->info.si_overrun++;

		return 0;

		goto out;

	}



	if (sig_ignored(t, sig))

		return 1;



	signalfd_notify(t, sig);

	pending = group ? &t->signal->shared_pending : &t->pending;

	list_add_tail(&q->list, &pending->list);

	sigaddset(&pending->signal, sig);

	complete_signal(sig, t, group);



	return 0;

out:

	unlock_task_sighand(t, &flags);

ret:

	return ret;

}



int send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p)

{

	unsigned long flags;

	int ret = -1;



	/*

	 * The rcu based delayed sighand destroy makes it possible to

	 * run this without tasklist lock held. The task struct itself

	 * cannot go away as create_timer did get_task_struct().

	 *

	 * We return -1, when the task is marked exiting, so

	 * posix_timer_event can redirect it to the group leader

	 */

	if (!likely(lock_task_sighand(p, &flags)))

		goto out_err;



	ret = do_send_sigqueue(sig, q, p, 0);



	unlock_task_sighand(p, &flags);

out_err:

	return ret;

	return do_send_sigqueue(q, p, 0);

}



int

send_group_sigqueue(int sig, struct sigqueue *q, struct task_struct *p)

{

	unsigned long flags;

	int ret;



	/* Since it_lock is held, p->sighand cannot be NULL. */

	spin_lock_irqsave(&p->sighand->siglock, flags);



	ret = do_send_sigqueue(sig, q, p, 1);



	spin_unlock_irqrestore(&p->sighand->siglock, flags);



	return ret;

	return do_send_sigqueue(q, p, 1);

}



/*