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signals: unify send_sigqueue/send_group_sigqueue completely

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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: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2008-04-30 00:52:56 -07:00 committed by Linus Torvalds
parent 4cd4b6d4e0
commit e62e6650e9
1 changed files with 21 additions and 37 deletions
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58
kernel/signal.c
View file

@ -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);
}
/*