Re: [PATCH 3/4] cleanup __exit_signal()

["Paul E. McKenney" <paulmck@us.ibm.com>]

On Mon, Feb 20, 2006 at 07:04:03PM +0300, Oleg Nesterov wrote:
> This patch factors out duplicated code under 'if' branches.
> Also, BUG_ON() conversions and whitespace cleanups.

Passed steamroller.  Looks sane to me.

						Thanx, Paul

Acked-by: <paulmck@us.ibm.com>
> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
> 
> --- 2.6.16-rc3/kernel/signal.c~3_ESIG	2006-02-20 02:02:03.000000000 +0300
> +++ 2.6.16-rc3/kernel/signal.c	2006-02-20 20:55:50.000000000 +0300
> @@ -341,24 +341,20 @@ void __exit_sighand(struct task_struct *
>   */
>  void __exit_signal(struct task_struct *tsk)
>  {
> -	struct signal_struct * sig = tsk->signal;
> -	struct sighand_struct * sighand;
> +	struct signal_struct *sig = tsk->signal;
> +	struct sighand_struct *sighand;
> +
> +	BUG_ON(!sig);
> +	BUG_ON(!atomic_read(&sig->count));
>  
> -	if (!sig)
> -		BUG();
> -	if (!atomic_read(&sig->count))
> -		BUG();
>  	rcu_read_lock();
>  	sighand = rcu_dereference(tsk->sighand);
>  	spin_lock(&sighand->siglock);
> +
>  	posix_cpu_timers_exit(tsk);
> -	if (atomic_dec_and_test(&sig->count)) {
> +	if (atomic_dec_and_test(&sig->count))
>  		posix_cpu_timers_exit_group(tsk);
> -		tsk->signal = NULL;
> -		__exit_sighand(tsk);
> -		spin_unlock(&sighand->siglock);
> -		flush_sigqueue(&sig->shared_pending);
> -	} else {
> +	else {
>  		/*
>  		 * If there is any task waiting for the group exit
>  		 * then notify it:
> @@ -369,7 +365,6 @@ void __exit_signal(struct task_struct *t
>  		}
>  		if (tsk == sig->curr_target)
>  			sig->curr_target = next_thread(tsk);
> -		tsk->signal = NULL;
>  		/*
>  		 * Accumulate here the counters for all threads but the
>  		 * group leader as they die, so they can be added into
> @@ -387,14 +382,18 @@ void __exit_signal(struct task_struct *t
>  		sig->nvcsw += tsk->nvcsw;
>  		sig->nivcsw += tsk->nivcsw;
>  		sig->sched_time += tsk->sched_time;
> -		__exit_sighand(tsk);
> -		spin_unlock(&sighand->siglock);
> -		sig = NULL;	/* Marker for below.  */
> +		sig = NULL; /* Marker for below. */
>  	}
> +
> +	tsk->signal = NULL;
> +	__exit_sighand(tsk);
> +	spin_unlock(&sighand->siglock);
>  	rcu_read_unlock();
> +
>  	clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
>  	flush_sigqueue(&tsk->pending);
>  	if (sig) {
> +		flush_sigqueue(&sig->shared_pending);
>  		__cleanup_signal(sig);
>  	}
>  }