Re: [PATCH v2] kernel: refactor: shorten has_pending_signals

[Andrea Calabrese]

On Thu, 2026-05-21 at 14:50 +0200, Oleg Nesterov wrote:
> On 05/20, Andrea Calabrese wrote:
> > 
> >  static inline bool has_pending_signals(sigset_t *signal, sigset_t
> > *blocked)
> >  {
> > -	unsigned long ready;
> > -	long i;
> > -
> > -	switch (_NSIG_WORDS) {
> > -	default:
> > -		for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
> > -			ready |= signal->sig[i] &~ blocked-
> > >sig[i];
> > -		break;
> > -
> > -	case 4: ready  = signal->sig[3] &~ blocked->sig[3];
> > -		ready |= signal->sig[2] &~ blocked->sig[2];
> > -		ready |= signal->sig[1] &~ blocked->sig[1];
> > -		ready |= signal->sig[0] &~ blocked->sig[0];
> > -		break;
> > -
> > -	case 2: ready  = signal->sig[1] &~ blocked->sig[1];
> > -		ready |= signal->sig[0] &~ blocked->sig[0];
> > -		break;
> > -
> > -	case 1: ready  = signal->sig[0] &~ blocked->sig[0];
> > -	}
> > -	return ready !=	0;
> > +	unsigned long ready = 0;
> > +	for (long i = 0; i < _NSIG_WORDS; i++)
> > +		ready |= signal->sig[i] & ~blocked->sig[i];
> > +	return ready != 0;
> >  }
> 
> Note that with your patch the main loop doesn't stop when ready
> becomes != 0...
> 
> OK, I guess the modern compilers doesn't need this hint even if
> _NSIG_WORDS > 1, so
> 
> Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> 
> 
> But since your patch is just a cleanup, you could do
> 
> 	for (int i = 0; i < _NSIG_WORDS; i++) {
> 		if (signal->sig[i] & ~blocked->sig[i])
> 			return true;
> 	}
> 
> 	return false;
> 
Good idea, I will send a v3 with this!


> but this is subjective, I won't insist.
> 
> Oleg.