Re: [RFC] change non-atomic bitops method

[Uwe Kleine-König]

Hello,

[added some more context again]

On Tue, Feb 03, 2015 at 03:14:43PM +0000, David Howells wrote:
> > > -     *p  |= mask;
> > > +     if ((*p & mask) == 0)
> > > +             *p  |= mask;
> > Care to fix the double space here while touching the code?
> > 
> > I think the more natural check here is:
> > 
> >         if ((~*p & mask) != 0)
> >                 *p |= mask;
> >
> > Might be a matter of taste, but this check is equivalent to
> > 
> > 	*p != (*p | mask)
> > 
> > which is what you really want to test for.
> I would argue that this is less clear as to what's going on.
OK, I admit that this equivalence is not obvious. Then maybe let the
compiler find the equivalence and do:

-	*p  |= mask;
+	if (*p != (*p | mask))
+		p |= mask;

?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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