Re: page_launder() bug

Horst von Brand (vonbrand@inf.utfsm.cl)
Mon, 07 May 2001 10:52:02 -0400

"David S. Miller" <davem@redhat.com> said:
> Jonathan Morton writes:
> > >- page_count(page) == (1 + !!page->buffers));
> >
> > Two inversions in a row?
>
> It is the most straightforward way to make a '1' or '0'
> integer from the NULL state of a pointer.

IMVHO, it is clearer to write:

page_count(page) == 1 + (page->buffers != NULL)

At least, the original poster wouldn't have wondered, and I wouldn't have
had to think a bit to find out what it meant... If gcc generates worse code
for this, it should be fixed.

-- 
Dr. Horst H. von Brand                       mailto:vonbrand@inf.utfsm.cl
Departamento de Informatica                     Fono: +56 32 654431
Universidad Tecnica Federico Santa Maria              +56 32 654239
Casilla 110-V, Valparaiso, Chile                Fax:  +56 32 797513
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