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SubjectRe: [PATCH 0/10] use safer test on the result of find_first_zero_bit
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Hi Julia,

On Wed, Jun 4, 2014 at 1:00 PM, Julia Lawall <julia.lawall@lip6.fr> wrote:
> OK, thanks. I was only looking at the C code.
>
> But the C code contains a loop that is followed by:
>
> if (!size)
> return result;
> tmp = *p;
>
> found_first:
> tmp |= ~0UL << size;
> if (tmp == ~0UL) /* Are any bits zero? */
> return result + size; /* Nope. */
>
> In the first return, it would seem that result == size. Could the second
> one be changed to just return size? It should not hurt performance.

"size" may have been changed between function entry and this line.
So you have to store it in a temporary.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds


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