Re: [PATCH] Futexes IV (Fast Lightweight Userspace Semaphores)

Hubertus Franke
2002-03-05T23:18:14Z

On Tuesday 05 March 2002 05:39 pm, Davide Libenzi wrote:
> On Tue, 5 Mar 2002, Rusty Russell wrote:
> > + pos_in_page = ((unsigned long)uaddr) % PAGE_SIZE;
> > +
> > + /* Must be "naturally" aligned, and not on page boundary. */
> > + if ((pos_in_page % __alignof__(atomic_t)) != 0
> > + || pos_in_page + sizeof(atomic_t) > PAGE_SIZE)
> > + return -EINVAL;
>
> How can this :
>
> (pos_in_page % __alignof__(atomic_t)) != 0
>
> to be false, and together this :
>
> pos_in_page + sizeof(atomic_t) > PAGE_SIZE
>
> to be true ?
> This is enough :
>
> if ((pos_in_page % __alignof__(atomic_t)) != 0)
>
>

I believe not all machine have alignof == sizeof
>
>
> - Davide
>
>
> -
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--
-- Hubertus Franke (frankeh@watson.ibm.com)