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

Davide Libenzi
2002-03-05T22:37:55Z

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)

- Davide