Re: [PATCH] futex: cmpxchg_futex_value_locked API change

From: Thomas Gleixner
Date: Thu Mar 10 2011 - 13:56:21 EST


On Wed, 9 Mar 2011, Michel Lespinasse wrote:
> On Tue, Mar 08, 2011 at 09:17:11PM +0100, Thomas Gleixner wrote:

Just looked at it again in detail before picking it up. Can we please
separate the s/int/u32/ changes from the real API change ?

>
> - pagefault_disable(); /* implies preempt_disable() */
> + /* Note that preemption is disabled by futex_atomic_cmpxchg_inatomic
> + * call sites. */

That wants to be a separate patch as well.

> -int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> +int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
> {
> int op = (encoded_op >> 28) & 7;
> int cmp = (encoded_op >> 24) & 15;
> @@ -197,7 +197,7 @@ int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
> if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
> oparg = 1 << oparg;
>
> - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
> + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> return -EFAULT;
>
> pagefault_disable();

So following the reasoning above, shouldn't that be the same for
futex_atomic_op_inuser() ?

Thanks,

tglx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/