Subject: Re: linux-next: build failure after merge of the aio tree

From: Benjamin LaHaise <[email-masked]>
Date: Thu, 4 Feb 2016 11:47:18 -0500

On Thu, Feb 04, 2016 at 04:17:42PM +0000, Russell King - ARM Linux wrote:
> That's the easy bit!
> 
> The problem you're going to run into is here:
> 
> #define __get_user_nocheck(x, ptr, size)                                \
> ({                                                                      \
>         int __gu_err;                                                   \
>         unsigned long __gu_val;                                         \
>         __uaccess_begin();                                              \
>         __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT);    \
>         __uaccess_end();                                                \
>         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
> 
> __gu_val will be 32-bit, even when you're wanting a 64-bit quantity.
> That's where the fun and games start...

You're right -- it's quite non-trivial.  How evil would it be to make a 
separate __get_user64() macro?

		-ben
-- 
"Thought is the essence of where you are now."