Re: [GIT PULL] Btrfs

Josh Boyer
2013-09-13T15:38:20Z

On Fri, Sep 13, 2013 at 11:06 AM, Josh Boyer <jwboyer@gmail.com> wrote:
> On Fri, Sep 13, 2013 at 8:15 AM, Russell King <rmk@arm.linux.org.uk> wrote:
>> On Fri, Sep 13, 2013 at 07:53:21AM -0400, Josh Boyer wrote:
>>> I'm not an ARM expert, so I don't know if ARM should use the
>>> asm-generic implementations, or just use __get_user/__put_user in all
>>> cases. I've CC'd rmk.
>>
>> Why do we have uaccess-unaligned.h ? Normally, these kinds of things
>> are spawned by architectures which have problems with unaligned accesses,
>> ARM being one of them, but afaik we've never need this.
>>
>> With the kernel-side trapping of unaligned accesses on older hardware,
>> we've always dealt with the normal accessor faulting.
>>
>> From what I can tell in the git history, these unaligned put_user and
>> get_user have existed all the way back to the dawn of git use.
>>
>> Can someone enlighten me why we have them?

I somehow fail at email and dropped Russell from CC on accident. Sigh.

> So while that gets sorted out, would it be safe to just do as Geert
> did on m68k and put:
>
> #define __put_user_unaligned(x, ptr) __put_user((x), (ptr))
>
> in arch/arm/include/asm/uaccess.h, and let the normal accessors and
> kernel-side trapping deal with things? I'm thinking that's a local
> fix until something gets sorted upstream, but I don't want to do it if
> it's going to break things.
>
> josh