Re: [PATCH -next v2 1/2] riscv: uaccess: rename __get/put_user_nocheck to __get/put_mem_nocheck

[Tong Tiangen]

在 2022/8/26 17:30, Arnd Bergmann 写道:
> On Mon, Aug 15, 2022 at 5:20 AM Tong Tiangen <tongtiangen@xxxxxxxxxx> wrote:
> > Current, The helpers __get/put_user_nocheck() is used by get/put_user() and
> > __get/put_kernel_nofault(), which is not always uaccess, so the name with
> > *user* is not appropriate.
> >
> > Also rename xxx_user_xxx to xxx_mem_xx  on the call path of
> > __get/put_user_nocheck()
> >
> > Only refactor code without any functional changes.
> >
> > Signed-off-by: Tong Tiangen <tongtiangen@xxxxxxxxxx>
>
> I would prefer this not being done, it just makes riscv diverge from the
> code on other architectures. While the new name does make more sense,
> it ends up making it harder to refactor this across architectures in the end.
>
> There are two important cleanups that I would like to see done in
> asm/uaccess.h across architectures:
>
>   - generalize the __get_user()/__put_user()/__get_kernel_nofault()/
>    __put_kernel_nofault() wrappers to the point that architectures do not
>    need to worry about the variable type stuff but instead just provide
>    trivial fixed-length helpers of some sort
>
> - change the calling conventions in a way that allows the use of the
>    asm-goto-with-output method for better object code on modern
>    compilers.
>
> The x86 version already has most of this, with their
> __get_user_size() macro supporting both the asm-goto label
> and the error code assignment, so the generalized code should
> probably be based on that approach.

I am very interested in the implementation of X86. I need to investigate 
and consider a cross architecture implementation.
However, I understand that the modification of the current patch has 
little to do with the two points mentioned above. We can optimize the 
code step by step.

Thanks,
Tong.

>         Arnd
>
> .