Re: [PATCH v12 1/6] uaccess: add generic fallback version of copy_mc_to_user()

[Mauro Carvalho Chehab <mchehab+huawei@kernel.org>]

Em Tue, 28 May 2024 16:59:10 +0800
Tong Tiangen <tongtiangen@huawei.com> escreveu:

> x86/powerpc has it's implementation of copy_mc_to_user(), we add generic
> fallback in include/linux/uaccess.h prepare for other architechures to
> enable CONFIG_ARCH_HAS_COPY_MC.
> 
> Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>
> Acked-by: Michael Ellerman <mpe@ellerman.id.au>
> ---
>  arch/powerpc/include/asm/uaccess.h | 1 +
>  arch/x86/include/asm/uaccess.h     | 1 +
>  include/linux/uaccess.h            | 8 ++++++++
>  3 files changed, 10 insertions(+)
> 
> diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
> index de10437fd206..df42e6ad647f 100644
> --- a/arch/powerpc/include/asm/uaccess.h
> +++ b/arch/powerpc/include/asm/uaccess.h
> @@ -381,6 +381,7 @@ copy_mc_to_user(void __user *to, const void *from, unsigned long n)
>  
>  	return n;
>  }
> +#define copy_mc_to_user copy_mc_to_user

Such define looks weird on my eyes. What to do you want to do here?

>  #endif
>  
>  extern long __copy_from_user_flushcache(void *dst, const void __user *src,
> diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
> index 0f9bab92a43d..309f2439327e 100644
> --- a/arch/x86/include/asm/uaccess.h
> +++ b/arch/x86/include/asm/uaccess.h
> @@ -497,6 +497,7 @@ copy_mc_to_kernel(void *to, const void *from, unsigned len);
>  
>  unsigned long __must_check
>  copy_mc_to_user(void __user *to, const void *from, unsigned len);
> +#define copy_mc_to_user copy_mc_to_user

Same here.

>  #endif
>  
>  /*
> diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
> index 3064314f4832..0dfa9241b6ee 100644
> --- a/include/linux/uaccess.h
> +++ b/include/linux/uaccess.h
> @@ -205,6 +205,14 @@ copy_mc_to_kernel(void *dst, const void *src, size_t cnt)
>  }
>  #endif
>  
> +#ifndef copy_mc_to_user
> +static inline unsigned long __must_check
> +copy_mc_to_user(void *dst, const void *src, size_t cnt)
> +{
> +	return copy_to_user(dst, src, cnt);
> +}
> +#endif
> +
>  static __always_inline void pagefault_disabled_inc(void)
>  {
>  	current->pagefault_disabled++;



Thanks,
Mauro