Re: [PATCH] fs: dax: fix build error on ARC

[Vineet Gupta]

On 10/6/20 7:54 PM, Randy Dunlap wrote:
> From: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> 
> fs/dax.c uses copy_user_page() but ARC does not provide that interface,
> resulting in a build error.
> 
> Provide copy_user_page() in <asm/page.h> (beside copy_page()) and
> add <asm/page.h> to fs/dax.c to fix the build error.
> 
> ../fs/dax.c: In function 'copy_cow_page_dax':
> ../fs/dax.c:702:2: error: implicit declaration of function 'copy_user_page'; did you mean 'copy_to_user_page'? [-Werror=implicit-function-declaration]
> 
> Fixes: cccbce671582 ("filesystem-dax: convert to dax_direct_access()")
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx>
> Cc: linux-snps-arc@xxxxxxxxxxxxxxxxxxx
> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> ---
> Vineet, This patch fixes the build error but is it correct for ARC?

Yep this looks good. Nothing special needs to be done for user pages on ARC.

Acked-by: Vineet Gupta <vgupts@xxxxxxxxxxxx>

Thx,
-Vineet

> 
>  arch/arc/include/asm/page.h |    1 +
>  fs/dax.c                    |    1 +
>  2 files changed, 2 insertions(+)
> 
> --- lnx-59-rc7.orig/fs/dax.c
> +++ lnx-59-rc7/fs/dax.c
> @@ -25,6 +25,7 @@
>  #include <linux/sizes.h>
>  #include <linux/mmu_notifier.h>
>  #include <linux/iomap.h>
> +#include <asm/page.h>
>  #include <asm/pgalloc.h>
>  
>  #define CREATE_TRACE_POINTS
> --- lnx-59-rc7.orig/arch/arc/include/asm/page.h
> +++ lnx-59-rc7/arch/arc/include/asm/page.h
> @@ -10,6 +10,7 @@
>  #ifndef __ASSEMBLY__
>  
>  #define clear_page(paddr)		memset((paddr), 0, PAGE_SIZE)
> +#define copy_user_page(to, from, vaddr, pg)	copy_page(to, from)
>  #define copy_page(to, from)		memcpy((to), (from), PAGE_SIZE)
>  
>  struct vm_area_struct;
> 
>