Re: [PATCH] metag/pgtable: Fix undeclared vm_area_struct warning

[Michal Hocko <mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On Wed 10-05-17 16:36:20, James Hogan wrote:
> Since commit 1f5307b1e094 ("mm, vmalloc: properly track vmalloc users"),
> linux/vmalloc.h includes asm/pgtable.h prior to declaring struct
> vm_area_struct, resulting in warnings such as the following on metag:
> 
> In file included from ./include/linux/vmalloc.h:10,
>                 from lib/ioremap.c:9:
> ./arch/metag/include/asm/pgtable.h:221: warning: ‘struct vm_area_struct’ declared inside parameter list
> ./arch/metag/include/asm/pgtable.h:221: warning: its scope is only this definition or declaration, which is probably not what you want
> 
> Metag's asm/pgtable.h doesn't actually need the definition of struct
> vm_area_struct, so just declare struct vm_area_struct in the header
> rather than including linux/mm_types.h.

This will be fixed in a different way [1]. It just waits for Andrew to
send the patch to Linus.

[1] http://lkml.kernel.org/r/20170509153702.GR6481-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org

Thanks for the fix anyway!

> 
> Fixes: 1f5307b1e094 ("mm, vmalloc: properly track vmalloc users")
> Signed-off-by: James Hogan <james.hogan-1AXoQHu6uovQT0dZR+AlfA@public.gmane.org>
> Cc: Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>
> Cc: linux-metag-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> ---
>  arch/metag/include/asm/pgtable.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/metag/include/asm/pgtable.h b/arch/metag/include/asm/pgtable.h
> index ffa3a3a2ecad..4ccb81943ca4 100644
> --- a/arch/metag/include/asm/pgtable.h
> +++ b/arch/metag/include/asm/pgtable.h
> @@ -88,6 +88,8 @@
>  
>  #include <asm/page.h>
>  
> +struct vm_area_struct;		/* vma defining user mapping in mm_types.h */
> +
>  /* zero page used for uninitialized stuff */
>  extern unsigned long empty_zero_page;
>  #define ZERO_PAGE(vaddr)	(virt_to_page(empty_zero_page))
> -- 
> 2.12.2

-- 
Michal Hocko
SUSE Labs