Re: [PATCH] arm/xen: Remove definiition of virt_to_pfn in asm/xen/page.h

From: Stefano Stabellini
Date: Wed May 07 2014 - 12:58:49 EST


On Wed, 7 May 2014, David Vrabel wrote:
> On 07/05/14 12:41, Stefano Stabellini wrote:
> > On Fri, 25 Apr 2014, Stefano Stabellini wrote:
> >> On Thu, 24 Apr 2014, David Vrabel wrote:
> >>> On 24/04/14 13:49, Julien Grall wrote:
> >>>> Hi David,
> >>>>
> >>>> On 04/24/2014 01:22 PM, David Vrabel wrote:
> >>>>> On 18/04/14 16:54, Julien Grall wrote:
> >>>>>> virt_to_pfn has been defined in asm/memory.h by the commit e26a9e0 "ARM: Better
> >>>>>> virt_to_page() handling"
> >>>>>>
> >>>>>> This will result of a compilation warning when CONFIG_XEN is enabled.
> >>>>>>
> >>>>>> arch/arm/include/asm/xen/page.h:80:0: warning: "virt_to_pfn" redefined [enabled by default]
> >>>>>> #define virt_to_pfn(v) (PFN_DOWN(__pa(v)))
> >>>>>> ^
> >>>>>> In file included from arch/arm/include/asm/page.h:163:0,
> >>>>>> from arch/arm/include/asm/xen/page.h:4,
> >>>>>> from include/xen/page.h:4,
> >>>>>> from arch/arm/xen/grant-table.c:33:
> >>>>>>
> >>>>>> The definition in memory.h is nearly the same (it directly expand PFN_DOWN),
> >>>>>> so we can safely drop virt_to_pfn in xen include.
> >>>>>
> >>>>>
> >>>>> This breaks the arm build for me.
> >>>>>
> >>>>> /local/davidvr/work/k.org/tip/drivers/block/xen-blkfront.c: In function
> >>>>> âsetup_blkringâ:
> >>>>> /local/davidvr/work/k.org/tip/drivers/block/xen-blkfront.c:1236:2:
> >>>>> error: implicit declaration of function âvirt_to_pfnâ
> >>>>> [-Werror=implicit-function-declaration]
> >>>>> err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
> >>>>> ^
> >>>>
> >>>> I don't have any issue to build the following branch with this patch on:
> >>>> - v3.15-rc2
> >>>> - xentip master
> >>>> - xentip for-linus-3.16
> >>>
> >>> Applied to devel/for-linus-3.16.
> >>>
> >>> If something else turns up for 3.15 (and I remember) I'll take it for
> >>> 3.15 instead.
> >>
> >> David,
> >> thank you very much for taking the patch in my absence.
> >>
> >> Considering that the problem is affecting everybody enabling CONFIG_XEN
> >> on ARM on v3.15, I don't think we can wait for the next merge window to
> >> send this fix upstream.
> >> Too many warnings for too many people.
> >
> > Unfortunately this commit breaks arm64 compilation, as virt_to_pfn has
> > not been introduced to arm64/include/asm/memory.h.
> > Has the patch been sent upstream yet?
>
> No.
>
> > We need this additional change for arm64:
> >
> > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
> > index e94f945..993bce5 100644
> > --- a/arch/arm64/include/asm/memory.h
> > +++ b/arch/arm64/include/asm/memory.h
> > @@ -138,6 +138,7 @@ static inline void *phys_to_virt(phys_addr_t x)
> > #define __pa(x) __virt_to_phys((unsigned long)(x))
> > #define __va(x) ((void *)__phys_to_virt((phys_addr_t)(x)))
> > #define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
> > +#define virt_to_pfn(x) __phys_to_pfn(__virt_to_phys(x))
>
> This would need an ack from an arm64 maintainer.

Certainly. Catalin is in CC.