Re: [Xen-devel] [PATCH v4] xen/grant-table: Avoid m2p_override duringmapping
From: Stefano Stabellini
Date: Wed Jan 22 2014 - 13:51:34 EST
On Wed, 22 Jan 2014, Zoltan Kiss wrote:
> On 22/01/14 16:39, Stefano Stabellini wrote:
> > On Tue, 21 Jan 2014, Zoltan Kiss wrote:
> > > @@ -121,7 +125,7 @@ static inline unsigned long mfn_to_pfn(unsigned long
> > > mfn)
> > > pfn = m2p_find_override_pfn(mfn, ~0);
> > > }
> > >
> > > - /*
> > > + /*
> > Spurious change?
> It removes a stray space from the original code. Not necessary, but if it's
> there, I think we can keep it.
Usually cosmetic changes are done in a separate patch, or at the very
least they are mentioned in the commit message.
> > > diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
> > > index 2ae8699..0060178 100644
> > > --- a/arch/x86/xen/p2m.c
> > > +++ b/arch/x86/xen/p2m.c
> > > @@ -872,15 +872,13 @@ static unsigned long mfn_hash(unsigned long mfn)
> > >
> > > /* Add an MFN override for a particular page */
> > > int m2p_add_override(unsigned long mfn, struct page *page,
> > > - struct gnttab_map_grant_ref *kmap_op)
> > > + struct gnttab_map_grant_ref *kmap_op, unsigned long pfn)
> > Do we really need to add another additional parameter to
> > m2p_add_override?
> > I would just let m2p_add_override and m2p_remove_override call
> > page_to_pfn again. It is not that expensive.
> Yes, because that page_to_pfn can return something different. That's why the
> v2 patches failed.
I am really curious: how can page_to_pfn return something different?
I don't think is supposed to happen.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/