Re: [PATCH 2/2] xen: rename wrong named pfn related variables

[Juergen Gross]

On 16.06.21 12:43, Juergen Gross wrote:
> On 16.06.21 11:56, Jan Beulich wrote:
> > On 16.06.2021 09:30, Juergen Gross wrote:
> > > --- a/arch/x86/xen/p2m.c
> > > +++ b/arch/x86/xen/p2m.c
> > > @@ -95,8 +95,8 @@ unsigned long *xen_p2m_addr __read_mostly;
> > >   EXPORT_SYMBOL_GPL(xen_p2m_addr);
> > >   unsigned long xen_p2m_size __read_mostly;
> > >   EXPORT_SYMBOL_GPL(xen_p2m_size);
> > > -unsigned long xen_max_p2m_pfn __read_mostly;
> > > -EXPORT_SYMBOL_GPL(xen_max_p2m_pfn);
> > > +unsigned long xen_p2m_max_size __read_mostly;
> > > +EXPORT_SYMBOL_GPL(xen_p2m_max_size);
> >
> > Instead of renaming the exported variable (which will break consumers
> > anyway), how about dropping the apparently unneeded export at this
> > occasion?
>
> Why do you think it isn't needed? It is being referenced via the inline
> function __pfn_to_mfn() in arch/x86/include/asm/xen/page.h. And
> __pfn_to_mfn() is used via lots of other inline functions and macros.
>
> > Further it looks to me as if xen_p2m_size and this variable
> > were actually always kept in sync, so I'd like to put up the question
> > of dropping one of the two.
>
> Hmm, should be possible, yes.

Looking into this it seems this is not possible.

xen_p2m_size always holds the number of p2m entries in the p2m table,
including invalid ones at the end. xen_p2m_pfn_limit however contains
the (rounded up) index after the last valid p2m entry.


Juergen

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