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