Re: pud_bad vs pud_bad

[Jeremy Fitzhardinge <jeremy@goop.org>]

Ingo Molnar wrote:
> * Jeremy Fitzhardinge <jeremy@goop.org> wrote:
>
>   
>> I'm looking at unifying the 32 and 64-bit versions of pud_bad.
>>
>> 32-bits defines it as:
>>
>> static inline int pud_bad(pud_t pud)
>> {
>> 	return (pud_val(pud) & ~(PTE_PFN_MASK | _KERNPG_TABLE | _PAGE_USER)) != 0;
>> }
>>
>> and 64 as:
>>
>> static inline int pud_bad(pud_t pud)
>> {
>> 	return (pud_val(pud) & ~(PTE_PFN_MASK | _PAGE_USER)) != _KERNPG_TABLE;
>> }
>>
>>
>> I'm inclined to go with the 64-bit version, but I'm wondering if there's 
>> something subtle I'm missing here.
>>     
>
> Why go with the 64-bit version? The 32-bit check looks more compact and 
> should result in smaller code.
>   

Well, its stricter.  But I don't really understand what condition its 
actually testing for.

    J