Re: [RFC PATCH v2 3/3] mm: make generic pXd_addr_end() macros inline functions

Christophe Leroy
2020-09-08T17:20:33Z

Le 08/09/2020 à 17:48, Alexander Gordeev a écrit :
> On Tue, Sep 08, 2020 at 07:19:38AM +0200, Christophe Leroy wrote:
>
> [...]
>
>>> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
>>> index 67ebc22cf83d..d9e7d16c2263 100644
>>> --- a/include/linux/pgtable.h
>>> +++ b/include/linux/pgtable.h
>>> @@ -656,31 +656,35 @@ static inline int arch_unmap_one(struct mm_struct *mm,
>>> */
>>> #ifndef pgd_addr_end
>>> -#define pgd_addr_end(pgd, addr, end) \
>>> -({ unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK; \
>>> - (__boundary - 1 < (end) - 1)? __boundary: (end); \
>>> -})
>>> +#define pgd_addr_end pgd_addr_end
>>
>> I think that #define is pointless, usually there is no such #define
>> for the default case.
>
> Default pgd_addr_end() gets overriden on s390 (arch/s390/include/asm/pgtable.h):
>
> #define pgd_addr_end pgd_addr_end
> static inline unsigned long pgd_addr_end(pgd_t pgd, unsigned long addr, unsigned long end)
> {
> return rste_addr_end_folded(pgd_val(pgd), addr, end);
> }

Yes, there in s390 the #define is needed to hit the #ifndef pgd_addr_end
that's in include/linux/pgtable.h

But in include/linux/pgtable.h, there is no need of an #define
pgd_addr_end pgd_addr_end I think

>
>>> +static inline unsigned long pgd_addr_end(pgd_t pgd, unsigned long addr, unsigned long end)
>>> +{ unsigned long __boundary = (addr + PGDIR_SIZE) & PGDIR_MASK;
>>> + return (__boundary - 1 < end - 1) ? __boundary : end;
>>> +}

Christophe