Re: [PATH V2 6/6] arm64: mm: Enable RCU fast_gup

[Steve Capper <steve.capper@linaro.org>]

On Wed, Aug 27, 2014 at 12:09:48PM +0100, Catalin Marinas wrote:
> On Thu, Aug 21, 2014 at 04:43:32PM +0100, Steve Capper wrote:
> > --- a/arch/arm64/include/asm/pgtable.h
> > +++ b/arch/arm64/include/asm/pgtable.h
> > @@ -256,7 +256,13 @@ static inline pmd_t pte_pmd(pte_t pte)
> >  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> >  #define pmd_trans_huge(pmd)	(pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT))
> >  #define pmd_trans_splitting(pmd)	pte_special(pmd_pte(pmd))
> > -#endif
> > +#ifdef CONFIG_HAVE_RCU_TABLE_FREE
> > +#define __HAVE_ARCH_PMDP_SPLITTING_FLUSH
> > +struct vm_area_struct;
> > +void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
> > +			  pmd_t *pmdp);
> > +#endif /* CONFIG_HAVE_RCU_TABLE_FREE */
> > +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
> >  
> >  #define pmd_young(pmd)		pte_young(pmd_pte(pmd))
> >  #define pmd_wrprotect(pmd)	pte_pmd(pte_wrprotect(pmd_pte(pmd)))
> > @@ -277,6 +283,7 @@ static inline pmd_t pte_pmd(pte_t pte)
> >  #define mk_pmd(page,prot)	pfn_pmd(page_to_pfn(page),prot)
> >  
> >  #define pmd_page(pmd)           pfn_to_page(__phys_to_pfn(pmd_val(pmd) & PHYS_MASK))
> > +#define pud_write(pud)		pmd_write(__pmd(pud_val(pud)))
> >  #define pud_pfn(pud)		(((pud_val(pud) & PUD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
> >  
> >  #define set_pmd_at(mm, addr, pmdp, pmd)	set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd))
> > @@ -376,6 +383,8 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
> >  	return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(addr);
> >  }
> >  
> > +#define pud_page(pud)           pmd_page(__pmd(pud_val(pud)))
> 
> I think you could define a pud_pte as you've done for pmd. The
> conversion would look slightly cleaner. Otherwise:

Thanks Catalin,
I've added pud_pte and pud_pmd helpers and that now looks a lot
clearer.

> 
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Thanks.

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