Re: [PATCH] arm64/mm: Use phys_to_page() to access pgtable memory

[Gavin Shan]

Hi Mark,

On 4/24/20 7:22 PM, Mark Rutland wrote:
> On Fri, Apr 24, 2020 at 02:48:54PM +1000, Gavin Shan wrote:
> > The macros {pgd, pud, pmd}_page() retrieves the page struct of the
> > corresponding page frame, which is reserved as page table. There
> > is already a macro (phys_to_page), defined in memory.h, to convert
> > the physical address to the page struct. So it's reasonable to
> > use that in pgtable.h.
> >
> > Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>
>
> It might be worth pointing out that phys_to_page() is defined as:
>
> #define phys_to_page(phys)      (pfn_to_page(__phys_to_pfn(phys)))
>
> ... so this is obviously equivalent.
>
> Given that, and given we already explicitly include <asm/memory.h>, this
> looks like a nice cleanup to me.
>
> With or without the commit message addition:
>
> Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx>
>
> Mark.

Thanks for the comments. I will post v2 shortly, which has the improved
commit log and your reviewed-by.

Thanks,
Gavin

> > ---
> >   arch/arm64/include/asm/pgtable.h | 6 +++---
> >   1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
> > index 538c85e62f86..8c20e2bd6287 100644
> > --- a/arch/arm64/include/asm/pgtable.h
> > +++ b/arch/arm64/include/asm/pgtable.h
> > @@ -508,7 +508,7 @@ static inline void pte_unmap(pte_t *pte) { }
> >   #define pte_set_fixmap_offset(pmd, addr)	pte_set_fixmap(pte_offset_phys(pmd, addr))
> >   #define pte_clear_fixmap()		clear_fixmap(FIX_PTE)
> >   
> > -#define pmd_page(pmd)		pfn_to_page(__phys_to_pfn(__pmd_to_phys(pmd)))
> > +#define pmd_page(pmd)			phys_to_page(__pmd_to_phys(pmd))
> >   
> >   /* use ONLY for statically allocated translation tables */
> >   #define pte_offset_kimg(dir,addr)	((pte_t *)__phys_to_kimg(pte_offset_phys((dir), (addr))))
> > @@ -566,7 +566,7 @@ static inline phys_addr_t pud_page_paddr(pud_t pud)
> >   #define pmd_set_fixmap_offset(pud, addr)	pmd_set_fixmap(pmd_offset_phys(pud, addr))
> >   #define pmd_clear_fixmap()		clear_fixmap(FIX_PMD)
> >   
> > -#define pud_page(pud)		pfn_to_page(__phys_to_pfn(__pud_to_phys(pud)))
> > +#define pud_page(pud)			phys_to_page(__pud_to_phys(pud))
> >   
> >   /* use ONLY for statically allocated translation tables */
> >   #define pmd_offset_kimg(dir,addr)	((pmd_t *)__phys_to_kimg(pmd_offset_phys((dir), (addr))))
> > @@ -624,7 +624,7 @@ static inline phys_addr_t pgd_page_paddr(pgd_t pgd)
> >   #define pud_set_fixmap_offset(pgd, addr)	pud_set_fixmap(pud_offset_phys(pgd, addr))
> >   #define pud_clear_fixmap()		clear_fixmap(FIX_PUD)
> >   
> > -#define pgd_page(pgd)		pfn_to_page(__phys_to_pfn(__pgd_to_phys(pgd)))
> > +#define pgd_page(pgd)			phys_to_page(__pgd_to_phys(pgd))
> >   
> >   /* use ONLY for statically allocated translation tables */
> >   #define pud_offset_kimg(dir,addr)	((pud_t *)__phys_to_kimg(pud_offset_phys((dir), (addr))))
> > --
> > 2.23.0