linux-kernel - Re: [PATCH v12 01/14] ARM: mm: add missing pud

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Message-ID: <20210202120708.GM1463@shell.armlinux.org.uk>
Date:   Tue, 2 Feb 2021 12:07:08 +0000
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Ding Tianhong <dingtianhong@...wei.com>
Cc:     Nicholas Piggin <npiggin@...il.com>, linux-mm@...ck.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Christoph Hellwig <hch@...radead.org>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Rick Edgecombe <rick.p.edgecombe@...el.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v12 01/14] ARM: mm: add missing pud_page define to
 2-level page tables

On Tue, Feb 02, 2021 at 07:47:04PM +0800, Ding Tianhong wrote:
> On 2021/2/2 19:13, Russell King - ARM Linux admin wrote:
> > On Tue, Feb 02, 2021 at 09:05:02PM +1000, Nicholas Piggin wrote:
> >> diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
> >> index c02f24400369..d63a5bb6bd0c 100644
> >> --- a/arch/arm/include/asm/pgtable.h
> >> +++ b/arch/arm/include/asm/pgtable.h
> >> @@ -166,6 +166,9 @@ extern struct page *empty_zero_page;
> >>  
> >>  extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
> >>  
> >> +#define pud_page(pud)		pmd_page(__pmd(pud_val(pud)))
> >> +#define pud_write(pud)		pmd_write(__pmd(pud_val(pud)))
> > 
> > As there is no PUD, does it really make sense to return a valid
> > struct page (which will be the PTE page) for pud_page(), which is
> > several tables above?
> > 
> --- a/arch/arm/include/asm/pgtable-2level.h
> +++ b/arch/arm/include/asm/pgtable-2level.h
> 
> +static inline int pud_none(pud_t pud)
> +{
> +          return 0;
> +}
> 
> I think it could be fix like this.

We already have that.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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