linux-kernel - Re: [PATCH v6 04/11] powerpc/mce_power: Use functions to track lockless pgtbl walks

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Message-ID: <e8a5db5a-d1a5-ef25-af46-c44949750e8a@c-s.fr>
Date:   Thu, 6 Feb 2020 06:48:12 +0100
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Leonardo Bras <leonardo@...ux.ibm.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Arnd Bergmann <arnd@...db.de>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>,
        Nicholas Piggin <npiggin@...il.com>,
        Steven Price <steven.price@....com>,
        Robin Murphy <robin.murphy@....com>,
        Mahesh Salgaonkar <mahesh@...ux.vnet.ibm.com>,
        Balbir Singh <bsingharora@...il.com>,
        Reza Arbab <arbab@...ux.ibm.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Allison Randal <allison@...utok.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Mike Rapoport <rppt@...ux.ibm.com>,
        Michal Suchanek <msuchanek@...e.de>
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        kvm-ppc@...r.kernel.org, linux-arch@...r.kernel.org,
        linux-mm@...ck.org
Subject: Re: [PATCH v6 04/11] powerpc/mce_power: Use functions to track
 lockless pgtbl walks



Le 06/02/2020 à 04:08, Leonardo Bras a écrit :
> Applies the new functions used for tracking lockless pgtable walks on
> addr_to_pfn().
> 
> local_irq_{save,restore} is already inside {begin,end}_lockless_pgtbl_walk,
> so there is no need to repeat it here.
> 
> Signed-off-by: Leonardo Bras <leonardo@...ux.ibm.com>
> ---
>   arch/powerpc/kernel/mce_power.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c
> index 1cbf7f1a4e3d..a9e38ef4e437 100644
> --- a/arch/powerpc/kernel/mce_power.c
> +++ b/arch/powerpc/kernel/mce_power.c
> @@ -29,7 +29,7 @@ unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
>   {
>   	pte_t *ptep;
>   	unsigned int shift;
> -	unsigned long pfn, flags;
> +	unsigned long pfn, irq_mask;

Why change the name ? flags is a well known historical name.

>   	struct mm_struct *mm;
>   
>   	if (user_mode(regs))
> @@ -37,7 +37,7 @@ unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
>   	else
>   		mm = &init_mm;
>   
> -	local_irq_save(flags);
> +	irq_mask = begin_lockless_pgtbl_walk();
>   	ptep = __find_linux_pte(mm->pgd, addr, NULL, &shift);
>   
>   	if (!ptep || pte_special(*ptep)) {
> @@ -53,7 +53,7 @@ unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
>   	}
>   
>   out:
> -	local_irq_restore(flags);
> +	end_lockless_pgtbl_walk(irq_mask);
>   	return pfn;
>   }
>   
> 

Christophe