linux-kernel - Re: [PATCH 1/3] mm/percpu: Remove some local variables in pcpu_populate

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Date:   Thu, 27 Jul 2023 16:08:07 -0700
From:   Dennis Zhou <dennis@...nel.org>
To:     Bibo Mao <maobibo@...ngson.cn>
Cc:     Huacai Chen <chenhuacai@...nel.org>, Tejun Heo <tj@...nel.org>,
        Christoph Lameter <cl@...ux.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        loongarch@...ts.linux.dev, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, WANG Xuerui <kernel@...0n.name>
Subject: Re: [PATCH 1/3] mm/percpu: Remove some local variables in
 pcpu_populate_pte

Hello,

On Wed, Jul 12, 2023 at 11:16:20AM +0800, Bibo Mao wrote:
> In function pcpu_populate_pte there are already variable defined,
> it can be reused for later use, here remove duplicated local
> variables.
> 
> Signed-off-by: Bibo Mao <maobibo@...ngson.cn>
> ---
>  mm/percpu.c | 24 +++++++++---------------
>  1 file changed, 9 insertions(+), 15 deletions(-)
> 
> diff --git a/mm/percpu.c b/mm/percpu.c
> index 28e07ede46f6..85e3f9b2a61f 100644
> --- a/mm/percpu.c
> +++ b/mm/percpu.c
> @@ -3189,32 +3189,26 @@ void __init __weak pcpu_populate_pte(unsigned long addr)
>  	pmd_t *pmd;
>  
>  	if (pgd_none(*pgd)) {
> -		p4d_t *new;
> -
> -		new = memblock_alloc(P4D_TABLE_SIZE, P4D_TABLE_SIZE);
> -		if (!new)
> +		p4d = memblock_alloc(P4D_TABLE_SIZE, P4D_TABLE_SIZE);
> +		if (!p4d)
>  			goto err_alloc;
> -		pgd_populate(&init_mm, pgd, new);
> +		pgd_populate(&init_mm, pgd, p4d);
>  	}
>  
>  	p4d = p4d_offset(pgd, addr);
>  	if (p4d_none(*p4d)) {
> -		pud_t *new;
> -
> -		new = memblock_alloc(PUD_TABLE_SIZE, PUD_TABLE_SIZE);
> -		if (!new)
> +		pud = memblock_alloc(PUD_TABLE_SIZE, PUD_TABLE_SIZE);
> +		if (!pud)
>  			goto err_alloc;
> -		p4d_populate(&init_mm, p4d, new);
> +		p4d_populate(&init_mm, p4d, pud);
>  	}
>  
>  	pud = pud_offset(p4d, addr);
>  	if (pud_none(*pud)) {
> -		pmd_t *new;
> -
> -		new = memblock_alloc(PMD_TABLE_SIZE, PMD_TABLE_SIZE);
> -		if (!new)
> +		pmd = memblock_alloc(PMD_TABLE_SIZE, PMD_TABLE_SIZE);
> +		if (!pmd)
>  			goto err_alloc;
> -		pud_populate(&init_mm, pud, new);
> +		pud_populate(&init_mm, pud, pmd);
>  	}
>  
>  	pmd = pmd_offset(pud, addr);
> -- 
> 2.27.0
> 

I've pulled this, but the other 2 are part of loongarch and should be
reviewed and pulled by those maintainers.

Thanks,
Dennis