linux-kernel - Re: [PATCH] m68k: One function call less in cf_tlb

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Message-ID: <alpine.LNX.2.21.1907060951060.67@nippy.intranet>
Date:   Sat, 6 Jul 2019 09:56:56 +1000 (AEST)
From:   Finn Thain <fthain@...egraphics.com.au>
To:     Markus Elfring <Markus.Elfring@....de>
cc:     linux-m68k@...ts.linux-m68k.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Greg Ungerer <gerg@...ux-m68k.org>,
        Michal Hocko <mhocko@...e.com>,
        Mike Rapoport <rppt@...ux.ibm.com>,
        LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] m68k: One function call less in cf_tlb_miss()


On Fri, 5 Jul 2019, Markus Elfring wrote:

> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Fri, 5 Jul 2019 17:11:37 +0200
> 
> Avoid an extra function call 

Not really. You've avoided an extra statement.

> by using a ternary operator instead of a conditional statement for a 
> setting selection.
> 
> This issue was detected by using the Coccinelle software.
> 
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---
>  arch/m68k/mm/mcfmmu.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c
> index 6cb1e41d58d0..02fc0778028e 100644
> --- a/arch/m68k/mm/mcfmmu.c
> +++ b/arch/m68k/mm/mcfmmu.c
> @@ -146,12 +146,10 @@ int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)
> 
>  	mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) |
>  		((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X);
> -
> -	if (dtlb)
> -		mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA);
> -	else
> -		mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA);
> -
> +	mmu_write(MMUOR,
> +		  dtlb
> +		  ? MMUOR_ACC | MMUOR_UAA
> +		  : MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA);

If you are trying to avoid redundancy, why not finish the job?

+     mmu_write(MMUOR, (dtlb ? 0 : MMUOR_ITLB) | MMUOR_ACC | MMUOR_UAA);

-- 

>  	local_irq_restore(flags);
>  	return 0;
>  }
> --
> 2.22.0
> 
>