linux-kernel - Re: [PATCH v2] riscv: Use PMD_SIZE to repalce PTE_PARENT

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Message-ID: <20191108072523.GA20338@infradead.org>
Date:   Thu, 7 Nov 2019 23:25:23 -0800
From:   Christoph Hellwig <hch@...radead.org>
To:     Zong Li <zong.li@...ive.com>
Cc:     linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org,
        paul.walmsley@...ive.com, palmer@...ive.com, Anup.Patel@....com
Subject: Re: [PATCH v2] riscv: Use PMD_SIZE to repalce PTE_PARENT_SIZE

On Mon, Nov 04, 2019 at 06:20:12PM -0800, Zong Li wrote:
>  	uintptr_t map_size = PAGE_SIZE;
>  
> -	/* Upgrade to PMD/PGDIR mappings whenever possible */
> -	if (!(base & (PTE_PARENT_SIZE - 1)) &&
> -	    !(size & (PTE_PARENT_SIZE - 1)))
> -		map_size = PTE_PARENT_SIZE;
> +	/* Upgrade to PMD_SIZE mappings whenever possible */
> +	if (!(base & (PMD_SIZE - 1)) &&
> +	    !(size & (PMD_SIZE - 1)))
> +		map_size = PMD_SIZE;

The check easily fits onto a single line now.  Also the map_size
variable is rather pointless.  Why not:

	if ((base & (PMD_SIZE - 1) || (size & (PMD_SIZE - 1)))
		return PAGE_SIZE;
	return PMD_SIZE;