linux-ext4 - Re: [PATCH 03/12] mm/pagewalk: Skip dax pages in pagewalk

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Message-ID: <20250605074637.GA7727@lst.de>
Date: Thu, 5 Jun 2025 09:46:37 +0200
From: Christoph Hellwig <hch@....de>
To: Dan Williams <dan.j.williams@...el.com>
Cc: Alistair Popple <apopple@...dia.com>, linux-mm@...ck.org,
	gerald.schaefer@...ux.ibm.com, jgg@...pe.ca, willy@...radead.org,
	david@...hat.com, linux-kernel@...r.kernel.org,
	nvdimm@...ts.linux.dev, linux-fsdevel@...r.kernel.org,
	linux-ext4@...r.kernel.org, linux-xfs@...r.kernel.org,
	jhubbard@...dia.com, hch@....de, zhang.lyra@...il.com,
	debug@...osinc.com, bjorn@...nel.org, balbirs@...dia.com,
	lorenzo.stoakes@...cle.com, linux-arm-kernel@...ts.infradead.org,
	loongarch@...ts.linux.dev, linuxppc-dev@...ts.ozlabs.org,
	linux-riscv@...ts.infradead.org, linux-cxl@...r.kernel.org,
	dri-devel@...ts.freedesktop.org, John@...ves.net
Subject: Re: [PATCH 03/12] mm/pagewalk: Skip dax pages in pagewalk

On Wed, Jun 04, 2025 at 06:59:09PM -0700, Dan Williams wrote:
> +/* return normal pages backed by the page allocator */
> +static inline struct page *vm_normal_gfp_pmd(struct vm_area_struct *vma,
> +					     unsigned long addr, pmd_t pmd)
> +{
> +	struct page *page = vm_normal_page_pmd(vma, addr, pmd);
> +
> +	if (!is_devdax_page(page) && !is_fsdax_page(page))
> +		return page;
> +	return NULL;

If you go for this make it more straight forward by having the
normal path in the main flow:

	if (is_devdax_page(page) || is_fsdax_page(page))
		return NULL;
	return page;

> +static inline struct page *vm_normal_gfp_pte(struct vm_area_struct *vma,
> +					     unsigned long addr, pte_t pte)
> +{
> +	struct page *page = vm_normal_page(vma, addr, pte);
> +
> +	if (!is_devdax_page(page) && !is_fsdax_page(page))
> +		return page;
> +	return NULL;

Same here.