linux-kernel - Re: [PATCH 1/4] mm/memory: convert do_page

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Message-ID: <860b4135-2d00-6864-df3f-e04689ec12e2@huawei.com>
Date:   Mon, 3 Jul 2023 17:29:12 +0800
From:   "zhangpeng (AS)" <zhangpeng362@...wei.com>
To:     Sidhartha Kumar <sidhartha.kumar@...cle.com>,
        <linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>
CC:     <akpm@...ux-foundation.org>, <willy@...radead.org>
Subject: Re: [PATCH 1/4] mm/memory: convert do_page_mkwrite() to use folios

On 2023/7/3 13:58, Sidhartha Kumar wrote:

> Saves one implicit call to compound_head();
>
> Signed-off-by: Sidhartha Kumar <sidhartha.kumar@...cle.com>
> ---
>   mm/memory.c | 10 +++++-----
>   1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 21fab27272092..098fac2f5efc0 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -2932,7 +2932,7 @@ static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma)
>   static vm_fault_t do_page_mkwrite(struct vm_fault *vmf)
>   {
>   	vm_fault_t ret;
> -	struct page *page = vmf->page;
> +	struct folio *folio = page_folio(vmf->page);
>   	unsigned int old_flags = vmf->flags;
>   
>   	vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
> @@ -2947,14 +2947,14 @@ static vm_fault_t do_page_mkwrite(struct vm_fault *vmf)
>   	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
>   		return ret;
>   	if (unlikely(!(ret & VM_FAULT_LOCKED))) {
> -		lock_page(page);
> -		if (!page->mapping) {
> -			unlock_page(page);
> +		folio_lock(folio);
> +		if (!folio_mapping(folio)) {

Could page->mapping be directly converted to folio->mapping?

Thanks,
Peng

> +			folio_unlock(folio);
>   			return 0; /* retry */
>   		}
>   		ret |= VM_FAULT_LOCKED;
>   	} else
> -		VM_BUG_ON_PAGE(!PageLocked(page), page);
> +		VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
>   	return ret;
>   }
>