Re: [PATCH 1/2] mm/memory: remove redundant pte_devmap case for copy_one_pte()

[Matthew Wilcox <willy@infradead.org>]

On Sun, Apr 19, 2020 at 11:30:16AM +0800, qiwuchen55@gmail.com wrote:
> From: chenqiwu <chenqiwu@xiaomi.com>
> 
> As discussed in patch[1], special mapping ptes such as device
> mapping ptes don't need to operate on their corresponding pages,
> so the redundant pte_devmap case can be removed.
> 
> [1] https://patchwork.kernel.org/patch/11494691/

This is a terrible changelog.  What it should say is something like:

Since commit 25b2995a35b6 ("mm: remove MEMORY_DEVICE_PUBLIC support"),
the assignment to 'page' has been unnecessary.  Remove it.

Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>

> Signed-off-by: chenqiwu <chenqiwu@xiaomi.com>
> ---
>  mm/memory.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/mm/memory.c b/mm/memory.c
> index f703fe8..2143827 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -802,8 +802,6 @@ struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
>  		get_page(page);
>  		page_dup_rmap(page, false);
>  		rss[mm_counter(page)]++;
> -	} else if (pte_devmap(pte)) {
> -		page = pte_page(pte);
>  	}
>  
>  out_set_pte:
> -- 
> 1.9.1
> 
>