linux-kernel - Re: [RFC v7 PATCH 1/4] mm: refactor do_munmap() to extract the common part

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Date:   Fri, 10 Aug 2018 12:20:55 +0200
From:   Vlastimil Babka <vbabka@...e.cz>
To:     Yang Shi <yang.shi@...ux.alibaba.com>, mhocko@...nel.org,
        willy@...radead.org, ldufour@...ux.vnet.ibm.com,
        kirill@...temov.name, akpm@...ux-foundation.org,
        peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
        alexander.shishkin@...ux.intel.com, jolsa@...hat.com,
        namhyung@...nel.org
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC v7 PATCH 1/4] mm: refactor do_munmap() to extract the common
 part

On 08/10/2018 01:36 AM, Yang Shi wrote:
> Introduces three new helper functions:
>   * addr_ok()
>   * munmap_lookup_vma()
>   * munlock_vmas()
> 
> They will be used by do_munmap() and the new do_munmap with zapping
> large mapping early in the later patch.
> 
> There is no functional change, just code refactor.
> 
> Reviewed-by: Laurent Dufour <ldufour@...ux.vnet.ibm.com>
> Signed-off-by: Yang Shi <yang.shi@...ux.alibaba.com>

Acked-by: Vlastimil Babka <vbabka@...e.cz>

Small nit below.

> @@ -2764,13 +2812,7 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
>  	 */
>  	if (mm->locked_vm) {
>  		struct vm_area_struct *tmp = vma;
> -		while (tmp && tmp->vm_start < end) {
> -			if (tmp->vm_flags & VM_LOCKED) {
> -				mm->locked_vm -= vma_pages(tmp);
> -				munlock_vma_pages_all(tmp);
> -			}
> -			tmp = tmp->vm_next;
> -		}
> +		munlock_vmas(tmp, end);

No need for 'tmp' here.
	
>  	}
>  
>  	/*
>