linux-kernel - Re: [RFC v3 PATCH 3/5] mm: refactor do_munmap() to extract the common part

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Message-ID: <20180702134226.GX19043@dhcp22.suse.cz>
Date:   Mon, 2 Jul 2018 15:42:26 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     Yang Shi <yang.shi@...ux.alibaba.com>
Cc:     willy@...radead.org, ldufour@...ux.vnet.ibm.com,
        akpm@...ux-foundation.org, peterz@...radead.org, mingo@...hat.com,
        acme@...nel.org, alexander.shishkin@...ux.intel.com,
        jolsa@...hat.com, namhyung@...nel.org, tglx@...utronix.de,
        hpa@...or.com, linux-mm@...ck.org, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC v3 PATCH 3/5] mm: refactor do_munmap() to extract the
 common part

On Sat 30-06-18 06:39:43, Yang Shi wrote:
> Introduces two new helper functions:
>   * munmap_addr_sanity()
>   * munmap_lookup_vma()
> 
> 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.

There are whitespace changes which make the code much harder to review
than necessary.
> +static inline bool munmap_addr_sanity(unsigned long start, size_t len)
>  {
> -	unsigned long end;
> -	struct vm_area_struct *vma, *prev, *last;
> +	if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE - start)
> +		return false;
>  
> -	if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start)
> -		return -EINVAL;

e.g. here.
-- 
Michal Hocko
SUSE Labs