linux-kernel - Re: [PATCH] mm/pgtable: Move extern zero_pfn outside __HAVE_COLOR_ZERO

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <19858112-8f10-493c-9873-84f2000b00b0@arm.com>
Date:   Tue, 16 Jun 2020 15:18:53 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     David Hildenbrand <david@...hat.com>, linux-mm@...ck.org
Cc:     Arnd Bergmann <arnd@...db.de>, linux-arch@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm/pgtable: Move extern zero_pfn outside
 __HAVE_COLOR_ZERO_PAGE



On 06/16/2020 01:09 PM, David Hildenbrand wrote:
> On 16.06.20 06:08, Anshuman Khandual wrote:
>> zero_pfn variable is required whether __HAVE_COLOR_ZERO_PAGE is enabled
> 
> Why is that relevant for this patch?

That just states how it is organized right now wrt __HAVE_COLOR_ZERO_PAGE.

> 
>> or not. Also it should not really be declared individually in all functions
>> where it gets used. Just move the declaration outside, which also makes it
>> available for other potential users.
> 
> So, all you're essentially doing is exposing zero_pfn in pgtable.h now.

Right, but it just happens in the process of consolidating three different
instances of 'extern unsigned long zero_pfn' in the same file which are
redundant.

> 
> If everybody should just use my_zero_pfn(), I don't really see the
> benefit of this patch, sorry.

It consolidates redundant declarations and reduces code. We could just have
a comment for zero_pfn stating that it should not be used directly.