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Subject: Re: [PATCH v1 3/4] powerpc/mm: remove linear mapping if __add_pages()
 fails in arch_add_memory()
To:     Oscar Salvador <osalvador@suse.de>, Mike Rapoport <rppt@kernel.org>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        linuxppc-dev@lists.ozlabs.org,
        Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Rashmica Gupta <rashmica.g@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@suse.com>,
        Wei Yang <richard.weiyang@linux.alibaba.com>
References: <20201029162718.29910-1-david@redhat.com>
 <20201029162718.29910-4-david@redhat.com>
 <20201104095007.GB4981@localhost.localdomain>
 <20201104120651.GQ4879@kernel.org>
 <20201104121109.GA5126@localhost.localdomain>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat GmbH
Message-ID: <4fd8b15c-3cbf-0016-69a8-235883c0bc46@redhat.com>
Date:   Wed, 11 Nov 2020 13:07:44 +0100
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On 04.11.20 13:11, Oscar Salvador wrote:
> On Wed, Nov 04, 2020 at 02:06:51PM +0200, Mike Rapoport wrote:
>> On Wed, Nov 04, 2020 at 10:50:07AM +0100, osalvador wrote:
>>> On Thu, Oct 29, 2020 at 05:27:17PM +0100, David Hildenbrand wrote:
>>>> Let's revert what we did in case seomthing goes wrong and we return an
>>>> error.
>>>
>>> Dumb question, but should not we do this for other arches as well?
>>
>> It seems arm64 and s390 already do that.
>> x86 could have its arch_add_memory() improved though :)
> 
> Right, I only stared at x86 and see it did not have it.
> I guess we want to have all arches aligned with this.

The ultimate goal would be to get rid of arch-specific arch_add_memory() 
implementations completely, providing arch_create_linear_mapping() / 
arch_remove_linear_mapping() instead (as indicated in patch #1).

The x86 variant certainly needs love, but I'll keep this patch set 
powerpc specific, so it can go via the powerpc tree in one piece. I'll 
add unifying these implementations onto my todo list.

Thanks!

-- 
Thanks,

David / dhildenb