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Date:   Wed, 4 Nov 2020 13:11:39 +0100
From:   Oscar Salvador <osalvador@suse.de>
To:     David Hildenbrand <david@redhat.com>
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>,
        Mike Rapoport <rppt@kernel.org>,
        Michal Hocko <mhocko@suse.com>,
        Wei Yang <richard.weiyang@linux.alibaba.com>
Subject: Re: [PATCH v1 3/4] powerpc/mm: remove linear mapping if
 __add_pages() fails in arch_add_memory()
Message-ID: <20201104121139.GB5126@localhost.localdomain>
References: <20201029162718.29910-1-david@redhat.com>
 <20201029162718.29910-4-david@redhat.com>
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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.
> 
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Rashmica Gupta <rashmica.g@gmail.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Mike Rapoport <rppt@kernel.org>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>

Reviewed-by: Oscar Salvador <osalvador@suse.de>

> ---
>  arch/powerpc/mm/mem.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
> index 685028451dd2..69b3e8072261 100644
> --- a/arch/powerpc/mm/mem.c
> +++ b/arch/powerpc/mm/mem.c
> @@ -165,7 +165,10 @@ int __ref arch_add_memory(int nid, u64 start, u64 size,
>  	rc = arch_create_linear_mapping(nid, start, size, params);
>  	if (rc)
>  		return rc;
> -	return __add_pages(nid, start_pfn, nr_pages, params);
> +	rc = __add_pages(nid, start_pfn, nr_pages, params);
> +	if (rc)
> +		arch_remove_linear_mapping(start, size);
> +	return rc;
>  }
>  
>  void __ref arch_remove_memory(int nid, u64 start, u64 size,
> -- 
> 2.26.2
> 

-- 
Oscar Salvador
SUSE L3