linux-kernel - Re: [PATCH v6 04/18] powerpc/pseries: add of_node_put() in dlpar_detach

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Message-ID: <ea4d4314-a7e8-f4cd-f9e0-15fedcd3510f@gmail.com>
Date:   Wed, 7 Nov 2018 06:58:56 -0800
From:   Frank Rowand <frowand.list@...il.com>
To:     Michael Ellerman <mpe@...erman.id.au>,
        Rob Herring <robh+dt@...nel.org>,
        Pantelis Antoniou <pantelis.antoniou@...sulko.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Alan Tull <atull@...nel.org>, Moritz Fischer <mdf@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        devicetree@...r.kernel.org, linux-fpga@...r.kernel.org
Subject: Re: [PATCH v6 04/18] powerpc/pseries: add of_node_put() in
 dlpar_detach_node()

On 11/7/18 4:23 AM, Michael Ellerman wrote:
> frowand.list@...il.com writes:
> 
>> From: Frank Rowand <frank.rowand@...y.com>
>>
>> "of: overlay: add missing of_node_get() in __of_attach_node_sysfs"
> 
> It would be clearer if you said 'The previous commit "of: overlay ..."

Will fix.


>> added a missing of_node_get() to __of_attach_node_sysfs().  This
>> results in a refcount imbalance for nodes attached with
>> dlpar_attach_node().  The calling sequence from dlpar_attach_node()
>> to __of_attach_node_sysfs() is:
>>
>>    dlpar_attach_node()
>>       of_attach_node()
>>          __of_attach_node_sysfs()
>>
>> Tested-by: Alan Tull <atull@...nel.org>
>> Signed-off-by: Frank Rowand <frank.rowand@...y.com>
>> ---
>>
>> ***** UNTESTED.  I need people with the affected PowerPC systems
>> *****            (systems that dynamically allocate and deallocate
>> *****            devicetree nodes) to test this patch.
> 
> This looks OK to me in light of the previous patch.
> 
> Acked-by: Michael Ellerman <mpe@...erman.id.au>
> 
> It also means dlpar_detach_node() is again behaving as described in the
> comment to of_detach_node().
> 
> It would be good to make mention of:
> 
>   Fixes: 68baf692c435 ("powerpc/pseries: Fix of_node_put() underflow during DLPAR remove")
> 
> Which removed an of_node_put() in the exact same place for different
> reasons.

OK.

-Frank

> 
> cheers
> 
>> diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
>> index 7625546caefd..17958043e7f7 100644
>> --- a/arch/powerpc/platforms/pseries/dlpar.c
>> +++ b/arch/powerpc/platforms/pseries/dlpar.c
>> @@ -270,6 +270,8 @@ int dlpar_detach_node(struct device_node *dn)
>>  	if (rc)
>>  		return rc;
>>  
>> +	of_node_put(dn);
>> +
>>  	return 0;
>>  }
>>  
>> -- 
>> Frank Rowand <frank.rowand@...y.com>
>