Subject: Re: [PATCH v2 07/14] of/reconfig: Always use the same structure for notifiers

From: Nathan Fontenot <[email-masked]>
Date: Tue, 25 Nov 2014 21:11:58 -0600

On 11/25/2014 05:07 PM, Benjamin Herrenschmidt wrote:
> On Mon, 2014-11-24 at 22:33 +0000, Grant Likely wrote:
>> The OF_RECONFIG notifier callback uses a different structure depending
>> on whether it is a node change or a property change. This is silly, and
>> not very safe. Rework the code to use the same data structure regardless
>> of the type of notifier.
> 
> I fell pretty good about this one except...
> 
>> diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
>> index b9d1dfdbe5bb..9fe6002c1d5a 100644
>> --- a/arch/powerpc/mm/numa.c
>> +++ b/arch/powerpc/mm/numa.c
>> @@ -1711,12 +1711,11 @@ static void stage_topology_update(int core_id)
>>  static int dt_update_callback(struct notifier_block *nb,
>>  				unsigned long action, void *data)
>>  {
>> -	struct of_prop_reconfig *update;
>> +	struct of_reconfig_data *update = data;
>>  	int rc = NOTIFY_DONE;
>>  
>>  	switch (action) {
>>  	case OF_RECONFIG_UPDATE_PROPERTY:
>> -		update = (struct of_prop_reconfig *)data;
> 
> Should we assert/bug on !update->dn / update->prop ?
> 
> (Same for the rest of the patch)
> 
> Or do you reckon it's pointless ?
> 

I'm not sure it's worth it, if those are NULL pointers the drivers/of
code would have tried to use them before invoking the notifier chain.
We won't make it this far if they're NULL.

Otherwise the patch looks good to me,

Reviewed-by: Nathan Fontenot <[email-masked]>

-Nathan