On 09/01/2015 03:44 PM, Christoph Hellwig wrote:
> On Tue, Sep 01, 2015 at 03:02:29PM +0200, Hannes Reinecke wrote:
>>>> + rcu_read_lock();
>>>> + pg = rcu_dereference(h->pg);
>>>> + if (!pg) {
>>>> + rcu_read_unlock();
>>>> + return -ENXIO;
>>>> + }
>>>
>>> What is this rcu_read_lock supposed to protect against given
>>> that struct alua_port_group isn't RCU freed? I think this needs
>>> to be another kref_get_unless_zero.
>>>
>> It's not freed now, but it'll be with one of the next patches (ie with
>> the 'rescan' patch).
>> I just kept it here for consistency, following the rule to always
>> enclose 'rcu_dereference' with 'rcu_read_lock()/rcu_read_unlock()'
>> pairs. Irrespective on whether it's being freed or not.
>
> After this patch this is the only RCU call in the driver. I don't
> think adding it here make any sense.
>
Right, I'll be moving it to the rescan patch then.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
[email protected] +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
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