Subject: Re: [RFC/PATCH] powerpc: Move CPM command handling into the cpm drivers

From: Jochen Friedrich <[email-masked]>
Date: Sat, 24 Nov 2007 18:53:34 +0100

Hi Vitaly,

>>> +       printk(KERN_ERR "%s(): Not able to issue CPM command\n",
>>> +               __FUNCTION__);
>>> +       return -EIO;  
>>>       
>> Do these need to be protected with a spin lock?
>>     
> Even that might be not enough - we may have simultaneous call of this func in non-smp case...
> I was thinking of some kind of refcount, so one that is going to issue CPM command, must do say pq_cpmp_get()
> and another driver won't be able to mangle with cpcr while it's not done with previous request.
>
> Yet I am not telling it was better the way it used to be - this approach looks okay but needs some efforts to defend against
> deadlocks while we are at it

Wouldn't spin_lock_irqsave() prevent a deadlock?

Thanks,
Jochen