Re: [Xen-devel] [PATCH v3 6/8] x86/vm-event: minor ASSERT fix, add 'unlikely'

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 07.07.16 at 10:35, <czuzu@xxxxxxxxxxxxxxx> wrote:
> On 7/7/2016 11:27 AM, Jan Beulich wrote:
>>>>> On 06.07.16 at 17:54, <czuzu@xxxxxxxxxxxxxxx> wrote:
>>> --- a/xen/arch/x86/vm_event.c
>>> +++ b/xen/arch/x86/vm_event.c
>>> @@ -96,14 +96,16 @@ void vm_event_register_write_resume(struct vcpu *v,
>>> vm_event_response_t *rsp)
>>>   {
>>>       if ( rsp->flags & VM_EVENT_FLAG_DENY )
>>>       {
>>> -        struct monitor_write_data *w = &v->arch.vm_event->write_data;
>>> +        struct monitor_write_data *w;
>>>   
>>> -        ASSERT(w);
>>> +        ASSERT(v->arch.vm_event);
>>>   
>>>           /* deny flag requires the vCPU to be paused */
>>>           if ( !atomic_read(&v->vm_event_pause_count) )
>>>               return;
>>>   
>>> +        w = &v->arch.vm_event->write_data;
>>> +
>>>           switch ( rsp->reason )
>>>           {
>>>           case VM_EVENT_REASON_MOV_TO_MSR:
>> I'd have preferred for you to leave alone the initializer, but we'll see
>> what the maintainers are going to say.
> 
> It's 'cleaner' this way, doesn't it? Not assigning a pointer to a 
> possibly invalid address...

It's a matter of taste, hence subject to the maintainers' opinions.

> Anyway, I'm preparing a v4, I'll probably drop this change if you won't 
> *subdue* to ack it (kidding).

I can't ack it anyway.

Jan


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