Re: [PATCH] evtchn: don't lose pending state if FIFO event array page is missing

[David Vrabel <david.vrabel@citrix.com>]

On 18/10/13 16:06, Jan Beulich wrote:
>>>> On 18.10.13 at 16:06, David Vrabel <david.vrabel@citrix.com> wrote:
>> @@ -322,16 +330,29 @@ static void cleanup_event_array(struct domain *d)
>>      xfree(d->evtchn_fifo);
>>  }
>>  
>> -static void set_priority_all(struct domain *d, unsigned int priority)
>> +static void setup_ports(struct domain *d)
>>  {
>>      unsigned int port;
>>  
>> +    /*
>> +     * For each port that is already bound:
>> +     *
>> +     * - save its pending state.
>> +     * - set default priority.
>> +     */
>>      for ( port = 1; port < d->max_evtchns; port++ )
>>      {
>> +        struct evtchn *evtchn;
>> +
>>          if ( !port_is_valid(d, port) )
>>              break;
>>  
>> -        evtchn_port_set_priority(d, evtchn_from_port(d, port), priority);
>> +        evtchn = evtchn_from_port(d, port);
>> +
>> +        if ( test_and_clear_bit(port, &shared_info(d, evtchn_pending)) )
> 
> So why test_and_clear rather than just test?

I thought of it as moving the bit, but it's not necessary so I'll
replace it with a plain test_bit().

Similarly, the evtchn->pending = 0 isn't needed either.

David