Re: [Xen-devel] [PATCH v5 4/9] ioreq-server: create basic ioreq server abstraction.

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 06.05.14 at 15:44, <Paul.Durrant@xxxxxxxxxx> wrote:
>> From: Paul Durrant
>> > >> > +static int hvm_replace_event_channel(struct vcpu *v, domid_t
>> > >> remote_domid,
>> > >> > +                                     evtchn_port_t *p_port)
>> > >> > +{
>> > >> > +    evtchn_port_t old_port, new_port;
>> > >> > +
>> > >> > +    new_port = alloc_unbound_xen_event_channel(v,
>> remote_domid,
>> > NULL);
>> > >> > +    if ( new_port < 0 )
>> > >> > +        return new_port;
>> > >>
>> > >> I'm pretty sure I commented on this too in a previous version:
>> > >> evtchn_port_t is an unsigned type, hence checking it to be negative
>> > >> is pointless.
>> > >
>> > > Yes, but as I'm pretty sure I responded,
>> > alloc_unbound_xen_event_channel()
>> > > doesn't return an evtchn_port_t!
>> >
>> > Which doesn't matter here at all: Once you store the function result
>> > in a variable of type evtchn_port_t, its original signedness is lost.
>> >
>> 
>> ...which is probably why I had these coded as unsigned longs originally. I'll
>> change them back.
> 
> ... and of course, I mean longs there and not unsigned longs!

In which case you ought to mean int, as that's what the function
returns. No need for widening that value.

Jan


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