[dpdk-dev] [PATCH] eal/linux: fix return after alarm registration failure

[Bruce Richardson]

On Wed, Jun 26, 2019 at 01:55:53PM +0200, Thomas Monjalon wrote:
> 26/06/2019 13:43, Burakov, Anatoly:
> > On 26-Jun-19 12:39 PM, David Marchand wrote:
> > > On Wed, Jun 26, 2019 at 1:36 PM Thomas Monjalon <thomas at monjalon.net> wrote:
> > > 
> > >> 26/06/2019 13:20, David Marchand:
> > >>> On Wed, Jun 26, 2019 at 12:41 PM Thomas Monjalon <thomas at monjalon.net>
> > >>> wrote:
> > >>>
> > >>>> When adding an alarm, if an error happen when registering
> > >>>> the common alarm callback, it is not considered as a major failure.
> > >>>> The alarm is then inserted in the list.
> > >>>> However it was returning an error code after inserting the alarm.
> > >>>>
> > >>>> The error code is reset to 0 so the behaviour and the return code
> > >>>> are consistent.
> > >>>> Other return code related lines are cleaned up for easier
> > >> understanding.
> > >>>>
> > >> [...]
> > >>>> --- a/lib/librte_eal/linux/eal/eal_alarm.c
> > >>>> +++ b/lib/librte_eal/linux/eal/eal_alarm.c
> > >>>>          if (!handler_registered) {
> > >>>> -               ret |= rte_intr_callback_register(&intr_handle,
> > >>>> +               ret = rte_intr_callback_register(&intr_handle,
> > >>>>                                  eal_alarm_callback, NULL);
> > >>>> -               handler_registered = (ret == 0) ? 1 : 0;
> > >>>> +               if (ret == 0)
> > >>>> +                       handler_registered = 1;
> > >>>> +               else
> > >>>> +                       /* not fatal, callback can be registered later
> > >> */
> > >>>> +                       ret = 0;
> > >>>>          }
> > >>>
> > >>> Well, then it means that you don't want to touch ret at all.
> > >>> How about:
> > >>> if (rte_intr_callback_register(&intr_handle,
> > >>>                                 eal_alarm_callback, NULL) == 0)
> > >>>          handler_registered = 1;
> > >>>
> > >>> ?
> > >>
> > >> Too much simple :)
> > >>
> > >> I think we try to avoid calling a function in a "if"
> > >> per coding style.
> > >> And my proposal has the benefit of offering a comment
> > >> about the non-fatal error.
> > >>
> > > 
> > > /* not fatal, callback can be registered later */
> > > if (rte_intr_callback_register(&intr_handle,
> > >                                eal_alarm_callback, NULL) == 0)
> > >         handler_registered = 1;
> > > 
> > 
> > I prefer the original. It's more explicit and conveys the intention 
> > better. Did i break the tie? :)
> 
> I was going to send a v2 with David's suggestion.
> Now I'm confused.
> 
I always tend to prefer shorter versions, so +1 for v2 (does that make it a
v3? :-) )

/Bruce