Re: [PATCH v2 4/4] vfio/ccw: Make vfio_ccw_register_irq_notifier() return a bool

[Eric Farman <farman@linux.ibm.com>]

On Thu, 2024-04-25 at 12:56 +0200, Markus Armbruster wrote:
> Cédric Le Goater <clg@redhat.com> writes:
> 
> > Since vfio_ccw_register_irq_notifier() takes an 'Error **'
> > argument,
> > best practices suggest to return a bool. See the qapi/error.h Rules
> > section.
> > 
> > Signed-off-by: Cédric Le Goater <clg@redhat.com>
> > ---
> >  hw/vfio/ccw.c | 22 +++++++++++-----------
> >  1 file changed, 11 insertions(+), 11 deletions(-)
> > 
> > diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
> > index
> > 6764388bc47a970329fce2233626ccb8178e0165..1c630f6e9abe93ae0c2b5615d
> > 4409669f096c8c9 100644
> > --- a/hw/vfio/ccw.c
> > +++ b/hw/vfio/ccw.c
> > @@ -379,7 +379,7 @@ read_err:
> >      css_inject_io_interrupt(sch);
> >  }
> >  
> > -static void vfio_ccw_register_irq_notifier(VFIOCCWDevice *vcdev,
> > +static bool vfio_ccw_register_irq_notifier(VFIOCCWDevice *vcdev,
> >                                             unsigned int irq,
> >                                             Error **errp)
> >  {
> > @@ -405,13 +405,13 @@ static void
> > vfio_ccw_register_irq_notifier(VFIOCCWDevice *vcdev,
> >          break;
> >      default:
> >          error_setg(errp, "vfio: Unsupported device irq(%d)", irq);
> > -        return;
> > +        return false;
> >      }
> >  
> >      if (vdev->num_irqs < irq + 1) {
> >          error_setg(errp, "vfio: IRQ %u not available (number of
> > irqs %u)",
> >                     irq, vdev->num_irqs);
> > -        return;
> > +        return false;
> >      }
> >  
> >      argsz = sizeof(*irq_info);
> > @@ -421,14 +421,14 @@ static void
> > vfio_ccw_register_irq_notifier(VFIOCCWDevice *vcdev,
> >      if (ioctl(vdev->fd, VFIO_DEVICE_GET_IRQ_INFO,
> >                irq_info) < 0 || irq_info->count < 1) {
> >          error_setg_errno(errp, errno, "vfio: Error getting irq
> > info");
> > -        return;
> > +        return false;
> >      }
> >  
> >      if (event_notifier_init(notifier, 0)) {
> >          error_setg_errno(errp, errno,
> >                           "vfio: Unable to init event notifier for
> > irq (%d)",
> >                           irq);
> > -        return;
> > +        return false;
> >      }
> >  
> >      fd = event_notifier_get_fd(notifier);
> > @@ -439,6 +439,8 @@ static void
> > vfio_ccw_register_irq_notifier(VFIOCCWDevice *vcdev,
> >          qemu_set_fd_handler(fd, NULL, NULL, vcdev);
> >          event_notifier_cleanup(notifier);
> >      }
> > +
> > +    return true;
> >  }
> >  
> >  static void vfio_ccw_unregister_irq_notifier(VFIOCCWDevice *vcdev,
> > @@ -602,20 +604,18 @@ static void vfio_ccw_realize(DeviceState
> > *dev, Error **errp)
> >          goto out_region_err;
> >      }
> >  
> > -    vfio_ccw_register_irq_notifier(vcdev, VFIO_CCW_IO_IRQ_INDEX,
> > &err);
> > -    if (err) {
> > +    if (!vfio_ccw_register_irq_notifier(vcdev,
> > VFIO_CCW_IO_IRQ_INDEX, &err)) {
> 
> Please pass errp instead of &err.
> 
> >          goto out_io_notifier_err;
> >      }
> >  
> >      if (vcdev->crw_region) {
> > -        vfio_ccw_register_irq_notifier(vcdev,
> > VFIO_CCW_CRW_IRQ_INDEX, &err);
> > -        if (err) {
> > +        if (!vfio_ccw_register_irq_notifier(vcdev,
> > VFIO_CCW_CRW_IRQ_INDEX,
> > +                                            &err)) {
> 
> Likewise.
> 
> >              goto out_irq_notifier_err;
> >          }
> >      }
> >  
> > -    vfio_ccw_register_irq_notifier(vcdev, VFIO_CCW_REQ_IRQ_INDEX,
> > &err);
> > -    if (err) {
> > +    if (!vfio_ccw_register_irq_notifier(vcdev,
> > VFIO_CCW_REQ_IRQ_INDEX, &err)) {
> >          /*
> >           * Report this error, but do not make it a failing
> > condition.
> >           * Lack of this IRQ in the host does not prevent normal
> > operation.
>             */
>            error_report_err(err);
> 
> Not this patch's problem, but here goes anyway: since this isn't an
> error, we shouldn't use error_report_err().  Would warn_report_err()
> be
> appropriate?  info_report_err() doesn't exist, but it could.
> 
> Preferably with errp instead of &err (two times):
> Reviewed-by: Markus Armbruster <armbru@redhat.com>
> 

Don't recall why I used error_report_err() instead of something else
(or creating info_), but probably just familiarity. There's no need for
it (or the equivalent code in -ap) to be error, and could be another
cleanup.

Reviewed-by: Eric Farman <farman@linux.ibm.com>