Re: [Qemu-devel] [PATCH 3/5] spapr: Add DRC release method

[Michael Roth]

Quoting Greg Kurz (2017-06-20 11:51:45)
> On Tue, 20 Jun 2017 09:53:30 +0800
> David Gibson <address@hidden> wrote:
> 
> > At the moment, spapr_drc_release() has an ugly switch on the DRC type to
> > call the right, device-specific release function.  This cleans it up by
> > doing that via a proper QOM method.
> > 
> > It's still arguably an abstraction violation for the DRC code to call into
> > the specific device code, but one mess at a time.
> > 
> 
> Maybe a second step would be to move DRC subclasses to spapr.c (CPU, LMB) and
> spapr_pci.c (PCI) ? This would allow each device-specific release function to
> have local scope at least.

I kind of prefer the proposed approach of registering a callback
function via drc_new(). This would make it easier to implement
unit tests without needing to rely on stub functions, and keeps the
type-specific handling constrained to matters relating to the DRC
itself and not the resources associated with them.

> 
> Reviewed-by: Greg Kurz <address@hidden>
> 
> > Signed-off-by: David Gibson <address@hidden>
> > ---
> >  hw/ppc/spapr_drc.c         | 22 ++++++----------------
> >  include/hw/ppc/spapr_drc.h |  1 +
> >  2 files changed, 7 insertions(+), 16 deletions(-)
> > 
> > diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c
> > index e5dff16..32e39f2 100644
> > --- a/hw/ppc/spapr_drc.c
> > +++ b/hw/ppc/spapr_drc.c
> > @@ -370,22 +370,9 @@ void spapr_drc_attach(sPAPRDRConnector *drc, 
> > DeviceState *d, void *fdt,
> >  
> >  static void spapr_drc_release(sPAPRDRConnector *drc)
> >  {
> > -    /* Calling release callbacks based on spapr_drc_type(drc). */
> > -    switch (spapr_drc_type(drc)) {
> > -    case SPAPR_DR_CONNECTOR_TYPE_CPU:
> > -        spapr_core_release(drc->dev);
> > -        break;
> > -    case SPAPR_DR_CONNECTOR_TYPE_PCI:
> > -        spapr_phb_remove_pci_device_cb(drc->dev);
> > -        break;
> > -    case SPAPR_DR_CONNECTOR_TYPE_LMB:
> > -        spapr_lmb_release(drc->dev);
> > -        break;
> > -    case SPAPR_DR_CONNECTOR_TYPE_PHB:
> > -    case SPAPR_DR_CONNECTOR_TYPE_VIO:
> > -    default:
> > -        g_assert(false);
> > -    }
> > +    sPAPRDRConnectorClass *drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
> > +
> > +    drck->release(drc->dev);
> >  
> >      drc->awaiting_release = false;
> >      g_free(drc->fdt);
> > @@ -629,6 +616,7 @@ static void spapr_drc_cpu_class_init(ObjectClass *k, 
> > void *data)
> >      drck->typeshift = SPAPR_DR_CONNECTOR_TYPE_SHIFT_CPU;
> >      drck->typename = "CPU";
> >      drck->drc_name_prefix = "CPU ";
> > +    drck->release = spapr_core_release;
> >  }
> >  
> >  static void spapr_drc_pci_class_init(ObjectClass *k, void *data)
> > @@ -638,6 +626,7 @@ static void spapr_drc_pci_class_init(ObjectClass *k, 
> > void *data)
> >      drck->typeshift = SPAPR_DR_CONNECTOR_TYPE_SHIFT_PCI;
> >      drck->typename = "28";
> >      drck->drc_name_prefix = "C";
> > +    drck->release = spapr_phb_remove_pci_device_cb;
> >  }
> >  
> >  static void spapr_drc_lmb_class_init(ObjectClass *k, void *data)
> > @@ -647,6 +636,7 @@ static void spapr_drc_lmb_class_init(ObjectClass *k, 
> > void *data)
> >      drck->typeshift = SPAPR_DR_CONNECTOR_TYPE_SHIFT_LMB;
> >      drck->typename = "MEM";
> >      drck->drc_name_prefix = "LMB ";
> > +    drck->release = spapr_lmb_release;
> >  }
> >  
> >  static const TypeInfo spapr_dr_connector_info = {
> > diff --git a/include/hw/ppc/spapr_drc.h b/include/hw/ppc/spapr_drc.h
> > index d9cacb3..6fd84d1 100644
> > --- a/include/hw/ppc/spapr_drc.h
> > +++ b/include/hw/ppc/spapr_drc.h
> > @@ -217,6 +217,7 @@ typedef struct sPAPRDRConnectorClass {
> >      sPAPRDREntitySense (*dr_entity_sense)(sPAPRDRConnector *drc);
> >      uint32_t (*isolate)(sPAPRDRConnector *drc);
> >      uint32_t (*unisolate)(sPAPRDRConnector *drc);
> > +    void (*release)(DeviceState *dev);
> >  
> >      /* QEMU interfaces for managing hotplug operations */
> >      bool (*release_pending)(sPAPRDRConnector *drc);
>