Re: [Qemu-devel] [PATCHv2 3/8] spapr: Simplify unplug path

[Greg Kurz <groug@kaod.org>]

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On Wed, 12 Jul 2017 12:04:51 +0200
Greg Kurz <groug@kaod.org> wrote:

> On Wed, 12 Jul 2017 15:53:12 +1000
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > spapr_lmb_release() and spapr_core_release() call hotplug_handler_unplug()
> > which after a bunch of indirection calls spapr_memory_unplug() or
> > spapr_core_unplug().  But we already know which is the appropriate thing
> > to call here, so we can just fold it directly into the release function.
> > 
> > Once that's done, there's no need for an hc->unplug method in the spapr
> > machine at all: since we also have an hc->unplug_request method, the
> > hotplug core will never use ->unplug.
> > 
> > Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> > ---  
> 
> Nice cleanup :)
> 
> Reviewed-by: Greg Kurz <groug@kaod.org>
> 
> >  hw/ppc/spapr.c | 54 ++++++++----------------------------------------------
> >  1 file changed, 8 insertions(+), 46 deletions(-)
> > 
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index 2a059d5..ff2aa6b 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -2818,6 +2818,9 @@ void spapr_lmb_release(DeviceState *dev)
> >  {
> >      HotplugHandler *hotplug_ctrl = qdev_get_hotplug_handler(dev);
> >      sPAPRMachineState *spapr = SPAPR_MACHINE(hotplug_ctrl);

BTW, maybe you can also drop the hotplug_ctrl variable since it only has
one trivial user.

> > +    PCDIMMDevice *dimm = PC_DIMM(dev);
> > +    PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
> > +    MemoryRegion *mr = ddc->get_memory_region(dimm);
> >      sPAPRDIMMState *ds = spapr_pending_dimm_unplugs_find(spapr, PC_DIMM(dev));
> >  
> >      /* This information will get lost if a migration occurs
> > @@ -2838,18 +2841,7 @@ void spapr_lmb_release(DeviceState *dev)
> >       * Now that all the LMBs have been removed by the guest, call the
> >       * pc-dimm unplug handler to cleanup up the pc-dimm device.
> >       */
> > -    hotplug_handler_unplug(hotplug_ctrl, dev, &error_abort);
> > -}
> > -
> > -static void spapr_memory_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,
> > -                                Error **errp)
> > -{
> > -    sPAPRMachineState *ms = SPAPR_MACHINE(hotplug_dev);
> > -    PCDIMMDevice *dimm = PC_DIMM(dev);
> > -    PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
> > -    MemoryRegion *mr = ddc->get_memory_region(dimm);
> > -
> > -    pc_dimm_memory_unplug(dev, &ms->hotplug_memory, mr);
> > +    pc_dimm_memory_unplug(dev, &spapr->hotplug_memory, mr);
> >      object_unparent(OBJECT(dev));
> >  }
> >  
> > @@ -2918,10 +2910,11 @@ static void *spapr_populate_hotplug_cpu_dt(CPUState *cs, int *fdt_offset,
> >      return fdt;
> >  }
> >  
> > -static void spapr_core_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,
> > -                              Error **errp)
> > +/* Callback to be called during DRC release. */
> > +void spapr_core_release(DeviceState *dev)
> >  {
> > -    MachineState *ms = MACHINE(qdev_get_machine());
> > +    HotplugHandler *hotplug_ctrl = qdev_get_hotplug_handler(dev);
> > +    MachineState *ms = MACHINE(hotplug_ctrl);

Same here.

> >      sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(ms);
> >      CPUCore *cc = CPU_CORE(dev);
> >      CPUArchId *core_slot = spapr_find_cpu_slot(ms, cc->core_id, NULL);
> > @@ -2945,15 +2938,6 @@ static void spapr_core_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,
> >      object_unparent(OBJECT(dev));
> >  }
> >  
> > -/* Callback to be called during DRC release. */
> > -void spapr_core_release(DeviceState *dev)
> > -{
> > -    HotplugHandler *hotplug_ctrl;
> > -
> > -    hotplug_ctrl = qdev_get_hotplug_handler(dev);
> > -    hotplug_handler_unplug(hotplug_ctrl, dev, &error_abort);
> > -}
> > -
> >  static
> >  void spapr_core_unplug_request(HotplugHandler *hotplug_dev, DeviceState *dev,
> >                                 Error **errp)
> > @@ -3159,27 +3143,6 @@ static void spapr_machine_device_plug(HotplugHandler *hotplug_dev,
> >      }
> >  }
> >  
> > -static void spapr_machine_device_unplug(HotplugHandler *hotplug_dev,
> > -                                      DeviceState *dev, Error **errp)
> > -{
> > -    sPAPRMachineState *sms = SPAPR_MACHINE(qdev_get_machine());
> > -    MachineClass *mc = MACHINE_GET_CLASS(qdev_get_machine());
> > -
> > -    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> > -        if (spapr_ovec_test(sms->ov5_cas, OV5_HP_EVT)) {
> > -            spapr_memory_unplug(hotplug_dev, dev, errp);
> > -        } else {
> > -            error_setg(errp, "Memory hot unplug not supported for this guest");
> > -        }
> > -    } else if (object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_CPU_CORE)) {
> > -        if (!mc->has_hotpluggable_cpus) {
> > -            error_setg(errp, "CPU hot unplug not supported on this machine");
> > -            return;
> > -        }
> > -        spapr_core_unplug(hotplug_dev, dev, errp);
> > -    }
> > -}
> > -
> >  static void spapr_machine_device_unplug_request(HotplugHandler *hotplug_dev,
> >                                                  DeviceState *dev, Error **errp)
> >  {
> > @@ -3397,7 +3360,6 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
> >      mc->get_hotplug_handler = spapr_get_hotplug_handler;
> >      hc->pre_plug = spapr_machine_device_pre_plug;
> >      hc->plug = spapr_machine_device_plug;
> > -    hc->unplug = spapr_machine_device_unplug;
> >      mc->cpu_index_to_instance_props = spapr_cpu_index_to_props;
> >      mc->possible_cpu_arch_ids = spapr_possible_cpu_arch_ids;
> >      hc->unplug_request = spapr_machine_device_unplug_request;  
> 


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