Re: [Qemu-devel] [RFC 1/3] spapr: Fold spapr_phb_add_pci_device() into its only caller

[Michael Roth]

Quoting David Gibson (2017-06-06 20:33:07)
> On Tue, Jun 06, 2017 at 04:37:27PM -0500, Michael Roth wrote:
> > Quoting David Gibson (2017-06-06 08:05:32)
> > > This function is fairly short, and so is its only caller.  There's no
> > > particular logical distinction between them, so fold them together.
> > > 
> > > Signed-off-by: David Gibson <address@hidden>
> > > ---
> > >  hw/ppc/spapr_pci.c | 53 
> > > ++++++++++++++++++++++-------------------------------
> > >  1 file changed, 22 insertions(+), 31 deletions(-)
> > > 
> > > diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> > > index 46e736d..a216f61 100644
> > > --- a/hw/ppc/spapr_pci.c
> > > +++ b/hw/ppc/spapr_pci.c
> > > @@ -1344,30 +1344,6 @@ static int spapr_create_pci_child_dt(sPAPRPHBState 
> > > *phb, PCIDevice *dev,
> > >      return offset;
> > >  }
> > > 
> > > -static void spapr_phb_add_pci_device(sPAPRDRConnector *drc,
> > > -                                     sPAPRPHBState *phb,
> > > -                                     PCIDevice *pdev,
> > > -                                     Error **errp)
> > > -{
> > > -    DeviceState *dev = DEVICE(pdev);
> > > -    void *fdt = NULL;
> > > -    int fdt_start_offset = 0, fdt_size;
> > > -
> > > -    fdt = create_device_tree(&fdt_size);
> > > -    fdt_start_offset = spapr_create_pci_child_dt(phb, pdev, fdt, 0);
> > > -    if (!fdt_start_offset) {
> > > -        error_setg(errp, "Failed to create pci child device tree node");
> > > -        goto out;
> > > -    }
> > > -
> > > -    spapr_drc_attach(drc, DEVICE(pdev),
> > > -                     fdt, fdt_start_offset, !dev->hotplugged, errp);
> > > -out:
> > > -    if (*errp) {
> > > -        g_free(fdt);
> > > -    }
> > > -}
> > > -
> > >  /* Callback to be called during DRC release. */
> > >  void spapr_phb_remove_pci_device_cb(DeviceState *dev)
> > >  {
> > > @@ -1429,6 +1405,8 @@ static void spapr_phb_hot_plug_child(HotplugHandler 
> > > *plug_handler,
> > >      Error *local_err = NULL;
> > >      PCIBus *bus = PCI_BUS(qdev_get_parent_bus(DEVICE(pdev)));
> > >      uint32_t slotnr = PCI_SLOT(pdev->devfn);
> > > +    void *fdt = NULL;
> > > +    int fdt_start_offset, fdt_size;
> > > 
> > >      /* if DR is disabled we don't need to do anything in the case of
> > >       * hotplug or coldplug callbacks
> > > @@ -1438,10 +1416,10 @@ static void 
> > > spapr_phb_hot_plug_child(HotplugHandler *plug_handler,
> > >           * we need to let them know it's not enabled
> > >           */
> > >          if (plugged_dev->hotplugged) {
> > > -            error_setg(errp, QERR_BUS_NO_HOTPLUG,
> > > +            error_setg(&local_err, QERR_BUS_NO_HOTPLUG,
> > >                         object_get_typename(OBJECT(phb)));
> > >          }
> > > -        return;
> > > +        goto out;
> > >      }
> > > 
> > >      g_assert(drc);
> > > @@ -1452,16 +1430,23 @@ static void 
> > > spapr_phb_hot_plug_child(HotplugHandler *plug_handler,
> > >       */
> > >      if (plugged_dev->hotplugged && bus->devices[PCI_DEVFN(slotnr, 0)] &&
> > >          PCI_FUNC(pdev->devfn) != 0) {
> > > -        error_setg(errp, "PCI: slot %d function 0 already ocuppied by 
> > > %s,"
> > > +        error_setg(&local_err, "PCI: slot %d function 0 already ocuppied 
> > > by %s,"
> > >                     " additional functions can no longer be exposed to 
> > > guest.",
> > >                     slotnr, bus->devices[PCI_DEVFN(slotnr, 0)]->name);
> > > -        return;
> > > +        goto out;
> > >      }
> > > 
> > > -    spapr_phb_add_pci_device(drc, phb, pdev, &local_err);
> > 
> > Since we never used local_err outside propagating it and immediately
> > bailing, and since we bail on errp in all prior callers, maybe we
> > should just drop local_err completely in favor errp.
> 
> That doesn't quite work.  The reason for the local_err pattern is so
> that we can tell locally if the error was triggered (errp might be
> NULL, so checking *errp isn't safe).

Ah, of course, not sure how I keep forgetting that detail.

> 
> > 
> > > +    fdt = create_device_tree(&fdt_size);
> > > +    fdt_start_offset = spapr_create_pci_child_dt(phb, pdev, fdt, 0);
> > > +    if (!fdt_start_offset) {
> > > +        error_setg(&local_err, "Failed to create pci child device tree 
> > > node");
> > > +        goto out;
> > > +    }
> > > +
> > > +    spapr_drc_attach(drc, DEVICE(pdev), fdt, fdt_start_offset,
> > > +                     !plugged_dev->hotplugged, &local_err);
> > >      if (local_err) {
> > > -        error_propagate(errp, local_err);
> > > -        return;
> > > +        goto out;
> > >      }
> > > 
> > >      /* If this is function 0, signal hotplug for all the device 
> > > functions.
> > > @@ -1485,6 +1470,12 @@ static void 
> > > spapr_phb_hot_plug_child(HotplugHandler *plug_handler,
> > >              }
> > >          }
> > >      }
> > > +
> > > +out:
> > > +    if (local_err) {
> > > +        error_propagate(errp, local_err);
> > > +        g_free(fdt);
> > > +    }
> > >  }
> > > 
> > >  static void spapr_phb_hot_unplug_child(HotplugHandler *plug_handler,
> > 
> 
> -- 
> David Gibson                    | I'll have my music baroque, and my code
> david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
>                                 | _way_ _around_!
> http://www.ozlabs.org/~dgibson