Re: [PATCH for-6.0 5/9] spapr: Simplify error path of spapr_core_plug()

[David Gibson]

On Sat, Nov 21, 2020 at 12:42:04AM +0100, Greg Kurz wrote:
> spapr_core_pre_plug() already guarantees that the slot for the given core
> ID is available. It is thus safe to assume that spapr_find_cpu_slot()
> returns a slot during plug. Turn the error path into an assertion.
> It is also safe to assume that no device is attached to the corresponding
> DRC and that spapr_drc_attach() shouldn't fail.
> 
> Pass &error_abort to spapr_drc_attach() and simplify error handling.
> 
> Signed-off-by: Greg Kurz <groug@kaod.org>

Applied to ppc-for-6.0, thanks.

> ---
>  hw/ppc/spapr.c | 21 ++++++++++-----------
>  1 file changed, 10 insertions(+), 11 deletions(-)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index da7586f548df..cfca033c7b14 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -3739,8 +3739,7 @@ int spapr_core_dt_populate(SpaprDrc *drc, 
> SpaprMachineState *spapr,
>      return 0;
>  }
>  
> -static void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
> -                            Error **errp)
> +static void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev)
>  {
>      SpaprMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev));
>      MachineClass *mc = MACHINE_GET_CLASS(spapr);
> @@ -3755,20 +3754,20 @@ static void spapr_core_plug(HotplugHandler 
> *hotplug_dev, DeviceState *dev,
>      int i;
>  
>      core_slot = spapr_find_cpu_slot(MACHINE(hotplug_dev), cc->core_id, 
> &index);
> -    if (!core_slot) {
> -        error_setg(errp, "Unable to find CPU core with core-id: %d",
> -                   cc->core_id);
> -        return;
> -    }
> +    g_assert(core_slot); /* Already checked in spapr_core_pre_plug() */
> +
>      drc = spapr_drc_by_id(TYPE_SPAPR_DRC_CPU,
>                            spapr_vcpu_id(spapr, cc->core_id));
>  
>      g_assert(drc || !mc->has_hotpluggable_cpus);
>  
>      if (drc) {
> -        if (!spapr_drc_attach(drc, dev, errp)) {
> -            return;
> -        }
> +        /*
> +         * spapr_core_pre_plug() already buys us this is a brand new
> +         * core being plugged into a free slot. Nothing should already
> +         * be attached to the corresponding DRC.
> +         */
> +        spapr_drc_attach(drc, dev, &error_abort);
>  
>          if (hotplugged) {
>              /*
> @@ -3981,7 +3980,7 @@ static void spapr_machine_device_plug(HotplugHandler 
> *hotplug_dev,
>      if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
>          spapr_memory_plug(hotplug_dev, dev);
>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_CPU_CORE)) {
> -        spapr_core_plug(hotplug_dev, dev, errp);
> +        spapr_core_plug(hotplug_dev, dev);
>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_PCI_HOST_BRIDGE)) 
> {
>          spapr_phb_plug(hotplug_dev, dev, errp);
>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_TPM_PROXY)) {

-- 
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

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