Re: [PATCH v2 2/3] hw/loongarch/virt: Remove unnecessary NULL pointer checking

[Markus Armbruster <armbru@redhat.com>]

Bibo Mao <maobibo@loongson.cn> writes:

> There is NULL pointer checking function error_propagate() already,
> it is not necessary to add checking for function parameter. Here remove
> NULL pointer checking with function parameter.
>
> Signed-off-by: Bibo Mao <maobibo@loongson.cn>
> ---
>  hw/loongarch/virt.c | 25 +++++++++++--------------
>  1 file changed, 11 insertions(+), 14 deletions(-)
>
> diff --git a/hw/loongarch/virt.c b/hw/loongarch/virt.c
> index a5840ff968..d82676d316 100644
> --- a/hw/loongarch/virt.c
> +++ b/hw/loongarch/virt.c
> @@ -868,21 +868,24 @@ static void virt_cpu_pre_plug(HotplugHandler *hotplug_dev,
>              error_setg(&err,
>                         "Invalid thread-id %u specified, must be in range 1:%u",
>                         cpu->thread_id, ms->smp.threads - 1);
> -            goto out;
> +            error_propagate(errp, err);
> +            return;

Make this

               error_setg(&err, ...);
               return;

>          }
>  
>          if ((cpu->core_id < 0) || (cpu->core_id >= ms->smp.cores)) {
>              error_setg(&err,
>                         "Invalid core-id %u specified, must be in range 1:%u",
>                         cpu->core_id, ms->smp.cores - 1);
> -            goto out;
> +            error_propagate(errp, err);
> +            return;

Likewise.

>          }
>  
>          if ((cpu->socket_id < 0) || (cpu->socket_id >= ms->smp.sockets)) {
>              error_setg(&err,
>                         "Invalid socket-id %u specified, must be in range 1:%u",
>                         cpu->socket_id, ms->smp.sockets - 1);
> -            goto out;
> +            error_propagate(errp, err);
> +            return;

Likewise.

>          }
>  
>          topo.socket_id = cpu->socket_id;
> @@ -895,7 +898,8 @@ static void virt_cpu_pre_plug(HotplugHandler *hotplug_dev,
>                         "cpu(id%d=%d:%d:%d) with arch-id %" PRIu64 " exists",
>                         cs->cpu_index, cpu->socket_id, cpu->core_id,
>                         cpu->thread_id, cpu_slot->arch_id);
> -            goto out;
> +            error_propagate(errp, err);
> +            return;

Likewise.

>          }
>      } else {
>          /* For cold-add cpu, find empty cpu slot */
> @@ -912,10 +916,6 @@ static void virt_cpu_pre_plug(HotplugHandler *hotplug_dev,
>      cpu->phy_id = cpu_slot->arch_id;
>      cs->cpu_index = cpu_slot - ms->possible_cpus->cpus;
>      numa_cpu_pre_plug(cpu_slot, dev, &err);

You need to pass errp instead of &err now.

> -out:
> -    if (err) {
> -        error_propagate(errp, err);
> -    }
>  }
>  
>  static void virt_cpu_unplug_request(HotplugHandler *hotplug_dev,
> @@ -935,9 +935,7 @@ static void virt_cpu_unplug_request(HotplugHandler *hotplug_dev,
>      }
>  
>      hotplug_handler_unplug_request(HOTPLUG_HANDLER(lvms->acpi_ged), dev, &err);
> -    if (err) {
> -        error_propagate(errp, err);
> -    }
> +    error_propagate(errp, err);
>  }

Correct, but I'd recomment to go one step further:

 static void virt_cpu_unplug_request(HotplugHandler *hotplug_dev,
                                     DeviceState *dev, Error **errp)
 {
     LoongArchVirtMachineState *lvms = LOONGARCH_VIRT_MACHINE(hotplug_dev);
-    Error *err = NULL;
     LoongArchCPU *cpu = LOONGARCH_CPU(dev);
     CPUState *cs = CPU(dev);
 
     if (cs->cpu_index == 0) {
-        error_setg(&err, "hot-unplug of boot cpu(id%d=%d:%d:%d) not supported",
+        error_setg(errp, "hot-unplug of boot cpu(id%d=%d:%d:%d) not supported",
                    cs->cpu_index, cpu->socket_id,
                    cpu->core_id, cpu->thread_id);
-        error_propagate(errp, err);
         return;
     }
 
-    hotplug_handler_unplug_request(HOTPLUG_HANDLER(lvms->acpi_ged), dev, &err);
-    if (err) {
-        error_propagate(errp, err);
-    }
+    hotplug_handler_unplug_request(HOTPLUG_HANDLER(lvms->acpi_ged), dev, errp);
 }

>  
>  static void virt_cpu_unplug(HotplugHandler *hotplug_dev,
> @@ -1001,9 +999,8 @@ static void virt_cpu_plug(HotplugHandler *hotplug_dev,
       cpu_slot = virt_find_cpu_slot(MACHINE(lvms), cpu->phy_id);
       cpu_slot->cpu = CPU(dev);
       if (lvms->ipi) {
           hotplug_handler_plug(HOTPLUG_HANDLER(lvms->ipi), dev, &err);
           if (err) {
               error_propagate(errp, err);
               return;
           }
       }

       if (lvms->extioi) {
           hotplug_handler_plug(HOTPLUG_HANDLER(lvms->extioi), dev, &err);
           if (err) {
               error_propagate(errp, err);
               return;
           }
       }
>  
>      if (lvms->acpi_ged) {
>          hotplug_handler_plug(HOTPLUG_HANDLER(lvms->acpi_ged), dev, &err);
> -        if (err) {
> -            error_propagate(errp, err);
> -        }
> +        error_propagate(errp, err);
> +        return;
>      }
>  
>      return;

Better make this work exactly like the other checks above, and drop the
final return, which serves no purpose:

           if (err) {
               error_propagate(errp, err);
               return;
           }
       }
   }