Re: [Qemu-devel] [PATCH v8 05/16] virtio-scsi: Catch BDS-BB removal/insertion

[Kevin Wolf]

Am 27.01.2016 um 18:59 hat Max Reitz geschrieben:
> Make use of the BDS-BB removal and insertion notifiers to remove or set
> up, respectively, virtio-scsi's op blockers.
> 
> Signed-off-by: Max Reitz <address@hidden>
> ---
>  hw/scsi/virtio-scsi.c           | 55 
> +++++++++++++++++++++++++++++++++++++++++
>  include/hw/virtio/virtio-scsi.h | 10 ++++++++
>  2 files changed, 65 insertions(+)
> 
> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
> index 607593c..b508b81 100644
> --- a/hw/scsi/virtio-scsi.c
> +++ b/hw/scsi/virtio-scsi.c
> @@ -757,6 +757,22 @@ static void virtio_scsi_change(SCSIBus *bus, SCSIDevice 
> *dev, SCSISense sense)
>      }
>  }
>  
> +static void virtio_scsi_blk_insert_notifier(Notifier *n, void *data)
> +{
> +    VirtIOSCSIBlkChangeNotifier *cn = DO_UPCAST(VirtIOSCSIBlkChangeNotifier,
> +                                                n, n);
> +    assert(cn->sd->conf.blk == data);
> +    blk_op_block_all(cn->sd->conf.blk, cn->s->blocker);
> +}
> +
> +static void virtio_scsi_blk_remove_notifier(Notifier *n, void *data)
> +{
> +    VirtIOSCSIBlkChangeNotifier *cn = DO_UPCAST(VirtIOSCSIBlkChangeNotifier,
> +                                                n, n);
> +    assert(cn->sd->conf.blk == data);
> +    blk_op_unblock_all(cn->sd->conf.blk, cn->s->blocker);
> +}
> +
>  static void virtio_scsi_hotplug(HotplugHandler *hotplug_dev, DeviceState 
> *dev,
>                                  Error **errp)
>  {
> @@ -765,6 +781,22 @@ static void virtio_scsi_hotplug(HotplugHandler 
> *hotplug_dev, DeviceState *dev,
>      SCSIDevice *sd = SCSI_DEVICE(dev);
>  
>      if (s->ctx && !s->dataplane_disabled) {
> +        VirtIOSCSIBlkChangeNotifier *insert_notifier, *remove_notifier;
> +
> +        insert_notifier = g_new0(VirtIOSCSIBlkChangeNotifier, 1);
> +        insert_notifier->n.notify = virtio_scsi_blk_insert_notifier;
> +        insert_notifier->s = s;
> +        insert_notifier->sd = sd;
> +        blk_add_insert_bs_notifier(sd->conf.blk, &insert_notifier->n);
> +        QTAILQ_INSERT_TAIL(&s->insert_notifiers, insert_notifier, next);
> +
> +        remove_notifier = g_new0(VirtIOSCSIBlkChangeNotifier, 1);
> +        remove_notifier->n.notify = virtio_scsi_blk_remove_notifier;
> +        remove_notifier->s = s;
> +        remove_notifier->sd = sd;
> +        blk_add_remove_bs_notifier(sd->conf.blk, &remove_notifier->n);
> +        QTAILQ_INSERT_TAIL(&s->remove_notifiers, remove_notifier, next);
> +
>          if (blk_op_is_blocked(sd->conf.blk, BLOCK_OP_TYPE_DATAPLANE, errp)) {
>              return;
>          }

If we take the error path here, won't we have dangling pointers in the
notifier list?

Kevin