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

[Fam Zheng <famz@redhat.com>]

On Wed, 01/27 18:59, Max Reitz wrote:
> 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 <mreitz@redhat.com>
> ---
>  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;
>          }
> @@ -787,6 +819,7 @@ static void virtio_scsi_hotunplug(HotplugHandler *hotplug_dev, DeviceState *dev,
>      VirtIODevice *vdev = VIRTIO_DEVICE(hotplug_dev);
>      VirtIOSCSI *s = VIRTIO_SCSI(vdev);
>      SCSIDevice *sd = SCSI_DEVICE(dev);
> +    VirtIOSCSIBlkChangeNotifier *insert_notifier, *remove_notifier;
>  
>      if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) {
>          virtio_scsi_push_event(s, sd,
> @@ -797,6 +830,25 @@ static void virtio_scsi_hotunplug(HotplugHandler *hotplug_dev, DeviceState *dev,
>      if (s->ctx) {
>          blk_op_unblock_all(sd->conf.blk, s->blocker);
>      }
> +
> +    QTAILQ_FOREACH(insert_notifier, &s->insert_notifiers, next) {
> +        if (insert_notifier->sd == sd) {
> +            notifier_remove(&insert_notifier->n);
> +            QTAILQ_REMOVE(&s->insert_notifiers, insert_notifier, next);
> +            g_free(insert_notifier);
> +            break;
> +        }
> +    }
> +
> +    QTAILQ_FOREACH(remove_notifier, &s->remove_notifiers, next) {
> +        if (remove_notifier->sd == sd) {
> +            notifier_remove(&remove_notifier->n);
> +            QTAILQ_REMOVE(&s->remove_notifiers, remove_notifier, next);
> +            g_free(remove_notifier);
> +            break;
> +        }
> +    }
> +
>      qdev_simple_device_unplug_cb(hotplug_dev, dev, errp);
>  }
>  
> @@ -911,6 +963,9 @@ static void virtio_scsi_device_realize(DeviceState *dev, Error **errp)
>      add_migration_state_change_notifier(&s->migration_state_notifier);
>  
>      error_setg(&s->blocker, "block device is in use by data plane");
> +
> +    QTAILQ_INIT(&s->insert_notifiers);
> +    QTAILQ_INIT(&s->remove_notifiers);
>  }
>  
>  static void virtio_scsi_instance_init(Object *obj)
> diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
> index 088fe9f..0394eb2 100644
> --- a/include/hw/virtio/virtio-scsi.h
> +++ b/include/hw/virtio/virtio-scsi.h
> @@ -76,6 +76,13 @@ typedef struct VirtIOSCSICommon {
>      VirtQueue **cmd_vqs;
>  } VirtIOSCSICommon;
>  
> +typedef struct VirtIOSCSIBlkChangeNotifier {
> +    Notifier n;
> +    struct VirtIOSCSI *s;
> +    SCSIDevice *sd;
> +    QTAILQ_ENTRY(VirtIOSCSIBlkChangeNotifier) next;
> +} VirtIOSCSIBlkChangeNotifier;
> +
>  typedef struct VirtIOSCSI {
>      VirtIOSCSICommon parent_obj;
>  
> @@ -86,6 +93,9 @@ typedef struct VirtIOSCSI {
>      /* Fields for dataplane below */
>      AioContext *ctx; /* one iothread per virtio-scsi-pci for now */
>  
> +    QTAILQ_HEAD(, VirtIOSCSIBlkChangeNotifier) insert_notifiers;
> +    QTAILQ_HEAD(, VirtIOSCSIBlkChangeNotifier) remove_notifiers;
> +
>      /* Vring is used instead of vq in dataplane code, because of the underlying
>       * memory layer thread safety */
>      VirtIOSCSIVring *ctrl_vring;
> -- 
> 2.7.0
> 

Reviewed-by: Fam Zheng <famz@redhat.com>