Re: [Qemu-block] [PATCH v8 04/16] virtio-blk: Functions for op blocker management

[Fam Zheng]

On Wed, 01/27 18:59, Max Reitz wrote:
> Put the code for setting up and removing op blockers into an own
> function, respectively. Then, we can invoke those functions whenever a
> BDS is removed from an virtio-blk BB or inserted into it.
> 
> Signed-off-by: Max Reitz <address@hidden>
> ---
>  hw/block/dataplane/virtio-blk.c | 77 
> +++++++++++++++++++++++++++++++----------
>  1 file changed, 59 insertions(+), 18 deletions(-)
> 
> diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
> index bc34046..ee0c4d4 100644
> --- a/hw/block/dataplane/virtio-blk.c
> +++ b/hw/block/dataplane/virtio-blk.c
> @@ -40,6 +40,8 @@ struct VirtIOBlockDataPlane {
>      EventNotifier *guest_notifier;  /* irq */
>      QEMUBH *bh;                     /* bh for guest notification */
>  
> +    Notifier insert_notifier, remove_notifier;
> +
>      /* Note that these EventNotifiers are assigned by value.  This is
>       * fine as long as you do not call event_notifier_cleanup on them
>       * (because you don't own the file descriptor or handle; you just
> @@ -137,6 +139,54 @@ static void handle_notify(EventNotifier *e)
>      blk_io_unplug(s->conf->conf.blk);
>  }
>  
> +static void data_plane_set_up_op_blockers(VirtIOBlockDataPlane *s)
> +{
> +    assert(!s->blocker);
> +    error_setg(&s->blocker, "block device is in use by data plane");
> +    blk_op_block_all(s->conf->conf.blk, s->blocker);
> +    blk_op_unblock(s->conf->conf.blk, BLOCK_OP_TYPE_RESIZE, s->blocker);
> +    blk_op_unblock(s->conf->conf.blk, BLOCK_OP_TYPE_DRIVE_DEL, s->blocker);
> +    blk_op_unblock(s->conf->conf.blk, BLOCK_OP_TYPE_BACKUP_SOURCE, 
> s->blocker);
> +    blk_op_unblock(s->conf->conf.blk, BLOCK_OP_TYPE_CHANGE, s->blocker);
> +    blk_op_unblock(s->conf->conf.blk, BLOCK_OP_TYPE_COMMIT_SOURCE, 
> s->blocker);
> +    blk_op_unblock(s->conf->conf.blk, BLOCK_OP_TYPE_COMMIT_TARGET, 
> s->blocker);
> +    blk_op_unblock(s->conf->conf.blk, BLOCK_OP_TYPE_EJECT, s->blocker);
> +    blk_op_unblock(s->conf->conf.blk, BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
> +                   s->blocker);
> +    blk_op_unblock(s->conf->conf.blk, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
> +                   s->blocker);
> +    blk_op_unblock(s->conf->conf.blk, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
> +                   s->blocker);
> +    blk_op_unblock(s->conf->conf.blk, BLOCK_OP_TYPE_MIRROR_SOURCE, 
> s->blocker);
> +    blk_op_unblock(s->conf->conf.blk, BLOCK_OP_TYPE_STREAM, s->blocker);
> +    blk_op_unblock(s->conf->conf.blk, BLOCK_OP_TYPE_REPLACE, s->blocker);
> +}
> +
> +static void data_plane_remove_op_blockers(VirtIOBlockDataPlane *s)
> +{
> +    if (s->blocker) {
> +        blk_op_unblock_all(s->conf->conf.blk, s->blocker);
> +        error_free(s->blocker);
> +        s->blocker = NULL;
> +    }
> +}
> +
> +static void data_plane_blk_insert_notifier(Notifier *n, void *data)
> +{
> +    VirtIOBlockDataPlane *s = container_of(n, VirtIOBlockDataPlane,
> +                                           insert_notifier);
> +    assert(s->conf->conf.blk == data);
> +    data_plane_set_up_op_blockers(s);
> +}
> +
> +static void data_plane_blk_remove_notifier(Notifier *n, void *data)
> +{
> +    VirtIOBlockDataPlane *s = container_of(n, VirtIOBlockDataPlane,
> +                                           remove_notifier);
> +    assert(s->conf->conf.blk == data);
> +    data_plane_remove_op_blockers(s);
> +}
> +
>  /* Context: QEMU global mutex held */
>  void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf,
>                                    VirtIOBlockDataPlane **dataplane,
> @@ -179,22 +229,12 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, 
> VirtIOBlkConf *conf,
>      s->ctx = iothread_get_aio_context(s->iothread);
>      s->bh = aio_bh_new(s->ctx, notify_guest_bh, s);
>  
> -    error_setg(&s->blocker, "block device is in use by data plane");
> -    blk_op_block_all(conf->conf.blk, s->blocker);
> -    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_RESIZE, s->blocker);
> -    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_DRIVE_DEL, s->blocker);
> -    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_BACKUP_SOURCE, s->blocker);
> -    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_CHANGE, s->blocker);
> -    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_COMMIT_SOURCE, s->blocker);
> -    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_COMMIT_TARGET, s->blocker);
> -    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_EJECT, s->blocker);
> -    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT, 
> s->blocker);
> -    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT, 
> s->blocker);
> -    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
> -                   s->blocker);
> -    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_MIRROR_SOURCE, s->blocker);
> -    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_STREAM, s->blocker);
> -    blk_op_unblock(conf->conf.blk, BLOCK_OP_TYPE_REPLACE, s->blocker);
> +    s->insert_notifier.notify = data_plane_blk_insert_notifier;
> +    s->remove_notifier.notify = data_plane_blk_remove_notifier;
> +    blk_add_insert_bs_notifier(conf->conf.blk, &s->insert_notifier);
> +    blk_add_remove_bs_notifier(conf->conf.blk, &s->remove_notifier);
> +
> +    data_plane_set_up_op_blockers(s);
>  
>      *dataplane = s;
>  }
> @@ -207,8 +247,9 @@ void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane 
> *s)
>      }
>  
>      virtio_blk_data_plane_stop(s);
> -    blk_op_unblock_all(s->conf->conf.blk, s->blocker);
> -    error_free(s->blocker);
> +    data_plane_remove_op_blockers(s);
> +    notifier_remove(&s->insert_notifier);
> +    notifier_remove(&s->remove_notifier);
>      qemu_bh_delete(s->bh);
>      object_unref(OBJECT(s->iothread));
>      g_free(s);
> -- 
> 2.7.0
> 

Reviewed-by: Fam Zheng <address@hidden>