Re: [Qemu-devel] [PATCH v1] virtio-scsi: fix object check failure

[Paolo Bonzini]

Il 18/06/2014 17:48, Ming Lei ha scritto:
> On Wed, Jun 18, 2014 at 11:43 PM, Michael S. Tsirkin <address@hidden> wrote:
> > On Wed, Jun 18, 2014 at 11:32:33PM +0800, Ming Lei wrote:
> > > In case of vhost-scsi, the object type of VirtIODevice isn't
> > > VirtIOSCSI, so use the cast trick to fix the problem like
> > > in virtio_scsi_handle_cmd().
> > >
> > > Also 'events_dropped' need to be accessed in the path,
> >
> > in which path?
>
> I mean vq's notify path, virtio_scsi_handle_event().

A better way is this:

- create a VirtIOSCSICommonClass struct and use it (virtio_scsi_common_info)

- add three members virtio_scsi_handle_ctrl, virtio_scsi_handle_event, 
virtio_scsi_handle_cmd to VirtIOSCSICommonClass

- initialize them to the existing functions in virtio_scsi_class_init

- initialize them to dummy empty functions in vhost_scsi_class_init

Which I should have done in the first place when rebasing vhost-scsi, 
and I didn't only because I was lazy and thought this could not happen. 
:(  Turns out it only didn't because at the time the kernel did not 
support events.

Paolo