Re: [PATCH 0/3] RFC: few random hacks to improve eventfd fallback path

[Maxim Levitsky]

On Thu, 2020-12-17 at 17:00 +0200, Maxim Levitsky wrote:
> These few patches are the result of a random hacking I did to make the qemu
> cope with eventfd allocation failure, when using an iothread,
> as it happened in bz #1897550.
> 
> I am not 100% sure which patches in this series are worth to merge, or if
> this can be fixed in a better way.
> 
> After this patch series applied, qemu still hangs while running reproducer for
> this BZ due to ABBA lock inversion which needs some heavy rework to get rid 
> of.
> I explained all the (gory) details in the bugzilla.
> 
> This patch series was (lightly) tested with make check, iotests and with
> the reproducer.
> 
> Best regards,
>       Maxim Levitsky
> 
> Maxim Levitsky (3):
>   scsi: virtio-scsi: don't process IO on fenced dataplane
>   virtio-scsi: don't uninitialize queues that we didn't initialize
>   event_notifier: handle initialization failure better
> 
>  hw/scsi/virtio-scsi-dataplane.c | 26 +++++++++++++++++++-------
>  include/qemu/event_notifier.h   |  1 +
>  util/event_notifier-posix.c     | 16 ++++++++++++++++
>  3 files changed, 36 insertions(+), 7 deletions(-)
> 
> -- 
> 2.26.2
> 
> 
Any update on this?
Best regards,
        Maxim Levitsky