Re: [PATCH v3 1/6] vfio-ccw: make it safe to access channel programs

Halil Pasic
2019-01-30T18:51:27Z

On Wed, 30 Jan 2019 14:22:07 +0100
Cornelia Huck <cohuck@redhat.com> wrote:

> When we get a solicited interrupt, the start function may have
> been cleared by a csch, but we still have a channel program
> structure allocated. Make it safe to call the cp accessors in
> any case, so we can call them unconditionally.

I read this like it is supposed to be safe regardless of
parallelism and threads. However I don't see any explicit
synchronization done for cp->initialized.

I've managed to figure out how is that supposed to be safe
for the cp_free() (which is probably our main concern) in
vfio_ccw_sch_io_todo(), but if fail when it comes to the one
in vfio_ccw_mdev_notifier().

Can you explain us how does the synchronization work?

Regards,
Halil