Re: [PATCH 2/3] vfio/virqfd: Drain events from eventfd in virqfd_wakeup()

Alex Williamson
2020-11-06T23:30:08Z

On Tue, 27 Oct 2020 13:55:22 +0000
David Woodhouse <dwmw2@infradead.org> wrote:

> From: David Woodhouse <dwmw@amazon.co.uk>
>
> Don't allow the events to accumulate in the eventfd counter, drain them
> as they are handled.
>
> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
> ---

Acked-by: Alex Williamson <alex.williamson@redhat.com>

Paolo, I assume you'll add this to your queue. Thanks,

Alex

> drivers/vfio/virqfd.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/vfio/virqfd.c b/drivers/vfio/virqfd.c
> index 997cb5d0a657..414e98d82b02 100644
> --- a/drivers/vfio/virqfd.c
> +++ b/drivers/vfio/virqfd.c
> @@ -46,6 +46,9 @@ static int virqfd_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync, void
> __poll_t flags = key_to_poll(key);
>
> if (flags & EPOLLIN) {
> + u64 cnt;
> + eventfd_ctx_do_read(virqfd->eventfd, &cnt);
> +
> /* An event has been signaled, call function */
> if ((!virqfd->handler ||
> virqfd->handler(virqfd->opaque, virqfd->data)) &&