From b1b397aeef8177f4f7bd91a0d5fa708f4752a499 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Tue, 27 Oct 2020 13:55:22 +0000 Subject: [PATCH] vfio/virqfd: Drain events from eventfd in virqfd_wakeup() Don't allow the events to accumulate in the eventfd counter, drain them as they are handled. Signed-off-by: David Woodhouse Message-Id: <20201027135523.646811-3-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini Acked-by: Alex Williamson --- 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)) &&