diff mbox series

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

Message ID 20201027135523.646811-3-dwmw2@infradead.org (mailing list archive)
State New, archived
Headers show
Series Allow in-kernel consumers to drain events from eventfd | expand

Commit Message

David Woodhouse Oct. 27, 2020, 1:55 p.m. UTC 
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>
---
 drivers/vfio/virqfd.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Alex Williamson Nov. 6, 2020, 11:29 p.m. UTC | #1 
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)) &&
Paolo Bonzini Nov. 8, 2020, 9:17 a.m. UTC | #2 
On 07/11/20 00:29, Alex Williamson 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
> 

Yes, thanks.

Paolo
diff mbox series

Patch

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)) &&