On Mon, Jan 12, 2026 at 10:54:15AM +0800, Jason Wang wrote: > On Fri, Jan 9, 2026 at 5:57 PM Simon Schippers > <[email protected]> wrote: > > > > On 1/9/26 07:04, Jason Wang wrote: > > > On Thu, Jan 8, 2026 at 3:48 PM Simon Schippers > > > <[email protected]> wrote: > > >> > > >> On 1/8/26 05:38, Jason Wang wrote: > > >>> On Thu, Jan 8, 2026 at 5:06 AM Simon Schippers > > >>> <[email protected]> wrote: > > >>>> > > >>>> Replace the direct use of ptr_ring in the vhost-net virtqueue with > > >>>> tun/tap ring wrapper helpers. Instead of storing an rx_ring pointer, > > >>>> the virtqueue now stores the interface type (IF_TUN, IF_TAP, or > > >>>> IF_NONE) > > >>>> and dispatches to the corresponding tun/tap helpers for ring > > >>>> produce, consume, and unconsume operations. > > >>>> > > >>>> Routing ring operations through the tun/tap helpers enables netdev > > >>>> queue wakeups, which are required for upcoming netdev queue flow > > >>>> control support shared by tun/tap and vhost-net. > > >>>> > > >>>> No functional change is intended beyond switching to the wrapper > > >>>> helpers. > > >>>> > > >>>> Co-developed-by: Tim Gebauer <[email protected]> > > >>>> Signed-off-by: Tim Gebauer <[email protected]> > > >>>> Co-developed by: Jon Kohler <[email protected]> > > >>>> Signed-off-by: Jon Kohler <[email protected]> > > >>>> Signed-off-by: Simon Schippers <[email protected]> > > >>>> --- > > >>>> drivers/vhost/net.c | 92 +++++++++++++++++++++++++++++---------------- > > >>>> 1 file changed, 60 insertions(+), 32 deletions(-) > > >>>> > > >>>> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c > > >>>> index 7f886d3dba7d..215556f7cd40 100644 > > >>>> --- a/drivers/vhost/net.c > > >>>> +++ b/drivers/vhost/net.c > > >>>> @@ -90,6 +90,12 @@ enum { > > >>>> VHOST_NET_VQ_MAX = 2, > > >>>> }; > > >>>> > > >>>> +enum if_type { > > >>>> + IF_NONE = 0, > > >>>> + IF_TUN = 1, > > >>>> + IF_TAP = 2, > > >>>> +}; > > >>> > > >>> This looks not elegant, can we simply export objects we want to use to > > >>> vhost like get_tap_socket()? > > >> > > >> No, we cannot do that. We would need access to both the ptr_ring and the > > >> net_device. However, the net_device is protected by an RCU lock. > > >> > > >> That is why {tun,tap}_ring_consume_batched() are used: > > >> they take the appropriate locks and handle waking the queue. > > > > > > How about introducing a callback in the ptr_ring itself, so vhost_net > > > only need to know about the ptr_ring? > > > > That would be great, but I'm not sure whether this should be the > > responsibility of the ptr_ring. > > > > If the ptr_ring were to keep track of the netdev queue, it could handle > > all the management itself - stopping the queue when full and waking it > > again once space becomes available. > > > > What would be your idea for implementing this? > > During ptr_ring_init() register a callback, the callback will be > trigger during ptr_ring_consume() or ptr_ring_consume_batched() when > ptr_ring find there's a space for ptr_ring_produce(). > > Thanks
Not sure the perceived elegance is worth the indirect call overhead. ptr_ring is trying hard to be low overhead. What this does is not really complex to justify that. We just need decent documentation. > > > > > > > > Thanks > > > > > >> > > >>> > > >>> Thanks > > >>> > > >> > > > > >
