netdev - [PATCH net-next v7 7/9] vhost-net: vhost-net: replace rx

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Message-ID: <5961e982-9c52-4e7a-b1ca-caaf4c4d0291@tu-dortmund.de>
Date: Thu, 8 Jan 2026 08:47:26 +0100
From: Simon Schippers <simon.schippers@...dortmund.de>
To: Jason Wang <jasowang@...hat.com>
Cc: willemdebruijn.kernel@...il.com, andrew+netdev@...n.ch,
        davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
        pabeni@...hat.com, mst@...hat.com, eperezma@...hat.com,
        leiyang@...hat.com, stephen@...workplumber.org, jon@...anix.com,
        tim.gebauer@...dortmund.de, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        virtualization@...ts.linux.dev
Subject: [PATCH net-next v7 7/9] vhost-net: vhost-net: replace rx_ring with
 tun/tap ring wrappers

On 1/8/26 05:38, Jason Wang wrote:
> On Thu, Jan 8, 2026 at 5:06 AM Simon Schippers
> <simon.schippers@...dortmund.de> 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 <tim.gebauer@...dortmund.de>
>> Signed-off-by: Tim Gebauer <tim.gebauer@...dortmund.de>
>> Co-developed by: Jon Kohler <jon@...anix.com>
>> Signed-off-by: Jon Kohler <jon@...anix.com>
>> Signed-off-by: Simon Schippers <simon.schippers@...dortmund.de>
>> ---
>>  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.

> 
> Thanks
>