Re: [PATCH net 1/2] veth: schedule the peer's NAPI after XDP_TX when only GRO is enabled

[Jesper Dangaard Brouer <hawk@kernel.org>]

On 10/18/26 11:08, Lorenzo Bianconi wrote:
>> veth_xdp_xmit() queues XDP_TX frames on the peer's ring if the peer has
>> NAPI. A peer with GRO enabled and no XDP program also has NAPI.
>>
>> veth_xdp_flush() then schedules the peer's NAPI, but only if the peer's
>> xdp_prog is set, so for such a peer the frames are never processed.
>> Nothing else schedules that NAPI by default.
>>
>> Once the ring is full, every XDP_TX frame is dropped, and so are the
>> skbs that veth_xmit() queues on the same ring.
>>
>> Commit 0e672f306a28 ("veth: check for NAPI instead of xdp_prog before
>> xmit of XDP frame") changed the check in veth_xdp_xmit() but not the one
>> in veth_xdp_flush(). Make veth_xdp_flush() check the napi pointer
>> instead of xdp_prog, as veth_xdp_xmit() does.
>>
>> Fixes: 0e672f306a28 ("veth: check for NAPI instead of xdp_prog before xmit of XDP frame")
>> Signed-off-by: Tianyi Gao <tianyi@cloudflare.com>
> 
> Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>


LGTM

Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>


>> ---
>>   drivers/net/veth.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/veth.c b/drivers/net/veth.c
>> index 643b97dc5245..9405ffac598a 100644
>> --- a/drivers/net/veth.c
>> +++ b/drivers/net/veth.c
>> @@ -612,7 +612,7 @@ static void veth_xdp_flush(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
>>   	rcv_priv = netdev_priv(rcv);
>>   	rcv_rq = &rcv_priv->rq[veth_select_rxq(rcv)];
>>   	/* xdp_ring is initialized on receive side? */
>> -	if (unlikely(!rcu_access_pointer(rcv_rq->xdp_prog)))
>> +	if (unlikely(!rcu_access_pointer(rcv_rq->napi)))
>>   		goto out;
>>   
>>   	__veth_xdp_flush(rcv_rq);
>> -- 
>> 2.55.0
>>