From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:39888 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730870AbeKVFpJ (ORCPT ); Thu, 22 Nov 2018 00:45:09 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Matthew Cover , "David S. Miller" Subject: [PATCH 4.14 08/21] tuntap: fix multiqueue rx Date: Wed, 21 Nov 2018 20:06:52 +0100 Message-Id: <20181121183422.431534668@linuxfoundation.org> In-Reply-To: <20181121183422.103826775@linuxfoundation.org> References: <20181121183422.103826775@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matthew Cover [ Upstream commit 8ebebcba559a1bfbaec7bbda64feb9870b9c58da ] When writing packets to a descriptor associated with a combined queue, the packets should end up on that queue. Before this change all packets written to any descriptor associated with a tap interface end up on rx-0, even when the descriptor is associated with a different queue. The rx traffic can be generated by either of the following. 1. a simple tap program which spins up multiple queues and writes packets to each of the file descriptors 2. tx from a qemu vm with a tap multiqueue netdev The queue for rx traffic can be observed by either of the following (done on the hypervisor in the qemu case). 1. a simple netmap program which opens and reads from per-queue descriptors 2. configuring RPS and doing per-cpu captures with rxtxcpu Alternatively, if you printk() the return value of skb_get_rx_queue() just before each instance of netif_receive_skb() in tun.c, you will get 65535 for every skb. Calling skb_record_rx_queue() to set the rx queue to the queue_index fixes the association between descriptor and rx queue. Signed-off-by: Matthew Cover Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/tun.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1214,6 +1214,7 @@ static void tun_rx_batched(struct tun_st if (!rx_batched || (!more && skb_queue_empty(queue))) { local_bh_disable(); + skb_record_rx_queue(skb, tfile->queue_index); netif_receive_skb(skb); local_bh_enable(); return; @@ -1233,8 +1234,11 @@ static void tun_rx_batched(struct tun_st struct sk_buff *nskb; local_bh_disable(); - while ((nskb = __skb_dequeue(&process_queue))) + while ((nskb = __skb_dequeue(&process_queue))) { + skb_record_rx_queue(nskb, tfile->queue_index); netif_receive_skb(nskb); + } + skb_record_rx_queue(skb, tfile->queue_index); netif_receive_skb(skb); local_bh_enable(); }