From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:53412 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753904AbeCGDeh (ORCPT ); Tue, 6 Mar 2018 22:34:37 -0500 Subject: Patch "virtio-net: disable NAPI only when enabled during XDP set" has been added to the 4.15-stable tree To: jasowang@redhat.com, davem@davemloft.net, gregkh@linuxfoundation.org, mst@redhat.com Cc: , From: Date: Tue, 06 Mar 2018 19:31:48 -0800 Message-ID: <152039350898134@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled virtio-net: disable NAPI only when enabled during XDP set to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: virtio-net-disable-napi-only-when-enabled-during-xdp-set.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Tue Mar 6 19:02:56 PST 2018 From: Jason Wang Date: Wed, 28 Feb 2018 18:20:04 +0800 Subject: virtio-net: disable NAPI only when enabled during XDP set From: Jason Wang [ Upstream commit 4e09ff5362843dff3accfa84c805c7f3a99de9cd ] We try to disable NAPI to prevent a single XDP TX queue being used by multiple cpus. But we don't check if device is up (NAPI is enabled), this could result stall because of infinite wait in napi_disable(). Fixing this by checking device state through netif_running() before. Fixes: 4941d472bf95b ("virtio-net: do not reset during XDP set") Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/virtio_net.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -2040,8 +2040,9 @@ static int virtnet_xdp_set(struct net_de } /* Make sure NAPI is not using any XDP TX queues for RX. */ - for (i = 0; i < vi->max_queue_pairs; i++) - napi_disable(&vi->rq[i].napi); + if (netif_running(dev)) + for (i = 0; i < vi->max_queue_pairs; i++) + napi_disable(&vi->rq[i].napi); netif_set_real_num_rx_queues(dev, curr_qp + xdp_qp); err = _virtnet_set_queues(vi, curr_qp + xdp_qp); @@ -2060,7 +2061,8 @@ static int virtnet_xdp_set(struct net_de } if (old_prog) bpf_prog_put(old_prog); - virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi); + if (netif_running(dev)) + virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi); } return 0; Patches currently in stable-queue which might be from jasowang@redhat.com are queue-4.15/tuntap-correctly-add-the-missing-xdp-flush.patch queue-4.15/virtio-net-disable-napi-only-when-enabled-during-xdp-set.patch queue-4.15/tuntap-disable-preemption-during-xdp-processing.patch