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[173.76.246.42]) by smtp.gmail.com with ESMTPSA id b83sm11119200qkg.12.2019.02.28.11.36.58 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 28 Feb 2019 11:36:59 -0800 (PST) Date: Thu, 28 Feb 2019 14:36:56 -0500 From: "Michael S. Tsirkin" To: Jakub Kicinski Cc: si-wei liu , "Samudrala, Sridhar" , Siwei Liu , Jiri Pirko , Stephen Hemminger , David Miller , Netdev , virtualization@lists.linux-foundation.org, virtio-dev , "Brandeburg, Jesse" , Alexander Duyck , Jason Wang , liran.alon@oracle.com Subject: Re: [virtio-dev] Re: net_failover slave udev renaming (was Re: [RFC PATCH net-next v6 4/4] netvsc: refactor notifier/event handling code to use the bypass framework) Message-ID: <20190228143511-mutt-send-email-mst@kernel.org> References: <20190227173710-mutt-send-email-mst@kernel.org> <20190227184601-mutt-send-email-mst@kernel.org> <20190227193923-mutt-send-email-mst@kernel.org> <20190227165205.307ed83c@cakuba.netronome.com> <20190227201857-mutt-send-email-mst@kernel.org> <20190227175218.736e13b6@cakuba.netronome.com> <20190227233812-mutt-send-email-mst@kernel.org> <20190228101356.39ac70aa@cakuba.netronome.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190228101356.39ac70aa@cakuba.netronome.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Feb 28, 2019 at 10:13:56AM -0800, Jakub Kicinski wrote: > On Wed, 27 Feb 2019 23:47:33 -0500, Michael S. Tsirkin wrote: > > On Wed, Feb 27, 2019 at 05:52:18PM -0800, Jakub Kicinski wrote: > > > > > Can the users who care about the naming put net_failover into > > > > > "user space will do the bond enslavement" mode, and do the bond > > > > > creation/management themselves from user space (in systemd/ > > > > > Network Manager) based on the failover flag? > > > > > > > > Putting issues of compatibility aside (userspace tends to be confused if > > > > you give it two devices with same MAC), how would you have it work in > > > > practice? Timer based hacks like netvsc where if userspace didn't > > > > respond within X seconds we assume it won't and do everything ourselves? > > > > > > Well, what I'm saying is basically if user space knows how to deal with > > > the auto-bonding, we can put aside net_failover for the most part. It > > > can either be blacklisted or it can have some knob which will > > > effectively disable the auto-enslavement. > > > > OK I guess we could add a module parameter to skip this. > > Is this what you mean? > > Yup. > > > > Auto-bonding capable user space can do the renames, spawn the bond, > > > etc. all by itself. I'm basically going back to my initial proposal > > > here :) There is a RedHat bugzilla for the NetworkManager team to do > > > this, but we merged net_failover before those folks got around to > > > implementing it. > > > > In particular because there's no policy involved whatsoever > > here so it's just mechanism being pushed up to userspace. > > > > > IOW if NM/systemd is capable of doing the auto-bonding itself it can > > > disable the kernel mechanism and take care of it all. If kernel is > > > booted with an old user space which doesn't have capable NM/systemd - > > > net_failover will kick in and do its best. > > > > Sure - it's just 2 lines of code, see below. > > > > Signed-off-by: Michael S. Tsirkin > > > > But I don't intend to bother until there's actual interest from > > userspace developers to bother. In particular it is not just NM/systemd > > even on Fedora - e.g. you will need to teach dracut to somehow detect > > and handle this - right now it gets confused if there are two devices > > with same MAC addresses. > > It is a bit of a the chicken or the egg situation ;) But users can > just blacklist, too. Anyway, I think this is far better than module > parameters Sorry I'm a bit confused. What is better than what? > for twiddling kernel-based interface naming policy.. :S I see your point. But my point is slave names don't really matter, only master name matters. So I am not sure there's any policy worth talking about here. > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > index 955b3e76eb8d..dd2b2c370003 100644 > > --- a/drivers/net/virtio_net.c > > +++ b/drivers/net/virtio_net.c > > @@ -43,6 +43,7 @@ static bool csum = true, gso = true, napi_tx; > > module_param(csum, bool, 0444); > > module_param(gso, bool, 0444); > > module_param(napi_tx, bool, 0644); > > +module_param(disable_failover, bool, 0644); > > > > /* FIXME: MTU in config. */ > > #define GOOD_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN) > > @@ -3163,6 +3164,7 @@ static int virtnet_probe(struct virtio_device *vdev) > > virtnet_init_settings(dev); > > > > - if (virtio_has_feature(vdev, VIRTIO_NET_F_STANDBY)) { > > + if (virtio_has_feature(vdev, VIRTIO_NET_F_STANDBY) && > > + !disable_failover) { > > vi->failover = net_failover_create(vi->dev); > > if (IS_ERR(vi->failover)) { > > err = PTR_ERR(vi->failover); > >