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Message-ID: <CAMArcTV04jucf9jV8GtWvq55=Ly0-AwObPSn+4C+o2QH=j94Lw@mail.gmail.com>
Date: Sun, 22 Sep 2019 21:35:55 +0900
From: Taehee Yoo <ap420073@...il.com>
To: Jakub Kicinski <jakub.kicinski@...ronome.com>
Cc: David Miller <davem@...emloft.net>,
Netdev <netdev@...r.kernel.org>, j.vosburgh@...il.com,
vfalico@...il.com, Andy Gospodarek <andy@...yhouse.net>,
Jiří Pírko <jiri@...nulli.us>,
sd@...asysnail.net, Roopa Prabhu <roopa@...ulusnetworks.com>,
saeedm@...lanox.com, manishc@...vell.com, rahulv@...vell.com,
kys@...rosoft.com, haiyangz@...rosoft.com,
Stephen Hemminger <stephen@...workplumber.org>,
sashal@...nel.org, hare@...e.de, varun@...lsio.com,
ubraun@...ux.ibm.com, kgraul@...ux.ibm.com,
Jay Vosburgh <jay.vosburgh@...onical.com>
Subject: Re: [PATCH net v3 10/11] vxlan: add adjacent link to limit depth level
On Sat, 21 Sep 2019 at 08:48, Jakub Kicinski
<jakub.kicinski@...ronome.com> wrote:
>
Hi Jakub,
Thank you so much for your detailed review!
> On Mon, 16 Sep 2019 22:48:01 +0900, Taehee Yoo wrote:
> > Current vxlan code doesn't limit the number of nested devices.
> > Nested devices would be handled recursively and this routine needs
> > huge stack memory. So, unlimited nested devices could make
> > stack overflow.
> >
> > In order to fix this issue, this patch adds adjacent links.
> > The adjacent link APIs internally check the depth level.
>
> > Fixes: acaf4e70997f ("net: vxlan: when lower dev unregisters remove vxlan dev as well")
> > Signed-off-by: Taehee Yoo <ap420073@...il.com>
>
> Minor nit picks here, I hope you don't mind.
>
> > diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
> > index 3d9bcc957f7d..0d5c8d22d8a4 100644
> > --- a/drivers/net/vxlan.c
> > +++ b/drivers/net/vxlan.c
> > @@ -3567,6 +3567,8 @@ static int __vxlan_dev_create(struct net *net, struct net_device *dev,
> > struct vxlan_net *vn = net_generic(net, vxlan_net_id);
> > struct vxlan_dev *vxlan = netdev_priv(dev);
> > struct vxlan_fdb *f = NULL;
> > + struct net_device *remote_dev = NULL;
> > + struct vxlan_rdst *dst = &vxlan->default_dst;
>
> Especially in places where reverse christmas tree variable ordering is
> adhered to, could you please preserve it? That'd mean:
>
> struct vxlan_net *vn = net_generic(net, vxlan_net_id);
> struct vxlan_dev *vxlan = netdev_priv(dev);
> struct net_device *remote_dev = NULL;
> struct vxlan_fdb *f = NULL;
> bool unregister = false;
> struct vxlan_rdst *dst;
> int err;
>
> dst = &vxlan->default_dst;
>
> here.
>
> > bool unregister = false;
> > int err;
> >
> > @@ -3577,14 +3579,14 @@ static int __vxlan_dev_create(struct net *net, struct net_device *dev,
> > dev->ethtool_ops = &vxlan_ethtool_ops;
> >
> > /* create an fdb entry for a valid default destination */
> > - if (!vxlan_addr_any(&vxlan->default_dst.remote_ip)) {
> > + if (!vxlan_addr_any(&dst->remote_ip)) {
> > err = vxlan_fdb_create(vxlan, all_zeros_mac,
> > - &vxlan->default_dst.remote_ip,
> > + &dst->remote_ip,
> > NUD_REACHABLE | NUD_PERMANENT,
> > vxlan->cfg.dst_port,
> > - vxlan->default_dst.remote_vni,
> > - vxlan->default_dst.remote_vni,
> > - vxlan->default_dst.remote_ifindex,
> > + dst->remote_vni,
> > + dst->remote_vni,
> > + dst->remote_ifindex,
> > NTF_SELF, &f);
> > if (err)
> > return err;
> > @@ -3595,26 +3597,43 @@ static int __vxlan_dev_create(struct net *net, struct net_device *dev,
> > goto errout;
> > unregister = true;
> >
> > + if (dst->remote_ifindex) {
> > + remote_dev = __dev_get_by_index(net, dst->remote_ifindex);
> > + if (!remote_dev)
> > + goto errout;
> > +
> > + err = netdev_upper_dev_link(remote_dev, dev, extack);
> > + if (err)
> > + goto errout;
> > + }
> > +
> > err = rtnl_configure_link(dev, NULL);
> > if (err)
> > - goto errout;
> > + goto unlink;
> >
> > if (f) {
> > - vxlan_fdb_insert(vxlan, all_zeros_mac,
> > - vxlan->default_dst.remote_vni, f);
> > + vxlan_fdb_insert(vxlan, all_zeros_mac, dst->remote_vni, f);
> >
> > /* notify default fdb entry */
> > err = vxlan_fdb_notify(vxlan, f, first_remote_rtnl(f),
> > RTM_NEWNEIGH, true, extack);
> > if (err) {
> > vxlan_fdb_destroy(vxlan, f, false, false);
> > + if (remote_dev)
> > + netdev_upper_dev_unlink(remote_dev, dev);
> > goto unregister;
> > }
> > }
> >
> > list_add(&vxlan->next, &vn->vxlan_list);
> > + if (remote_dev) {
> > + dst->remote_dev = remote_dev;
> > + dev_hold(remote_dev);
> > + }
> > return 0;
> > -
> > +unlink:
> > + if (remote_dev)
> > + netdev_upper_dev_unlink(remote_dev, dev);
> > errout:
> > /* unregister_netdevice() destroys the default FDB entry with deletion
> > * notification. But the addition notification was not sent yet, so
> > @@ -3936,6 +3955,8 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[],
> > struct net_device *lowerdev;
> > struct vxlan_config conf;
> > int err;
> > + bool linked = false;
> > + bool disabled = false;
>
> Same here.
>
> > err = vxlan_nl2conf(tb, data, dev, &conf, true, extack);
> > if (err)
> > @@ -3946,6 +3967,16 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[],
> > if (err)
> > return err;
> >
> > + if (lowerdev) {
> > + if (dst->remote_dev && lowerdev != dst->remote_dev) {
> > + netdev_adjacent_dev_disable(dst->remote_dev, dev);
> > + disabled = true;
> > + }
> > + err = netdev_upper_dev_link(lowerdev, dev, extack);
> > + if (err)
> > + goto err;
>
> would you mind naming the label errout? there is an err variable, and
> other places in this file use errout
>
> > + linked = true;
> > + }
> > /* handle default dst entry */
> > if (!vxlan_addr_equal(&conf.remote_ip, &dst->remote_ip)) {
> > u32 hash_index = fdb_head_index(vxlan, all_zeros_mac, conf.vni);
> > @@ -3962,7 +3993,7 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[],
> > NTF_SELF, true, extack);
> > if (err) {
> > spin_unlock_bh(&vxlan->hash_lock[hash_index]);
> > - return err;
> > + goto err;
> > }
> > }
> > if (!vxlan_addr_any(&dst->remote_ip))
> > @@ -3979,8 +4010,24 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[],
> > if (conf.age_interval != vxlan->cfg.age_interval)
> > mod_timer(&vxlan->age_timer, jiffies);
> >
> > + if (disabled) {
> > + netdev_adjacent_dev_enable(dst->remote_dev, dev);
> > + netdev_upper_dev_unlink(dst->remote_dev, dev);
> > + dev_put(dst->remote_dev);
> > + }
> > + if (linked) {
> > + dst->remote_dev = lowerdev;
> > + dev_hold(dst->remote_dev);
> > + }
> > +
> > vxlan_config_apply(dev, &conf, lowerdev, vxlan->net, true);
> > return 0;
> > +err:
> > + if (linked)
> > + netdev_upper_dev_unlink(lowerdev, dev);
> > + if (disabled)
> > + netdev_adjacent_dev_enable(dst->remote_dev, dev);
> > + return err;
> > }
> >
> > static void vxlan_dellink(struct net_device *dev, struct list_head *head)
> > @@ -3991,6 +4038,10 @@ static void vxlan_dellink(struct net_device *dev, struct list_head *head)
> >
> > list_del(&vxlan->next);
> > unregister_netdevice_queue(dev, head);
> > + if (vxlan->default_dst.remote_dev) {
> > + netdev_upper_dev_unlink(vxlan->default_dst.remote_dev, dev);
> > + dev_put(vxlan->default_dst.remote_dev);
> > + }
> > }
> >
> > static size_t vxlan_get_size(const struct net_device *dev)
> > diff --git a/include/net/vxlan.h b/include/net/vxlan.h
> > index dc1583a1fb8a..08e237d7aa73 100644
> > --- a/include/net/vxlan.h
> > +++ b/include/net/vxlan.h
> > @@ -197,6 +197,7 @@ struct vxlan_rdst {
> > u8 offloaded:1;
> > __be32 remote_vni;
> > u32 remote_ifindex;
> > + struct net_device *remote_dev;
> > struct list_head list;
> > struct rcu_head rcu;
> > struct dst_cache dst_cache;
>
Thank you for letting me know about "reverse christmas tree variable ordering".
I will send a v4 patch that will include things that you mentioned.
Thank you!
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