| Message ID | 20200908091037.2709823-18-idosch@idosch.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | nexthop: Add support for nexthop objects offload | expand |
On 9/8/20 3:10 AM, Ido Schimmel wrote: > From: Ido Schimmel <idosch@nvidia.com> > > When registering a new notifier to the nexthop notification chain, > replay all the existing nexthops to the new notifier so that it will > have a complete picture of the available nexthops. > > Signed-off-by: Ido Schimmel <idosch@nvidia.com> > --- > net/ipv4/nexthop.c | 54 ++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 52 insertions(+), 2 deletions(-) > > diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c > index b40c343ca969..6505a0a28df2 100644 > --- a/net/ipv4/nexthop.c > +++ b/net/ipv4/nexthop.c > @@ -156,6 +156,27 @@ static int call_nexthop_notifiers(struct net *net, > return notifier_to_errno(err); > } > > +static int call_nexthop_notifier(struct notifier_block *nb, struct net *net, > + enum nexthop_event_type event_type, > + struct nexthop *nh, > + struct netlink_ext_ack *extack) > +{ > + struct nh_notifier_info info = { > + .net = net, > + .extack = extack, > + }; > + int err; > + > + err = nh_notifier_info_init(&info, nh); > + if (err) > + return err; > + > + err = nb->notifier_call(nb, event_type, &info); > + nh_notifier_info_fini(&info); > + > + return notifier_to_errno(err); > +} > + > static unsigned int nh_dev_hashfn(unsigned int val) > { > unsigned int mask = NH_DEV_HASHSIZE - 1; > @@ -2116,11 +2137,40 @@ static struct notifier_block nh_netdev_notifier = { > .notifier_call = nh_netdev_event, > }; > > +static int nexthops_dump(struct net *net, struct notifier_block *nb, > + struct netlink_ext_ack *extack) > +{ > + struct rb_root *root = &net->nexthop.rb_root; > + struct rb_node *node; > + int err = 0; > + > + for (node = rb_first(root); node; node = rb_next(node)) { > + struct nexthop *nh; > + > + nh = rb_entry(node, struct nexthop, rb_node); > + err = call_nexthop_notifier(nb, net, NEXTHOP_EVENT_REPLACE, nh, > + extack); > + if (err) > + break; > + } > + > + return err; > +} > + > int register_nexthop_notifier(struct net *net, struct notifier_block *nb, > struct netlink_ext_ack *extack) > { > - return blocking_notifier_chain_register(&net->nexthop.notifier_chain, > - nb); > + int err; > + > + rtnl_lock(); > + err = nexthops_dump(net, nb, extack); can the unlock be moved here? register function below should not need it. > + if (err) > + goto unlock; > + err = blocking_notifier_chain_register(&net->nexthop.notifier_chain, > + nb); > +unlock: > + rtnl_unlock(); > + return err; > } > EXPORT_SYMBOL(register_nexthop_notifier); > >
On Tue, Sep 08, 2020 at 09:37:10AM -0600, David Ahern wrote: > On 9/8/20 3:10 AM, Ido Schimmel wrote: > > From: Ido Schimmel <idosch@nvidia.com> > > > > When registering a new notifier to the nexthop notification chain, > > replay all the existing nexthops to the new notifier so that it will > > have a complete picture of the available nexthops. > > > > Signed-off-by: Ido Schimmel <idosch@nvidia.com> > > --- > > net/ipv4/nexthop.c | 54 ++++++++++++++++++++++++++++++++++++++++++++-- > > 1 file changed, 52 insertions(+), 2 deletions(-) > > > > diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c > > index b40c343ca969..6505a0a28df2 100644 > > --- a/net/ipv4/nexthop.c > > +++ b/net/ipv4/nexthop.c > > @@ -156,6 +156,27 @@ static int call_nexthop_notifiers(struct net *net, > > return notifier_to_errno(err); > > } > > > > +static int call_nexthop_notifier(struct notifier_block *nb, struct net *net, > > + enum nexthop_event_type event_type, > > + struct nexthop *nh, > > + struct netlink_ext_ack *extack) > > +{ > > + struct nh_notifier_info info = { > > + .net = net, > > + .extack = extack, > > + }; > > + int err; > > + > > + err = nh_notifier_info_init(&info, nh); > > + if (err) > > + return err; > > + > > + err = nb->notifier_call(nb, event_type, &info); > > + nh_notifier_info_fini(&info); > > + > > + return notifier_to_errno(err); > > +} > > + > > static unsigned int nh_dev_hashfn(unsigned int val) > > { > > unsigned int mask = NH_DEV_HASHSIZE - 1; > > @@ -2116,11 +2137,40 @@ static struct notifier_block nh_netdev_notifier = { > > .notifier_call = nh_netdev_event, > > }; > > > > +static int nexthops_dump(struct net *net, struct notifier_block *nb, > > + struct netlink_ext_ack *extack) > > +{ > > + struct rb_root *root = &net->nexthop.rb_root; > > + struct rb_node *node; > > + int err = 0; > > + > > + for (node = rb_first(root); node; node = rb_next(node)) { > > + struct nexthop *nh; > > + > > + nh = rb_entry(node, struct nexthop, rb_node); > > + err = call_nexthop_notifier(nb, net, NEXTHOP_EVENT_REPLACE, nh, > > + extack); > > + if (err) > > + break; > > + } > > + > > + return err; > > +} > > + > > int register_nexthop_notifier(struct net *net, struct notifier_block *nb, > > struct netlink_ext_ack *extack) > > { > > - return blocking_notifier_chain_register(&net->nexthop.notifier_chain, > > - nb); > > + int err; > > + > > + rtnl_lock(); > > + err = nexthops_dump(net, nb, extack); > > can the unlock be moved here? register function below should not need it. It can result in this unlikely race: <t0> - rtnl_lock(); nexthops_dump(); rtnl_unlock() <t1> - Nexthop is added / deleted <t2> - blocking_notifier_chain_register() It is possible to flip the order: <t0> - blocking_notifier_chain_register() <t1> - rtnl_lock(); nexthops_dump(); rtnl_unlock() Worst case: <t0> - blocking_notifier_chain_register() <t1> - Nexthop is added / deleted <t2> - rtnl_lock(); nexthops_dump(); rtnl_unlock() Which is OK. If we get a delete notification for a nexthop we don't know, we ignore it. If we get two replace notifications for the same nexthop we just "update" it. > > > + if (err) > > + goto unlock; > > + err = blocking_notifier_chain_register(&net->nexthop.notifier_chain, > > + nb); > > +unlock: > > + rtnl_unlock(); > > + return err; > > } > > EXPORT_SYMBOL(register_nexthop_notifier); > > > > >
diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c index b40c343ca969..6505a0a28df2 100644 --- a/net/ipv4/nexthop.c +++ b/net/ipv4/nexthop.c @@ -156,6 +156,27 @@ static int call_nexthop_notifiers(struct net *net, return notifier_to_errno(err); } +static int call_nexthop_notifier(struct notifier_block *nb, struct net *net, + enum nexthop_event_type event_type, + struct nexthop *nh, + struct netlink_ext_ack *extack) +{ + struct nh_notifier_info info = { + .net = net, + .extack = extack, + }; + int err; + + err = nh_notifier_info_init(&info, nh); + if (err) + return err; + + err = nb->notifier_call(nb, event_type, &info); + nh_notifier_info_fini(&info); + + return notifier_to_errno(err); +} + static unsigned int nh_dev_hashfn(unsigned int val) { unsigned int mask = NH_DEV_HASHSIZE - 1; @@ -2116,11 +2137,40 @@ static struct notifier_block nh_netdev_notifier = { .notifier_call = nh_netdev_event, }; +static int nexthops_dump(struct net *net, struct notifier_block *nb, + struct netlink_ext_ack *extack) +{ + struct rb_root *root = &net->nexthop.rb_root; + struct rb_node *node; + int err = 0; + + for (node = rb_first(root); node; node = rb_next(node)) { + struct nexthop *nh; + + nh = rb_entry(node, struct nexthop, rb_node); + err = call_nexthop_notifier(nb, net, NEXTHOP_EVENT_REPLACE, nh, + extack); + if (err) + break; + } + + return err; +} + int register_nexthop_notifier(struct net *net, struct notifier_block *nb, struct netlink_ext_ack *extack) { - return blocking_notifier_chain_register(&net->nexthop.notifier_chain, - nb); + int err; + + rtnl_lock(); + err = nexthops_dump(net, nb, extack); + if (err) + goto unlock; + err = blocking_notifier_chain_register(&net->nexthop.notifier_chain, + nb); +unlock: + rtnl_unlock(); + return err; } EXPORT_SYMBOL(register_nexthop_notifier);