Re: [Bridge] [PATCH RFC net-next 0/3] net: vlan: fix bridge binding behavior and add selftests

[Sevinj Aghayeva <sevinj.aghayeva@gmail.com>]

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On Mon, Aug 22, 2022 at 4:01 AM Nikolay Aleksandrov <razor@blackwall.org>
wrote:

> On 20/08/2022 14:33, Sevinj Aghayeva wrote:
> > On Thu, Aug 18, 2022 at 8:00 AM Nikolay Aleksandrov <razor@blackwall.org>
> wrote:
> >>
> >> On 18/08/2022 14:50, Sevinj Aghayeva wrote:
> [snip]
> >>
> >> Hi,
> >> Handling all vlan device-related changes in br_vlan_device_event()
> sounds good to me.
> >> Please add it to br_vlan.c.
> >
> > Hi Nik,
> >
> > Can you please review this diff before I make it into a proper patchset?
> Thanks!
> >
>
> Hi,
> A few comments inline below, but in general when you prepare the rfc
> commit please
> explain the motivation in detail why this way was chosen and a new
> notification type
> is needed (e.g. why not use NETDEV_CHANGEINFODATA or extend NETDEV_CHANGE).
> As I mentioned earlier it'd be nice to get feedback from others about
> adding this
> new notification, so they should know the "why" in detail.
>

Sure, I will do that in the RFC patchset, but first I want to make sure I
got the details right before making the RFC patchset. Thanks for the
feedback. Please see inline.

>
> > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> > index 2563d30736e9..0ce3da42325e 100644
> > --- a/include/linux/netdevice.h
> > +++ b/include/linux/netdevice.h
> > @@ -2762,6 +2762,7 @@ enum netdev_cmd {
> >   NETDEV_UNREGISTER,
> >   NETDEV_CHANGEMTU, /* notify after mtu change happened */
> >   NETDEV_CHANGEADDR, /* notify after the address change */
> > + NETDEV_CHANGE_DETAILS,
> >   NETDEV_PRE_CHANGEADDR, /* notify before the address change */
> >   NETDEV_GOING_DOWN,
> >   NETDEV_CHANGENAME,
> > @@ -2837,6 +2838,13 @@ struct netdev_notifier_changelowerstate_info {
> >   void *lower_state_info; /* is lower dev state */
> >  };
> >
> > +struct netdev_notifier_change_details_info {
> > + struct netdev_notifier_info info; /* must be first */
> > + union {
> > + bool bridge_binding;
>
> this should be in a vlan-specific structure, defined in if_vlan.h
> every other link type which wants to use the notification would define its
> own struct type
>

Okay, will move it there.


>
> > + } details;
> > +};
> > +
> >  struct netdev_notifier_pre_changeaddr_info {
> >   struct netdev_notifier_info info; /* must be first */
> >   const unsigned char *dev_addr;
> > @@ -3836,6 +3844,8 @@ int __dev_set_mtu(struct net_device *, int);
> >  int dev_set_mtu(struct net_device *, int);
> >  int dev_pre_changeaddr_notify(struct net_device *dev, const char *addr,
> >         struct netlink_ext_ack *extack);
> > +int dev_change_details_notify(struct net_device *dev, bool
> bridge_binding,
> > +       struct netlink_ext_ack *extack);
>
> this helper is not needed


> >  int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa,
> >   struct netlink_ext_ack *extack);
> >  int dev_set_mac_address_user(struct net_device *dev, struct sockaddr
> *sa,
> > diff --git a/net/8021q/vlan.h b/net/8021q/vlan.h
> > index 5eaf38875554..71947cdcfaaa 100644
> > --- a/net/8021q/vlan.h
> > +++ b/net/8021q/vlan.h
> > @@ -130,7 +130,7 @@ void vlan_dev_set_ingress_priority(const struct
> > net_device *dev,
> >  int vlan_dev_set_egress_priority(const struct net_device *dev,
> >   u32 skb_prio, u16 vlan_prio);
> >  void vlan_dev_free_egress_priority(const struct net_device *dev);
> > -int vlan_dev_change_flags(const struct net_device *dev, u32 flag, u32
> mask);
> > +int vlan_dev_change_flags(struct net_device *dev, u32 flag, u32 mask);
> >  void vlan_dev_get_realdev_name(const struct net_device *dev, char
> *result,
> >          size_t size);
> >
> > diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
> > index 839f2020b015..489baa8435de 100644
> > --- a/net/8021q/vlan_dev.c
> > +++ b/net/8021q/vlan_dev.c
> > @@ -211,7 +211,7 @@ int vlan_dev_set_egress_priority(const struct
> > net_device *dev,
> >  /* Flags are defined in the vlan_flags enum in
> >   * include/uapi/linux/if_vlan.h file.
> >   */
> > -int vlan_dev_change_flags(const struct net_device *dev, u32 flags, u32
> mask)
> > +int vlan_dev_change_flags(struct net_device *dev, u32 flags, u32 mask)
>
> please don't remove the const, this function shouldn't change dev's struct
>

I tried not to remove const, but it seems impossible because
call_netdevice_notifiers_info that we eventually call from
vlan_dev_change_flags takes a non-const struct info that has a dev field
being set from the const vlan_dev_change_flags.


>
> >  {
> >   struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
> >   u32 old_flags = vlan->flags;
> > @@ -223,19 +223,29 @@ int vlan_dev_change_flags(const struct
> > net_device *dev, u32 flags, u32 mask)
> >
> >   vlan->flags = (old_flags & ~mask) | (flags & mask);
> >
> > - if (netif_running(dev) && (vlan->flags ^ old_flags) & VLAN_FLAG_GVRP) {
> > + if (!netif_running(dev))
> > + return 0;
> > +
> > + if ((vlan->flags ^ old_flags) & VLAN_FLAG_GVRP) {
> >   if (vlan->flags & VLAN_FLAG_GVRP)
> >   vlan_gvrp_request_join(dev);
> >   else
> >   vlan_gvrp_request_leave(dev);
> >   }
> >
> > - if (netif_running(dev) && (vlan->flags ^ old_flags) & VLAN_FLAG_MVRP) {
> > + if ((vlan->flags ^ old_flags) & VLAN_FLAG_MVRP) {
> >   if (vlan->flags & VLAN_FLAG_MVRP)
> >   vlan_mvrp_request_join(dev);
> >   else
> >   vlan_mvrp_request_leave(dev);
> >   }
> > +
> > + if ((vlan->flags ^ old_flags) & VLAN_FLAG_BRIDGE_BINDING &&
> > +     netif_is_bridge_master(vlan->real_dev)) {
> > + dev_change_details_notify(dev,
> > +     !!(vlan->flags & VLAN_FLAG_BRIDGE_BINDING), NULL);
>
> this helper is not needed, just fill in the details here and send the
> notification
>
>
Okay, in that case I will need to export call_netdevice_notifiers_info so
that I can call it from here.

> + }
> > +
> >   return 0;
> >  }
> >
> > diff --git a/net/bridge/br.c b/net/bridge/br.c
> > index 96e91d69a9a8..62e939c6a3f0 100644
> > --- a/net/bridge/br.c
> > +++ b/net/bridge/br.c
> > @@ -51,6 +51,11 @@ static int br_device_event(struct notifier_block
> > *unused, unsigned long event, v
> >   }
> >   }
> >
> > + if (is_vlan_dev(dev)) {
> > + br_vlan_device_event(dev, event, ptr);
> > + return NOTIFY_DONE;
> > + }
> > +
> >   /* not a port of a bridge */
> >   p = br_port_get_rtnl(dev);
> >   if (!p)
> > diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
> > index 06e5f6faa431..a9a08e49c76c 100644
> > --- a/net/bridge/br_private.h
> > +++ b/net/bridge/br_private.h
> > @@ -1470,6 +1470,8 @@ void br_vlan_get_stats(const struct
> net_bridge_vlan *v,
> >  void br_vlan_port_event(struct net_bridge_port *p, unsigned long event);
> >  int br_vlan_bridge_event(struct net_device *dev, unsigned long event,
> >   void *ptr);
> > +void br_vlan_device_event(struct net_device *dev, unsigned long event,
> > +   void *ptr);
> >  void br_vlan_rtnl_init(void);
> >  void br_vlan_rtnl_uninit(void);
> >  void br_vlan_notify(const struct net_bridge *br,
> > @@ -1701,6 +1703,11 @@ static inline int br_vlan_bridge_event(struct
> > net_device *dev,
> >   return 0;
> >  }
> >
> > +static void br_vlan_device_event(struct net_device *dev,
> > + unsigned long event, void *ptr)
> > +{
> > +}
> > +
> >  static inline void br_vlan_rtnl_init(void)
> >  {
> >  }
> > diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
> > index 0f5e75ccac79..70a9950df175 100644
> > --- a/net/bridge/br_vlan.c
> > +++ b/net/bridge/br_vlan.c
> > @@ -1768,6 +1768,20 @@ void br_vlan_port_event(struct net_bridge_port
> > *p, unsigned long event)
> >   }
> >  }
> >
> > +void br_vlan_device_event(struct net_device *dev, unsigned long
> > event, void *ptr)
> > +{
> > + struct netdev_notifier_change_details_info *info;
> > + struct net_device *br_dev;
> > +
> > + switch (event) {
> > + case NETDEV_CHANGE_DETAILS:
> > + info = ptr;
> > + br_dev = vlan_dev_priv(dev)->real_dev;
>
> you're not guaranteed to have a bridge device as its real_dev, so you
> should
> validate that the vlan's real dev is a bridge
>

Okay, will do.


>
> > + br_vlan_upper_change(br_dev, dev, info->details.bridge_binding);
> > + break;
> > + }
> > +}
> > +
> >  static bool br_vlan_stats_fill(struct sk_buff *skb,
> >          const struct net_bridge_vlan *v)
> >  {
> > diff --git a/net/core/dev.c b/net/core/dev.c
> > index 30a1603a7225..dcdbc625585d 100644
> > --- a/net/core/dev.c
> > +++ b/net/core/dev.c
> > @@ -1624,7 +1624,7 @@ const char *netdev_cmd_to_name(enum netdev_cmd cmd)
> >   N(POST_INIT) N(RELEASE) N(NOTIFY_PEERS) N(JOIN) N(CHANGEUPPER)
> >   N(RESEND_IGMP) N(PRECHANGEMTU) N(CHANGEINFODATA) N(BONDING_INFO)
> >   N(PRECHANGEUPPER) N(CHANGELOWERSTATE) N(UDP_TUNNEL_PUSH_INFO)
> > - N(UDP_TUNNEL_DROP_INFO) N(CHANGE_TX_QUEUE_LEN)
> > + N(UDP_TUNNEL_DROP_INFO) N(CHANGE_TX_QUEUE_LEN) N(CHANGE_DETAILS)
> >   N(CVLAN_FILTER_PUSH_INFO) N(CVLAN_FILTER_DROP_INFO)
> >   N(SVLAN_FILTER_PUSH_INFO) N(SVLAN_FILTER_DROP_INFO)
> >   N(PRE_CHANGEADDR) N(OFFLOAD_XSTATS_ENABLE) N(OFFLOAD_XSTATS_DISABLE)
> > @@ -8767,6 +8767,27 @@ int dev_pre_changeaddr_notify(struct net_device
> > *dev, const char *addr,
> >  }
> >  EXPORT_SYMBOL(dev_pre_changeaddr_notify);
> >
> > +/**
> > + * dev_change_details_notify - Call NETDEV_PRE_CHANGE_DETAILS.
> > + * @dev: device
> > + * @bridge_binding: bridge binding setting
> > + * @extack: netlink extended ack
> > + */
> > +int dev_change_details_notify(struct net_device *dev, bool
> bridge_binding,
> > +       struct netlink_ext_ack *extack)
> > +{
> > + struct netdev_notifier_change_details_info info = {
> > + .info.dev = dev,
> > + .info.extack = extack,
> > + .details.bridge_binding = bridge_binding,
> > + };
> > + int rc;
> > +
> > + rc = call_netdevice_notifiers_info(NETDEV_CHANGE_DETAILS, &info.info);
> > + return notifier_to_errno(rc);
> > +}
> > +EXPORT_SYMBOL(dev_change_details_notify);
> > +
>
> this helper is unnecessary, just fill in the struct at the caller site and
> send the notification directly
>

Okay, will remove it.

Thanks for the review! I will send the updated patch soon.

>
> >  /**
> >   * dev_set_mac_address - Change Media Access Control Address
> >   * @dev: device
> >
> >
> >>
> >> Thanks,
> >>  Nik
> >>
> >>
>
> Cheers,
>  Nik
>
>
>

-- 

Sevinj.Aghayeva

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