Subject: Re: [PATCH] bonding: If IP route look-up to send an ARP fails, mark in bonding structure as no ARP sent.

From: Ding Tianhong <[email-masked]>
Date: Thu, 21 Nov 2013 09:10:31 +0800

On 2013/11/21 8:53, rama nichanamatlu wrote:
> During the creation of VLAN's atop bonding the underlying interfaces are made part of VLAN's, and at the same bonding driver gets aware that VLAN's exists above it and hence would consult IP routing for every ARP to  be sent to determine the route which tells bonding driver the correct VLAN tag to attach to the outgoing ARP packet. But, during the VLAN creation when vlan driver puts the underlying interface into default vlan and then actual vlan, in-between this if bonding driver consults the IP for a route, IP fails to provide a correct route and upon which bonding driver drops the ARP packet. ARP monitor when it
> comes around next time, sees no ARP response and fails-over to the next available slave. Consulting for a IP route, ip_route_output(),happens in bond_arp_send_all().
> 
> To prevent this false fail-over, when bonding driver fails to send an ARP out it marks in its private structure, bonding{},  not to expect an ARP response, when ARP monitor comes around next time ARP sending will be tried again.
> 
> Extensively tested in a VM environment; sr-iov intf->bonding intf->vlan intf. All virtual interfaces created at boot time.
> 

please reorganize the changelog, it is too log for a line, please make it in 80 chats.

> Orabug: 17172660
> Signed-off-by: Venkat Venkatsubra <[email-masked]>
> Signed-off-by: Rama Nichanamatlu <[email-masked]>
> ---
>  drivers/net/bonding/bond_main.c | 13 ++++++++-----
>  drivers/net/bonding/bonding.h   |  1 +
>  2 files changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index dde6b4a..d475161 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -2661,7 +2661,7 @@ static int bond_has_this_ip(struct bonding *bond, __be32 ip)
>   * switches in VLAN mode (especially if ports are configured as
>   * "native" to a VLAN) might not pass non-tagged frames.
>   */
> -static void bond_arp_send(struct net_device *slave_dev, int arp_op, __be32 dest_ip, __be32 src_ip, unsigned short vlan_id)
> +static void bond_arp_send(struct bonding *bond, struct net_device *slave_dev, int arp_op, __be32 dest_ip, __be32 src_ip, unsigned short vlan_id)

no need to add bond, the bond could be get from slave, see slave->bond

Ding
>  {
>      struct sk_buff *skb;
>  @@ -2683,6 +2683,7 @@ static void bond_arp_send(struct net_device *slave_dev, int arp_op, __be32 dest_
>          }
>      }
>      arp_xmit(skb);
> +    bond->arp_sent=true;
>  }
>   @@ -2700,7 +2701,7 @@ static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
>          pr_debug("basa: target %x\n", targets[i]);
>          if (!bond->vlgrp) {
>              pr_debug("basa: empty vlan: arp_send\n");
> -            bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
> +            bond_arp_send(bond, slave->dev, ARPOP_REQUEST, targets[i],
>                        bond->master_ip, 0);
>              continue;
>          }
> @@ -2726,7 +2727,7 @@ static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
>          if (rt->dst.dev == bond->dev) {
>              ip_rt_put(rt);
>              pr_debug("basa: rtdev == bond->dev: arp_send\n");
> -            bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
> +            bond_arp_send(bond, slave->dev, ARPOP_REQUEST, targets[i],
>                        bond->master_ip, 0);
>              continue;
>          }
> @@ -2744,7 +2745,7 @@ static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
>           if (vlan_id) {
>              ip_rt_put(rt);
> -            bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
> +            bond_arp_send(bond, slave->dev, ARPOP_REQUEST, targets[i],
>                        vlan->vlan_ip, vlan_id);
>              continue;
>          }
> @@ -3206,7 +3207,7 @@ void bond_activebackup_arp_mon(struct work_struct *work)
>       should_notify_peers = bond_should_notify_peers(bond);
>  -    if (bond_ab_arp_inspect(bond, delta_in_ticks)) {
> +    if (bond->arp_sent && bond_ab_arp_inspect(bond, delta_in_ticks)) {
>          read_unlock(&bond->lock);
>          rtnl_lock();
>          read_lock(&bond->lock);
> @@ -3218,6 +3219,7 @@ void bond_activebackup_arp_mon(struct work_struct *work)
>          read_lock(&bond->lock);
>      }
>  +    bond->arp_sent=false;
>      bond_ab_arp_probe(bond);
>   re_arm:
> @@ -4425,6 +4427,7 @@ static void bond_setup(struct net_device *bond_dev)
>       bond_dev->hw_features &= ~(NETIF_F_ALL_CSUM & ~NETIF_F_NO_CSUM);
>      bond_dev->features |= bond_dev->hw_features;
> +    bond->arp_sent=false;
>  }
>   static void bond_work_cancel_all(struct bonding *bond)
> diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
> index e9a3c56..3878bbd 100644
> --- a/drivers/net/bonding/bonding.h
> +++ b/drivers/net/bonding/bonding.h
> @@ -253,6 +253,7 @@ struct bonding {
>      /* debugging suport via debugfs */
>      struct     dentry *debug_dir;
>  #endif /* CONFIG_DEBUG_FS */
> +        bool arp_sent;
>  };
>   #define bond_slave_get_rcu(dev) \