From: Jie Wang wangjie125@huawei.com
commit 4e5bd03ae34652cd932ab4c91c71c511793df75c upstream.
In Linux bonding scenario, one packet is copied to several copies and sent by all slave device of bond0 in mode 3(broadcast mode). The mode 3 xmit function bond_xmit_broadcast() only ueses the last slave device's tx result as the final result. In this case, if the last slave device is down, then it always return NET_XMIT_DROP, even though the other slave devices xmit success. It may cause the tx statistics error, and cause the application (e.g. scp) consider the network is unreachable.
For example, use the following command to configure server A.
echo 3 > /sys/class/net/bond0/bonding/mode ifconfig bond0 up ifenslave bond0 eth0 eth1 ifconfig bond0 192.168.1.125 ifconfig eth0 up ifconfig eth1 down The slave device eth0 and eth1 are connected to server B(192.168.1.107). Run the ping 192.168.1.107 -c 3 -i 0.2 command, the following information is displayed.
PING 192.168.1.107 (192.168.1.107) 56(84) bytes of data. 64 bytes from 192.168.1.107: icmp_seq=1 ttl=64 time=0.077 ms 64 bytes from 192.168.1.107: icmp_seq=2 ttl=64 time=0.056 ms 64 bytes from 192.168.1.107: icmp_seq=3 ttl=64 time=0.051 ms
192.168.1.107 ping statistics 0 packets transmitted, 3 received
Actually, the slave device eth0 of the bond successfully sends three ICMP packets, but the result shows that 0 packets are transmitted.
Also if we use scp command to get remote files, the command end with the following printings.
ssh_exchange_identification: read: Connection timed out
So this patch modifies the bond_xmit_broadcast to return NET_XMIT_SUCCESS if one slave device in the bond sends packets successfully. If all slave devices send packets fail, the discarded packets stats is increased. The skb is released when there is no slave device in the bond or the last slave device is down.
Fixes: ae46f184bc1f ("bonding: propagate transmit status") Signed-off-by: Jie Wang wangjie125@huawei.com Signed-off-by: Guangbin Huang huangguangbin2@huawei.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/bonding/bond_main.c | 30 ++++++++++++++++++++++-------- 1 file changed, 22 insertions(+), 8 deletions(-)
--- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -4562,25 +4562,39 @@ static netdev_tx_t bond_xmit_broadcast(s struct bonding *bond = netdev_priv(bond_dev); struct slave *slave = NULL; struct list_head *iter; + bool xmit_suc = false; + bool skb_used = false;
bond_for_each_slave_rcu(bond, slave, iter) { - if (bond_is_last_slave(bond, slave)) - break; - if (bond_slave_is_up(slave) && slave->link == BOND_LINK_UP) { - struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); + struct sk_buff *skb2;
+ if (!(bond_slave_is_up(slave) && slave->link == BOND_LINK_UP)) + continue; + + if (bond_is_last_slave(bond, slave)) { + skb2 = skb; + skb_used = true; + } else { + skb2 = skb_clone(skb, GFP_ATOMIC); if (!skb2) { net_err_ratelimited("%s: Error: %s: skb_clone() failed\n", bond_dev->name, __func__); continue; } - bond_dev_queue_xmit(bond, skb2, slave->dev); } + + if (bond_dev_queue_xmit(bond, skb2, slave->dev) == NETDEV_TX_OK) + xmit_suc = true; } - if (slave && bond_slave_is_up(slave) && slave->link == BOND_LINK_UP) - return bond_dev_queue_xmit(bond, skb, slave->dev);
- return bond_tx_drop(bond_dev, skb); + if (!skb_used) + dev_kfree_skb_any(skb); + + if (xmit_suc) + return NETDEV_TX_OK; + + atomic_long_inc(&bond_dev->tx_dropped); + return NET_XMIT_DROP; }
/*------------------------- Device initialization ---------------------------*/