[PATCH AUTOSEL 5.10 06/28] tun: fix bonding active backup with arp monitoring

Sasha Levin
2021-11-26T02:38:14Z

From: Nicolas Dichtel <nicolas.dichtel@6wind.com>

[ Upstream commit a31d27fbed5d518734cb60956303eb15089a7634 ]

As stated in the bonding doc, trans_start must be set manually for drivers
using NETIF_F_LLTX:
Drivers that use NETIF_F_LLTX flag must also update
netdev_queue->trans_start. If they do not, then the ARP monitor will
immediately fail any slaves using that driver, and those slaves will stay
down.

Link: https://www.kernel.org/doc/html/v5.15/networking/bonding.html#arp-monitor-operation
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/tun.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index c671d8e257741..ffbc7eda95eed 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1021,6 +1021,7 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct tun_struct *tun = netdev_priv(dev);
int txq = skb->queue_mapping;
+ struct netdev_queue *queue;
struct tun_file *tfile;
int len = skb->len;

@@ -1065,6 +1066,10 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
if (ptr_ring_produce(&tfile->tx_ring, skb))
goto drop;

+ /* NETIF_F_LLTX requires to do our own update of trans_start */
+ queue = netdev_get_tx_queue(dev, txq);
+ queue->trans_start = jiffies;
+
/* Notify and wake up reader process */
if (tfile->flags & TUN_FASYNC)
kill_fasync(&tfile->fasync, SIGIO, POLL_IN);
--
2.33.0