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udp_tunnel: Fix udp_tunnel_nic work-queue type
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Turn udp_tunnel_nic work-queue to an ordered work-queue. This queue
holds the UDP-tunnel configuration commands of the different netdevs.
When the netdevs are functions of the same NIC the order of
execution may be crucial.

Problem example:
NIC with 2 PFs, both PFs declare offload quota of up to 3 UDP-ports.
 $ifconfig eth2 1.1.1.1/16 up

 $ip link add eth2_19503 type vxlan id 5049 remote 1.1.1.2 dev eth2 dstport 19053
 $ip link set dev eth2_19503 up

 $ip link add eth2_19504 type vxlan id 5049 remote 1.1.1.3 dev eth2 dstport 19054
 $ip link set dev eth2_19504 up

 $ip link add eth2_19505 type vxlan id 5049 remote 1.1.1.4 dev eth2 dstport 19055
 $ip link set dev eth2_19505 up

 $ip link add eth2_19506 type vxlan id 5049 remote 1.1.1.5 dev eth2 dstport 19056
 $ip link set dev eth2_19506 up

NIC RX port offload infrastructure offloads the first 3 UDP-ports (on
all devices which sets NETIF_F_RX_UDP_TUNNEL_PORT feature) and not
UDP-port 19056. So both PFs gets this offload configuration.

 $ip link set dev eth2_19504 down

This triggers udp-tunnel-core to remove the UDP-port 19504 from
offload-ports-list and offload UDP-port 19056 instead.

In this scenario it is important that the UDP-port of 19504 will be
removed from both PFs before trying to add UDP-port 19056. The NIC can
stop offloading a UDP-port only when all references are removed.
Otherwise the NIC may report exceeding of the offload quota.

Fixes: cc4e383 ("udp_tunnel: add central NIC RX port offload infrastructure")
Signed-off-by: Aya Levin <[email protected]>
Reviewed-by: Tariq Toukan <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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ayalevin authored and davem330 committed Sep 13, 2021
1 parent d7807a9 commit e50e711
Showing 1 changed file with 1 addition and 1 deletion.
2 changes: 1 addition & 1 deletion net/ipv4/udp_tunnel_nic.c
Original file line number Diff line number Diff line change
Expand Up @@ -935,7 +935,7 @@ static int __init udp_tunnel_nic_init_module(void)
{
int err;

udp_tunnel_nic_workqueue = alloc_workqueue("udp_tunnel_nic", 0, 0);
udp_tunnel_nic_workqueue = alloc_ordered_workqueue("udp_tunnel_nic", 0);
if (!udp_tunnel_nic_workqueue)
return -ENOMEM;

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