From c0ce219ead0086f1bf79ff6071df1822ee0804c9 Mon Sep 17 00:00:00 2001 From: Ilya Maximets Date: Sat, 7 Dec 2019 15:46:17 +0100 Subject: netdev-afxdp: Avoid removing of XDP program if not loaded. 'bpf_set_link_xdp_fd' generates netlink event regardless of actual changes it does, so if-notifier will receive link update even if there was no XDP program previously loaded on the interface. OVS tries to remove XDP program if device configuration was not successful triggering if-notifier that triggers bridge reconfiguration and another attempt to add failed port. And so on in the infinite loop. This patch avoids the issue by not removing XDP program if it wasn't loaded. Since loading of the XDP program is one of the last steps of port configuration, this should help to avoid infinite re-addition for most types of misconfiguration. Signed-off-by: Ilya Maximets Acked-by: William Tu --- lib/netdev-afxdp.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/lib/netdev-afxdp.c b/lib/netdev-afxdp.c index 7b452c459..ad66e8e7c 100644 --- a/lib/netdev-afxdp.c +++ b/lib/netdev-afxdp.c @@ -568,7 +568,7 @@ netdev_afxdp_get_numa_id(const struct netdev *netdev) static void xsk_remove_xdp_program(uint32_t ifindex, int xdpmode) { - uint32_t flags; + uint32_t ret, flags, prog_id = 0; flags = XDP_FLAGS_UPDATE_IF_NOEXIST; @@ -578,6 +578,18 @@ xsk_remove_xdp_program(uint32_t ifindex, int xdpmode) flags |= XDP_FLAGS_DRV_MODE; } + /* Check whether XDP program is loaded. */ + ret = bpf_get_link_xdp_id(ifindex, &prog_id, flags); + if (ret) { + VLOG_ERR("Failed to get XDP prog id (%s)", ovs_strerror(errno)); + return; + } + + if (!prog_id) { + VLOG_INFO("No XDP program is loaded at ifindex %d", ifindex); + return; + } + bpf_set_link_xdp_fd(ifindex, -1, flags); } -- 2.14.1