From c0a8a9c274936543e436aef691499304ce3127dc Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 5 Feb 2021 15:37:11 +0200 Subject: [PATCH] net: dsa: automatically bring user ports down when master goes down This is not fixing any actual bug that I know of, but having a DSA interface that is up even when its lower (master) interface is down is one of those things that just do not sound right. Yes, DSA checks if the master is up before actually bringing the user interface up, but nobody prevents bringing the master interface down immediately afterwards... Then the user ports would attempt dev_queue_xmit on an interface that is down, and wonder what's wrong. This patch prevents that from happening. NETDEV_GOING_DOWN is the notification emitted _before_ the master actually goes down, and we are protected by the rtnl_mutex, so all is well. For those of you reading this because you were doing switch testing such as latency measurements for autonomously forwarded traffic, and you needed a controlled environment with no extra packets sent by the network stack, this patch breaks that, because now the user ports go down too, which may shut down the PHY etc. But please don't do it like that, just do instead: tc qdisc add dev eno2 clsact tc filter add dev eno2 egress flower action drop Tested with two cascaded DSA switches: $ ip link set eno2 down sja1105 spi2.0 sw0p2: Link is Down mscc_felix 0000:00:00.5 swp0: Link is Down fsl_enetc 0000:00:00.2 eno2: Link is Down Signed-off-by: Vladimir Oltean Reviewed-by: Andrew Lunn Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- net/dsa/slave.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/net/dsa/slave.c b/net/dsa/slave.c index c95e3bd..f77e9ee 100644 --- a/net/dsa/slave.c +++ b/net/dsa/slave.c @@ -2081,6 +2081,30 @@ static int dsa_slave_netdevice_event(struct notifier_block *nb, err = dsa_port_lag_change(dp, info->lower_state_info); return notifier_from_errno(err); } + case NETDEV_GOING_DOWN: { + struct dsa_port *dp, *cpu_dp; + struct dsa_switch_tree *dst; + LIST_HEAD(close_list); + + if (!netdev_uses_dsa(dev)) + return NOTIFY_DONE; + + cpu_dp = dev->dsa_ptr; + dst = cpu_dp->ds->dst; + + list_for_each_entry(dp, &dst->ports, list) { + if (!dsa_is_user_port(dp->ds, dp->index)) + continue; + + list_add(&dp->slave->close_list, &close_list); + } + + dev_close_many(&close_list, true); + + return NOTIFY_OK; + } + default: + break; } return NOTIFY_DONE; -- 2.7.4