Commit c146f9bc authored Jan 06, 2022 by Vladimir Oltean Committed by David S. Miller Jan 06, 2022

net: dsa: hold rtnl_mutex when calling dsa_master_{setup,teardown}



DSA needs to simulate master tracking events when a binding is first
with a DSA master established and torn down, in order to give drivers
the simplifying guarantee that ->master_state_change calls are made
only when the master's readiness state to pass traffic changes.
master_state_change() provide a operational bool that DSA driver can use
to understand if DSA master is operational or not.
To avoid races, we need to block the reception of
NETDEV_UP/NETDEV_CHANGE/NETDEV_GOING_DOWN events in the netdev notifier
chain while we are changing the master's dev->dsa_ptr (this changes what
netdev_uses_dsa(dev) reports).

The dsa_master_setup() and dsa_master_teardown() functions optionally
require the rtnl_mutex to be held, if the tagger needs the master to be
promiscuous, these functions call dev_set_promiscuity(). Move the
rtnl_lock() from that function and make it top-level.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent a1ff94c2

net/dsa/dsa2.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -1038,6 +1038,8 @@ static int dsa_tree_setup_master(struct dsa_switch_tree *dst)
		struct dsa_port *dp;
		int err;

		rtnl_lock();

		list_for_each_entry(dp, &dst->ports, list) {
		if (dsa_port_is_cpu(dp)) {
		err = dsa_master_setup(dp->master, dp);
		@@ -1046,6 +1048,8 @@ static int dsa_tree_setup_master(struct dsa_switch_tree *dst)
		}
		}

		rtnl_unlock();

		return 0;
		}

		@@ -1053,9 +1057,13 @@ static void dsa_tree_teardown_master(struct dsa_switch_tree *dst)
		{
		struct dsa_port *dp;

		rtnl_lock();

		list_for_each_entry(dp, &dst->ports, list)
		if (dsa_port_is_cpu(dp))
		dsa_master_teardown(dp->master);

		rtnl_unlock();
		}

		static int dsa_tree_setup_lags(struct dsa_switch_tree *dst)

net/dsa/master.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -267,9 +267,9 @@ static void dsa_master_set_promiscuity(struct net_device *dev, int inc)
		if (!ops->promisc_on_master)
		return;

		rtnl_lock();
		ASSERT_RTNL();

		dev_set_promiscuity(dev, inc);
		rtnl_unlock();
		}

		static ssize_t tagging_show(struct device d, struct device_attribute attr,