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

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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>
This commit is contained in:
Vladimir Oltean 2022-01-06 01:11:15 +02:00 committed by David S. Miller
parent a1ff94c297
commit c146f9bc19
2 changed files with 10 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

8
net/dsa/dsa2.c
View file

@ -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)

4
net/dsa/master.c
View file

@ -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,