[RFC PATCH v2 net-next 3/4] net: dsa: hold rtnl_mutex when calling dsa_master_{setup,teardown}
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STALE1764d
From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: 2021-12-09 17:39:50
Subsystem:
networking [dsa], networking [general], the rest · Maintainers:
Andrew Lunn, Vladimir Oltean, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Revision v2 of 2 in this series.
Revisions (2)
- rfc [diff vs current]
- v2 current
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_up and ->master_going_down calls are made in exactly this order. To avoid races, we need to block the reception of NETDEV_UP/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> --- net/dsa/dsa2.c | 8 ++++++++ net/dsa/master.c | 4 ++-- 2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index a6cb3470face..6d4422c9e334 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c@@ -1015,6 +1015,8 @@ 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);
@@ -1023,6 +1025,8 @@ static int dsa_tree_setup_master(struct dsa_switch_tree *dst) } } + rtnl_unlock(); + return 0; }
@@ -1030,9 +1034,13 @@ 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)
diff --git a/net/dsa/master.c b/net/dsa/master.c
index f4efb244f91d..2199104ca7df 100644
--- a/net/dsa/master.c
+++ b/net/dsa/master.c@@ -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,
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2.25.1