Re: [PATCH AUTOSEL 5.16 203/217] net: dsa: hold rtnl_mutex when calling dsa_master_{setup,teardown}
From: Vladimir Oltean <olteanv@gmail.com>
Date: 2022-01-18 12:13:36
Also in:
lkml, stable
Hi Sasha, On Mon, Jan 17, 2022 at 09:19:26PM -0500, Sasha Levin wrote:
From: Vladimir Oltean <vladimir.oltean@nxp.com> [ Upstream commit c146f9bc195a9dc3ad7fd000a14540e7c9df952d ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org> ---
Please drop this patch from all stable branches (5.16, 5.15, 5.10). Thanks.
quoted hunk ↗ jump to hunk
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 826957b6442b0..834f26539da73 100644 --- a/net/dsa/dsa2.c +++ b/net/dsa/dsa2.c@@ -997,6 +997,8 @@ 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);@@ -1005,6 +1007,8 @@ static int dsa_tree_setup_master(struct dsa_switch_tree *dst) } } + rtnl_unlock(); + return 0; }@@ -1012,9 +1016,13 @@ 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 e8e19857621bd..16b7dfd22bf5d 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,-- 2.34.1