git.openwrt.org Git - openwrt/staging/981213.git/blob

   1 From c146f9bc195a9dc3ad7fd000a14540e7c9df952d Mon Sep 17 00:00:00 2001
   2 From: Vladimir Oltean <vladimir.oltean@nxp.com>
   3 Date: Thu, 6 Jan 2022 01:11:15 +0200
   4 Subject: [PATCH 4/6] net: dsa: hold rtnl_mutex when calling
   5  dsa_master_{setup,teardown}
   6
   7 DSA needs to simulate master tracking events when a binding is first
   8 with a DSA master established and torn down, in order to give drivers
   9 the simplifying guarantee that ->master_state_change calls are made
  10 only when the master's readiness state to pass traffic changes.
  11 master_state_change() provide a operational bool that DSA driver can use
  12 to understand if DSA master is operational or not.
  13 To avoid races, we need to block the reception of
  14 NETDEV_UP/NETDEV_CHANGE/NETDEV_GOING_DOWN events in the netdev notifier
  15 chain while we are changing the master's dev->dsa_ptr (this changes what
  16 netdev_uses_dsa(dev) reports).
  17
  18 The dsa_master_setup() and dsa_master_teardown() functions optionally
  19 require the rtnl_mutex to be held, if the tagger needs the master to be
  20 promiscuous, these functions call dev_set_promiscuity(). Move the
  21 rtnl_lock() from that function and make it top-level.
  22
  23 Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
  24 Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
  25 Signed-off-by: David S. Miller <davem@davemloft.net>
  26 ---
  27  net/dsa/dsa2.c   | 8 ++++++++
  28  net/dsa/master.c | 4 ++--
  29  2 files changed, 10 insertions(+), 2 deletions(-)
  30
  31 diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
  32 index a0d84f9f864f..52fb1958b535 100644
  33 --- a/net/dsa/dsa2.c
  34 +++ b/net/dsa/dsa2.c
  35 @@ -1038,6 +1038,8 @@ static int dsa_tree_setup_master(struct dsa_switch_tree *dst)
  36         struct dsa_port *dp;
  37         int err;
  38
  39 +       rtnl_lock();
  40 +
  41         list_for_each_entry(dp, &dst->ports, list) {
  42                 if (dsa_port_is_cpu(dp)) {
  43                         err = dsa_master_setup(dp->master, dp);
  44 @@ -1046,6 +1048,8 @@ static int dsa_tree_setup_master(struct dsa_switch_tree *dst)
  45                 }
  46         }
  47
  48 +       rtnl_unlock();
  49 +
  50         return 0;
  51  }
  52
  53 @@ -1053,9 +1057,13 @@ static void dsa_tree_teardown_master(struct dsa_switch_tree *dst)
  54  {
  55         struct dsa_port *dp;
  56
  57 +       rtnl_lock();
  58 +
  59         list_for_each_entry(dp, &dst->ports, list)
  60                 if (dsa_port_is_cpu(dp))
  61                         dsa_master_teardown(dp->master);
  62 +
  63 +       rtnl_unlock();
  64  }
  65
  66  static int dsa_tree_setup_lags(struct dsa_switch_tree *dst)
  67 diff --git a/net/dsa/master.c b/net/dsa/master.c
  68 index f4efb244f91d..2199104ca7df 100644
  69 --- a/net/dsa/master.c
  70 +++ b/net/dsa/master.c
  71 @@ -267,9 +267,9 @@ static void dsa_master_set_promiscuity(struct net_device *dev, int inc)
  72         if (!ops->promisc_on_master)
  73                 return;
  74
  75 -       rtnl_lock();
  76 +       ASSERT_RTNL();
  77 +
  78         dev_set_promiscuity(dev, inc);
  79 -       rtnl_unlock();
  80  }
  81
  82  static ssize_t tagging_show(struct device *d, struct device_attribute *attr,
  83 --
  84 2.34.1
  85