The br_setlink() function extracts the struct net_bridge pointer a bit
sloppy.  It's easy to interpret the code wrong.  This patch attempts to
clear things up a bit.

Signed-off-by: Joachim Wiberg <troglo...@gmail.com>
---
 net/bridge/br_netlink.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 7fca8ff13ec7..8f4297287b32 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -1040,6 +1040,8 @@ int br_setlink(struct net_device *dev, struct nlmsghdr 
*nlh, u16 flags,
                return 0;
 
        p = br_port_get_rtnl(dev);
+       if (p)
+               br = p->br;
        /* We want to accept dev as bridge itself if the AF_SPEC
         * is set to see if someone is setting vlan info on the bridge
         */
@@ -1055,17 +1057,17 @@ int br_setlink(struct net_device *dev, struct nlmsghdr 
*nlh, u16 flags,
                        if (err)
                                return err;
 
-                       spin_lock_bh(&p->br->lock);
+                       spin_lock_bh(&br->lock);
                        err = br_setport(p, tb, extack);
-                       spin_unlock_bh(&p->br->lock);
+                       spin_unlock_bh(&br->lock);
                } else {
                        /* Binary compatibility with old RSTP */
                        if (nla_len(protinfo) < sizeof(u8))
                                return -EINVAL;
 
-                       spin_lock_bh(&p->br->lock);
+                       spin_lock_bh(&br->lock);
                        err = br_set_port_state(p, nla_get_u8(protinfo));
-                       spin_unlock_bh(&p->br->lock);
+                       spin_unlock_bh(&br->lock);
                }
                if (err)
                        goto out;
-- 
2.25.1

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