cfg80211: fix phy80211 symlink creation

When I moved around the code here, I neglected that we could still
call register_netdev() or similar without the wiphy mutex held,
which then calls cfg80211_register_wdev() - that's also done from
cfg80211_register_netdevice(), but the phy80211 symlink creation
was only there. Now, the symlink isn't needed for a *pure* wdev,
but a netdev not registered via cfg80211_register_wdev() should
still have the symlink, so move the creation to the right place.

Cc: stable@vger.kernel.org
Fixes: 2fe8ef1062 ("cfg80211: change netdev registration/unregistration semantics")
Link: https://lore.kernel.org/r/20210608113226.a5dc4c1e488c.Ia42fe663cefe47b0883af78c98f284c5555bbe5d@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/core.c

@@ -1340,6 +1340,11 @@ void cfg80211_register_wdev(struct cfg80211_registered_device *rdev,
 	rdev->devlist_generation++;
 	wdev->registered = true;
 
+	if (wdev->netdev &&
+	    sysfs_create_link(&wdev->netdev->dev.kobj, &rdev->wiphy.dev.kobj,
+			      "phy80211"))
+		pr_err("failed to add phy80211 symlink to netdev!\n");
+
 	nl80211_notify_iface(rdev, wdev, NL80211_CMD_NEW_INTERFACE);
 }
 
@@ -1365,14 +1370,6 @@ int cfg80211_register_netdevice(struct net_device *dev)
 	if (ret)
 		goto out;
 
-	if (sysfs_create_link(&dev->dev.kobj, &rdev->wiphy.dev.kobj,
-			      "phy80211")) {
-		pr_err("failed to add phy80211 symlink to netdev!\n");
-		unregister_netdevice(dev);
-		ret = -EINVAL;
-		goto out;
-	}
-
 	cfg80211_register_wdev(rdev, wdev);
 	ret = 0;
 out: