mac80211: make master netdev handling sane

Currently, almost every interface type has a 'bss' pointer
pointing to BSS information. This BSS information, however,
is for a _local_ BSS, not for the BSS we joined, so having
it on a STA mode interface makes little sense, but now they
have it pointing to the master device, which is an AP mode
virtual interface. However, except for some bitrate control
data, this pointer is only used in AP/VLAN modes (for power
saving stations.)

Overall, it is not necessary to even have the master netdev
be a valid virtual interface, and it doesn't have to be on
the list of interfaces either.

This patch changes the master netdev to be special, it now
 - no longer is on the list of virtual interfaces, which
   lets me remove a lot of tests for that
 - no longer has sub_if_data attached, since that isn't used

Additionally, this patch changes some vlan/ap mode handling
that is related to these 'bss' pointers described above (but
in the VLAN case they actually make sense because there they
point to the AP they belong to); it also adds some debugging
code to IEEE80211_DEV_TO_SUB_IF to validate it is not called
on the master netdev any more.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 28 insertions, 68 deletions

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 1c4d3ba6b87..863923964d2 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -105,7 +105,7 @@ static int ieee80211_master_open(struct net_device *dev)
 
 	/* we hold the RTNL here so can safely walk the list */
 	list_for_each_entry(sdata, &local->interfaces, list) {
-		if (sdata->dev != dev && netif_running(sdata->dev)) {
+		if (netif_running(sdata->dev)) {
 			res = 0;
 			break;
 		}
@@ -126,7 +126,7 @@ static int ieee80211_master_stop(struct net_device *dev)
 
 	/* we hold the RTNL here so can safely walk the list */
 	list_for_each_entry(sdata, &local->interfaces, list)
-		if (sdata->dev != dev && netif_running(sdata->dev))
+		if (netif_running(sdata->dev))
 			dev_close(sdata->dev);
 
 	return 0;
@@ -194,7 +194,7 @@ static int ieee80211_open(struct net_device *dev)
 	list_for_each_entry(nsdata, &local->interfaces, list) {
 		struct net_device *ndev = nsdata->dev;
 
-		if (ndev != dev && ndev != local->mdev && netif_running(ndev)) {
+		if (ndev != dev && netif_running(ndev)) {
 			/*
 			 * Allow only a single IBSS interface to be up at any
 			 * time. This is restricted because beacon distribution
@@ -210,30 +210,6 @@ static int ieee80211_open(struct net_device *dev)
 				return -EBUSY;
 
 			/*
-			 * Disallow multiple IBSS/STA mode interfaces.
-			 *
-			 * This is a technical restriction, it is possible although
-			 * most likely not IEEE 802.11 compliant to have multiple
-			 * STAs with just a single hardware (the TSF timer will not
-			 * be adjusted properly.)
-			 *
-			 * However, because mac80211 uses the master device's BSS
-			 * information for each STA/IBSS interface, doing this will
-			 * currently corrupt that BSS information completely, unless,
-			 * a not very useful case, both STAs are associated to the
-			 * same BSS.
-			 *
-			 * To remove this restriction, the BSS information needs to
-			 * be embedded in the STA/IBSS mode sdata instead of using
-			 * the master device's BSS structure.
-			 */
-			if ((sdata->vif.type == IEEE80211_IF_TYPE_STA ||
-			     sdata->vif.type == IEEE80211_IF_TYPE_IBSS) &&
-			    (nsdata->vif.type == IEEE80211_IF_TYPE_STA ||
-			     nsdata->vif.type == IEEE80211_IF_TYPE_IBSS))
-				return -EBUSY;
-
-			/*
 			 * The remaining checks are only performed for interfaces
 			 * with the same MAC address.
 			 */
@@ -252,7 +228,7 @@ static int ieee80211_open(struct net_device *dev)
 			 */
 			if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN &&
 			    nsdata->vif.type == IEEE80211_IF_TYPE_AP)
-				sdata->u.vlan.ap = nsdata;
+				sdata->bss = &nsdata->u.ap;
 		}
 	}
 
@@ -262,10 +238,13 @@ static int ieee80211_open(struct net_device *dev)
 			return -ENOLINK;
 		break;
 	case IEEE80211_IF_TYPE_VLAN:
-		if (!sdata->u.vlan.ap)
+		if (!sdata->bss)
 			return -ENOLINK;
+		list_add(&sdata->u.vlan.list, &sdata->bss->vlans);
 		break;
 	case IEEE80211_IF_TYPE_AP:
+		sdata->bss = &sdata->u.ap;
+		break;
 	case IEEE80211_IF_TYPE_STA:
 	case IEEE80211_IF_TYPE_MNTR:
 	case IEEE80211_IF_TYPE_IBSS:
@@ -283,14 +262,13 @@ static int ieee80211_open(struct net_device *dev)
 		if (local->ops->start)
 			res = local->ops->start(local_to_hw(local));
 		if (res)
-			return res;
+			goto err_del_bss;
 		need_hw_reconfig = 1;
 		ieee80211_led_radio(local, local->hw.conf.radio_enabled);
 	}
 
 	switch (sdata->vif.type) {
 	case IEEE80211_IF_TYPE_VLAN:
-		list_add(&sdata->u.vlan.list, &sdata->u.vlan.ap->u.ap.vlans);
 		/* no need to tell driver */
 		break;
 	case IEEE80211_IF_TYPE_MNTR:
@@ -404,6 +382,10 @@ static int ieee80211_open(struct net_device *dev)
  err_stop:
 	if (!local->open_count && local->ops->stop)
 		local->ops->stop(local_to_hw(local));
+ err_del_bss:
+	sdata->bss = NULL;
+	if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
+		list_del(&sdata->u.vlan.list);
 	return res;
 }
 
@@ -486,7 +468,6 @@ static int ieee80211_stop(struct net_device *dev)
 	switch (sdata->vif.type) {
 	case IEEE80211_IF_TYPE_VLAN:
 		list_del(&sdata->u.vlan.list);
-		sdata->u.vlan.ap = NULL;
 		/* no need to tell driver */
 		break;
 	case IEEE80211_IF_TYPE_MNTR:
@@ -549,6 +530,8 @@ static int ieee80211_stop(struct net_device *dev)
 		local->ops->remove_interface(local_to_hw(local), &conf);
 	}
 
+	sdata->bss = NULL;
+
 	if (local->open_count == 0) {
 		if (netif_running(local->mdev))
 			dev_close(local->mdev);
@@ -1659,7 +1642,7 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 	int result;
 	enum ieee80211_band band;
 	struct net_device *mdev;
-	struct ieee80211_sub_if_data *sdata;
+	struct wireless_dev *mwdev;
 
 	/*
 	 * generic code guarantees at least one band,
@@ -1699,8 +1682,7 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 	hw->ampdu_queues = 0;
 #endif
 
-	/* for now, mdev needs sub_if_data :/ */
-	mdev = alloc_netdev_mq(sizeof(struct ieee80211_sub_if_data),
+	mdev = alloc_netdev_mq(sizeof(struct wireless_dev),
 			       "wmaster%d", ether_setup,
 			       ieee80211_num_queues(hw));
 	if (!mdev)
@@ -1709,13 +1691,13 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 	if (ieee80211_num_queues(hw) > 1)
 		mdev->features |= NETIF_F_MULTI_QUEUE;
 
-	sdata = IEEE80211_DEV_TO_SUB_IF(mdev);
-	mdev->ieee80211_ptr = &sdata->wdev;
-	sdata->wdev.wiphy = local->hw.wiphy;
+	mwdev = netdev_priv(mdev);
+	mdev->ieee80211_ptr = mwdev;
+	mwdev->wiphy = local->hw.wiphy;
 
 	local->mdev = mdev;
 
-	ieee80211_rx_bss_list_init(mdev);
+	ieee80211_rx_bss_list_init(local);
 
 	mdev->hard_start_xmit = ieee80211_master_start_xmit;
 	mdev->open = ieee80211_master_open;
@@ -1724,16 +1706,6 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 	mdev->header_ops = &ieee80211_header_ops;
 	mdev->set_multicast_list = ieee80211_master_set_multicast_list;
 
-	sdata->vif.type = IEEE80211_IF_TYPE_AP;
-	sdata->dev = mdev;
-	sdata->local = local;
-	sdata->u.ap.force_unicast_rateidx = -1;
-	sdata->u.ap.max_ratectrl_rateidx = -1;
-	ieee80211_if_sdata_init(sdata);
-
-	/* no RCU needed since we're still during init phase */
-	list_add_tail(&sdata->list, &local->interfaces);
-
 	name = wiphy_dev(local->hw.wiphy)->driver->name;
 	local->hw.workqueue = create_freezeable_workqueue(name);
 	if (!local->hw.workqueue) {
@@ -1779,9 +1751,6 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 	if (result < 0)
 		goto fail_dev;
 
-	ieee80211_debugfs_add_netdev(IEEE80211_DEV_TO_SUB_IF(local->mdev));
-	ieee80211_if_set_type(local->mdev, IEEE80211_IF_TYPE_AP);
-
 	result = ieee80211_init_rate_ctrl_alg(local,
 					      hw->rate_control_algorithm);
 	if (result < 0) {
@@ -1801,7 +1770,7 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 	ieee80211_install_qdisc(local->mdev);
 
 	/* add one default STA interface */
-	result = ieee80211_if_add(local->mdev, "wlan%d", NULL,
+	result = ieee80211_if_add(local, "wlan%d", NULL,
 				  IEEE80211_IF_TYPE_STA, NULL);
 	if (result)
 		printk(KERN_WARNING "%s: Failed to add default virtual iface\n",
@@ -1817,7 +1786,6 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 fail_wep:
 	rate_control_deinitialize(local);
 fail_rate:
-	ieee80211_debugfs_remove_netdev(IEEE80211_DEV_TO_SUB_IF(local->mdev));
 	unregister_netdevice(local->mdev);
 	local->mdev = NULL;
 fail_dev:
@@ -1827,10 +1795,8 @@ fail_sta_info:
 	debugfs_hw_del(local);
 	destroy_workqueue(local->hw.workqueue);
 fail_workqueue:
-	if (local->mdev != NULL) {
-		ieee80211_if_free(local->mdev);
-		local->mdev = NULL;
-	}
+	if (local->mdev)
+		free_netdev(local->mdev);
 fail_mdev_alloc:
 	wiphy_unregister(local->hw.wiphy);
 	return result;
@@ -1858,24 +1824,19 @@ void ieee80211_unregister_hw(struct ieee80211_hw *hw)
 	 */
 
 	/*
-	 * First, we remove all non-master interfaces. Do this because they
-	 * may have bss pointer dependency on the master, and when we free
-	 * the master these would be freed as well, breaking our list
-	 * iteration completely.
+	 * First, we remove all virtual interfaces.
 	 */
 	list_for_each_entry_safe(sdata, tmp, &local->interfaces, list) {
-		if (sdata->dev == local->mdev)
-			continue;
 		list_del(&sdata->list);
 		__ieee80211_if_del(local, sdata);
 	}
 
 	/* then, finally, remove the master interface */
-	__ieee80211_if_del(local, IEEE80211_DEV_TO_SUB_IF(local->mdev));
+	unregister_netdevice(local->mdev);
 
 	rtnl_unlock();
 
-	ieee80211_rx_bss_list_deinit(local->mdev);
+	ieee80211_rx_bss_list_deinit(local);
 	ieee80211_clear_tx_pending(local);
 	sta_info_stop(local);
 	rate_control_deinitialize(local);
@@ -1892,8 +1853,7 @@ void ieee80211_unregister_hw(struct ieee80211_hw *hw)
 	wiphy_unregister(local->hw.wiphy);
 	ieee80211_wep_free(local);
 	ieee80211_led_exit(local);
-	ieee80211_if_free(local->mdev);
-	local->mdev = NULL;
+	free_netdev(local->mdev);
 }
 EXPORT_SYMBOL(ieee80211_unregister_hw);