On Mon, 2021-04-26 at 12:05 -0700, Aloka Dixit wrote:

+ * @IEEE80211_HW_SUPPORTS_MBSSID_AP: Hardware supports multiple BSSID
+ *	advertisements in AP mode.
+ * @IEEE80211_HW_SUPPORTS_EMA_AP: Hardware supports enhanced multiple BSSID
+ *	advertisements in AP mode.

Is there a good reason for these - the driver can just set the extended
nl80211 flags instead and we can check, or nl80211 already checked?

+static int ieee80211_set_mbssid_options(struct ieee80211_sub_if_data *sdata,
+					struct cfg80211_mbssid_config params)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct wiphy *wiphy = local->hw.wiphy;
+	struct net_device *parent;
+	struct ieee80211_sub_if_data *psdata;
+
+	if (!params.count || sdata->vif.type != NL80211_IFTYPE_AP ||
+	    !ieee80211_hw_check(&local->hw, SUPPORTS_MBSSID_AP))
+		return -EINVAL;
+
+	sdata->vif.mbssid.parent = NULL;
+	sdata->vif.mbssid.flags = IEEE80211_VIF_MBSSID_TX;
+	if (params.parent) {
+		parent = __dev_get_by_index(wiphy_net(wiphy), params.parent);
+		if (!parent || !parent->ieee80211_ptr)
+			return -EINVAL;

Hm wait, didn't I see the same code in cfg80211 - maybe cfg80211 should
just pass the pointer?

 static int ieee80211_del_iface(struct wiphy *wiphy, struct wireless_dev *wdev)
 {
+	struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
+	struct ieee80211_local *local;
+	struct ieee80211_vif *vif;
+
+	if (!sdata)
+		return 0;
+
+	local = sdata->local;
+	vif = &sdata->vif;
+	if (vif->type == NL80211_IFTYPE_AP &&
+	    ieee80211_hw_check(&local->hw, SUPPORTS_MBSSID_AP)) {
+		if (vif->mbssid.flags & IEEE80211_VIF_MBSSID_TX) {
+			struct ieee80211_sub_if_data *child, *tmpsdata;
+
+			wiphy_unlock(local->hw.wiphy);
+			mutex_lock(&local->iflist_mtx);

I really don't think you can drop the locking like that in the middle of
something. That's almost always a recipe for disaster.

Same here.

johannes