cfg80211: introduce sync regdom set API for self-managed

A self-managed device will sometimes need to set its regdomain synchronously.
Notably it should be set before usermode has a chance to query it. Expose
a new API to accomplish this which requires the RTNL.
Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Reviewed-by: Ilan Peer <ilan.peer@intel.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -3788,6 +3788,20 @@ int regulatory_hint(struct wiphy *wiphy, const char *alpha2);
 int regulatory_set_wiphy_regd(struct wiphy *wiphy,
 			      struct ieee80211_regdomain *rd);
 
+/**
+ * regulatory_set_wiphy_regd_sync_rtnl - set regdom for self-managed drivers
+ * @wiphy: the wireless device we want to process the regulatory domain on
+ * @rd: the regulatory domain information to use for this wiphy
+ *
+ * This functions requires the RTNL to be held and applies the new regdomain
+ * synchronously to this wiphy. For more details see
+ * regulatory_set_wiphy_regd().
+ *
+ * Return: 0 on success. -EINVAL, -EPERM
+ */
+int regulatory_set_wiphy_regd_sync_rtnl(struct wiphy *wiphy,
+					struct ieee80211_regdomain *rd);
+
 /**
  * wiphy_apply_custom_regulatory - apply a custom driver regulatory domain
  * @wiphy: the wireless device we want to process the regulatory domain on

net/wireless/reg.c

@@ -2897,8 +2897,8 @@ int set_regdom(const struct ieee80211_regdomain *rd)
 	return 0;
 }
 
-int regulatory_set_wiphy_regd(struct wiphy *wiphy,
-			      struct ieee80211_regdomain *rd)
+static int __regulatory_set_wiphy_regd(struct wiphy *wiphy,
+				       struct ieee80211_regdomain *rd)
 {
 	const struct ieee80211_regdomain *regd;
 	const struct ieee80211_regdomain *prev_regd;
@@ -2928,12 +2928,39 @@ int regulatory_set_wiphy_regd(struct wiphy *wiphy,
 	spin_unlock(&reg_requests_lock);
 
 	kfree(prev_regd);
+	return 0;
+}
+
+int regulatory_set_wiphy_regd(struct wiphy *wiphy,
+			      struct ieee80211_regdomain *rd)
+{
+	int ret = __regulatory_set_wiphy_regd(wiphy, rd);
+
+	if (ret)
+		return ret;
 
 	schedule_work(&reg_work);
 	return 0;
 }
 EXPORT_SYMBOL(regulatory_set_wiphy_regd);
 
+int regulatory_set_wiphy_regd_sync_rtnl(struct wiphy *wiphy,
+					struct ieee80211_regdomain *rd)
+{
+	int ret;
+
+	ASSERT_RTNL();
+
+	ret = __regulatory_set_wiphy_regd(wiphy, rd);
+	if (ret)
+		return ret;
+
+	/* process the request immediately */
+	reg_process_self_managed_hints();
+	return 0;
+}
+EXPORT_SYMBOL(regulatory_set_wiphy_regd_sync_rtnl);
+
 void wiphy_regulatory_register(struct wiphy *wiphy)
 {
 	struct regulatory_request *lr;