cfg80211: force WIPHY_FLAG_CUSTOM_REGULATORY on wiphy_apply_custom_regulatory()

wiphy_apply_custom_regulatory() implies WIPHY_FLAG_CUSTOM_REGULATORY
but we never enforced it, do that now and warn if the driver
didn't set it. All drivers should be following this today already.

Having WIPHY_FLAG_CUSTOM_REGULATORY does not however mean you will
use wiphy_apply_custom_regulatory() though, you may have your own
_orig value set up tools / helpers. The intel drivers are examples
of this type of driver.
Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -2441,7 +2441,9 @@ struct cfg80211_ops {
  * 	has its own custom regulatory domain and cannot identify the
  * 	ISO / IEC 3166 alpha2 it belongs to. When this is enabled
  * 	we will disregard the first regulatory hint (when the
- * 	initiator is %REGDOM_SET_BY_CORE).
+ * 	initiator is %REGDOM_SET_BY_CORE). Drivers that use
+ * 	wiphy_apply_custom_regulatory() should have this flag set
+ * 	or the regulatory core will set it for wiphy.
  * @WIPHY_FLAG_STRICT_REGULATORY: tells us the driver for this device will
  *	ignore regulatory domain settings until it gets its own regulatory
  *	domain via its regulatory_hint() unless the regulatory hint is
@@ -3471,6 +3473,9 @@ int regulatory_hint(struct wiphy *wiphy, const char *alpha2);
  * custom regulatory domain will be trusted completely and as such previous
  * default channel settings will be disregarded. If no rule is found for a
  * channel on the regulatory domain the channel will be disabled.
+ * Drivers using this for a wiphy should also set the wiphy flag
+ * WIPHY_FLAG_CUSTOM_REGULATORY or cfg80211 will set it for the wiphy
+ * that called this helper.
  */
 void wiphy_apply_custom_regulatory(struct wiphy *wiphy,
 				   const struct ieee80211_regdomain *regd);

net/wireless/reg.c

@@ -1292,6 +1292,10 @@ void wiphy_apply_custom_regulatory(struct wiphy *wiphy,
 	enum ieee80211_band band;
 	unsigned int bands_set = 0;
 
+	WARN(!(wiphy->flags & WIPHY_FLAG_CUSTOM_REGULATORY),
+	     "wiphy should have WIPHY_FLAG_CUSTOM_REGULATORY\n");
+	wiphy->flags |= WIPHY_FLAG_CUSTOM_REGULATORY;
+
 	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 		if (!wiphy->bands[band])
 			continue;