Now I'm confused, and I probably confused you as well ...

-u32 ieee80211_mandatory_rates(struct ieee80211_local *local,
+u32 ieee80211_mandatory_rates(struct ieee80211_sub_if_data *sdata,
 			      enum ieee80211_band band)
 {
+	struct ieee80211_local *local = sdata->local;
 	struct ieee80211_supported_band *sband;
 	struct ieee80211_rate *bitrates;
 	u32 mandatory_rates;

Shouldn't we just remove the sdata/local argument? We don't need it
after all, except for the fallback case that never happens (so we can do
something like "return 1" after the warning)?

johannes