mac80211: disallow fixing bitrates with hw rate control

When hw rate control is used, these parameters have
no meaning because the hardware cannot get at them
right now, so disallow setting them. Also clean up
the function a bit.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/cfg.c

@@ -1399,15 +1399,25 @@ static int ieee80211_set_bitrate_mask(struct wiphy *wiphy,
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
-	int i, err = -EINVAL;
+	int i;
 	u32 target_rate;
 	struct ieee80211_supported_band *sband;
 
+	/*
+	 * This _could_ be supported by providing a hook for
+	 * drivers for this function, but at this point it
+	 * doesn't seem worth bothering.
+	 */
+	if (local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL)
+		return -EOPNOTSUPP;
+
 	sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 
-	/* target_rate = -1, rate->fixed = 0 means auto only, so use all rates
+	/*
+	 * target_rate = -1, rate->fixed = 0 means auto only, so use all rates
 	 * target_rate = X, rate->fixed = 1 means only rate X
-	 * target_rate = X, rate->fixed = 0 means all rates <= X */
+	 * target_rate = X, rate->fixed = 0 means all rates <= X
+	 */
 	sdata->max_ratectrl_rateidx = -1;
 	sdata->force_unicast_rateidx = -1;
 
@@ -1418,20 +1428,18 @@ static int ieee80211_set_bitrate_mask(struct wiphy *wiphy,
 	else
 		return 0;
 
-	for (i=0; i< sband->n_bitrates; i++) {
-		struct ieee80211_rate *brate = &sband->bitrates[i];
-		int this_rate = brate->bitrate;
+	for (i = 0; i< sband->n_bitrates; i++) {
+		if (target_rate != sband->bitrates[i].bitrate)
+			continue;
 
-		if (target_rate == this_rate) {
-			sdata->max_ratectrl_rateidx = i;
-			if (mask->fixed)
-				sdata->force_unicast_rateidx = i;
-			err = 0;
-			break;
-		}
+		/* requested bitrate found */
+		sdata->max_ratectrl_rateidx = i;
+		if (mask->fixed)
+			sdata->force_unicast_rateidx = i;
+		return 0;
 	}
 
-	return err;
+	return -EINVAL;
 }
 
 struct cfg80211_ops mac80211_config_ops = {