mac80211: fix minstrel_ht sampling intervals (patch by Daniel Halperin)

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@25964 3c298f89-4303-0410-b956-a3cf2f4a3e73

package/mac80211/patches/560-mac80211_minstrel_ht_sampling_fix.patch

@@ -0,0 +1,50 @@
+--- a/net/mac80211/rc80211_minstrel_ht.c
++++ b/net/mac80211/rc80211_minstrel_ht.c
+@@ -415,10 +415,8 @@ minstrel_ht_tx_status(void *priv, struct
+ 		mi->sample_count--;
+ 	}
+ 
+-	if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE) {
++	if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
+ 		mi->sample_packets += info->status.ampdu_len;
+-		minstrel_next_sample_idx(mi);
+-	}
+ 
+ 	for (i = 0; !last; i++) {
+ 		last = (i == IEEE80211_TX_MAX_RATES - 1) ||
+@@ -553,13 +551,14 @@ minstrel_get_sample_rate(struct minstrel
+ 	sample_idx = sample_table[mg->column][mg->index];
+ 	mr = &mg->rates[sample_idx];
+ 	sample_idx += mi->sample_group * MCS_GROUP_RATES;
++	minstrel_next_sample_idx(mi);
+ 
+ 	/*
+ 	 * When not using MRR, do not sample if the probability is already
+ 	 * higher than 95% to avoid wasting airtime
+ 	 */
+ 	if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100)))
+-		goto next;
++		return -1;
+ 
+ 	/*
+ 	 * Make sure that lower rates get sampled only occasionally,
+@@ -568,17 +567,13 @@ minstrel_get_sample_rate(struct minstrel
+ 	if (minstrel_get_duration(sample_idx) >
+ 	    minstrel_get_duration(mi->max_tp_rate)) {
+ 		if (mr->sample_skipped < 20)
+-			goto next;
++			return -1;
+ 
+ 		if (mi->sample_slow++ > 2)
+-			goto next;
++			return -1;
+ 	}
+ 
+ 	return sample_idx;
+-
+-next:
+-	minstrel_next_sample_idx(mi);
+-	return -1;
+ }
+ 
+ static void