mac80211: Send nullfunc frames at lower rate during connection monitor

Recently mac80211 was changed to use nullfunc instead of probe
request for connection monitoring for tx ack status reporting
hardwares. Sometimes in congested network, STA got disconnected
quickly after the association. It was observered that the rate
control was not adopted to environment due to minimal transmission.

As the nullfunc are used for monitoring purpose, these frames should
not be sacrificed for rate control updation. So it is better to send
the monitoring null func frames at minimum rate that could help to
retain the connection.

Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 10 insertions, 3 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index c4e8901c96f6..0e5d8daba1ee 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -348,6 +348,7 @@ void ieee80211_send_nullfunc(struct ieee80211_local *local,
 {
         struct sk_buff *skb;
         struct ieee80211_hdr_3addr *nullfunc;
+        struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
 
         skb = ieee80211_nullfunc_get(&local->hw, &sdata->vif);
         if (!skb)
@@ -358,6 +359,10 @@ void ieee80211_send_nullfunc(struct ieee80211_local *local,
                 nullfunc->frame_control |= cpu_to_le16(IEEE80211_FCTL_PM);
 
         IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
+        if (ifmgd->flags & (IEEE80211_STA_BEACON_POLL |
+                            IEEE80211_STA_CONNECTION_POLL))
+                IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_CTL_USE_MINRATE;
+
         ieee80211_tx_skb(sdata, skb);
 }
 
diff --git a/net/mac80211/rate.c b/net/mac80211/rate.c
index f61244c0e0a2..ff5c3aa48a15 100644
--- a/net/mac80211/rate.c
+++ b/net/mac80211/rate.c
@@ -199,7 +199,7 @@ static void rate_control_release(struct kref *kref)
         kfree(ctrl_ref);
 }
 
-static bool rc_no_data_or_no_ack(struct ieee80211_tx_rate_control *txrc)
+static bool rc_no_data_or_no_ack_use_min(struct ieee80211_tx_rate_control *txrc)
 {
         struct sk_buff *skb = txrc->skb;
         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
@@ -208,7 +208,9 @@ static bool rc_no_data_or_no_ack(struct ieee80211_tx_rate_control *txrc)
 
         fc = hdr->frame_control;
 
-        return (info->flags & IEEE80211_TX_CTL_NO_ACK) || !ieee80211_is_data(fc);
+        return (info->flags & (IEEE80211_TX_CTL_NO_ACK |
+                               IEEE80211_TX_CTL_USE_MINRATE)) ||
+                !ieee80211_is_data(fc);
 }
 
 static void rc_send_low_broadcast(s8 *idx, u32 basic_rates,
@@ -262,7 +264,7 @@ bool rate_control_send_low(struct ieee80211_sta *sta,
         struct ieee80211_supported_band *sband = txrc->sband;
         int mcast_rate;
 
-        if (!sta || !priv_sta || rc_no_data_or_no_ack(txrc)) {
+        if (!sta || !priv_sta || rc_no_data_or_no_ack_use_min(txrc)) {
                 if ((sband->band != IEEE80211_BAND_2GHZ) ||
                     !(info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
                         info->control.rates[0].idx =