mac80211: add helper for management / no-ack frame rate decision

All current rate control algorithms agree to send management and no-ack
frames at the lowest rate. They also agree to do this when sta
and the private rate control data is NULL. We add a hlper to mac80211
for this and simplify the rate control algorithm code.

Developers wishing to make enhancements to rate control algorithms
are for broadcast/multicast can opt to not use this in their
gate_rate() mac80211 callback.

Cc: Zhu Yi <yi.zhu@intel.com>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Cc: ipw3945-devel@lists.sourceforge.net
Cc: Gabor Juhos <juhosg@openwrt.org>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Cc: Derek Smithies <derek@indranet.co.nz>
Cc: Chittajit Mitra <Chittajit.Mitra@Atheros.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 5 insertions, 29 deletions

diff --git a/drivers/net/wireless/ath/ath9k/rc.c b/drivers/net/wireless/ath/ath9k/rc.c
index 2c72901..630fcf4 100644
--- a/drivers/net/wireless/ath/ath9k/rc.c
+++ b/drivers/net/wireless/ath/ath9k/rc.c
@@ -1518,23 +1518,11 @@ exit:
 static void ath_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
 			 struct ieee80211_tx_rate_control *txrc)
 {
-	struct ieee80211_supported_band *sband = txrc->sband;
-	struct sk_buff *skb = txrc->skb;
-	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
-	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
 	struct ath_softc *sc = priv;
 	struct ath_rate_priv *ath_rc_priv = priv_sta;
-	__le16 fc = hdr->frame_control;
 
-	/* lowest rate for management and NO_ACK frames */
-	if (!ieee80211_is_data(fc) ||
-	    tx_info->flags & IEEE80211_TX_CTL_NO_ACK || !sta) {
-		tx_info->control.rates[0].idx = rate_lowest_index(sband, sta);
-		tx_info->control.rates[0].count =
-			(tx_info->flags & IEEE80211_TX_CTL_NO_ACK) ?
-				1 : ATH_MGT_TXMAXTRY;
+	if (rate_control_send_low(sta, priv_sta, txrc))
 		return;
-	}
 
 	/* Find tx rate for unicast frames */
 	ath_rc_ratefind(sc, ath_rc_priv, txrc);
diff --git a/drivers/net/wireless/iwlwifi/iwl-3945-rs.c b/drivers/net/wireless/iwlwifi/iwl-3945-rs.c
index 2b77692..a16bd41 100644
--- a/drivers/net/wireless/iwlwifi/iwl-3945-rs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-3945-rs.c
@@ -673,7 +673,6 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
 	s8 scale_action = 0;
 	unsigned long flags;
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
-	__le16 fc;
 	u16 rate_mask = sta ? sta->supp_rates[sband->band] : 0;
 	s8 max_rate_idx = -1;
 	struct iwl_priv *priv = (struct iwl_priv *)priv_r;
@@ -681,16 +680,10 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
 
 	IWL_DEBUG_RATE(priv, "enter\n");
 
-	/* Send management frames and NO_ACK data using lowest rate. */
-	fc = hdr->frame_control;
-	if (!ieee80211_is_data(fc) || info->flags & IEEE80211_TX_CTL_NO_ACK ||
-	    !sta || !priv_sta) {
-		IWL_DEBUG_RATE(priv, "leave: No STA priv data to update!\n");
-		info->control.rates[0].idx = rate_lowest_index(sband, sta);
-		if (info->flags & IEEE80211_TX_CTL_NO_ACK)
-			info->control.rates[0].count = 1;
+	if (rate_control_send_low(sta, priv_sta, txrc))
 		return;
-	}
+
+	rate_mask = sta->supp_rates[sband->band];
 
 	/* get user max rate if set */
 	max_rate_idx = txrc->max_rate_idx;
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-rs.c b/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
index 3fea027..6328041 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
@@ -2481,13 +2481,8 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta, void *priv_sta,
 	}
 
 	/* Send management frames and NO_ACK data using lowest rate. */
-	if (!ieee80211_is_data(hdr->frame_control) ||
-	    info->flags & IEEE80211_TX_CTL_NO_ACK || !sta || !lq_sta) {
-		info->control.rates[0].idx = rate_lowest_index(sband, sta);
-		if (info->flags & IEEE80211_TX_CTL_NO_ACK)
-			info->control.rates[0].count = 1;
+	if (rate_control_send_low(sta, priv_sta, txrc))
 		return;
-	}
 
 	rate_idx  = lq_sta->last_txrate_idx;