mac80211: call rate_control_send_low() internally

There's no rate control algorithm that *doesn't* want to call
it internally, and calling it internally will let us modify
its behaviour in the future.

Signed-off-by: Johannes Berg <[e-mail]>

Documentation/driver-api/80211/mac80211-advanced.rst

···
 .. kernel-doc:: include/net/mac80211.h
    :functions: ieee80211_tx_rate_control
 
-.. kernel-doc:: include/net/mac80211.h
-   :functions: rate_control_send_low
-
 TBD
 
 This part of the book describes mac80211 internals.

drivers/net/wireless/intel/iwlegacy/3945-rs.c

···
 		il_sta = NULL;
 	}
 
-	if (rate_control_send_low(sta, il_sta, txrc))
-		return;
-
 	rate_mask = sta->supp_rates[sband->band];
 
 	/* get user max rate if set */

drivers/net/wireless/intel/iwlegacy/4965-rs.c

···
 		il_sta = NULL;
 	}
 
-	/* Send management frames and NO_ACK data using lowest rate. */
-	if (rate_control_send_low(sta, il_sta, txrc))
-		return;
-
 	if (!lq_sta)
 		return;
 

drivers/net/wireless/intel/iwlwifi/dvm/rs.c

···
 		priv_sta = NULL;
 	}
 
-	/* Send management frames and NO_ACK data using lowest rate. */
-	if (rate_control_send_low(sta, priv_sta, txrc))
-		return;
-
 	rate_idx  = lq_sta->last_txrate_idx;
 
 	if (lq_sta->last_rate_n_flags & RATE_MCS_HT_MSK) {

drivers/net/wireless/intel/iwlwifi/mvm/rs.c

···
 		mvm_sta = NULL;
 	}
 
-	/* Send management frames and NO_ACK data using lowest rate. */
-	if (rate_control_send_low(sta, mvm_sta, txrc))
-		return;
-
 	if (!mvm_sta)
 		return;
 

drivers/net/wireless/realtek/rtlwifi/rc.c

···
 	u8 try_per_rate, i, rix;
 	bool not_data = !ieee80211_is_data(fc);
 
-	if (rate_control_send_low(sta, priv_sta, txrc))
-		return;
-
 	rix = _rtl_rc_get_highest_rix(rtlpriv, sta, skb, not_data);
 	try_per_rate = 1;
 	_rtl_rc_rate_set_series(rtlpriv, sta, &rates[0], txrc,

include/net/mac80211.h

···
 	return (sta == NULL || sta->supp_rates[band] & BIT(index));
 }
 
-/**
- * rate_control_send_low - helper for drivers for management/no-ack frames
- *
- * Rate control algorithms that agree to use the lowest rate to
- * send management frames and NO_ACK data with the respective hw
- * retries should use this in the beginning of their mac80211 get_rate
- * callback. If true is returned the rate control can simply return.
- * If false is returned we guarantee that sta and sta and priv_sta is
- * not null.
- *
- * Rate control algorithms wishing to do more intelligent selection of
- * rate for multicast/broadcast frames may choose to not use this.
- *
- * @sta: &struct ieee80211_sta pointer to the target destination. Note
- * 	that this may be null.
- * @priv_sta: private rate control structure. This may be null.
- * @txrc: rate control information we sholud populate for mac80211.
- */
-bool rate_control_send_low(struct ieee80211_sta *sta,
-			   void *priv_sta,
-			   struct ieee80211_tx_rate_control *txrc);
-
-
 static inline s8
 rate_lowest_index(struct ieee80211_supported_band *sband,
 		  struct ieee80211_sta *sta)

net/mac80211/rate.c

···
 }
 
 
-bool rate_control_send_low(struct ieee80211_sta *pubsta,
-			   void *priv_sta,
-			   struct ieee80211_tx_rate_control *txrc)
+static bool rate_control_send_low(struct ieee80211_sta *pubsta,
+				  struct ieee80211_tx_rate_control *txrc)
 {
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
 	struct ieee80211_supported_band *sband = txrc->sband;
···
 	int mcast_rate;
 	bool use_basicrate = false;
 
-	if (!pubsta || !priv_sta || rc_no_data_or_no_ack_use_min(txrc)) {
+	if (!pubsta || rc_no_data_or_no_ack_use_min(txrc)) {
 		__rate_control_send_low(txrc->hw, sband, pubsta, info,
 					txrc->rate_idx_mask);
 
···
 	}
 	return false;
 }
-EXPORT_SYMBOL(rate_control_send_low);
 
 static bool rate_idx_match_legacy_mask(s8 *rate_idx, int n_bitrates, u32 mask)
 {
···
 	if (ieee80211_hw_check(&sdata->local->hw, HAS_RATE_CONTROL))
 		return;
 
+	if (rate_control_send_low(ista, txrc))
+		return;
+
 	if (ista) {
 		spin_lock_bh(&sta->rate_ctrl_lock);
 		ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);
 		spin_unlock_bh(&sta->rate_ctrl_lock);
 	} else {
-		ref->ops->get_rate(ref->priv, NULL, NULL, txrc);
+		rate_control_send_low(NULL, txrc);
 	}
 
 	if (ieee80211_hw_check(&sdata->local->hw, SUPPORTS_RC_TABLE))

net/mac80211/rc80211_minstrel.c

···
 	int delta;
 	int sampling_ratio;
 
-	/* management/no-ack frames do not use rate control */
-	if (rate_control_send_low(sta, priv_sta, txrc))
-		return;
-
 	/* check multi-rate-retry capabilities & adjust lookaround_rate */
 	mrr_capable = mp->has_mrr &&
 		      !txrc->rts &&

net/mac80211/rc80211_minstrel_ht.c

···
 	struct minstrel_priv *mp = priv;
 	int sample_idx;
 
-	if (rate_control_send_low(sta, priv_sta, txrc))
-		return;
-
 	if (!msp->is_ht)
 		return mac80211_minstrel.get_rate(priv, sta, &msp->legacy, txrc);