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>

1 files changed, 23 insertions, 0 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index d98fac5..a861259 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2094,6 +2094,29 @@ static inline int rate_supported(struct ieee80211_sta *sta,
 	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)