cfg80211/mac80211: Use more generic bitrate mask for rate control

Extend struct cfg80211_bitrate_mask to actually use a bitfield mask
instead of just a single fixed or maximum rate index. This change
itself does not modify the behavior (except for debugfs files), but it
prepares cfg80211 and mac80211 for a new nl80211 command for setting
which rates can be used in TX rate control.

Since frames are now going through the rate control algorithm
unconditionally, the internal IEEE80211_TX_INTFL_RCALGO flag can now
be removed. The RC implementations can use the rate_idx_mask value to
optimize their behavior if only a single rate is enabled.

The old max_rate_idx in struct ieee80211_tx_rate_control is maintained
(but commented as deprecated) for backwards compatibility with existing
RC implementations. Once these implementations have been updated to
use the more generic rate_idx_mask, the max_rate_idx value can be
removed.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 4961168f5091..d3a44812f8bf 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -519,7 +519,11 @@ ieee80211_tx_h_rate_ctrl(struct ieee80211_tx_data *tx)
         txrc.bss_conf = &tx->sdata->vif.bss_conf;
         txrc.skb = tx->skb;
         txrc.reported_rate.idx = -1;
-        txrc.max_rate_idx = tx->sdata->max_ratectrl_rateidx;
+        txrc.rate_idx_mask = tx->sdata->rc_rateidx_mask[tx->channel->band];
+        if (txrc.rate_idx_mask == (1 << sband->n_bitrates) - 1)
+                txrc.max_rate_idx = -1;
+        else
+                txrc.max_rate_idx = fls(txrc.rate_idx_mask) - 1;
         txrc.ap = tx->sdata->vif.type == NL80211_IFTYPE_AP;
 
         /* set up RTS protection if desired */
@@ -2178,7 +2182,11 @@ struct sk_buff *ieee80211_beacon_get_tim(struct ieee80211_hw *hw,
         txrc.bss_conf = &sdata->vif.bss_conf;
         txrc.skb = skb;
         txrc.reported_rate.idx = -1;
-        txrc.max_rate_idx = sdata->max_ratectrl_rateidx;
+        txrc.rate_idx_mask = sdata->rc_rateidx_mask[band];
+        if (txrc.rate_idx_mask == (1 << sband->n_bitrates) - 1)
+                txrc.max_rate_idx = -1;
+        else
+                txrc.max_rate_idx = fls(txrc.rate_idx_mask) - 1;
         txrc.ap = true;
         rate_control_get_rate(sdata, NULL, &txrc);