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>
diff --git a/net/mac80211/rate.c b/net/mac80211/rate.c
index 6349e7f..c74b7c8 100644
--- a/net/mac80211/rate.c
+++ b/net/mac80211/rate.c
@@ -249,6 +249,38 @@
}
EXPORT_SYMBOL(rate_control_send_low);
+static void rate_idx_match_mask(struct ieee80211_tx_rate *rate,
+ int n_bitrates, u32 mask)
+{
+ int j;
+
+ /* See whether the selected rate or anything below it is allowed. */
+ for (j = rate->idx; j >= 0; j--) {
+ if (mask & (1 << j)) {
+ /* Okay, found a suitable rate. Use it. */
+ rate->idx = j;
+ return;
+ }
+ }
+
+ /* Try to find a higher rate that would be allowed */
+ for (j = rate->idx + 1; j < n_bitrates; j++) {
+ if (mask & (1 << j)) {
+ /* Okay, found a suitable rate. Use it. */
+ rate->idx = j;
+ return;
+ }
+ }
+
+ /*
+ * Uh.. No suitable rate exists. This should not really happen with
+ * sane TX rate mask configurations. However, should someone manage to
+ * configure supported rates and TX rate mask in incompatible way,
+ * allow the frame to be transmitted with whatever the rate control
+ * selected.
+ */
+}
+
void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
struct sta_info *sta,
struct ieee80211_tx_rate_control *txrc)
@@ -258,6 +290,7 @@
struct ieee80211_sta *ista = NULL;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
int i;
+ u32 mask;
if (sta) {
ista = &sta->sta;
@@ -270,23 +303,31 @@
info->control.rates[i].count = 1;
}
- if (sta && sdata->force_unicast_rateidx > -1) {
- info->control.rates[0].idx = sdata->force_unicast_rateidx;
- } else {
- ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);
- info->flags |= IEEE80211_TX_INTFL_RCALGO;
- }
+ ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);
/*
- * try to enforce the maximum rate the user wanted
+ * Try to enforce the rateidx mask the user wanted. skip this if the
+ * default mask (allow all rates) is used to save some processing for
+ * the common case.
*/
- if (sdata->max_ratectrl_rateidx > -1)
+ mask = sdata->rc_rateidx_mask[info->band];
+ if (mask != (1 << txrc->sband->n_bitrates) - 1) {
+ if (sta) {
+ /* Filter out rates that the STA does not support */
+ mask &= sta->sta.supp_rates[info->band];
+ }
+ /*
+ * Make sure the rate index selected for each TX rate is
+ * included in the configured mask and change the rate indexes
+ * if needed.
+ */
for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
+ /* Rate masking supports only legacy rates for now */
if (info->control.rates[i].flags & IEEE80211_TX_RC_MCS)
continue;
- info->control.rates[i].idx =
- min_t(s8, info->control.rates[i].idx,
- sdata->max_ratectrl_rateidx);
+ rate_idx_match_mask(&info->control.rates[i],
+ txrc->sband->n_bitrates, mask);
+ }
}
BUG_ON(info->control.rates[0].idx < 0);