[PATCH 16/21] mac80211: add helper for management / no-ack frame rate decision

Luis R. Rodriguez
2009-07-15T00:14:29Z

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>
Cc: Reinette Chatre <reinette.chatre@intel.com>
Cc: ipw3945-devel@lists.sourceforge.net
Cc: Gabor Juhos <juhosg@openwrt.org>
Cc: 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>
---
drivers/net/wireless/ath/ath9k/rc.c | 14 +------------
drivers/net/wireless/iwlwifi/iwl-3945-rs.c | 13 ++---------
drivers/net/wireless/iwlwifi/iwl-agn-rs.c | 7 +-----
include/net/mac80211.h | 23 ++++++++++++++++++++++
net/mac80211/rate.c | 29 ++++++++++++++++++++++++++++
net/mac80211/rc80211_minstrel.c | 22 +--------------------
net/mac80211/rc80211_pid_algo.c | 11 +---------
7 files changed, 59 insertions(+), 60 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..695a841 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_r, txrc))
return;
- }

rate_idx = lq_sta->last_txrate_idx;

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 9428258..7dd67a1 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2097,6 +2097,29 @@ 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)
diff --git a/net/mac80211/rate.c b/net/mac80211/rate.c
index ac5c8e9..b33efc4 100644
--- a/net/mac80211/rate.c
+++ b/net/mac80211/rate.c
@@ -198,6 +198,35 @@ static void rate_control_release(struct kref *kref)
kfree(ctrl_ref);
}

+static bool rc_no_data_or_no_ack(struct ieee80211_tx_rate_control *txrc)
+{
+ struct sk_buff *skb = txrc->skb;
+ struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+ struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+ __le16 fc;
+
+ fc = hdr->frame_control;
+
+ return ((info->flags & IEEE80211_TX_CTL_NO_ACK) || !ieee80211_is_data(fc));
+}
+
+bool rate_control_send_low(struct ieee80211_sta *sta,
+ void *priv_sta,
+ struct ieee80211_tx_rate_control *txrc)
+{
+ struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
+
+ if (!sta || !priv_sta || rc_no_data_or_no_ack(txrc)) {
+ info->control.rates[0].idx = rate_lowest_index(txrc->sband, sta);
+ info->control.rates[0].count =
+ (info->flags & IEEE80211_TX_CTL_NO_ACK) ?
+ 1 : txrc->hw->max_rate_tries;
+ return true;
+ }
+ return false;
+}
+EXPORT_SYMBOL(rate_control_send_low);
+
void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
struct sta_info *sta,
struct ieee80211_tx_rate_control *txrc)
diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c
index 5bdce0c..7c51429 100644
--- a/net/mac80211/rc80211_minstrel.c
+++ b/net/mac80211/rc80211_minstrel.c
@@ -70,19 +70,6 @@ rix_to_ndx(struct minstrel_sta_info *mi, int rix)
return i;
}

-static inline bool
-use_low_rate(struct sk_buff *skb)
-{
- struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
- struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
- __le16 fc;
-
- fc = hdr->frame_control;
-
- return ((info->flags & IEEE80211_TX_CTL_NO_ACK) || !ieee80211_is_data(fc));
-}
-
-
static void
minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
{
@@ -231,7 +218,6 @@ minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
void *priv_sta, struct ieee80211_tx_rate_control *txrc)
{
struct sk_buff *skb = txrc->skb;
- struct ieee80211_supported_band *sband = txrc->sband;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
struct minstrel_sta_info *mi = priv_sta;
struct minstrel_priv *mp = priv;
@@ -244,14 +230,8 @@ minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
int mrr_ndx[3];
int sample_rate;

- if (!sta || !mi || use_low_rate(skb)) {
- ar[0].idx = rate_lowest_index(sband, sta);
- if (info->flags & IEEE80211_TX_CTL_NO_ACK)
- ar[0].count = 1;
- else
- ar[0].count = mp->max_retry;
+ if (rate_control_send_low(sta, priv_sta, txrc))
return;
- }

mrr = mp->has_mrr && !txrc->rts && !txrc->bss_conf->use_cts_prot;

diff --git a/net/mac80211/rc80211_pid_algo.c b/net/mac80211/rc80211_pid_algo.c
index 5496077..8c053be 100644
--- a/net/mac80211/rc80211_pid_algo.c
+++ b/net/mac80211/rc80211_pid_algo.c
@@ -276,11 +276,9 @@ rate_control_pid_get_rate(void *priv, struct ieee80211_sta *sta,
{
struct sk_buff *skb = txrc->skb;
struct ieee80211_supported_band *sband = txrc->sband;
- struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
struct rc_pid_sta_info *spinfo = priv_sta;
int rateidx;
- __le16 fc;

if (txrc->rts)
info->control.rates[0].count =
@@ -290,15 +288,8 @@ rate_control_pid_get_rate(void *priv, struct ieee80211_sta *sta,
txrc->hw->conf.short_frame_max_tx_count;

/* Send management frames and NO_ACK data using lowest rate. */
- fc = hdr->frame_control;
- if (!sta || !spinfo || !ieee80211_is_data(fc) ||
- info->flags & IEEE80211_TX_CTL_NO_ACK) {
- 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;
- }

rateidx = spinfo->txrate_idx;

--
1.6.0.6