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mac80211: add helper for management / no-ack frame rate decision
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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>
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Luis R. Rodriguez authored and John W. Linville committed Jul 24, 2009
1 parent 943ab70 commit 4c6d4f5
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Showing 7 changed files with 59 additions and 60 deletions.
14 changes: 1 addition & 13 deletions drivers/net/wireless/ath/ath9k/rc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1518,23 +1518,11 @@ static void ath_tx_status(void *priv, struct ieee80211_supported_band *sband,
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);
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13 changes: 3 additions & 10 deletions drivers/net/wireless/iwlwifi/iwl-3945-rs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -673,24 +673,17 @@ 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;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);

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;
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7 changes: 1 addition & 6 deletions drivers/net/wireless/iwlwifi/iwl-agn-rs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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_sta, txrc))
return;
}

rate_idx = lq_sta->last_txrate_idx;

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23 changes: 23 additions & 0 deletions include/net/mac80211.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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)
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29 changes: 29 additions & 0 deletions net/mac80211/rate.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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)
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22 changes: 1 addition & 21 deletions net/mac80211/rc80211_minstrel.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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)
{
Expand Down Expand Up @@ -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;
Expand All @@ -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;

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11 changes: 1 addition & 10 deletions net/mac80211/rc80211_pid_algo.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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 =
Expand All @@ -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;

Expand Down

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