On Sun, Apr 14, 2013 at 12:03:44AM +0200, Felix Fietkau wrote:
> Allow rate control modules to pass a rate selection table to mac80211
> and the driver. This allows drivers to fetch the most recent rate
> selection from the sta pointer for already buffered frames. This allows
> rate control to respond faster to sudden link changes and it is also a
> step towards adding minstrel_ht support to drivers like iwlwifi.
>
> When a driver sets IEEE80211_HW_SUPPORTS_RC_TABLE, mac80211 will not
> fill info->control.rates with rates from the rate table (to preserve
> explicit overrides by the rate control module). The driver then
> explicitly calls ieee80211_get_tx_rates to merge overrides from
> info->control.rates with defaults from the sta rate table.
>
> Signed-off-by: Felix Fietkau <nbd@xxxxxxxxxxx>
> ---
> include/net/mac80211.h | 65 ++++++++++
> net/mac80211/rate.c | 317 ++++++++++++++++++++++++++++++++++++++++---------
> net/mac80211/tx.c | 137 ++++++---------------
> 3 files changed, 357 insertions(+), 162 deletions(-)
>
> diff --git a/include/net/mac80211.h b/include/net/mac80211.h
> index 3cef0dd..f39e439 100644
> --- a/include/net/mac80211.h
> +++ b/include/net/mac80211.h
> @@ -561,6 +561,9 @@ enum mac80211_rate_control_flags {
> /* maximum number of rate stages */
> #define IEEE80211_TX_MAX_RATES 4
>
> +/* maximum number of rate table entries */
> +#define IEEE80211_TX_RATE_TABLE_SIZE 4
> +
> /**
> * struct ieee80211_tx_rate - rate selection/status
> *
> @@ -657,6 +660,7 @@ struct ieee80211_tx_info {
> s8 rts_cts_rate_idx;
> u8 use_rts:1;
> u8 use_cts_prot:1;
> + u8 short_preamble:1;
> /* 2 bytes free */
> };
> /* only needed before rate control */
> @@ -678,6 +682,8 @@ struct ieee80211_tx_info {
> struct {
> struct ieee80211_tx_rate driver_rates[
> IEEE80211_TX_MAX_RATES];
> + u8 pad[4];
> +
> void *rate_driver_data[
> IEEE80211_TX_INFO_RATE_DRIVER_DATA_SIZE / sizeof(void *)];
> };
> @@ -1223,6 +1229,24 @@ enum ieee80211_sta_rx_bandwidth {
> };
>
> /**
> + * struct ieee80211_sta_rates - station rate selection table
> + *
> + * @rcu_head: RCU head used for freeing the table on update
> + * @rates: transmit rates/flags to be used by default.
> + * Overriding entries per-packet is possible by using cb tx control.
> + */
> +struct ieee80211_sta_rates {
> + struct rcu_head rcu_head;
> + struct {
> + u8 idx;
> + u8 count;
> + u8 count_cts;
> + u8 count_rts;
> + u16 flags;
> + } rate[IEEE80211_TX_RATE_TABLE_SIZE];
> +};
> +
> +/**
> * struct ieee80211_sta - station table entry
> *
> * A station table entry represents a station we are possibly
> @@ -1249,6 +1273,7 @@ enum ieee80211_sta_rx_bandwidth {
> * notifications and capabilities. The value is only valid after
> * the station moves to associated state.
> * @smps_mode: current SMPS mode (off, static or dynamic)
> + * @tx_rates: rate control selection table
> */
> struct ieee80211_sta {
> u32 supp_rates[IEEE80211_NUM_BANDS];
> @@ -1262,6 +1287,7 @@ struct ieee80211_sta {
> u8 rx_nss;
> enum ieee80211_sta_rx_bandwidth bandwidth;
> enum ieee80211_smps_mode smps_mode;
> + struct ieee80211_sta_rates __rcu *rates;
>
> /* must be last */
> u8 drv_priv[0] __aligned(sizeof(void *));
> @@ -1417,6 +1443,9 @@ struct ieee80211_tx_control {
> * for different virtual interfaces. See the doc section on HW queue
> * control for more details.
> *
> + * @IEEE80211_HW_SUPPORTS_RC_TABLE: The driver supports using a rate
> + * selection table provided by the rate control algorithm.
> + *
> * @IEEE80211_HW_P2P_DEV_ADDR_FOR_INTF: Use the P2P Device address for any
> * P2P Interface. This will be honoured even if more than one interface
> * is supported.
> @@ -1449,6 +1478,7 @@ enum ieee80211_hw_flags {
> IEEE80211_HW_SUPPORTS_PER_STA_GTK = 1<<21,
> IEEE80211_HW_AP_LINK_PS = 1<<22,
> IEEE80211_HW_TX_AMPDU_SETUP_IN_HW = 1<<23,
> + IEEE80211_HW_SUPPORTS_RC_TABLE = 1<<24,
> IEEE80211_HW_P2P_DEV_ADDR_FOR_INTF = 1<<25,
> IEEE80211_HW_TIMING_BEACON_ONLY = 1<<26,
> };
> @@ -3135,6 +3165,25 @@ void ieee80211_sta_set_buffered(struct ieee80211_sta *sta,
> u8 tid, bool buffered);
>
> /**
> + * ieee80211_get_tx_rates - get the selected transmit rates for a packet
> + *
> + * Call this function in a driver with per-packet rate selection support
> + * to combine the rate info in the packet tx info with the most recent
> + * rate selection table for the station entry.
> + *
> + * @vif: &struct ieee80211_vif pointer from the add_interface callback.
> + * @sta: the receiver station to which this packet is sent.
> + * @skb: the frame to be transmitted.
> + * @dest: buffer for extracted rate/retry information
> + * @max_rates: maximum number of rates to fetch
> + */
> +void ieee80211_get_tx_rates(struct ieee80211_vif *vif,
> + struct ieee80211_sta *sta,
> + struct sk_buff *skb,
> + struct ieee80211_tx_rate *dest,
> + int max_rates);
> +
> +/**
> * ieee80211_tx_status - transmit status callback
> *
> * Call this function for all transmitted frames after they have been
> @@ -4210,6 +4259,22 @@ bool rate_usable_index_exists(struct ieee80211_supported_band *sband,
> return false;
> }
>
> +/**
> + * rate_control_set_rates - pass the sta rate selection to mac80211/driver
> + *
> + * When not doing a rate control probe to test rates, rate control should pass
> + * its rate selection to mac80211. If the driver supports receiving a station
> + * rate table, it will use it to ensure that frames are always sent based on
> + * the most recent rate control module decision.
> + *
> + * @hw: pointer as obtained from ieee80211_alloc_hw()
> + * @sta: &struct ieee80211_sta pointer to the target destination.
@pubsta:
> + * @rates: new tx rate set to be used for this station.
> + */
> +int rate_control_set_rates(struct ieee80211_hw *hw,
> + struct ieee80211_sta *pubsta,
> + struct ieee80211_sta_rates *rates);
> +
> int ieee80211_rate_control_register(struct rate_control_ops *ops);
> void ieee80211_rate_control_unregister(struct rate_control_ops *ops);
>
> diff --git a/net/mac80211/rate.c b/net/mac80211/rate.c
> index 5d545dd..d774751 100644
> --- a/net/mac80211/rate.c
> +++ b/net/mac80211/rate.c
> @@ -252,6 +252,23 @@ rate_lowest_non_cck_index(struct ieee80211_supported_band *sband,
> return 0;
> }
>
> +static void __rate_control_send_low(struct ieee80211_hw *hw,
> + struct ieee80211_supported_band *sband,
> + struct ieee80211_sta *sta,
> + struct ieee80211_tx_info *info)
> +{
> + if ((sband->band != IEEE80211_BAND_2GHZ) ||
> + !(info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
> + info->control.rates[0].idx = rate_lowest_index(sband, sta);
> + else
> + info->control.rates[0].idx =
> + rate_lowest_non_cck_index(sband, sta);
> +
> + info->control.rates[0].count =
> + (info->flags & IEEE80211_TX_CTL_NO_ACK) ?
> + 1 : hw->max_rate_tries;
> +}
> +
>
> bool rate_control_send_low(struct ieee80211_sta *sta,
> void *priv_sta,
> @@ -262,16 +279,8 @@ bool rate_control_send_low(struct ieee80211_sta *sta,
> int mcast_rate;
>
> if (!sta || !priv_sta || rc_no_data_or_no_ack_use_min(txrc)) {
> - if ((sband->band != IEEE80211_BAND_2GHZ) ||
> - !(info->flags & IEEE80211_TX_CTL_NO_CCK_RATE))
> - info->control.rates[0].idx =
> - rate_lowest_index(txrc->sband, sta);
> - else
> - info->control.rates[0].idx =
> - rate_lowest_non_cck_index(txrc->sband, sta);
> - info->control.rates[0].count =
> - (info->flags & IEEE80211_TX_CTL_NO_ACK) ?
> - 1 : txrc->hw->max_rate_tries;
> + __rate_control_send_low(txrc->hw, sband, sta, info);
> +
> if (!sta && txrc->bss) {
> mcast_rate = txrc->bss_conf->mcast_rate[sband->band];
> if (mcast_rate > 0) {
> @@ -355,7 +364,8 @@ static bool rate_idx_match_mcs_mask(struct ieee80211_tx_rate *rate,
>
>
> static void rate_idx_match_mask(struct ieee80211_tx_rate *rate,
> - struct ieee80211_tx_rate_control *txrc,
> + struct ieee80211_supported_band *sband,
> + enum nl80211_chan_width chan_width,
> u32 mask,
> u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN])
> {
> @@ -375,27 +385,17 @@ static void rate_idx_match_mask(struct ieee80211_tx_rate *rate,
> IEEE80211_TX_RC_USE_SHORT_PREAMBLE);
> alt_rate.count = rate->count;
> if (rate_idx_match_legacy_mask(&alt_rate,
> - txrc->sband->n_bitrates,
> - mask)) {
> + sband->n_bitrates, mask)) {
> *rate = alt_rate;
> return;
> }
> } else {
> - struct sk_buff *skb = txrc->skb;
> - struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
> - __le16 fc;
> -
> /* handle legacy rates */
> - if (rate_idx_match_legacy_mask(rate, txrc->sband->n_bitrates,
> - mask))
> + if (rate_idx_match_legacy_mask(rate, sband->n_bitrates, mask))
> return;
>
> /* if HT BSS, and we handle a data frame, also try HT rates */
> - if (txrc->bss_conf->chandef.width == NL80211_CHAN_WIDTH_20_NOHT)
> - return;
> -
> - fc = hdr->frame_control;
> - if (!ieee80211_is_data(fc))
> + if (chan_width == NL80211_CHAN_WIDTH_20_NOHT)
> return;
>
> alt_rate.idx = 0;
> @@ -408,7 +408,7 @@ static void rate_idx_match_mask(struct ieee80211_tx_rate *rate,
>
> alt_rate.flags |= IEEE80211_TX_RC_MCS;
>
> - if (txrc->bss_conf->chandef.width == NL80211_CHAN_WIDTH_40)
> + if (chan_width == NL80211_CHAN_WIDTH_40)
> alt_rate.flags |= IEEE80211_TX_RC_40_MHZ_WIDTH;
>
> if (rate_idx_match_mcs_mask(&alt_rate, mcs_mask)) {
> @@ -426,6 +426,220 @@ static void rate_idx_match_mask(struct ieee80211_tx_rate *rate,
> */
> }
>
> +static void rate_fixup_ratelist(struct ieee80211_vif *vif,
> + struct ieee80211_supported_band *sband,
> + struct ieee80211_tx_info *info,
> + struct ieee80211_tx_rate *rates,
> + int max_rates)
> +{
> + struct ieee80211_rate *rate;
> + bool inval = false;
> + int i;
> +
> + /*
> + * set up the RTS/CTS rate as the fastest basic rate
> + * that is not faster than the data rate
> + *
> + * XXX: Should this check all retry rates?
> + */
> + if (!(rates[0].flags & IEEE80211_TX_RC_MCS)) {
> + s8 baserate = 0;
> +
> + rate = &sband->bitrates[rates[0].idx];
> +
> + for (i = 0; i < sband->n_bitrates; i++) {
> + /* must be a basic rate */
> + if (!(vif->bss_conf.basic_rates & BIT(i)))
> + continue;
> + /* must not be faster than the data rate */
> + if (sband->bitrates[i].bitrate > rate->bitrate)
> + continue;
> + /* maximum */
> + if (sband->bitrates[baserate].bitrate <
> + sband->bitrates[i].bitrate)
> + baserate = i;
> + }
> +
> + info->control.rts_cts_rate_idx = baserate;
> + }
> +
> + for (i = 0; i < max_rates; i++) {
> + /*
> + * make sure there's no valid rate following
> + * an invalid one, just in case drivers don't
> + * take the API seriously to stop at -1.
> + */
> + if (inval) {
> + rates[i].idx = -1;
> + continue;
> + }
> + if (rates[i].idx < 0) {
> + inval = true;
> + continue;
> + }
> +
> + /*
> + * For now assume MCS is already set up correctly, this
> + * needs to be fixed.
> + */
> + if (rates[i].flags & IEEE80211_TX_RC_MCS) {
> + WARN_ON(rates[i].idx > 76);
> +
> + if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
> + info->control.use_cts_prot)
> + rates[i].flags |=
> + IEEE80211_TX_RC_USE_CTS_PROTECT;
> + continue;
> + }
> +
> + /* set up RTS protection if desired */
> + if (info->control.use_rts) {
> + rates[i].flags |= IEEE80211_TX_RC_USE_RTS_CTS;
> + info->control.use_cts_prot = false;
> + }
> +
> + /* RC is busted */
> + if (WARN_ON_ONCE(rates[i].idx >= sband->n_bitrates)) {
> + rates[i].idx = -1;
> + continue;
> + }
> +
> + rate = &sband->bitrates[rates[i].idx];
> +
> + /* set up short preamble */
> + if (info->control.short_preamble &&
> + rate->flags & IEEE80211_RATE_SHORT_PREAMBLE)
> + rates[i].flags |= IEEE80211_TX_RC_USE_SHORT_PREAMBLE;
> +
> + /* set up G protection */
> + if (!(rates[i].flags & IEEE80211_TX_RC_USE_RTS_CTS) &&
> + info->control.use_cts_prot &&
> + rate->flags & IEEE80211_RATE_ERP_G)
> + rates[i].flags |= IEEE80211_TX_RC_USE_CTS_PROTECT;
> + }
> +}
> +
> +
> +static void rate_control_fill_sta_table(struct ieee80211_sta *sta,
> + struct ieee80211_tx_info *info,
> + struct ieee80211_tx_rate *rates,
> + int max_rates)
> +{
> + struct ieee80211_sta_rates *ratetbl = NULL;
> + int i;
> +
> + if (sta)
> + ratetbl = rcu_dereference(sta->rates);
> +
> + /* Fill remaining rate slots with data from the sta rate table. */
> + max_rates = min_t(int, max_rates, IEEE80211_TX_RATE_TABLE_SIZE);
> + for (i = 0; i < max_rates; i++) {
> + if (i < ARRAY_SIZE(info->control.rates) &&
> + info->control.rates[i].idx >= 0 &&
> + info->control.rates[i].count) {
> + if (rates != info->control.rates)
> + rates[i] = info->control.rates[i];
> + } else if (ratetbl) {
> + rates[i].idx = ratetbl->rate[i].idx;
> + rates[i].flags = ratetbl->rate[i].flags;
> + if (info->control.use_rts)
> + rates[i].count = ratetbl->rate[i].count_rts;
> + else if (info->control.use_cts_prot)
> + rates[i].count = ratetbl->rate[i].count_cts;
> + else
> + rates[i].count = ratetbl->rate[i].count;
> + } else {
> + rates[i].idx = -1;
> + rates[i].count = 0;
> + }
> +
> + if (rates[i].idx < 0 || !rates[i].count)
> + break;
> + }
> +}
> +
> +static void rate_control_apply_mask(struct ieee80211_sub_if_data *sdata,
> + struct ieee80211_sta *sta,
> + struct ieee80211_supported_band *sband,
> + struct ieee80211_tx_info *info,
> + struct ieee80211_tx_rate *rates,
> + int max_rates)
> +{
> + enum nl80211_chan_width chan_width;
> + u8 mcs_mask[IEEE80211_HT_MCS_MASK_LEN];
> + bool has_mcs_mask;
> + u32 mask;
> + int i;
> +
> + /*
> + * 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.
> + */
> + mask = sdata->rc_rateidx_mask[info->band];
> + has_mcs_mask = sdata->rc_has_mcs_mask[info->band];
> + if (mask == (1 << sband->n_bitrates) - 1 && !has_mcs_mask)
> + return;
> +
> + if (has_mcs_mask)
> + memcpy(mcs_mask, sdata->rc_rateidx_mcs_mask[info->band],
> + sizeof(mcs_mask));
> + else
> + memset(mcs_mask, 0xff, sizeof(mcs_mask));
> +
> + if (sta) {
> + /* Filter out rates that the STA does not support */
> + mask &= sta->supp_rates[info->band];
> + for (i = 0; i < sizeof(mcs_mask); i++)
> + mcs_mask[i] &= sta->ht_cap.mcs.rx_mask[i];
> + }
> +
> + /*
> + * Make sure the rate index selected for each TX rate is
> + * included in the configured mask and change the rate indexes
> + * if needed.
> + */
> + chan_width = sdata->vif.bss_conf.chandef.width;
> + for (i = 0; i < max_rates; i++) {
> + /* Skip invalid rates */
> + if (rates[i].idx < 0)
> + break;
> +
> + rate_idx_match_mask(&rates[i], sband, mask, chan_width,
> + mcs_mask);
> + }
> +}
> +
> +void ieee80211_get_tx_rates(struct ieee80211_vif *vif,
> + struct ieee80211_sta *sta,
> + struct sk_buff *skb,
> + struct ieee80211_tx_rate *dest,
> + int max_rates)
> +{
> + struct ieee80211_sub_if_data *sdata;
> + struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
> + struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
> + struct ieee80211_supported_band *sband;
> +
> + rate_control_fill_sta_table(sta, info, dest, max_rates);
> +
> + if (!vif)
> + return;
> +
> + sdata = vif_to_sdata(vif);
> + sband = sdata->local->hw.wiphy->bands[info->band];
> +
> + if (ieee80211_is_data(hdr->frame_control))
> + rate_control_apply_mask(sdata, sta, sband, info, dest, max_rates);
> +
> + if(dest[0].idx < 0)
space
I gave it a try, I hope you won't mind the feedback for the typos.
It does not compile:
error: ‘struct ieee80211_tx_data’ has no member named ‘rate’
it likely misses the diff for ieee80211_i.h, however that's what I did
to quickly run without IEEE80211_HW_SUPPORTS_RC_TABLE so far.
Karl
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