Re: [PATCH v2 14/15] mac80211: add helper for management / no-ack frame rate decision

[reinette chatre <reinette.chatre@intel.com>]

Hi Luis,

On Fri, 2009-06-05 at 17:03 -0700, Luis R. Rodriguez wrote:
> 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 |   21 ++-----------------
>  drivers/net/wireless/iwlwifi/iwl-agn-rs.c  |   12 +----------
>  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(+), 73 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath9k/rc.c b/drivers/net/wireless/ath/ath9k/rc.c
> index d8d2152..9199ce9 100644
> diff --git a/drivers/net/wireless/iwlwifi/iwl-3945-rs.c b/drivers/net/wireless/iwlwifi/iwl-3945-rs.c
> index bd2f709..8bd496f 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 = 0;
>  	s8 max_rate_idx = -1;
>  	struct iwl_priv *priv = (struct iwl_priv *)priv_r;
> @@ -681,24 +680,10 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta,
>  
>  	IWL_DEBUG_RATE(priv, "enter\n");
>  
> -	if (sta)
> -		rate_mask = sta->supp_rates[sband->band];
> -
> -	/* 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");
> -		if (!rate_mask)
> -			info->control.rates[0].idx =
> -					rate_lowest_index(sband, NULL);
> -		else
> -			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 ff20e50..7a3e4dd 100644
> --- a/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
> +++ b/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
> @@ -2485,18 +2485,8 @@ static void rs_get_rate(void *priv_r, struct ieee80211_sta *sta, void *priv_sta,
>  		mask_bit = sta->supp_rates[sband->band];
>  
>  	/* 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) {
> -		if (!mask_bit)
> -			info->control.rates[0].idx =
> -					rate_lowest_index(sband, NULL);
> -		else
> -			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;


The iwlwifi way of computing rates is not captured in the new helper. We
used to do it in the way you change it to, but run into the
"rs_get_rate" WARN very often (see
http://www.kerneloops.org/searchweek.php?search=rs_get_rate and
http://www.intellinuxwireless.org/bugzilla/show_bug.cgi?id=1822 ). We
submitted patch "iwlwifi: fix rs_get_rate WARN_ON()" to address that.

Changing this back will make that warning reappear.


Reinette