Re: [PATCH] mac80211: Make some mlme timers module paramaters.

[Johannes Berg <johannes@sipsolutions.net>]

On Fri, 2011-02-04 at 15:30 -0800, greearb@candelatech.com wrote:
> From: Ben Greear <greearb@candelatech.com>
> 
> This allows users to tune the connection-loss algorithms
> to be more or less lenient.  In particular, larger
> null-func retries helps when using lots of virtual
> stations on a loaded network.

I see this has been merged, but I really think it should be reverted. It
doesn't really fix anything, and it makes the behaviour less
predictable. Also, even on a loaded network the nullfunc frames should
be transmitted quickly as they go out on VO. I'm thinking the fact that
it doesn't will also affect other things -- like the bufferbloat
discussion -- and fixing the problem would be a much better idea.

johannes

> Signed-off-by: Ben Greear <greearb@candelatech.com>
> ---
> :100644 100644 e059b3a... f77adf1... M	net/mac80211/mlme.c
>  net/mac80211/mlme.c |   34 +++++++++++++++++++++++-----------
>  1 files changed, 23 insertions(+), 11 deletions(-)
> 
> diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
> index e059b3a..f77adf1 100644
> --- a/net/mac80211/mlme.c
> +++ b/net/mac80211/mlme.c
> @@ -28,8 +28,15 @@
>  #include "rate.h"
>  #include "led.h"
>  
> -#define IEEE80211_MAX_NULLFUNC_TRIES 2
> -#define IEEE80211_MAX_PROBE_TRIES 5
> +static int max_nullfunc_tries = 2;
> +module_param(max_nullfunc_tries, int, 0644);
> +MODULE_PARM_DESC(max_nullfunc_tries,
> +		 "Maximum nullfunc tx tries before disconnecting (reason 4).");
> +
> +static int max_probe_tries = 5;
> +module_param(max_probe_tries, int, 0644);
> +MODULE_PARM_DESC(max_probe_tries,
> +		 "Maximum probe tries before disconnecting (reason 4).");
>  
>  /*
>   * Beacon loss timeout is calculated as N frames times the
> @@ -51,7 +58,11 @@
>   * a probe request because of beacon loss or for
>   * checking the connection still works.
>   */
> -#define IEEE80211_PROBE_WAIT		(HZ / 2)
> +static int probe_wait_ms = 500;
> +module_param(probe_wait_ms, int, 0644);
> +MODULE_PARM_DESC(probe_wait_ms,
> +		 "Maximum time(ms) to wait for probe response"
> +		 " before disconnecting (reason 4).");
>  
>  /*
>   * Weight given to the latest Beacon frame when calculating average signal
> @@ -1116,7 +1127,7 @@ static void ieee80211_mgd_probe_ap_send(struct ieee80211_sub_if_data *sdata)
>  	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
>  	const u8 *ssid;
>  	u8 *dst = ifmgd->associated->bssid;
> -	u8 unicast_limit = max(1, IEEE80211_MAX_PROBE_TRIES - 3);
> +	u8 unicast_limit = max(1, max_probe_tries - 3);
>  
>  	/*
>  	 * Try sending broadcast probe requests for the last three
> @@ -1142,7 +1153,7 @@ static void ieee80211_mgd_probe_ap_send(struct ieee80211_sub_if_data *sdata)
>  	}
>  
>  	ifmgd->probe_send_count++;
> -	ifmgd->probe_timeout = jiffies + IEEE80211_PROBE_WAIT;
> +	ifmgd->probe_timeout = jiffies + msecs_to_jiffies(probe_wait_ms);
>  	run_again(ifmgd, ifmgd->probe_timeout);
>  }
>  
> @@ -1243,7 +1254,8 @@ static void __ieee80211_connection_loss(struct ieee80211_sub_if_data *sdata)
>  
>  	memcpy(bssid, ifmgd->associated->bssid, ETH_ALEN);
>  
> -	printk(KERN_DEBUG "Connection to AP %pM lost.\n", bssid);
> +	printk(KERN_DEBUG "%s: Connection to AP %pM lost.\n",
> +	       sdata->name, bssid);
>  
>  	ieee80211_set_disassoc(sdata, true, true);
>  	mutex_unlock(&ifmgd->mtx);
> @@ -1988,9 +2000,9 @@ void ieee80211_sta_work(struct ieee80211_sub_if_data *sdata)
>  		memcpy(bssid, ifmgd->associated->bssid, ETH_ALEN);
>  
>  		if (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS)
> -			max_tries = IEEE80211_MAX_NULLFUNC_TRIES;
> +			max_tries = max_nullfunc_tries;
>  		else
> -			max_tries = IEEE80211_MAX_PROBE_TRIES;
> +			max_tries = max_probe_tries;
>  
>  		/* ACK received for nullfunc probing frame */
>  		if (!ifmgd->probe_send_count)
> @@ -2022,7 +2034,7 @@ void ieee80211_sta_work(struct ieee80211_sub_if_data *sdata)
>  				    "%s: Failed to send nullfunc to AP %pM"
>  				    " after %dms, disconnecting.\n",
>  				    sdata->name,
> -				    bssid, (1000 * IEEE80211_PROBE_WAIT)/HZ);
> +				    bssid, probe_wait_ms);
>  #endif
>  			ieee80211_sta_connection_lost(sdata, bssid);
>  		} else if (ifmgd->probe_send_count < max_tries) {
> @@ -2031,7 +2043,7 @@ void ieee80211_sta_work(struct ieee80211_sub_if_data *sdata)
>  				    "%s: No probe response from AP %pM"
>  				    " after %dms, try %d/%i\n",
>  				    sdata->name,
> -				    bssid, (1000 * IEEE80211_PROBE_WAIT)/HZ,
> +				    bssid, probe_wait_ms,
>  				    ifmgd->probe_send_count, max_tries);
>  #endif
>  			ieee80211_mgd_probe_ap_send(sdata);
> @@ -2044,7 +2056,7 @@ void ieee80211_sta_work(struct ieee80211_sub_if_data *sdata)
>  				    "%s: No probe response from AP %pM"
>  				    " after %dms, disconnecting.\n",
>  				    sdata->name,
> -				    bssid, (1000 * IEEE80211_PROBE_WAIT)/HZ);
> +				    bssid, probe_wait_ms);
>  
>  			ieee80211_sta_connection_lost(sdata, bssid);
>  		}