Re: [PATCH-v2] mac80211: Requeue work for all iftypes after scan completion

[Sachin Kulkarni <Sachin.Kulkarni@imgtec.com>]

On 07/21/2014 04:38 PM, Sachin Kulkarni wrote:
>
> From: Sachin Kulkarni<sachin.kulkarni@imgtec.com>
>
> During a hw scan ieee80211_iface_work ignores work items for all vifs. 
> However
> after the scan complete work is requeued only for STA, ADHOC and MESH 
> iftypes.
> This occasionally results in event processing getting delayed for 
> iftype AP when
> it coexists with a STA, and when the scan durations are very long.
>
> Signed-off-by: Sachin Kulkarni<sachin.kulkarni@imgtec.com>
> Cc: linux-wireless@vger.kernel.org
> Cc: johannes@sipsolutions.net
> ---
> v2: Fix white space after comma
>
> We have a test scenario where there are 2 VIFs: one STA and one AP. 
> The STA is
> not connected to anyone while the AP has a station connected to it. 
> The hardware
> we are using currently has scan durations of ~8 sec and a new scan 
> request is
> generated every 10 s. This results in a window of only 2 s when work 
> items can
> be processed by ieee80211_iface_work. We came across scenarios where 
> the AP is
> trying to tear down a AMPDU session, and the 
> IEEE80211_SDATA_QUEUE_AGG_STOP
> event gets queued. However the work item for this gets ignored by the 
> ieee80211_iface_work
> since a hw scan is in progress most of the time. When the scan 
> completes however
> the work item for the AP does not get requeued, and by the time the
> IEEE80211_SDATA_QUEUE_AGG_STOP gets processed in some other work items 
> context,
> the TX frames just keep getting queued up, since the tid has not been 
> destroyed.
> This results in disconnections since things like ARP timeouts etc start
> happening.
> ---
>  net/mac80211/mlme.c |    5 +++--
>  1 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
> index 931330b..49af420 100644
> --- a/net/mac80211/mlme.c
> +++ b/net/mac80211/mlme.c
> @@ -3647,9 +3647,10 @@ static void ieee80211_restart_sta_timer(struct 
> ieee80211_sub_if_data *sdata)
>          if (!(flags&   IEEE80211_HW_CONNECTION_MONITOR))
>              ieee80211_queue_work(&sdata->local->hw,
> &sdata->u.mgd.monitor_work);
> -        /* and do all the other regular work too */
> -        ieee80211_queue_work(&sdata->local->hw,&sdata->work);
>      }
> +
> +    /* and do all the other regular work too */
> +    ieee80211_queue_work(&sdata->local->hw,&sdata->work);
>  }
>
>  #ifdef CONFIG_PM
>
>
Sorry Johannes, it looks like my Thunderbird is removing the white space 
for some reason !! I will try to resend the patch by some other means soon.