[PATCH] mac80211: Fix the way ADDBA request count being modified

[PATCH] mac80211: Fix the way ADDBA request count being modified

[Vasanthakumar Thiagarajan]

addba_req_num[tid] is supposed to have the count of consecutive
addba request attempts on 'tid' which failed. This count is checked
against a retry threshold (3 times) before starting the addba negotiation.
This patch fixes the way this addba count is incremented/reset and thereby
avoids indefinite addba attempts.

Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
---
 net/mac80211/agg-tx.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index 43d00ff..9e5762a 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -132,6 +132,9 @@ static int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
 
 	state = &sta->ampdu_mlme.tid_state_tx[tid];
 
+	if (*state == HT_AGG_STATE_OPERATIONAL)
+		sta->ampdu_mlme.addba_req_num[tid] = 0;
+
 	*state = HT_AGG_STATE_REQ_STOP_BA_MSK |
 		(initiator << HT_AGG_STATE_INITIATOR_SHIFT);
 
@@ -337,6 +340,7 @@ int ieee80211_start_tx_ba_session(struct ieee80211_hw *hw, u8 *ra, u16 tid)
 			 sta->ampdu_mlme.tid_tx[tid]->dialog_token,
 			 sta->ampdu_mlme.tid_tx[tid]->ssn,
 			 0x40, 5000);
+	sta->ampdu_mlme.addba_req_num[tid]++;
 	/* activate the timer for the recipient's addBA response */
 	sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.expires =
 				jiffies + ADDBA_RESP_INTERVAL;
@@ -606,7 +610,6 @@ void ieee80211_stop_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u8 tid)
 
 	*state = HT_AGG_STATE_IDLE;
 	/* from now on packets are no longer put onto sta->pending */
-	sta->ampdu_mlme.addba_req_num[tid] = 0;
 	kfree(sta->ampdu_mlme.tid_tx[tid]);
 	sta->ampdu_mlme.tid_tx[tid] = NULL;
 
@@ -689,7 +692,6 @@ void ieee80211_process_addba_resp(struct ieee80211_local *local,
 
 		sta->ampdu_mlme.addba_req_num[tid] = 0;
 	} else {
-		sta->ampdu_mlme.addba_req_num[tid]++;
 		___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
 	}
 	spin_unlock_bh(&sta->lock);
-- 
1.5.5.1

Re: [PATCH] mac80211: Fix the way ADDBA request count being modified

[Johannes Berg]

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On Tue, 2009-06-09 at 14:11 +0530, Vasanthakumar Thiagarajan wrote:
> addba_req_num[tid] is supposed to have the count of consecutive
> addba request attempts on 'tid' which failed. This count is checked
> against a retry threshold (3 times) before starting the addba negotiation.
> This patch fixes the way this addba count is incremented/reset and thereby
> avoids indefinite addba attempts.

I've never actually seen this hit in practise, so I'll trust you on
it :)

johannes

> Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
> ---
>  net/mac80211/agg-tx.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
> index 43d00ff..9e5762a 100644
> --- a/net/mac80211/agg-tx.c
> +++ b/net/mac80211/agg-tx.c
> @@ -132,6 +132,9 @@ static int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
>  
>  	state = &sta->ampdu_mlme.tid_state_tx[tid];
>  
> +	if (*state == HT_AGG_STATE_OPERATIONAL)
> +		sta->ampdu_mlme.addba_req_num[tid] = 0;
> +
>  	*state = HT_AGG_STATE_REQ_STOP_BA_MSK |
>  		(initiator << HT_AGG_STATE_INITIATOR_SHIFT);
>  
> @@ -337,6 +340,7 @@ int ieee80211_start_tx_ba_session(struct ieee80211_hw *hw, u8 *ra, u16 tid)
>  			 sta->ampdu_mlme.tid_tx[tid]->dialog_token,
>  			 sta->ampdu_mlme.tid_tx[tid]->ssn,
>  			 0x40, 5000);
> +	sta->ampdu_mlme.addba_req_num[tid]++;
>  	/* activate the timer for the recipient's addBA response */
>  	sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer.expires =
>  				jiffies + ADDBA_RESP_INTERVAL;
> @@ -606,7 +610,6 @@ void ieee80211_stop_tx_ba_cb(struct ieee80211_hw *hw, u8 *ra, u8 tid)
>  
>  	*state = HT_AGG_STATE_IDLE;
>  	/* from now on packets are no longer put onto sta->pending */
> -	sta->ampdu_mlme.addba_req_num[tid] = 0;
>  	kfree(sta->ampdu_mlme.tid_tx[tid]);
>  	sta->ampdu_mlme.tid_tx[tid] = NULL;
>  
> @@ -689,7 +692,6 @@ void ieee80211_process_addba_resp(struct ieee80211_local *local,
>  
>  		sta->ampdu_mlme.addba_req_num[tid] = 0;
>  	} else {
> -		sta->ampdu_mlme.addba_req_num[tid]++;
>  		___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);
>  	}
>  	spin_unlock_bh(&sta->lock);

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Re: [PATCH] mac80211: Fix the way ADDBA request count being modified

[Vasanthakumar Thiagarajan]

On Tue, Jun 09, 2009 at 07:31:58PM +0530, Johannes Berg wrote:
> On Tue, 2009-06-09 at 14:11 +0530, Vasanthakumar Thiagarajan wrote:
> > addba_req_num[tid] is supposed to have the count of consecutive
> > addba request attempts on 'tid' which failed. This count is checked
> > against a retry threshold (3 times) before starting the addba negotiation.
> > This patch fixes the way this addba count is incremented/reset and thereby
> > avoids indefinite addba attempts.
> 
> I've never actually seen this hit in practise, so I'll trust you on
> it :)
> 
> johannes
> 

I have seen this happening with most of the 11n APs around when AMPDU
is disabled (configured to deny addba) on them.

Vasanth

Re: [PATCH] mac80211: Fix the way ADDBA request count being modified

[Johannes Berg]

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On Tue, 2009-06-09 at 19:38 +0530, Vasanthakumar Thiagarajan wrote:

> I have seen this happening with most of the 11n APs around when AMPDU
> is disabled (configured to deny addba) on them.

Makes sense, I don't think I ever had an AP that supported that specific
setting (rather than simply disabling all of 11n). Anyway, thanks for
the testing and the fix.

johannes

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