Commit 8ade0082 authored by Johannes Berg's avatar Johannes Berg Committed by John W. Linville
Browse files

mac80211: fix addba timer (again...) 



commit 2171abc5
  Author: Johannes Berg <johannes@sipsolutions.net>
  Date:   Thu Oct 29 08:34:00 2009 +0100

      mac80211: fix addba timer

left a problem in there, even if the timer was
never started it could be deleted and then added.

Linus pointed out that del_timer_sync() isn't
actually needed if we make the timer able to
deal with no longer being needed when it gets
queued _while_ we're in the locked section that
also deletes it. For that the timer function only
needs to check the HT_ADDBA_RECEIVED_MSK bit as
well as the HT_ADDBA_REQUESTED_MSK bit, only if
the former is clear should it do anything.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 70e3bb50

net/mac80211/agg-tx.c

+8 −10
Original line number Diff line number Diff line
@@ -173,12 +173,14 @@ static void sta_addba_resp_timer_expired(unsigned long data) 


	/* check if the TID waits for addBA response */

	spin_lock_bh(&sta->lock);

	if (!(*state & HT_ADDBA_REQUESTED_MSK)) {

	if ((*state & (HT_ADDBA_REQUESTED_MSK | HT_ADDBA_RECEIVED_MSK)) !=

						HT_ADDBA_REQUESTED_MSK) {

		spin_unlock_bh(&sta->lock);

		*state = HT_AGG_STATE_IDLE;

#ifdef CONFIG_MAC80211_HT_DEBUG

		printk(KERN_DEBUG "timer expired on tid %d but we are not "

				"expecting addBA response there", tid);

				"(or no longer) expecting addBA response there",

			tid);

#endif

		return;

	}
@@ -666,21 +668,21 @@ void ieee80211_process_addba_resp(struct ieee80211_local *local, 


	state = &sta->ampdu_mlme.tid_state_tx[tid];



	del_timer_sync(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);



	spin_lock_bh(&sta->lock);



	if (!(*state & HT_ADDBA_REQUESTED_MSK))

		goto timer_still_needed;

		goto out;



	if (mgmt->u.action.u.addba_resp.dialog_token !=

		sta->ampdu_mlme.tid_tx[tid]->dialog_token) {

#ifdef CONFIG_MAC80211_HT_DEBUG

		printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);

#endif /* CONFIG_MAC80211_HT_DEBUG */

		goto timer_still_needed;

		goto out;

	}



	del_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);



#ifdef CONFIG_MAC80211_HT_DEBUG

	printk(KERN_DEBUG "switched off addBA timer for tid %d \n", tid);

#endif /* CONFIG_MAC80211_HT_DEBUG */
@@ -699,10 +701,6 @@ void ieee80211_process_addba_resp(struct ieee80211_local *local, 
		___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR);

	}



	goto out;



 timer_still_needed:

	add_timer(&sta->ampdu_mlme.tid_tx[tid]->addba_resp_timer);

 out:

	spin_unlock_bh(&sta->lock);

}

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