mac80211: aggregation: Convert timers to use timer_setup()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

This removes the tid mapping array and expands the tid structures to
add a pointer back to the station, along with the tid index itself.

Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
[switch tid variables to u8, the valid range is 0-15 at most,
 initialize tid_tx->sta/tid properly]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 18 insertions, 26 deletions

diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index bef516ec47f9..3680b380e70c 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -422,15 +422,12 @@ int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
  * add Block Ack response will arrive from the recipient.
  * If this timer expires sta_addba_resp_timer_expired will be executed.
  */
-static void sta_addba_resp_timer_expired(unsigned long data)
+static void sta_addba_resp_timer_expired(struct timer_list *t)
 {
-	/* not an elegant detour, but there is no choice as the timer passes
-	 * only one argument, and both sta_info and TID are needed, so init
-	 * flow in sta_info_create gives the TID as data, while the timer_to_id
-	 * array gives the sta through container_of */
-	u16 tid = *(u8 *)data;
-	struct sta_info *sta = container_of((void *)data,
-		struct sta_info, timer_to_tid[tid]);
+	struct tid_ampdu_tx *tid_tx_timer =
+		from_timer(tid_tx_timer, t, addba_resp_timer);
+	struct sta_info *sta = tid_tx_timer->sta;
+	u8 tid = tid_tx_timer->tid;
 	struct tid_ampdu_tx *tid_tx;
 
 	/* check if the TID waits for addBA response */
@@ -525,21 +522,17 @@ void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
  * After accepting the AddBA Response we activated a timer,
  * resetting it after each frame that we send.
  */
-static void sta_tx_agg_session_timer_expired(unsigned long data)
+static void sta_tx_agg_session_timer_expired(struct timer_list *t)
 {
-	/* not an elegant detour, but there is no choice as the timer passes
-	 * only one argument, and various sta_info are needed here, so init
-	 * flow in sta_info_create gives the TID as data, while the timer_to_id
-	 * array gives the sta through container_of */
-	u8 *ptid = (u8 *)data;
-	u8 *timer_to_id = ptid - *ptid;
-	struct sta_info *sta = container_of(timer_to_id, struct sta_info,
-					 timer_to_tid[0]);
+	struct tid_ampdu_tx *tid_tx_timer =
+		from_timer(tid_tx_timer, t, session_timer);
+	struct sta_info *sta = tid_tx_timer->sta;
+	u8 tid = tid_tx_timer->tid;
 	struct tid_ampdu_tx *tid_tx;
 	unsigned long timeout;
 
 	rcu_read_lock();
-	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[*ptid]);
+	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
 	if (!tid_tx || test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
 		rcu_read_unlock();
 		return;
@@ -555,9 +548,9 @@ static void sta_tx_agg_session_timer_expired(unsigned long data)
 	rcu_read_unlock();
 
 	ht_dbg(sta->sdata, "tx session timer expired on %pM tid %d\n",
-	       sta->sta.addr, (u16)*ptid);
+	       sta->sta.addr, tid);
 
-	ieee80211_stop_tx_ba_session(&sta->sta, *ptid);
+	ieee80211_stop_tx_ba_session(&sta->sta, tid);
 }
 
 int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
@@ -670,16 +663,15 @@ int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
 	__set_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);
 
 	tid_tx->timeout = timeout;
+	tid_tx->sta = sta;
+	tid_tx->tid = tid;
 
 	/* response timer */
-	setup_timer(&tid_tx->addba_resp_timer,
-		    sta_addba_resp_timer_expired,
-		    (unsigned long)&sta->timer_to_tid[tid]);
+	timer_setup(&tid_tx->addba_resp_timer, sta_addba_resp_timer_expired, 0);
 
 	/* tx timer */
-	setup_deferrable_timer(&tid_tx->session_timer,
-			       sta_tx_agg_session_timer_expired,
-			       (unsigned long)&sta->timer_to_tid[tid]);
+	timer_setup(&tid_tx->session_timer,
+		    sta_tx_agg_session_timer_expired, TIMER_DEFERRABLE);
 
 	/* assign a dialog token */
 	sta->ampdu_mlme.dialog_token_allocator++;