mac80211: redefine usage of the mac80211 workqueue

The mac80211 workqueue exists to enable mac80211 and drivers
to queue their own work on a single threaded workqueue. mac80211
takes care to flush the workqueue during suspend but we never
really had requirements on drivers for how they should use
the workqueue in consideration for suspend.

We extend mac80211 to document how the mac80211 workqueue should
be used, how it should not be used and finally move raw access to
the workqueue to mac80211 only. Drivers and mac80211 use helpers
to queue work onto the mac80211 workqueue:

  * ieee80211_queue_work()
  * ieee80211_queue_delayed_work()

These helpers will now warn if mac80211 already completed its
suspend cycle and someone is trying to queue work. mac80211
flushes the mac80211 workqueue prior to suspend a few times,
but we haven't taken the care to ensure drivers won't add more
work after suspend. To help with this we add a warning when
someone tries to add work and mac80211 already completed the
suspend cycle.

Drivers should ensure they cancel any work or delayed work
in the mac80211 stop() callback.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 9 insertions, 8 deletions

diff --git a/drivers/net/wireless/ath/ath9k/virtual.c b/drivers/net/wireless/ath/ath9k/virtual.c
index e1d419e02b4..19b88f8177f 100644
--- a/drivers/net/wireless/ath/ath9k/virtual.c
+++ b/drivers/net/wireless/ath/ath9k/virtual.c
@@ -351,7 +351,7 @@ void ath9k_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 			 * Drop from tasklet to work to allow mutex for channel
 			 * change.
 			 */
-			queue_work(aphy->sc->hw->workqueue,
+			ieee80211_queue_work(aphy->sc->hw,
 				   &aphy->sc->chan_work);
 		}
 	}
@@ -367,7 +367,7 @@ static void ath9k_mark_paused(struct ath_wiphy *aphy)
 	struct ath_softc *sc = aphy->sc;
 	aphy->state = ATH_WIPHY_PAUSED;
 	if (!__ath9k_wiphy_pausing(sc))
-		queue_work(sc->hw->workqueue, &sc->chan_work);
+		ieee80211_queue_work(sc->hw, &sc->chan_work);
 }
 
 static void ath9k_pause_iter(void *data, u8 *mac, struct ieee80211_vif *vif)
@@ -521,7 +521,7 @@ int ath9k_wiphy_select(struct ath_wiphy *aphy)
 			spin_unlock_bh(&sc->wiphy_lock);
 			ath_radio_disable(sc);
 			ath_radio_enable(sc);
-			queue_work(aphy->sc->hw->workqueue,
+			ieee80211_queue_work(aphy->sc->hw,
 				   &aphy->sc->chan_work);
 			return -EBUSY; /* previous select still in progress */
 		}
@@ -541,7 +541,7 @@ int ath9k_wiphy_select(struct ath_wiphy *aphy)
 
 	if (now) {
 		/* Ready to request channel change immediately */
-		queue_work(aphy->sc->hw->workqueue, &aphy->sc->chan_work);
+		ieee80211_queue_work(aphy->sc->hw, &aphy->sc->chan_work);
 	}
 
 	/*
@@ -648,8 +648,9 @@ try_again:
 		       "change\n");
 	}
 
-	queue_delayed_work(sc->hw->workqueue, &sc->wiphy_work,
-			   sc->wiphy_scheduler_int);
+	ieee80211_queue_delayed_work(sc->hw,
+				     &sc->wiphy_work,
+				     sc->wiphy_scheduler_int);
 }
 
 void ath9k_wiphy_set_scheduler(struct ath_softc *sc, unsigned int msec_int)
@@ -657,8 +658,8 @@ void ath9k_wiphy_set_scheduler(struct ath_softc *sc, unsigned int msec_int)
 	cancel_delayed_work_sync(&sc->wiphy_work);
 	sc->wiphy_scheduler_int = msecs_to_jiffies(msec_int);
 	if (sc->wiphy_scheduler_int)
-		queue_delayed_work(sc->hw->workqueue, &sc->wiphy_work,
-				   sc->wiphy_scheduler_int);
+		ieee80211_queue_delayed_work(sc->hw, &sc->wiphy_work,
+					     sc->wiphy_scheduler_int);
 }
 
 /* caller must hold wiphy_lock */