openwrtv4/package/kernel/mac80211/patches/300-pending_work.patch

commit 930b0dffd1731f3f418f9132faea720a23b7af61
Author: Johannes Berg <johannes.berg@intel.com>
Date:   Tue Jun 3 11:18:47 2014 +0200

    mac80211: fix station/driver powersave race
    
    It is currently possible to have a race due to the station PS
    unblock work like this:
     * station goes to sleep with frames buffered in the driver
     * driver blocks wakeup
     * station wakes up again
     * driver flushes/returns frames, and unblocks, which schedules
       the unblock work
     * unblock work starts to run, and checks that the station is
       awake (i.e. that the WLAN_STA_PS_STA flag isn't set)
     * we process a received frame with PM=1, setting the flag again
     * ieee80211_sta_ps_deliver_wakeup() runs, delivering all frames
       to the driver, and then clearing the WLAN_STA_PS_DRIVER and
       WLAN_STA_PS_STA flags
    
    In this scenario, mac80211 will think that the station is awake,
    while it really is asleep, and any TX'ed frames should be filtered
    by the device (it will know that the station is sleeping) but then
    passed to mac80211 again, which will not buffer it either as it
    thinks the station is awake, and eventually the packets will be
    dropped.
    
    Fix this by moving the clearing of the flags to exactly where we
    learn about the situation. This creates a problem of reordering,
    so introduce another flag indicating that delivery is being done,
    this new flag also queues frames and is cleared only while the
    spinlock is held (which the queuing code also holds) so that any
    concurrent delivery/TX is handled correctly.
    
    Reported-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
    Signed-off-by: Johannes Berg <johannes.berg@intel.com>

commit 6df35206bc6c1c6aad1d8077df5786b4a7f77873
Author: Felix Fietkau <nbd@openwrt.org>
Date:   Fri May 23 19:58:14 2014 +0200

    mac80211: reduce packet loss notifications under load
    
    During strong signal fluctuations under high throughput, few consecutive
    failed A-MPDU transmissions can easily trigger packet loss notification,
    and thus (in AP mode) client disconnection.
    
    Reduce the number of false positives by checking the A-MPDU status flag
    and treating a failed A-MPDU as a single packet.
    
    Signed-off-by: Felix Fietkau <nbd@openwrt.org>

commit 7b7843a36fbcc568834404c7430ff895d8502131
Author: Felix Fietkau <nbd@openwrt.org>
Date:   Fri May 23 19:26:32 2014 +0200

    mac80211: fix a memory leak on sta rate selection table
    
    Cc: stable@vger.kernel.org
    Reported-by: Christophe Prévotaux <cprevotaux@nltinc.com>
    Signed-off-by: Felix Fietkau <nbd@openwrt.org>

commit 96892d6aa0a153423070addf3070bc79578b3897
Author: Felix Fietkau <nbd@openwrt.org>
Date:   Mon May 19 21:20:49 2014 +0200

    ath9k: avoid passing buffers to the hardware during flush
    
    The commit "ath9k: fix possible hang on flush" changed the receive code
    to always link rx descriptors of processed frames, even when flushing.
    In some cases, this leads to flushed rx buffers being passed to the
    hardware while rx is already stopped.
    
    Signed-off-by: Felix Fietkau <nbd@openwrt.org>

--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -34,7 +34,8 @@ static inline bool ath9k_check_auto_slee
  * buffer (or rx fifo). This can incorrectly acknowledge packets
  * to a sender if last desc is self-linked.
  */
-static void ath_rx_buf_link(struct ath_softc *sc, struct ath_rxbuf *bf)
+static void ath_rx_buf_link(struct ath_softc *sc, struct ath_rxbuf *bf,
+			    bool flush)
 {
 	struct ath_hw *ah = sc->sc_ah;
 	struct ath_common *common = ath9k_hw_common(ah);
@@ -59,18 +60,19 @@ static void ath_rx_buf_link(struct ath_s
 			     common->rx_bufsize,
 			     0);
 
-	if (sc->rx.rxlink == NULL)
-		ath9k_hw_putrxbuf(ah, bf->bf_daddr);
-	else
+	if (sc->rx.rxlink)
 		*sc->rx.rxlink = bf->bf_daddr;
+	else if (!flush)
+		ath9k_hw_putrxbuf(ah, bf->bf_daddr);
 
 	sc->rx.rxlink = &ds->ds_link;
 }
 
-static void ath_rx_buf_relink(struct ath_softc *sc, struct ath_rxbuf *bf)
+static void ath_rx_buf_relink(struct ath_softc *sc, struct ath_rxbuf *bf,
+			      bool flush)
 {
 	if (sc->rx.buf_hold)
-		ath_rx_buf_link(sc, sc->rx.buf_hold);
+		ath_rx_buf_link(sc, sc->rx.buf_hold, flush);
 
 	sc->rx.buf_hold = bf;
 }
@@ -442,7 +444,7 @@ int ath_startrecv(struct ath_softc *sc)
 	sc->rx.buf_hold = NULL;
 	sc->rx.rxlink = NULL;
 	list_for_each_entry_safe(bf, tbf, &sc->rx.rxbuf, list) {
-		ath_rx_buf_link(sc, bf);
+		ath_rx_buf_link(sc, bf, false);
 	}
 
 	/* We could have deleted elements so the list may be empty now */
@@ -1118,12 +1120,12 @@ requeue_drop_frag:
 requeue:
 		list_add_tail(&bf->list, &sc->rx.rxbuf);
 
-		if (edma) {
-			ath_rx_edma_buf_link(sc, qtype);
-		} else {
-			ath_rx_buf_relink(sc, bf);
+		if (!edma) {
+			ath_rx_buf_relink(sc, bf, flush);
 			if (!flush)
 				ath9k_hw_rxena(ah);
+		} else if (!flush) {
+			ath_rx_edma_buf_link(sc, qtype);
 		}
 
 		if (!budget--)
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -100,7 +100,8 @@ static void __cleanup_single_sta(struct 
 	struct ps_data *ps;
 
 	if (test_sta_flag(sta, WLAN_STA_PS_STA) ||
-	    test_sta_flag(sta, WLAN_STA_PS_DRIVER)) {
+	    test_sta_flag(sta, WLAN_STA_PS_DRIVER) ||
+	    test_sta_flag(sta, WLAN_STA_PS_DELIVER)) {
 		if (sta->sdata->vif.type == NL80211_IFTYPE_AP ||
 		    sta->sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
 			ps = &sdata->bss->ps;
@@ -111,6 +112,7 @@ static void __cleanup_single_sta(struct 
 
 		clear_sta_flag(sta, WLAN_STA_PS_STA);
 		clear_sta_flag(sta, WLAN_STA_PS_DRIVER);
+		clear_sta_flag(sta, WLAN_STA_PS_DELIVER);
 
 		atomic_dec(&ps->num_sta_ps);
 		sta_info_recalc_tim(sta);
@@ -125,7 +127,7 @@ static void __cleanup_single_sta(struct 
 	if (ieee80211_vif_is_mesh(&sdata->vif))
 		mesh_sta_cleanup(sta);
 
-	cancel_work_sync(&sta->drv_unblock_wk);
+	cancel_work_sync(&sta->drv_deliver_wk);
 
 	/*
 	 * Destroy aggregation state here. It would be nice to wait for the
@@ -227,6 +229,7 @@ struct sta_info *sta_info_get_by_idx(str
  */
 void sta_info_free(struct ieee80211_local *local, struct sta_info *sta)
 {
+	struct ieee80211_sta_rates *rates;
 	int i;
 
 	if (sta->rate_ctrl)
@@ -238,6 +241,10 @@ void sta_info_free(struct ieee80211_loca
 		kfree(sta->tx_lat);
 	}
 
+	rates = rcu_dereference_protected(sta->sta.rates, true);
+	if (rates)
+		kfree(rates);
+
 	sta_dbg(sta->sdata, "Destroyed STA %pM\n", sta->sta.addr);
 
 	kfree(sta);
@@ -252,33 +259,23 @@ static void sta_info_hash_add(struct iee
 	rcu_assign_pointer(local->sta_hash[STA_HASH(sta->sta.addr)], sta);
 }
 
-static void sta_unblock(struct work_struct *wk)
+static void sta_deliver_ps_frames(struct work_struct *wk)
 {
 	struct sta_info *sta;
 
-	sta = container_of(wk, struct sta_info, drv_unblock_wk);
+	sta = container_of(wk, struct sta_info, drv_deliver_wk);
 
 	if (sta->dead)
 		return;
 
-	if (!test_sta_flag(sta, WLAN_STA_PS_STA)) {
-		local_bh_disable();
+	local_bh_disable();
+	if (!test_sta_flag(sta, WLAN_STA_PS_STA))
 		ieee80211_sta_ps_deliver_wakeup(sta);
-		local_bh_enable();
-	} else if (test_and_clear_sta_flag(sta, WLAN_STA_PSPOLL)) {
-		clear_sta_flag(sta, WLAN_STA_PS_DRIVER);
-
-		local_bh_disable();
+	else if (test_and_clear_sta_flag(sta, WLAN_STA_PSPOLL))
 		ieee80211_sta_ps_deliver_poll_response(sta);
-		local_bh_enable();
-	} else if (test_and_clear_sta_flag(sta, WLAN_STA_UAPSD)) {
-		clear_sta_flag(sta, WLAN_STA_PS_DRIVER);
-
-		local_bh_disable();
+	else if (test_and_clear_sta_flag(sta, WLAN_STA_UAPSD))
 		ieee80211_sta_ps_deliver_uapsd(sta);
-		local_bh_enable();
-	} else
-		clear_sta_flag(sta, WLAN_STA_PS_DRIVER);
+	local_bh_enable();
 }
 
 static int sta_prepare_rate_control(struct ieee80211_local *local,
@@ -340,7 +337,7 @@ struct sta_info *sta_info_alloc(struct i
 
 	spin_lock_init(&sta->lock);
 	spin_lock_init(&sta->ps_lock);
-	INIT_WORK(&sta->drv_unblock_wk, sta_unblock);
+	INIT_WORK(&sta->drv_deliver_wk, sta_deliver_ps_frames);
 	INIT_WORK(&sta->ampdu_mlme.work, ieee80211_ba_session_work);
 	mutex_init(&sta->ampdu_mlme.mtx);
 #ifdef CPTCFG_MAC80211_MESH
@@ -1140,8 +1137,15 @@ void ieee80211_sta_ps_deliver_wakeup(str
 	}
 
 	ieee80211_add_pending_skbs(local, &pending);
-	clear_sta_flag(sta, WLAN_STA_PS_DRIVER);
-	clear_sta_flag(sta, WLAN_STA_PS_STA);
+
+	/* now we're no longer in the deliver code */
+	clear_sta_flag(sta, WLAN_STA_PS_DELIVER);
+
+	/* The station might have polled and then woken up before we responded,
+	 * so clear these flags now to avoid them sticking around.
+	 */
+	clear_sta_flag(sta, WLAN_STA_PSPOLL);
+	clear_sta_flag(sta, WLAN_STA_UAPSD);
 	spin_unlock(&sta->ps_lock);
 
 	atomic_dec(&ps->num_sta_ps);
@@ -1542,10 +1546,26 @@ void ieee80211_sta_block_awake(struct ie
 
 	trace_api_sta_block_awake(sta->local, pubsta, block);
 
-	if (block)
+	if (block) {
 		set_sta_flag(sta, WLAN_STA_PS_DRIVER);
-	else if (test_sta_flag(sta, WLAN_STA_PS_DRIVER))
-		ieee80211_queue_work(hw, &sta->drv_unblock_wk);
+		return;
+	}
+
+	if (!test_sta_flag(sta, WLAN_STA_PS_DRIVER))
+		return;
+
+	if (!test_sta_flag(sta, WLAN_STA_PS_STA)) {
+		set_sta_flag(sta, WLAN_STA_PS_DELIVER);
+		clear_sta_flag(sta, WLAN_STA_PS_DRIVER);
+		ieee80211_queue_work(hw, &sta->drv_deliver_wk);
+	} else if (test_sta_flag(sta, WLAN_STA_PSPOLL) ||
+		   test_sta_flag(sta, WLAN_STA_UAPSD)) {
+		/* must be asleep in this case */
+		clear_sta_flag(sta, WLAN_STA_PS_DRIVER);
+		ieee80211_queue_work(hw, &sta->drv_deliver_wk);
+	} else {
+		clear_sta_flag(sta, WLAN_STA_PS_DRIVER);
+	}
 }
 EXPORT_SYMBOL(ieee80211_sta_block_awake);
 
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -541,6 +541,23 @@ static void ieee80211_tx_latency_end_msr
  */
 #define STA_LOST_PKT_THRESHOLD	50
 
+static void ieee80211_lost_packet(struct sta_info *sta, struct sk_buff *skb)
+{
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+
+	/* This packet was aggregated but doesn't carry status info */
+	if ((info->flags & IEEE80211_TX_CTL_AMPDU) &&
+	    !(info->flags & IEEE80211_TX_STAT_AMPDU))
+		return;
+
+	if (++sta->lost_packets < STA_LOST_PKT_THRESHOLD)
+		return;
+
+	cfg80211_cqm_pktloss_notify(sta->sdata->dev, sta->sta.addr,
+				    sta->lost_packets, GFP_ATOMIC);
+	sta->lost_packets = 0;
+}
+
 void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct sk_buff *skb2;
@@ -680,12 +697,8 @@ void ieee80211_tx_status(struct ieee8021
 			if (info->flags & IEEE80211_TX_STAT_ACK) {
 				if (sta->lost_packets)
 					sta->lost_packets = 0;
-			} else if (++sta->lost_packets >= STA_LOST_PKT_THRESHOLD) {
-				cfg80211_cqm_pktloss_notify(sta->sdata->dev,
-							    sta->sta.addr,
-							    sta->lost_packets,
-							    GFP_ATOMIC);
-				sta->lost_packets = 0;
+			} else {
+				ieee80211_lost_packet(sta, skb);
 			}
 		}
 
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1107,6 +1107,8 @@ static void sta_ps_end(struct sta_info *
 		return;
 	}
 
+	set_sta_flag(sta, WLAN_STA_PS_DELIVER);
+	clear_sta_flag(sta, WLAN_STA_PS_STA);
 	ieee80211_sta_ps_deliver_wakeup(sta);
 }
 
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -82,6 +82,7 @@ enum ieee80211_sta_info_flags {
 	WLAN_STA_TOFFSET_KNOWN,
 	WLAN_STA_MPSP_OWNER,
 	WLAN_STA_MPSP_RECIPIENT,
+	WLAN_STA_PS_DELIVER,
 };
 
 #define ADDBA_RESP_INTERVAL HZ
@@ -265,7 +266,7 @@ struct ieee80211_tx_latency_stat {
  * @last_rx_rate_vht_nss: rx status nss of last data packet
  * @lock: used for locking all fields that require locking, see comments
  *	in the header file.
- * @drv_unblock_wk: used for driver PS unblocking
+ * @drv_deliver_wk: used for delivering frames after driver PS unblocking
  * @listen_interval: listen interval of this station, when we're acting as AP
  * @_flags: STA flags, see &enum ieee80211_sta_info_flags, do not use directly
  * @ps_lock: used for powersave (when mac80211 is the AP) related locking
@@ -345,7 +346,7 @@ struct sta_info {
 	void *rate_ctrl_priv;
 	spinlock_t lock;
 
-	struct work_struct drv_unblock_wk;
+	struct work_struct drv_deliver_wk;
 
 	u16 listen_interval;
 
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -469,7 +469,8 @@ ieee80211_tx_h_unicast_ps_buf(struct iee
 		return TX_CONTINUE;
 
 	if (unlikely((test_sta_flag(sta, WLAN_STA_PS_STA) ||
-		      test_sta_flag(sta, WLAN_STA_PS_DRIVER)) &&
+		      test_sta_flag(sta, WLAN_STA_PS_DRIVER) ||
+		      test_sta_flag(sta, WLAN_STA_PS_DELIVER)) &&
 		     !(info->flags & IEEE80211_TX_CTL_NO_PS_BUFFER))) {
 		int ac = skb_get_queue_mapping(tx->skb);
 
@@ -486,7 +487,8 @@ ieee80211_tx_h_unicast_ps_buf(struct iee
 		 * ahead and Tx the packet.
 		 */
 		if (!test_sta_flag(sta, WLAN_STA_PS_STA) &&
-		    !test_sta_flag(sta, WLAN_STA_PS_DRIVER)) {
+		    !test_sta_flag(sta, WLAN_STA_PS_DRIVER) &&
+		    !test_sta_flag(sta, WLAN_STA_PS_DELIVER)) {
 			spin_unlock(&sta->ps_lock);
 			return TX_CONTINUE;
 		}