mac80211: do not pass PS frames out of mac80211 again

In order to handle powersave frames properly we had needed
to pass these out to the device queues again, and introduce
the skb->requeue bit. This, however, also has unnecessary
overhead by needing to 'clean up' already tried frames, and
this clean-up code is also buggy when software encryption
is used.

Instead of sending the frames via the master netdev queue
again, simply put them into the pending queue. This also
fixes a problem where frames for that particular station
could be reordered when some were still on the software
queues and older ones are re-injected into the software
queue after them.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/linux/skbuff.h

@@ -304,9 +304,6 @@ typedef unsigned char *sk_buff_data_t;
  *	@tc_verd: traffic control verdict
  *	@ndisc_nodetype: router type (from link layer)
  *	@do_not_encrypt: set to prevent encryption of this frame
- *	@requeue: set to indicate that the wireless core should attempt
- *		a software retry on this frame if we failed to
- *		receive an ACK for it
  *	@dma_cookie: a cookie to one of several possible DMA operations
  *		done by skb DMA functions
  *	@secmark: security marking
@@ -380,7 +377,6 @@ struct sk_buff {
 #endif
 #if defined(CONFIG_MAC80211) || defined(CONFIG_MAC80211_MODULE)
 	__u8			do_not_encrypt:1;
-	__u8			requeue:1;
 #endif
 	/* 0/13/14 bit hole */
 

include/net/mac80211.h

@@ -239,6 +239,8 @@ struct ieee80211_bss_conf {
  * @IEEE80211_TX_INTFL_NEED_TXPROCESSING: completely internal to mac80211,
  *	used to indicate that a pending frame requires TX processing before
  *	it can be sent out.
+ * @IEEE80211_TX_INTFL_RETRIED: completely internal to mac80211,
+ *	used to indicate that a frame was already retried due to PS
  */
 enum mac80211_tx_control_flags {
 	IEEE80211_TX_CTL_REQ_TX_STATUS		= BIT(0),
@@ -256,6 +258,7 @@ enum mac80211_tx_control_flags {
 	IEEE80211_TX_CTL_RATE_CTRL_PROBE	= BIT(12),
 	IEEE80211_TX_INTFL_RCALGO		= BIT(13),
 	IEEE80211_TX_INTFL_NEED_TXPROCESSING	= BIT(14),
+	IEEE80211_TX_INTFL_RETRIED		= BIT(15),
 };
 
 /**

net/core/skbuff.c

@@ -552,7 +552,6 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
 	new->vlan_tci		= old->vlan_tci;
 #if defined(CONFIG_MAC80211) || defined(CONFIG_MAC80211_MODULE)
 	new->do_not_encrypt	= old->do_not_encrypt;
-	new->requeue		= old->requeue;
 #endif
 
 	skb_copy_secmark(new, old);

net/mac80211/ieee80211_i.h

@@ -589,6 +589,7 @@ enum queue_stop_reason {
 	IEEE80211_QUEUE_STOP_REASON_AGGREGATION,
 	IEEE80211_QUEUE_STOP_REASON_SUSPEND,
 	IEEE80211_QUEUE_STOP_REASON_PENDING,
+	IEEE80211_QUEUE_STOP_REASON_SKB_ADD,
 };
 
 struct ieee80211_master_priv {
@@ -1121,6 +1122,10 @@ void ieee80211_wake_queue_by_reason(struct ieee80211_hw *hw, int queue,
 				    enum queue_stop_reason reason);
 void ieee80211_stop_queue_by_reason(struct ieee80211_hw *hw, int queue,
 				    enum queue_stop_reason reason);
+void ieee80211_add_pending_skb(struct ieee80211_local *local,
+			       struct sk_buff *skb);
+int ieee80211_add_pending_skbs(struct ieee80211_local *local,
+			       struct sk_buff_head *skbs);
 
 void ieee80211_send_auth(struct ieee80211_sub_if_data *sdata,
 			 u16 transaction, u16 auth_alg,

net/mac80211/main.c

@@ -369,60 +369,12 @@ static void ieee80211_tasklet_handler(unsigned long data)
 	}
 }
 
-/* Remove added headers (e.g., QoS control), encryption header/MIC, etc. to
- * make a prepared TX frame (one that has been given to hw) to look like brand
- * new IEEE 802.11 frame that is ready to go through TX processing again.
- */
-static void ieee80211_remove_tx_extra(struct ieee80211_local *local,
-				      struct ieee80211_key *key,
-				      struct sk_buff *skb)
-{
-	unsigned int hdrlen, iv_len, mic_len;
-	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
-
-	hdrlen = ieee80211_hdrlen(hdr->frame_control);
-
-	if (!key)
-		goto no_key;
-
-	switch (key->conf.alg) {
-	case ALG_WEP:
-		iv_len = WEP_IV_LEN;
-		mic_len = WEP_ICV_LEN;
-		break;
-	case ALG_TKIP:
-		iv_len = TKIP_IV_LEN;
-		mic_len = TKIP_ICV_LEN;
-		break;
-	case ALG_CCMP:
-		iv_len = CCMP_HDR_LEN;
-		mic_len = CCMP_MIC_LEN;
-		break;
-	default:
-		goto no_key;
-	}
-
-	if (skb->len >= hdrlen + mic_len &&
-	    !(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
-		skb_trim(skb, skb->len - mic_len);
-	if (skb->len >= hdrlen + iv_len) {
-		memmove(skb->data + iv_len, skb->data, hdrlen);
-		hdr = (struct ieee80211_hdr *)skb_pull(skb, iv_len);
-	}
-
-no_key:
-	if (ieee80211_is_data_qos(hdr->frame_control)) {
-		hdr->frame_control &= ~cpu_to_le16(IEEE80211_STYPE_QOS_DATA);
-		memmove(skb->data + IEEE80211_QOS_CTL_LEN, skb->data,
-			hdrlen - IEEE80211_QOS_CTL_LEN);
-		skb_pull(skb, IEEE80211_QOS_CTL_LEN);
-	}
-}
-
 static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
 					    struct sta_info *sta,
 					    struct sk_buff *skb)
 {
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+
 	sta->tx_filtered_count++;
 
 	/*
@@ -464,16 +416,15 @@ static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
 	 */
 	if (test_sta_flags(sta, WLAN_STA_PS) &&
 	    skb_queue_len(&sta->tx_filtered) < STA_MAX_TX_BUFFER) {
-		ieee80211_remove_tx_extra(local, sta->key, skb);
 		skb_queue_tail(&sta->tx_filtered, skb);
 		return;
 	}
 
-	if (!test_sta_flags(sta, WLAN_STA_PS) && !skb->requeue) {
+	if (!test_sta_flags(sta, WLAN_STA_PS) &&
+	    !(info->flags & IEEE80211_TX_INTFL_RETRIED)) {
 		/* Software retry the packet once */
-		skb->requeue = 1;
-		ieee80211_remove_tx_extra(local, sta->key, skb);
-		dev_queue_xmit(skb);
+		info->flags |= IEEE80211_TX_INTFL_RETRIED;
+		ieee80211_add_pending_skb(local, skb);
 		return;
 	}
 

net/mac80211/rx.c

@@ -797,8 +797,7 @@ static int ap_sta_ps_end(struct sta_info *sta)
 {
 	struct ieee80211_sub_if_data *sdata = sta->sdata;
 	struct ieee80211_local *local = sdata->local;
-	struct sk_buff *skb;
-	int sent = 0;
+	int sent, buffered;
 
 	atomic_dec(&sdata->bss->num_sta_ps);
 
@@ -814,22 +813,16 @@ static int ap_sta_ps_end(struct sta_info *sta)
 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
 
 	/* Send all buffered frames to the station */
-	while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL) {
-		sent++;
-		skb->requeue = 1;
-		dev_queue_xmit(skb);
-	}
-	while ((skb = skb_dequeue(&sta->ps_tx_buf)) != NULL) {
-		local->total_ps_buffered--;
-		sent++;
+	sent = ieee80211_add_pending_skbs(local, &sta->tx_filtered);
+	buffered = ieee80211_add_pending_skbs(local, &sta->ps_tx_buf);
+	sent += buffered;
+	local->total_ps_buffered -= buffered;
+
 #ifdef CONFIG_MAC80211_VERBOSE_PS_DEBUG
-		printk(KERN_DEBUG "%s: STA %pM aid %d send PS frame "
-		       "since STA not sleeping anymore\n", sdata->dev->name,
-		       sta->sta.addr, sta->sta.aid);
+	printk(KERN_DEBUG "%s: STA %pM aid %d sending %d filtered/%d PS frames "
+	       "since STA not sleeping anymore\n", sdata->dev->name,
+	       sta->sta.addr, sta->sta.aid, sent - buffered, buffered);
 #endif /* CONFIG_MAC80211_VERBOSE_PS_DEBUG */
-		skb->requeue = 1;
-		dev_queue_xmit(skb);
-	}
 
 	return sent;
 }

net/mac80211/tx.c

@@ -400,6 +400,7 @@ ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)
 			sta_info_set_tim_bit(sta);
 
 		info->control.jiffies = jiffies;
+		info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 		skb_queue_tail(&sta->ps_tx_buf, tx->skb);
 		return TX_QUEUED;
 	}
@@ -420,7 +421,7 @@ ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)
 		 * frame filtering and keeps a station  blacklist on its own
 		 * (e.g: p54), so that frames can be delivered unimpeded.
 		 *
-		 * Note: It should be save to disable the filter now.
+		 * Note: It should be safe to disable the filter now.
 		 * As, it is really unlikely that we still have any pending
 		 * frame for this station in the hw's buffers/fifos left,
 		 * that is not rejected with a unsuccessful tx_status yet.

net/mac80211/util.c

@@ -341,6 +341,52 @@ void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
 }
 EXPORT_SYMBOL(ieee80211_stop_queue);
 
+void ieee80211_add_pending_skb(struct ieee80211_local *local,
+			       struct sk_buff *skb)
+{
+	struct ieee80211_hw *hw = &local->hw;
+	unsigned long flags;
+	int queue = skb_get_queue_mapping(skb);
+
+	spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
+	__ieee80211_stop_queue(hw, queue, IEEE80211_QUEUE_STOP_REASON_SKB_ADD);
+	__ieee80211_stop_queue(hw, queue, IEEE80211_QUEUE_STOP_REASON_PENDING);
+	skb_queue_tail(&local->pending[queue], skb);
+	__ieee80211_wake_queue(hw, queue, IEEE80211_QUEUE_STOP_REASON_SKB_ADD);
+	spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
+}
+
+int ieee80211_add_pending_skbs(struct ieee80211_local *local,
+			       struct sk_buff_head *skbs)
+{
+	struct ieee80211_hw *hw = &local->hw;
+	struct sk_buff *skb;
+	unsigned long flags;
+	int queue, ret = 0, i;
+
+	spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
+	for (i = 0; i < hw->queues; i++)
+		__ieee80211_stop_queue(hw, i,
+			IEEE80211_QUEUE_STOP_REASON_SKB_ADD);
+
+	while ((skb = skb_dequeue(skbs))) {
+		ret++;
+		queue = skb_get_queue_mapping(skb);
+		skb_queue_tail(&local->pending[queue], skb);
+	}
+
+	for (i = 0; i < hw->queues; i++) {
+		if (ret)
+			__ieee80211_stop_queue(hw, i,
+				IEEE80211_QUEUE_STOP_REASON_PENDING);
+		__ieee80211_wake_queue(hw, i,
+			IEEE80211_QUEUE_STOP_REASON_SKB_ADD);
+	}
+	spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
+
+	return ret;
+}
+
 void ieee80211_stop_queues_by_reason(struct ieee80211_hw *hw,
 				    enum queue_stop_reason reason)
 {

net/mac80211/wme.c

@@ -101,7 +101,7 @@ u16 ieee80211_select_queue(struct net_device *dev, struct sk_buff *skb)
 	 * Now we know the 1d priority, fill in the QoS header if
 	 * there is one (and we haven't done this before).
 	 */
-	if (!skb->requeue && ieee80211_is_data_qos(hdr->frame_control)) {
+	if (ieee80211_is_data_qos(hdr->frame_control)) {
 		u8 *p = ieee80211_get_qos_ctl(hdr);
 		u8 ack_policy = 0;
 		tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;