openwrtv3/package/mac80211/patches/544-ath9k_defer_buffer_setup.patch

--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -48,8 +48,9 @@ static u16 bits_per_symbol[][2] = {
 #define IS_HT_RATE(_rate)     ((_rate) & 0x80)
 
 static void ath_tx_send_normal(struct ath_softc *sc, struct ath_txq *txq,
-			       struct ath_atx_tid *tid,
-			       struct list_head *bf_head);
+			       struct ath_atx_tid *tid, struct sk_buff *skb);
+static void ath_tx_complete(struct ath_softc *sc, struct sk_buff *skb,
+			    int tx_flags, struct ath_txq *txq);
 static void ath_tx_complete_buf(struct ath_softc *sc, struct ath_buf *bf,
 				struct ath_txq *txq, struct list_head *bf_q,
 				struct ath_tx_status *ts, int txok, int sendbar);
@@ -61,6 +62,10 @@ static void ath_tx_rc_status(struct ath_
 			     int txok, bool update_rc);
 static void ath_tx_update_baw(struct ath_softc *sc, struct ath_atx_tid *tid,
 			      int seqno);
+static struct ath_buf *ath_tx_setup_buffer(struct ath_softc *sc,
+					   struct ath_txq *txq,
+					   struct ath_atx_tid *tid,
+					   struct sk_buff *skb);
 
 enum {
 	MCS_HT20,
@@ -164,14 +169,13 @@ static void ath_tx_flush_tid(struct ath_
 		fi = get_frame_info(skb);
 		bf = fi->bf;
 
-		list_add_tail(&bf->list, &bf_head);
-
 		spin_unlock_bh(&txq->axq_lock);
-		if (fi->retries) {
+		if (bf && fi->retries) {
+			list_add_tail(&bf->list, &bf_head);
 			ath_tx_update_baw(sc, tid, bf->bf_state.seqno);
 			ath_tx_complete_buf(sc, bf, txq, &bf_head, &ts, 0, 1);
 		} else {
-			ath_tx_send_normal(sc, txq, NULL, &bf_head);
+			ath_tx_send_normal(sc, txq, NULL, skb);
 		}
 		spin_lock_bh(&txq->axq_lock);
 	}
@@ -234,6 +238,13 @@ static void ath_tid_drain(struct ath_sof
 		fi = get_frame_info(skb);
 		bf = fi->bf;
 
+		if (!bf) {
+			spin_unlock(&txq->axq_lock);
+			ath_tx_complete(sc, skb, ATH_TX_ERROR, txq);
+			spin_lock(&txq->axq_lock);
+			continue;
+		}
+
 		list_add_tail(&bf->list, &bf_head);
 
 		if (fi->retries)
@@ -760,8 +771,14 @@ static enum ATH_AGGR_STATUS ath_tx_form_
 		skb = skb_peek(&tid->buf_q);
 		fi = get_frame_info(skb);
 		bf = fi->bf;
-		seqno = bf->bf_state.seqno;
+		if (!fi->bf)
+			bf = ath_tx_setup_buffer(sc, txq, tid, skb);
 
+		if (!bf)
+			continue;
+
+		bf->bf_state.bf_type |= BUF_AMPDU;
+		seqno = bf->bf_state.seqno;
 		if (!bf_first)
 			bf_first = bf;
 
@@ -1434,13 +1451,11 @@ static void ath_tx_txqaddbuf(struct ath_
 }
 
 static void ath_tx_send_ampdu(struct ath_softc *sc, struct ath_atx_tid *tid,
-			      struct ath_buf *bf, struct ath_tx_control *txctl)
+			      struct sk_buff *skb, struct ath_tx_control *txctl)
 {
-	struct ath_frame_info *fi = get_frame_info(bf->bf_mpdu);
+	struct ath_frame_info *fi = get_frame_info(skb);
 	struct list_head bf_head;
-	u16 seqno = bf->bf_state.seqno;
-
-	bf->bf_state.bf_type |= BUF_AMPDU;
+	struct ath_buf *bf;
 
 	/*
 	 * Do not queue to h/w when any of the following conditions is true:
@@ -1450,25 +1465,29 @@ static void ath_tx_send_ampdu(struct ath
 	 * - h/w queue depth exceeds low water mark
 	 */
 	if (!skb_queue_empty(&tid->buf_q) || tid->paused ||
-	    !BAW_WITHIN(tid->seq_start, tid->baw_size, seqno) ||
+	    !BAW_WITHIN(tid->seq_start, tid->baw_size, tid->seq_next) ||
 	    txctl->txq->axq_ampdu_depth >= ATH_AGGR_MIN_QDEPTH) {
 		/*
 		 * Add this frame to software queue for scheduling later
 		 * for aggregation.
 		 */
 		TX_STAT_INC(txctl->txq->axq_qnum, a_queued_sw);
-		__skb_queue_tail(&tid->buf_q, bf->bf_mpdu);
+		__skb_queue_tail(&tid->buf_q, skb);
 		if (!txctl->an || !txctl->an->sleeping)
 			ath_tx_queue_tid(txctl->txq, tid);
 		return;
 	}
 
+	bf = ath_tx_setup_buffer(sc, txctl->txq, tid, skb);
+	if (!bf)
+		return;
+
+	bf->bf_state.bf_type |= BUF_AMPDU;
 	INIT_LIST_HEAD(&bf_head);
 	list_add(&bf->list, &bf_head);
 
 	/* Add sub-frame to BAW */
-	if (!fi->retries)
-		ath_tx_addto_baw(sc, tid, seqno);
+	ath_tx_addto_baw(sc, tid, bf->bf_state.seqno);
 
 	/* Queue to h/w without aggregation */
 	TX_STAT_INC(txctl->txq->axq_qnum, a_queued_hw);
@@ -1478,13 +1497,21 @@ static void ath_tx_send_ampdu(struct ath
 }
 
 static void ath_tx_send_normal(struct ath_softc *sc, struct ath_txq *txq,
-			       struct ath_atx_tid *tid,
-			       struct list_head *bf_head)
+			       struct ath_atx_tid *tid, struct sk_buff *skb)
 {
-	struct ath_frame_info *fi;
+	struct ath_frame_info *fi = get_frame_info(skb);
+	struct list_head bf_head;
 	struct ath_buf *bf;
 
-	bf = list_first_entry(bf_head, struct ath_buf, list);
+	bf = fi->bf;
+	if (!bf)
+		bf = ath_tx_setup_buffer(sc, txq, tid, skb);
+
+	if (!bf)
+		return;
+
+	INIT_LIST_HEAD(&bf_head);
+	list_add_tail(&bf->list, &bf_head);
 	bf->bf_state.bf_type &= ~BUF_AMPDU;
 
 	/* update starting sequence number for subsequent ADDBA request */
@@ -1492,9 +1519,8 @@ static void ath_tx_send_normal(struct at
 		INCR(tid->seq_start, IEEE80211_SEQ_MAX);
 
 	bf->bf_lastbf = bf;
-	fi = get_frame_info(bf->bf_mpdu);
 	ath_buf_set_rate(sc, bf, fi->framelen);
-	ath_tx_txqaddbuf(sc, txq, bf_head, false);
+	ath_tx_txqaddbuf(sc, txq, &bf_head, false);
 	TX_STAT_INC(txq->axq_qnum, queued);
 }
 
@@ -1717,6 +1743,10 @@ static void ath_buf_set_rate(struct ath_
 
 }
 
+/*
+ * Assign a descriptor (and sequence number if necessary,
+ * and map buffer for DMA. Frees skb on error
+ */
 static struct ath_buf *ath_tx_setup_buffer(struct ath_softc *sc,
 					   struct ath_txq *txq,
 					   struct ath_atx_tid *tid,
@@ -1734,7 +1764,7 @@ static struct ath_buf *ath_tx_setup_buff
 	bf = ath_tx_get_buffer(sc);
 	if (!bf) {
 		ath_dbg(common, ATH_DBG_XMIT, "TX buffers are full\n");
-		return NULL;
+		goto error;
 	}
 
 	ATH_TXBUF_RESET(bf);
@@ -1757,7 +1787,7 @@ static struct ath_buf *ath_tx_setup_buff
 		ath_err(ath9k_hw_common(sc->sc_ah),
 			"dma_mapping_error() on TX\n");
 		ath_tx_return_buffer(sc, bf);
-		return NULL;
+		goto error;
 	}
 
 	frm_type = get_hw_packet_type(skb);
@@ -1779,18 +1809,20 @@ static struct ath_buf *ath_tx_setup_buff
 	fi->bf = bf;
 
 	return bf;
+
+error:
+	dev_kfree_skb_any(skb);
+	return NULL;
 }
 
 /* FIXME: tx power */
-static int ath_tx_start_dma(struct ath_softc *sc, struct sk_buff *skb,
+static void ath_tx_start_dma(struct ath_softc *sc, struct sk_buff *skb,
 			     struct ath_tx_control *txctl)
 {
 	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
-	struct list_head bf_head;
 	struct ath_atx_tid *tid = NULL;
 	struct ath_buf *bf;
-	int ret = 0;
 	u8 tidno;
 
 	spin_lock_bh(&txctl->txq->axq_lock);
@@ -1803,21 +1835,16 @@ static int ath_tx_start_dma(struct ath_s
 		WARN_ON(tid->ac->txq != txctl->txq);
 	}
 
-	bf = ath_tx_setup_buffer(sc, txctl->txq, tid, skb);
-	if (unlikely(!bf)) {
-		ret = -ENOMEM;
-		goto out;
-	}
-
 	if ((tx_info->flags & IEEE80211_TX_CTL_AMPDU) && tid) {
 		/*
 		 * Try aggregation if it's a unicast data frame
 		 * and the destination is HT capable.
 		 */
-		ath_tx_send_ampdu(sc, tid, bf, txctl);
+		ath_tx_send_ampdu(sc, tid, skb, txctl);
 	} else {
-		INIT_LIST_HEAD(&bf_head);
-		list_add_tail(&bf->list, &bf_head);
+		bf = ath_tx_setup_buffer(sc, txctl->txq, tid, skb);
+		if (!bf)
+			goto out;
 
 		bf->bf_state.bfs_paprd = txctl->paprd;
 
@@ -1831,12 +1858,11 @@ static int ath_tx_start_dma(struct ath_s
 		if (tx_info->flags & IEEE80211_TX_CTL_CLEAR_PS_FILT)
 			ath9k_hw_set_clrdmask(sc->sc_ah, bf->bf_desc, true);
 
-		ath_tx_send_normal(sc, txctl->txq, tid, &bf_head);
+		ath_tx_send_normal(sc, txctl->txq, tid, skb);
 	}
 
 out:
 	spin_unlock_bh(&txctl->txq->axq_lock);
-	return ret;
 }
 
 /* Upon failure caller should free skb */
@@ -1904,7 +1930,8 @@ int ath_tx_start(struct ieee80211_hw *hw
 	}
 	spin_unlock_bh(&txq->axq_lock);
 
-	return ath_tx_start_dma(sc, skb, txctl);
+	ath_tx_start_dma(sc, skb, txctl);
+	return 0;
 }
 
 /*****************/