1 files changed, 26 insertions, 23 deletions

diff --git a/drivers/net/wireless/ath/wcn36xx/dxe.c b/drivers/net/wireless/ath/wcn36xx/dxe.c
index 8e1dbfda6538..aff04ef66266 100644
--- a/drivers/net/wireless/ath/wcn36xx/dxe.c
+++ b/drivers/net/wireless/ath/wcn36xx/dxe.c
@@ -403,8 +403,21 @@ static void reap_tx_dxes(struct wcn36xx *wcn, struct wcn36xx_dxe_ch *ch)
 			dma_unmap_single(wcn->dev, ctl->desc->src_addr_l,
 					 ctl->skb->len, DMA_TO_DEVICE);
 			info = IEEE80211_SKB_CB(ctl->skb);
-			if (!(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS)) {
-				/* Keep frame until TX status comes */
+			if (info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS) {
+				if (info->flags & IEEE80211_TX_CTL_NO_ACK) {
+					info->flags |= IEEE80211_TX_STAT_NOACK_TRANSMITTED;
+					ieee80211_tx_status_irqsafe(wcn->hw, ctl->skb);
+				} else {
+					/* Wait for the TX ack indication or timeout... */
+					spin_lock(&wcn->dxe_lock);
+					if (WARN_ON(wcn->tx_ack_skb))
+						ieee80211_free_txskb(wcn->hw, wcn->tx_ack_skb);
+					wcn->tx_ack_skb = ctl->skb; /* Tracking ref */
+					mod_timer(&wcn->tx_ack_timer, jiffies + HZ / 10);
+					spin_unlock(&wcn->dxe_lock);
+				}
+				/* do not free, ownership transferred to mac80211 status cb */
+			} else {
 				ieee80211_free_txskb(wcn->hw, ctl->skb);
 			}
 
@@ -426,7 +439,6 @@ static irqreturn_t wcn36xx_irq_tx_complete(int irq, void *dev)
 {
 	struct wcn36xx *wcn = (struct wcn36xx *)dev;
 	int int_src, int_reason;
-	bool transmitted = false;
 
 	wcn36xx_dxe_read_register(wcn, WCN36XX_DXE_INT_SRC_RAW_REG, &int_src);
 
@@ -466,7 +478,6 @@ static irqreturn_t wcn36xx_irq_tx_complete(int irq, void *dev)
 		if (int_reason & (WCN36XX_CH_STAT_INT_DONE_MASK |
 				  WCN36XX_CH_STAT_INT_ED_MASK)) {
 			reap_tx_dxes(wcn, &wcn->dxe_tx_h_ch);
-			transmitted = true;
 		}
 	}
 
@@ -479,7 +490,6 @@ static irqreturn_t wcn36xx_irq_tx_complete(int irq, void *dev)
 					   WCN36XX_DXE_0_INT_CLR,
 					   WCN36XX_INT_MASK_CHAN_TX_L);
 
-
 		if (int_reason & WCN36XX_CH_STAT_INT_ERR_MASK ) {
 			wcn36xx_dxe_write_register(wcn,
 						   WCN36XX_DXE_0_INT_ERR_CLR,
@@ -507,25 +517,8 @@ static irqreturn_t wcn36xx_irq_tx_complete(int irq, void *dev)
 		if (int_reason & (WCN36XX_CH_STAT_INT_DONE_MASK |
 				  WCN36XX_CH_STAT_INT_ED_MASK)) {
 			reap_tx_dxes(wcn, &wcn->dxe_tx_l_ch);
-			transmitted = true;
-		}
-	}
-
-	spin_lock(&wcn->dxe_lock);
-	if (wcn->tx_ack_skb && transmitted) {
-		struct ieee80211_tx_info *info = IEEE80211_SKB_CB(wcn->tx_ack_skb);
-
-		/* TX complete, no need to wait for 802.11 ack indication */
-		if (info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS &&
-		    info->flags & IEEE80211_TX_CTL_NO_ACK) {
-			info->flags |= IEEE80211_TX_STAT_NOACK_TRANSMITTED;
-			del_timer(&wcn->tx_ack_timer);
-			ieee80211_tx_status_irqsafe(wcn->hw, wcn->tx_ack_skb);
-			wcn->tx_ack_skb = NULL;
-			ieee80211_wake_queues(wcn->hw);
 		}
 	}
-	spin_unlock(&wcn->dxe_lock);
 
 	return IRQ_HANDLED;
 }
@@ -613,6 +606,10 @@ static int wcn36xx_rx_handle_packets(struct wcn36xx *wcn,
 	dxe = ctl->desc;
 
 	while (!(READ_ONCE(dxe->ctrl) & WCN36xx_DXE_CTRL_VLD)) {
+		/* do not read until we own DMA descriptor */
+		dma_rmb();
+
+		/* read/modify DMA descriptor */
 		skb = ctl->skb;
 		dma_addr = dxe->dst_addr_l;
 		ret = wcn36xx_dxe_fill_skb(wcn->dev, ctl, GFP_ATOMIC);
@@ -623,9 +620,15 @@ static int wcn36xx_rx_handle_packets(struct wcn36xx *wcn,
 			dma_unmap_single(wcn->dev, dma_addr, WCN36XX_PKT_SIZE,
 					DMA_FROM_DEVICE);
 			wcn36xx_rx_skb(wcn, skb);
-		} /* else keep old skb not submitted and use it for rx DMA */
+		}
+		/* else keep old skb not submitted and reuse it for rx DMA
+		 * (dropping the packet that it contained)
+		 */
 
+		/* flush descriptor changes before re-marking as valid */
+		dma_wmb();
 		dxe->ctrl = ctrl;
+
 		ctl = ctl->next;
 		dxe = ctl->desc;
 	}