[PATCH 1/2 net] ibmvnic: Fix overflowing firmware/hardware TX queue

@@ -705,6 +705,7 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 	u8 *hdrs = (u8 *)&adapter->tx_rx_desc_req;
 	struct device *dev = &adapter->vdev->dev;
 	struct ibmvnic_tx_buff *tx_buff = NULL;
+	struct ibmvnic_sub_crq_queue *tx_scrq;
 	struct ibmvnic_tx_pool *tx_pool;
 	unsigned int tx_send_failed = 0;
 	unsigned int tx_map_failed = 0;

@@ -724,6 +725,7 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 	int ret = 0;
 
 	tx_pool = &adapter->tx_pool[queue_num];
+	tx_scrq = adapter->tx_scrq[queue_num];
 	txq = netdev_get_tx_queue(netdev, skb_get_queue_mapping(skb));
 	handle_array = (u64 *)((u8 *)(adapter->login_rsp_buf) +
 				   be32_to_cpu(adapter->login_rsp_buf->

@@ -826,6 +828,14 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 		ret = NETDEV_TX_BUSY;
 		goto out;
 	}
+
+	atomic_inc(&tx_scrq->used);
+
+	if (atomic_read(&tx_scrq->used) >= adapter->req_tx_entries_per_subcrq) {
+		netdev_info(netdev, "Stopping queue %d\n", queue_num);
+		netif_stop_subqueue(netdev, queue_num);
+	}
+
 	tx_packets++;
 	tx_bytes += skb->len;
 	txq->trans_start = jiffies;

@@ -1213,6 +1223,7 @@ static struct ibmvnic_sub_crq_queue *init_sub_crq_queue(struct ibmvnic_adapter
 	scrq->adapter = adapter;
 	scrq->size = 4 * PAGE_SIZE / sizeof(*scrq->msgs);
 	scrq->cur = 0;
+	atomic_set(&scrq->used, 0);
 	scrq->rx_skb_top = NULL;
 	spin_lock_init(&scrq->lock);
 

@@ -1355,8 +1366,22 @@ static int ibmvnic_complete_tx(struct ibmvnic_adapter *adapter,
 						 DMA_TO_DEVICE);
 			}
 
-			if (txbuff->last_frag)
+			if (txbuff->last_frag) {
+				atomic_dec(&scrq->used);
+
+				if (atomic_read(&scrq->used) <=
+				    (adapter->req_tx_entries_per_subcrq / 2) &&
+				    netif_subqueue_stopped(adapter->netdev,
+							   txbuff->skb)) {
+					netif_wake_subqueue(adapter->netdev,
+							    scrq->pool_index);
+					netdev_dbg(adapter->netdev,
+						   "Started queue %d\n",
+						   scrq->pool_index);
+				}
+
 				dev_kfree_skb_any(txbuff->skb);
+			}
 
 			adapter->tx_pool[pool].free_map[adapter->tx_pool[pool].
 						     producer_index] = index;

@@ -863,6 +863,7 @@ struct ibmvnic_sub_crq_queue {
 	spinlock_t lock;
 	struct sk_buff *rx_skb_top;
 	struct ibmvnic_adapter *adapter;
+	atomic_t used;
 };
 
 struct ibmvnic_long_term_buff {

@@ -404,7 +404,7 @@ static int ibmvnic_open(struct net_device *netdev)
 	send_map_query(adapter);
 	for (i = 0; i < rxadd_subcrqs; i++) {
 		init_rx_pool(adapter, &adapter->rx_pool[i],
-			     IBMVNIC_BUFFS_PER_POOL, i,
+			     adapter->req_rx_add_entries_per_subcrq, i,
 			     be64_to_cpu(size_array[i]), 1);
 		if (alloc_rx_pool(adapter, &adapter->rx_pool[i])) {
 			dev_err(dev, "Couldn't alloc rx pool\n");

@@ -419,23 +419,23 @@ static int ibmvnic_open(struct net_device *netdev)
 	for (i = 0; i < tx_subcrqs; i++) {
 		tx_pool = &adapter->tx_pool[i];
 		tx_pool->tx_buff =
-		    kcalloc(adapter->max_tx_entries_per_subcrq,
+		    kcalloc(adapter->req_tx_entries_per_subcrq,
 			    sizeof(struct ibmvnic_tx_buff), GFP_KERNEL);
 		if (!tx_pool->tx_buff)
 			goto tx_pool_alloc_failed;
 
 		if (alloc_long_term_buff(adapter, &tx_pool->long_term_buff,
-					 adapter->max_tx_entries_per_subcrq *
+					 adapter->req_tx_entries_per_subcrq *
 					 adapter->req_mtu))
 			goto tx_ltb_alloc_failed;
 
 		tx_pool->free_map =
-		    kcalloc(adapter->max_tx_entries_per_subcrq,
+		    kcalloc(adapter->req_tx_entries_per_subcrq,
 			    sizeof(int), GFP_KERNEL);
 		if (!tx_pool->free_map)
 			goto tx_fm_alloc_failed;
 
-		for (j = 0; j < adapter->max_tx_entries_per_subcrq; j++)
+		for (j = 0; j < adapter->req_tx_entries_per_subcrq; j++)
 			tx_pool->free_map[j] = j;
 
 		tx_pool->consumer_index = 0;

@@ -746,7 +746,7 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 
 	tx_pool->consumer_index =
 	    (tx_pool->consumer_index + 1) %
-		adapter->max_tx_entries_per_subcrq;
+		adapter->req_tx_entries_per_subcrq;
 
 	tx_buff = &tx_pool->tx_buff[index];
 	tx_buff->skb = skb;

@@ -819,7 +819,7 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 
 		if (tx_pool->consumer_index == 0)
 			tx_pool->consumer_index =
-				adapter->max_tx_entries_per_subcrq - 1;
+				adapter->req_tx_entries_per_subcrq - 1;
 		else
 			tx_pool->consumer_index--;
 

@@ -1387,7 +1387,7 @@ static int ibmvnic_complete_tx(struct ibmvnic_adapter *adapter,
 						     producer_index] = index;
 			adapter->tx_pool[pool].producer_index =
 			    (adapter->tx_pool[pool].producer_index + 1) %
-			    adapter->max_tx_entries_per_subcrq;
+			    adapter->req_tx_entries_per_subcrq;
 		}
 		/* remove tx_comp scrq*/
 		next->tx_comp.first = 0;