Merge branch 'mlx4_en-fixes'

Tariq Toukan says:

====================
mlx4_en fixes

This patchset by Moshe contains fixes to the mlx4 Eth driver,
addressing issues in restart flow.

Patch 1 protects the restart task from being rescheduled while active.
  Please queue for -stable >= v2.6.
Patch 2 reconstructs SQs stuck in error state, and adds prints for improved
  debuggability.
  Please queue for -stable >= v3.12.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/en_netdev.c

@@ -1378,8 +1378,10 @@ static void mlx4_en_tx_timeout(struct net_device *dev, unsigned int txqueue)
 		tx_ring->cons, tx_ring->prod);
 
 	priv->port_stats.tx_timeout++;
-	en_dbg(DRV, priv, "Scheduling watchdog\n");
-	queue_work(mdev->workqueue, &priv->watchdog_task);
+	if (!test_and_set_bit(MLX4_EN_STATE_FLAG_RESTARTING, &priv->state)) {
+		en_dbg(DRV, priv, "Scheduling port restart\n");
+		queue_work(mdev->workqueue, &priv->restart_task);
+	}
 }
 
 
@@ -1733,6 +1735,7 @@ int mlx4_en_start_port(struct net_device *dev)
 				mlx4_en_deactivate_cq(priv, cq);
 				goto tx_err;
 			}
+			clear_bit(MLX4_EN_TX_RING_STATE_RECOVERING, &tx_ring->state);
 			if (t != TX_XDP) {
 				tx_ring->tx_queue = netdev_get_tx_queue(dev, i);
 				tx_ring->recycle_ring = NULL;
@@ -1829,6 +1832,7 @@ int mlx4_en_start_port(struct net_device *dev)
 		local_bh_enable();
 	}
 
+	clear_bit(MLX4_EN_STATE_FLAG_RESTARTING, &priv->state);
 	netif_tx_start_all_queues(dev);
 	netif_device_attach(dev);
 
@@ -1999,7 +2003,7 @@ void mlx4_en_stop_port(struct net_device *dev, int detach)
 static void mlx4_en_restart(struct work_struct *work)
 {
 	struct mlx4_en_priv *priv = container_of(work, struct mlx4_en_priv,
-						 watchdog_task);
+						 restart_task);
 	struct mlx4_en_dev *mdev = priv->mdev;
 	struct net_device *dev = priv->dev;
 
@@ -2377,7 +2381,7 @@ static int mlx4_en_change_mtu(struct net_device *dev, int new_mtu)
 	if (netif_running(dev)) {
 		mutex_lock(&mdev->state_lock);
 		if (!mdev->device_up) {
-			/* NIC is probably restarting - let watchdog task reset
+			/* NIC is probably restarting - let restart task reset
 			 * the port */
 			en_dbg(DRV, priv, "Change MTU called with card down!?\n");
 		} else {
@@ -2386,7 +2390,9 @@ static int mlx4_en_change_mtu(struct net_device *dev, int new_mtu)
 			if (err) {
 				en_err(priv, "Failed restarting port:%d\n",
 					 priv->port);
-				queue_work(mdev->workqueue, &priv->watchdog_task);
+				if (!test_and_set_bit(MLX4_EN_STATE_FLAG_RESTARTING,
+						      &priv->state))
+					queue_work(mdev->workqueue, &priv->restart_task);
 			}
 		}
 		mutex_unlock(&mdev->state_lock);
@@ -2792,7 +2798,8 @@ static int mlx4_xdp_set(struct net_device *dev, struct bpf_prog *prog)
 		if (err) {
 			en_err(priv, "Failed starting port %d for XDP change\n",
 			       priv->port);
-			queue_work(mdev->workqueue, &priv->watchdog_task);
+			if (!test_and_set_bit(MLX4_EN_STATE_FLAG_RESTARTING, &priv->state))
+				queue_work(mdev->workqueue, &priv->restart_task);
 		}
 	}
 
@@ -3165,7 +3172,7 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
 	priv->counter_index = MLX4_SINK_COUNTER_INDEX(mdev->dev);
 	spin_lock_init(&priv->stats_lock);
 	INIT_WORK(&priv->rx_mode_task, mlx4_en_do_set_rx_mode);
-	INIT_WORK(&priv->watchdog_task, mlx4_en_restart);
+	INIT_WORK(&priv->restart_task, mlx4_en_restart);
 	INIT_WORK(&priv->linkstate_task, mlx4_en_linkstate);
 	INIT_DELAYED_WORK(&priv->stats_task, mlx4_en_do_get_stats);
 	INIT_DELAYED_WORK(&priv->service_task, mlx4_en_service_task);

drivers/net/ethernet/mellanox/mlx4/en_tx.c

@@ -392,6 +392,35 @@ int mlx4_en_free_tx_buf(struct net_device *dev, struct mlx4_en_tx_ring *ring)
 	return cnt;
 }
 
+static void mlx4_en_handle_err_cqe(struct mlx4_en_priv *priv, struct mlx4_err_cqe *err_cqe,
+				   u16 cqe_index, struct mlx4_en_tx_ring *ring)
+{
+	struct mlx4_en_dev *mdev = priv->mdev;
+	struct mlx4_en_tx_info *tx_info;
+	struct mlx4_en_tx_desc *tx_desc;
+	u16 wqe_index;
+	int desc_size;
+
+	en_err(priv, "CQE error - cqn 0x%x, ci 0x%x, vendor syndrome: 0x%x syndrome: 0x%x\n",
+	       ring->sp_cqn, cqe_index, err_cqe->vendor_err_syndrome, err_cqe->syndrome);
+	print_hex_dump(KERN_WARNING, "", DUMP_PREFIX_OFFSET, 16, 1, err_cqe, sizeof(*err_cqe),
+		       false);
+
+	wqe_index = be16_to_cpu(err_cqe->wqe_index) & ring->size_mask;
+	tx_info = &ring->tx_info[wqe_index];
+	desc_size = tx_info->nr_txbb << LOG_TXBB_SIZE;
+	en_err(priv, "Related WQE - qpn 0x%x, wqe index 0x%x, wqe size 0x%x\n", ring->qpn,
+	       wqe_index, desc_size);
+	tx_desc = ring->buf + (wqe_index << LOG_TXBB_SIZE);
+	print_hex_dump(KERN_WARNING, "", DUMP_PREFIX_OFFSET, 16, 1, tx_desc, desc_size, false);
+
+	if (test_and_set_bit(MLX4_EN_STATE_FLAG_RESTARTING, &priv->state))
+		return;
+
+	en_err(priv, "Scheduling port restart\n");
+	queue_work(mdev->workqueue, &priv->restart_task);
+}
+
 int mlx4_en_process_tx_cq(struct net_device *dev,
 			  struct mlx4_en_cq *cq, int napi_budget)
 {
@@ -438,13 +467,10 @@ int mlx4_en_process_tx_cq(struct net_device *dev,
 		dma_rmb();
 
 		if (unlikely((cqe->owner_sr_opcode & MLX4_CQE_OPCODE_MASK) ==
-			     MLX4_CQE_OPCODE_ERROR)) {
-			struct mlx4_err_cqe *cqe_err = (struct mlx4_err_cqe *)cqe;
-
-			en_err(priv, "CQE error - vendor syndrome: 0x%x syndrome: 0x%x\n",
-			       cqe_err->vendor_err_syndrome,
-			       cqe_err->syndrome);
-		}
+			     MLX4_CQE_OPCODE_ERROR))
+			if (!test_and_set_bit(MLX4_EN_TX_RING_STATE_RECOVERING, &ring->state))
+				mlx4_en_handle_err_cqe(priv, (struct mlx4_err_cqe *)cqe, index,
+						       ring);
 
 		/* Skip over last polled CQE */
 		new_index = be16_to_cpu(cqe->wqe_index) & size_mask;

drivers/net/ethernet/mellanox/mlx4/mlx4_en.h

@@ -271,6 +271,10 @@ struct mlx4_en_page_cache {
 	} buf[MLX4_EN_CACHE_SIZE];
 };
 
+enum {
+	MLX4_EN_TX_RING_STATE_RECOVERING,
+};
+
 struct mlx4_en_priv;
 
 struct mlx4_en_tx_ring {
@@ -317,6 +321,7 @@ struct mlx4_en_tx_ring {
 	 * Only queue_stopped might be used if BQL is not properly working.
 	 */
 	unsigned long		queue_stopped;
+	unsigned long		state;
 	struct mlx4_hwq_resources sp_wqres;
 	struct mlx4_qp		sp_qp;
 	struct mlx4_qp_context	sp_context;
@@ -530,6 +535,10 @@ struct mlx4_en_stats_bitmap {
 	struct mutex mutex; /* for mutual access to stats bitmap */
 };
 
+enum {
+	MLX4_EN_STATE_FLAG_RESTARTING,
+};
+
 struct mlx4_en_priv {
 	struct mlx4_en_dev *mdev;
 	struct mlx4_en_port_profile *prof;
@@ -595,7 +604,7 @@ struct mlx4_en_priv {
 	struct mlx4_en_cq *rx_cq[MAX_RX_RINGS];
 	struct mlx4_qp drop_qp;
 	struct work_struct rx_mode_task;
-	struct work_struct watchdog_task;
+	struct work_struct restart_task;
 	struct work_struct linkstate_task;
 	struct delayed_work stats_task;
 	struct delayed_work service_task;
@@ -641,6 +650,7 @@ struct mlx4_en_priv {
 	u32 pflags;
 	u8 rss_key[MLX4_EN_RSS_KEY_SIZE];
 	u8 rss_hash_fn;
+	unsigned long state;
 };
 
 enum mlx4_en_wol {