netxen: fix deadlock on dev close

netxen: fix deadlock on dev close

The tx ring accounting fix in commit cb2107be43d2fc5eadec58b92b
("netxen: fix tx ring accounting") introduced intermittent
deadlock when inteface is going down.

This was possibly combined effect of speculative tx pause,
calling netif_tx_lock instead of queue lock and unclean
synchronization with napi which could end up unmasking
interrupt.

Signed-off-by: Dhananjay Phadke <dhananjay@netxen.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/netxen/netxen_nic_main.c b/drivers/net/netxen/netxen_nic_main.c
index 9a7c4c8..370c52f 100644
--- a/drivers/net/netxen/netxen_nic_main.c
+++ b/drivers/net/netxen/netxen_nic_main.c
@@ -215,9 +215,9 @@
 
 	for (ring = 0; ring < adapter->max_sds_rings; ring++) {
 		sds_ring = &recv_ctx->sds_rings[ring];
-		napi_disable(&sds_ring->napi);
 		netxen_nic_disable_int(sds_ring);
-		synchronize_irq(sds_ring->irq);
+		napi_synchronize(&sds_ring->napi);
+		napi_disable(&sds_ring->napi);
 	}
 }
 
@@ -833,11 +833,11 @@
 
 	adapter->ahw.linkup = 0;
 
-	netxen_napi_enable(adapter);
-
 	if (adapter->max_sds_rings > 1)
 		netxen_config_rss(adapter, 1);
 
+	netxen_napi_enable(adapter);
+
 	if (adapter->capabilities & NX_FW_CAPABILITY_LINK_NOTIFICATION)
 		netxen_linkevent_request(adapter, 1);
 	else
@@ -851,8 +851,9 @@
 static void
 netxen_nic_down(struct netxen_adapter *adapter, struct net_device *netdev)
 {
+	spin_lock(&adapter->tx_clean_lock);
 	netif_carrier_off(netdev);
-	netif_stop_queue(netdev);
+	netif_tx_disable(netdev);
 
 	if (adapter->stop_port)
 		adapter->stop_port(adapter);
@@ -863,9 +864,10 @@
 	netxen_napi_disable(adapter);
 
 	netxen_release_tx_buffers(adapter);
+	spin_unlock(&adapter->tx_clean_lock);
 
-	FLUSH_SCHEDULED_WORK();
 	del_timer_sync(&adapter->watchdog_timer);
+	FLUSH_SCHEDULED_WORK();
 }
 
 
@@ -1645,6 +1647,9 @@
 	struct netxen_adapter *adapter =
 		container_of(work, struct netxen_adapter, tx_timeout_task);
 
+	if (!netif_running(adapter->netdev))
+		return;
+
 	printk(KERN_ERR "%s %s: transmit timeout, resetting.\n",
 	       netxen_nic_driver_name, adapter->netdev->name);
 
@@ -1757,7 +1762,8 @@
 
 	if ((work_done < budget) && tx_complete) {
 		napi_complete(&sds_ring->napi);
-		netxen_nic_enable_int(sds_ring);
+		if (netif_running(adapter->netdev))
+			netxen_nic_enable_int(sds_ring);
 	}
 
 	return work_done;