commit 7a9905e64272c8021a8cfaf6015dd0fb8eeeb378
author Rajesh Borundia <rajesh.borundia@qlogic.com> Mon Oct 18 02:03:41 2010 +0000
committer David S. Miller <davem@davemloft.net> Mon Oct 18 07:22:51 2010 -0700
tree 085ccb214fcc14dd2589516bba768a7c23fcef0a
parent 3666e0b04f092f9d9da8a6d6a3820de6c870407c

netxen: fix race in tx stop queue

There is race between netif_stop_queue and netif_stopped_queue
check.So check once again if buffers are available to avoid race.
With above logic we can also get rid of tx lock in process_cmd_ring.

Signed-off-by: Rajesh Borundia <rajesh.borundia@qlogic.com>
Signed-off-by: Amit Kumar Salecha <amit.salecha@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/netxen/netxen_nic_main.c

diff --git a/drivers/net/netxen/netxen_nic_main.c b/drivers/net/netxen/netxen_nic_main.c
index 2c6ceeb..83ee554 100644
--- a/drivers/net/netxen/netxen_nic_main.c
+++ b/drivers/net/netxen/netxen_nic_main.c
@@ -125,11 +125,6 @@
 		struct nx_host_tx_ring *tx_ring)
 {
 	NXWRIO(adapter, tx_ring->crb_cmd_producer, tx_ring->producer);
-
-	if (netxen_tx_avail(tx_ring) <= TX_STOP_THRESH) {
-		netif_stop_queue(adapter->netdev);
-		smp_mb();
-	}
 }
 
 static uint32_t crb_cmd_consumer[4] = {
@@ -1209,7 +1204,7 @@
 		adapter->max_mc_count = 16;
 
 	netdev->netdev_ops	   = &netxen_netdev_ops;
-	netdev->watchdog_timeo     = 2*HZ;
+	netdev->watchdog_timeo     = 5*HZ;
 
 	netxen_nic_change_mtu(netdev, netdev->mtu);
 
@@ -1825,9 +1820,13 @@
 	/* 4 fragments per cmd des */
 	no_of_desc = (frag_count + 3) >> 2;
 
-	if (unlikely(no_of_desc + 2 > netxen_tx_avail(tx_ring))) {
+	if (unlikely(netxen_tx_avail(tx_ring) <= TX_STOP_THRESH)) {
 		netif_stop_queue(netdev);
-		return NETDEV_TX_BUSY;
+		smp_mb();
+		if (netxen_tx_avail(tx_ring) > TX_STOP_THRESH)
+			netif_start_queue(netdev);
+		else
+			return NETDEV_TX_BUSY;
 	}
 
 	producer = tx_ring->producer;