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>

diff --git a/drivers/net/netxen/netxen_nic.h b/drivers/net/netxen/netxen_nic.h
index 6dca3574e35507a94ca7e5b1b518a06199e99e03..92f89af0720e666e32be4840f24c5d937d83f849 100644 (file)
--- a/drivers/net/netxen/netxen_nic.h
+++ b/drivers/net/netxen/netxen_nic.h
@@ -175,7 +175,10 @@
 #define        MAX_NUM_CARDS           4
 
 #define MAX_BUFFERS_PER_CMD    32
-#define TX_STOP_THRESH         ((MAX_SKB_FRAGS >> 2) + 4)
+#define MAX_TSO_HEADER_DESC    2
+#define MGMT_CMD_DESC_RESV     4
+#define TX_STOP_THRESH         ((MAX_SKB_FRAGS >> 2) + MAX_TSO_HEADER_DESC \
+                                                       + MGMT_CMD_DESC_RESV)
 #define NX_MAX_TX_TIMEOUTS     2
 
 /*

diff --git a/drivers/net/netxen/netxen_nic_hw.c b/drivers/net/netxen/netxen_nic_hw.c
index 29d7b93d0493be12e4a5def185282371b5cd400d..10e2f13d8903133cfdae95c3fc07ee5a24ae76d5 100644 (file)
--- a/drivers/net/netxen/netxen_nic_hw.c
+++ b/drivers/net/netxen/netxen_nic_hw.c
@@ -598,8 +598,14 @@ netxen_send_cmd_descs(struct netxen_adapter *adapter,
 
        if (nr_desc >= netxen_tx_avail(tx_ring)) {
                netif_tx_stop_queue(tx_ring->txq);
-               __netif_tx_unlock_bh(tx_ring->txq);
-               return -EBUSY;
+               smp_mb();
+               if (netxen_tx_avail(tx_ring) > nr_desc) {
+                       if (netxen_tx_avail(tx_ring) > TX_STOP_THRESH)
+                               netif_tx_wake_queue(tx_ring->txq);
+               } else {
+                       __netif_tx_unlock_bh(tx_ring->txq);
+                       return -EBUSY;
+               }
        }
 
        do {

diff --git a/drivers/net/netxen/netxen_nic_init.c b/drivers/net/netxen/netxen_nic_init.c
index a2d805aa75cd3a9698803d4358cbf1aa412f2330..95fe552aa2795a1a3a38bd5263c1eea8cfff5d13 100644 (file)
--- a/drivers/net/netxen/netxen_nic_init.c
+++ b/drivers/net/netxen/netxen_nic_init.c
@@ -1763,14 +1763,10 @@ int netxen_process_cmd_ring(struct netxen_adapter *adapter)
 
                smp_mb();
 
-               if (netif_queue_stopped(netdev) && netif_carrier_ok(netdev)) {
-                       __netif_tx_lock(tx_ring->txq, smp_processor_id());
-                       if (netxen_tx_avail(tx_ring) > TX_STOP_THRESH) {
+               if (netif_queue_stopped(netdev) && netif_carrier_ok(netdev))
+                       if (netxen_tx_avail(tx_ring) > TX_STOP_THRESH)
                                netif_wake_queue(netdev);
-                               adapter->tx_timeo_cnt = 0;
-                       }
-                       __netif_tx_unlock(tx_ring->txq);
-               }
+               adapter->tx_timeo_cnt = 0;
        }
        /*
         * If everything is freed up to consumer then check if the ring is full

diff --git a/drivers/net/netxen/netxen_nic_main.c b/drivers/net/netxen/netxen_nic_main.c
index 2c6ceeb592b3d4d7b1fe8cf12fb1de1f265f568e..83ee5544aced3d56a1c4c8aa7e49f164cc655a50 100644 (file)
--- a/drivers/net/netxen/netxen_nic_main.c
+++ b/drivers/net/netxen/netxen_nic_main.c
@@ -125,11 +125,6 @@ netxen_nic_update_cmd_producer(struct netxen_adapter *adapter,
                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 @@ netxen_setup_netdev(struct netxen_adapter *adapter,
                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 @@ netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
        /* 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;