netxen: fix tx ring accounting

This forces every update of tx ring producer to check for
availability of space for next full TSO command. Earlier
firmware control commands didn't care to pause tx queue.

Stop the tx queue if there's not enough space to transmit one full
LSO command left on the tx ring after current transmit. This avoids
returning NETDEV_TX_BUSY after checking distance between producer
and consumer on every cpu.

Restart the tx queue only if we have cleaned up enough tx
descriptors.

Signed-off-by: Dhananjay Phadke <dhananjay@netxen.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 1 deletions

diff --git a/drivers/net/netxen/netxen_nic.h b/drivers/net/netxen/netxen_nic.h
index ab11c2b3f0fe..970cedeb5f37 100644
--- a/drivers/net/netxen/netxen_nic.h
+++ b/drivers/net/netxen/netxen_nic.h
@@ -169,6 +169,7 @@
 #define MAX_NUM_CARDS           4
 
 #define MAX_BUFFERS_PER_CMD     32
+#define TX_STOP_THRESH          ((MAX_SKB_FRAGS >> 2) + 4)
 
 /*
  * Following are the states of the Phantom. Phantom will set them and
@@ -1436,7 +1437,7 @@ int netxen_nic_set_mac(struct net_device *netdev, void *p);
 struct net_device_stats *netxen_nic_get_stats(struct net_device *netdev);
 
 void netxen_nic_update_cmd_producer(struct netxen_adapter *adapter,
-                struct nx_host_tx_ring *tx_ring, uint32_t crb_producer);
+                struct nx_host_tx_ring *tx_ring);
 
 /*
  * NetXen Board information
@@ -1538,6 +1539,14 @@ dma_watchdog_wakeup(struct netxen_adapter *adapter)
 }
 
 
+static inline u32 netxen_tx_avail(struct nx_host_tx_ring *tx_ring)
+{
+        smp_mb();
+        return find_diff_among(tx_ring->producer,
+                        tx_ring->sw_consumer, tx_ring->num_desc);
+
+}
+
 int netxen_get_flash_mac_addr(struct netxen_adapter *adapter, __le64 *mac);
 int netxen_p3_get_mac_addr(struct netxen_adapter *adapter, __le64 *mac);
 extern void netxen_change_ringparam(struct netxen_adapter *adapter);