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>

diff --git a/drivers/net/netxen/netxen_nic.h b/drivers/net/netxen/netxen_nic.h
index ab11c2b3f0fe0ab2ddb42dc7f430a7a6311d5251..970cedeb5f37ba6923454aea9a2fc41ef63519cc 100644 (file)
--- 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);

diff --git a/drivers/net/netxen/netxen_nic_hw.c b/drivers/net/netxen/netxen_nic_hw.c
index 9702509ce3c5088e52e1456f5820ac32a42f117a..ce3b89d2cbb6c11e3ab5749446bec617dcc4edeb 100644 (file)
--- a/drivers/net/netxen/netxen_nic_hw.c
+++ b/drivers/net/netxen/netxen_nic_hw.c
@@ -488,7 +488,7 @@ netxen_send_cmd_descs(struct netxen_adapter *adapter,
 
        tx_ring->producer = producer;
 
-       netxen_nic_update_cmd_producer(adapter, tx_ring, producer);
+       netxen_nic_update_cmd_producer(adapter, tx_ring);
 
        netif_tx_unlock_bh(adapter->netdev);
 

diff --git a/drivers/net/netxen/netxen_nic_init.c b/drivers/net/netxen/netxen_nic_init.c
index 6f77ad58e3b3d00752861b9626a95493041cbf22..bdb143d2b5c7a4f2032d19d746875dc3dfef01db 100644 (file)
--- a/drivers/net/netxen/netxen_nic_init.c
+++ b/drivers/net/netxen/netxen_nic_init.c
@@ -1292,7 +1292,6 @@ int netxen_process_cmd_ring(struct netxen_adapter *adapter)
                return 1;
 
        sw_consumer = tx_ring->sw_consumer;
-       barrier(); /* hw_consumer can change underneath */
        hw_consumer = le32_to_cpu(*(tx_ring->hw_consumer));
 
        while (sw_consumer != hw_consumer) {
@@ -1319,14 +1318,15 @@ int netxen_process_cmd_ring(struct netxen_adapter *adapter)
                        break;
        }
 
-       tx_ring->sw_consumer = sw_consumer;
-
        if (count && netif_running(netdev)) {
+               tx_ring->sw_consumer = sw_consumer;
+
                smp_mb();
+
                if (netif_queue_stopped(netdev) && netif_carrier_ok(netdev)) {
                        netif_tx_lock(netdev);
-                       netif_wake_queue(netdev);
-                       smp_mb();
+                       if (netxen_tx_avail(tx_ring) > TX_STOP_THRESH)
+                               netif_wake_queue(netdev);
                        netif_tx_unlock(netdev);
                }
        }
@@ -1343,7 +1343,6 @@ int netxen_process_cmd_ring(struct netxen_adapter *adapter)
         * There is still a possible race condition and the host could miss an
         * interrupt. The card has to take care of this.
         */
-       barrier(); /* hw_consumer can change underneath */
        hw_consumer = le32_to_cpu(*(tx_ring->hw_consumer));
        done = (sw_consumer == hw_consumer);
        spin_unlock(&adapter->tx_clean_lock);

diff --git a/drivers/net/netxen/netxen_nic_main.c b/drivers/net/netxen/netxen_nic_main.c
index 98737ef72936a34cef220d06cdfb30be0d941424..71daa3d5f114174f7ec13015b49fa8d45cb9d2a6 100644 (file)
--- a/drivers/net/netxen/netxen_nic_main.c
+++ b/drivers/net/netxen/netxen_nic_main.c
@@ -107,9 +107,14 @@ static uint32_t crb_cmd_producer[4] = {
 
 void
 netxen_nic_update_cmd_producer(struct netxen_adapter *adapter,
-               struct nx_host_tx_ring *tx_ring, u32 producer)
+               struct nx_host_tx_ring *tx_ring)
 {
-       NXWR32(adapter, tx_ring->crb_cmd_producer, producer);
+       NXWR32(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] = {
@@ -119,9 +124,9 @@ static uint32_t crb_cmd_consumer[4] = {
 
 static inline void
 netxen_nic_update_cmd_consumer(struct netxen_adapter *adapter,
-               struct nx_host_tx_ring *tx_ring, u32 consumer)
+               struct nx_host_tx_ring *tx_ring)
 {
-       NXWR32(adapter, tx_ring->crb_cmd_consumer, consumer);
+       NXWR32(adapter, tx_ring->crb_cmd_consumer, tx_ring->sw_consumer);
 }
 
 static uint32_t msi_tgt_status[8] = {
@@ -900,8 +905,11 @@ netxen_nic_attach(struct netxen_adapter *adapter)
                tx_ring->crb_cmd_producer = crb_cmd_producer[adapter->portnum];
                tx_ring->crb_cmd_consumer = crb_cmd_consumer[adapter->portnum];
 
-               netxen_nic_update_cmd_producer(adapter, tx_ring, 0);
-               netxen_nic_update_cmd_consumer(adapter, tx_ring, 0);
+               tx_ring->producer = 0;
+               tx_ring->sw_consumer = 0;
+
+               netxen_nic_update_cmd_producer(adapter, tx_ring);
+               netxen_nic_update_cmd_consumer(adapter, tx_ring);
        }
 
        for (ring = 0; ring < adapter->max_rds_rings; ring++) {
@@ -1362,7 +1370,7 @@ netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
        dma_addr_t temp_dma;
        int i, k;
 
-       u32 producer, consumer;
+       u32 producer;
        int frag_count, no_of_desc;
        u32 num_txd = tx_ring->num_desc;
        bool is_tso = false;
@@ -1372,15 +1380,13 @@ netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
        /* 4 fragments per cmd des */
        no_of_desc = (frag_count + 3) >> 2;
 
-       producer = tx_ring->producer;
-       smp_mb();
-       consumer = tx_ring->sw_consumer;
-       if ((no_of_desc+2) >= find_diff_among(producer, consumer, num_txd)) {
+       if (unlikely(no_of_desc + 2) > netxen_tx_avail(tx_ring)) {
                netif_stop_queue(netdev);
-               smp_mb();
                return NETDEV_TX_BUSY;
        }
 
+       producer = tx_ring->producer;
+
        hwdesc = &tx_ring->desc_head[producer];
        netxen_clear_cmddesc((u64 *)hwdesc);
        pbuf = &tx_ring->cmd_buf_arr[producer];
@@ -1493,7 +1499,7 @@ netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
        tx_ring->producer = producer;
        adapter->stats.txbytes += skb->len;
 
-       netxen_nic_update_cmd_producer(adapter, tx_ring, producer);
+       netxen_nic_update_cmd_producer(adapter, tx_ring);
 
        adapter->stats.xmitcalled++;