netxen: remove low level tx lock

o eliminate tx lock in netxen adapter struct, instead pound on netdev
  tx lock appropriately.
o remove old "concurrent transmit" code that unnecessarily drops and
  reacquires tx lock in hard_xmit_frame(), this is already serialized
  the netdev xmit lock.
o reduce scope of tx lock in tx cleanup. tx cleanup operates on
  different section of the ring than transmitting cpus and is
  guarded by producer and consumer indices. This fixes a race
  caused by rx softirq preemption on realtime kernels.

Signed-off-by: Dhananjay Phadke <dhananjay@netxen.com>
Tested-by: Vernon Mauery <mauery@us.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 3 insertions, 11 deletions

diff --git a/drivers/net/netxen/netxen_nic.h b/drivers/net/netxen/netxen_nic.h
index 8b6546ccb47b..070421b9e4f9 100644
--- a/drivers/net/netxen/netxen_nic.h
+++ b/drivers/net/netxen/netxen_nic.h
@@ -85,7 +85,7 @@
         (sizeof(struct netxen_cmd_buffer) * adapter->max_tx_desc_count)
 #define RCV_BUFFSIZE    \
         (sizeof(struct netxen_rx_buffer) * rcv_desc->max_rx_desc_count)
-#define find_diff_among(a,b,range) ((a)<=(b)?((b)-(a)):((b)+(range)-(a)))
+#define find_diff_among(a,b,range) ((a)<(b)?((b)-(a)):((b)+(range)-(a)))
 
 #define NETXEN_NETDEV_STATUS            0x1
 #define NETXEN_RCV_PRODUCER_OFFSET      0
@@ -204,7 +204,7 @@ enum {
                         ? RCV_DESC_LRO :        \
                         (RCV_DESC_NORMAL)))
 
-#define MAX_CMD_DESCRIPTORS             1024
+#define MAX_CMD_DESCRIPTORS             4096
 #define MAX_RCV_DESCRIPTORS             16384
 #define MAX_CMD_DESCRIPTORS_HOST        (MAX_CMD_DESCRIPTORS / 4)
 #define MAX_RCV_DESCRIPTORS_1G          (MAX_RCV_DESCRIPTORS / 4)
@@ -824,9 +824,7 @@ struct netxen_adapter_stats {
         u64  uphcong;
         u64  upmcong;
         u64  updunno;
-        u64  skbfreed;
         u64  txdropped;
-        u64  txnullskb;
         u64  csummed;
         u64  no_rcv;
         u64  rxbytes;
@@ -888,8 +886,6 @@ struct netxen_adapter {
         int mtu;
         int portnum;
 
-        spinlock_t tx_lock;
-        spinlock_t lock;
         struct work_struct watchdog_task;
         struct timer_list watchdog_timer;
         struct work_struct  tx_timeout_task;
@@ -898,16 +894,12 @@ struct netxen_adapter {
 
         u32 cmd_producer;
         __le32 *cmd_consumer;
-
         u32 last_cmd_consumer;
+
         u32 max_tx_desc_count;
         u32 max_rx_desc_count;
         u32 max_jumbo_rx_desc_count;
         u32 max_lro_rx_desc_count;
-        /* Num of instances active on cmd buffer ring */
-        u32 proc_cmd_buf_counter;
-
-        u32 num_threads, total_threads; /*Use to keep track of xmit threads */
 
         u32 flags;
         u32 irq;