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>
diff --git a/drivers/net/netxen/netxen_nic_main.c b/drivers/net/netxen/netxen_nic_main.c
index 9595520..dc4d593 100644
--- a/drivers/net/netxen/netxen_nic_main.c
+++ b/drivers/net/netxen/netxen_nic_main.c
@@ -317,7 +317,6 @@
adapter->ahw.pdev = pdev;
adapter->ahw.pci_func = pci_func_id;
- spin_lock_init(&adapter->tx_lock);
/* remap phys address */
mem_base = pci_resource_start(pdev, 0); /* 0 is for BAR 0 */
@@ -533,7 +532,6 @@
adapter->watchdog_timer.data = (unsigned long)adapter;
INIT_WORK(&adapter->watchdog_task, netxen_watchdog_task);
adapter->ahw.pdev = pdev;
- adapter->proc_cmd_buf_counter = 0;
adapter->ahw.revision_id = pdev->revision;
/* make sure Window == 1 */
@@ -952,41 +950,17 @@
struct netxen_skb_frag *buffrag;
unsigned int i;
- u32 producer = 0;
+ u32 producer, consumer;
u32 saved_producer = 0;
struct cmd_desc_type0 *hwdesc;
int k;
struct netxen_cmd_buffer *pbuf = NULL;
- static int dropped_packet = 0;
int frag_count;
- u32 local_producer = 0;
- u32 max_tx_desc_count = 0;
- u32 last_cmd_consumer = 0;
int no_of_desc;
+ u32 num_txd = adapter->max_tx_desc_count;
- adapter->stats.xmitcalled++;
frag_count = skb_shinfo(skb)->nr_frags + 1;
- if (unlikely(skb->len <= 0)) {
- dev_kfree_skb_any(skb);
- adapter->stats.badskblen++;
- return NETDEV_TX_OK;
- }
-
- if (frag_count > MAX_BUFFERS_PER_CMD) {
- printk("%s: %s netxen_nic_xmit_frame: frag_count (%d) "
- "too large, can handle only %d frags\n",
- netxen_nic_driver_name, netdev->name,
- frag_count, MAX_BUFFERS_PER_CMD);
- adapter->stats.txdropped++;
- if ((++dropped_packet & 0xff) == 0xff)
- printk("%s: %s droppped packets = %d\n",
- netxen_nic_driver_name, netdev->name,
- dropped_packet);
-
- return NETDEV_TX_OK;
- }
-
/* There 4 fragments per descriptor */
no_of_desc = (frag_count + 3) >> 2;
if (netdev->features & NETIF_F_TSO) {
@@ -1001,27 +975,16 @@
}
}
- spin_lock_bh(&adapter->tx_lock);
- if (adapter->total_threads >= MAX_XMIT_PRODUCERS) {
- goto out_requeue;
+ producer = adapter->cmd_producer;
+ smp_mb();
+ consumer = adapter->last_cmd_consumer;
+ if ((no_of_desc+2) > find_diff_among(producer, consumer, num_txd)) {
+ netif_stop_queue(netdev);
+ smp_mb();
+ return NETDEV_TX_BUSY;
}
- local_producer = adapter->cmd_producer;
- k = adapter->cmd_producer;
- max_tx_desc_count = adapter->max_tx_desc_count;
- last_cmd_consumer = adapter->last_cmd_consumer;
- if ((k + no_of_desc) >=
- ((last_cmd_consumer <= k) ? last_cmd_consumer + max_tx_desc_count :
- last_cmd_consumer)) {
- goto out_requeue;
- }
- k = get_index_range(k, max_tx_desc_count, no_of_desc);
- adapter->cmd_producer = k;
- adapter->total_threads++;
- adapter->num_threads++;
- spin_unlock_bh(&adapter->tx_lock);
/* Copy the descriptors into the hardware */
- producer = local_producer;
saved_producer = producer;
hwdesc = &hw->cmd_desc_head[producer];
memset(hwdesc, 0, sizeof(struct cmd_desc_type0));
@@ -1061,8 +1024,7 @@
/* move to next desc. if there is a need */
if ((i & 0x3) == 0) {
k = 0;
- producer = get_next_index(producer,
- adapter->max_tx_desc_count);
+ producer = get_next_index(producer, num_txd);
hwdesc = &hw->cmd_desc_head[producer];
memset(hwdesc, 0, sizeof(struct cmd_desc_type0));
pbuf = &adapter->cmd_buf_arr[producer];
@@ -1080,7 +1042,6 @@
buffrag->dma = temp_dma;
buffrag->length = temp_len;
- DPRINTK(INFO, "for loop. i=%d k=%d\n", i, k);
switch (k) {
case 0:
hwdesc->buffer1_length = cpu_to_le16(temp_len);
@@ -1101,7 +1062,7 @@
}
frag++;
}
- producer = get_next_index(producer, adapter->max_tx_desc_count);
+ producer = get_next_index(producer, num_txd);
/* might change opcode to TX_TCP_LSO */
netxen_tso_check(adapter, &hw->cmd_desc_head[saved_producer], skb);
@@ -1128,7 +1089,7 @@
/* copy the first 64 bytes */
memcpy(((void *)hwdesc) + 2,
(void *)(skb->data), first_hdr_len);
- producer = get_next_index(producer, max_tx_desc_count);
+ producer = get_next_index(producer, num_txd);
if (more_hdr) {
hwdesc = &hw->cmd_desc_head[producer];
@@ -1141,35 +1102,19 @@
hwdesc,
(hdr_len -
first_hdr_len));
- producer = get_next_index(producer, max_tx_desc_count);
+ producer = get_next_index(producer, num_txd);
}
}
- spin_lock_bh(&adapter->tx_lock);
+ adapter->cmd_producer = producer;
adapter->stats.txbytes += skb->len;
- /* Code to update the adapter considering how many producer threads
- are currently working */
- if ((--adapter->num_threads) == 0) {
- /* This is the last thread */
- u32 crb_producer = adapter->cmd_producer;
- netxen_nic_update_cmd_producer(adapter, crb_producer);
- wmb();
- adapter->total_threads = 0;
- }
+ netxen_nic_update_cmd_producer(adapter, adapter->cmd_producer);
- adapter->stats.xmitfinished++;
+ adapter->stats.xmitcalled++;
netdev->trans_start = jiffies;
- spin_unlock_bh(&adapter->tx_lock);
return NETDEV_TX_OK;
-
-out_requeue:
- netif_stop_queue(netdev);
- adapter->flags |= NETXEN_NETDEV_STATUS;
-
- spin_unlock_bh(&adapter->tx_lock);
- return NETDEV_TX_BUSY;
}
static void netxen_watchdog(unsigned long v)
@@ -1194,9 +1139,13 @@
printk(KERN_ERR "%s %s: transmit timeout, resetting.\n",
netxen_nic_driver_name, adapter->netdev->name);
- netxen_nic_close(adapter->netdev);
- netxen_nic_open(adapter->netdev);
+ netxen_nic_disable_int(adapter);
+ napi_disable(&adapter->napi);
+
adapter->netdev->trans_start = jiffies;
+
+ napi_enable(&adapter->napi);
+ netxen_nic_enable_int(adapter);
netif_wake_queue(adapter->netdev);
}