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netxen: remove low level tx lock
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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>
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Dhananjay Phadke authored and Jeff Garzik committed Mar 26, 2008
1 parent 05aaa02 commit ba53e6b
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Showing 4 changed files with 43 additions and 157 deletions.
14 changes: 3 additions & 11 deletions drivers/net/netxen/netxen_nic.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand All @@ -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;
Expand Down
2 changes: 0 additions & 2 deletions drivers/net/netxen/netxen_nic_ethtool.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -70,9 +70,7 @@ static const struct netxen_nic_stats netxen_nic_gstrings_stats[] = {
{"uphcong", NETXEN_NIC_STAT(stats.uphcong)},
{"upmcong", NETXEN_NIC_STAT(stats.upmcong)},
{"updunno", NETXEN_NIC_STAT(stats.updunno)},
{"skb_freed", NETXEN_NIC_STAT(stats.skbfreed)},
{"tx_dropped", NETXEN_NIC_STAT(stats.txdropped)},
{"tx_null_skb", NETXEN_NIC_STAT(stats.txnullskb)},
{"csummed", NETXEN_NIC_STAT(stats.csummed)},
{"no_rcv", NETXEN_NIC_STAT(stats.no_rcv)},
{"rx_bytes", NETXEN_NIC_STAT(stats.rxbytes)},
Expand Down
89 changes: 18 additions & 71 deletions drivers/net/netxen/netxen_nic_init.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1197,96 +1197,50 @@ u32 netxen_process_rcv_ring(struct netxen_adapter *adapter, int ctxid, int max)
/* Process Command status ring */
int netxen_process_cmd_ring(struct netxen_adapter *adapter)
{
u32 last_consumer;
u32 consumer;
int count1 = 0;
int count2 = 0;
u32 last_consumer, consumer;
int count = 0, i;
struct netxen_cmd_buffer *buffer;
struct pci_dev *pdev;
struct pci_dev *pdev = adapter->pdev;
struct net_device *netdev = adapter->netdev;
struct netxen_skb_frag *frag;
u32 i;
int done;
int done = 0;

spin_lock(&adapter->tx_lock);
last_consumer = adapter->last_cmd_consumer;
DPRINTK(INFO, "procesing xmit complete\n");
/* we assume in this case that there is only one port and that is
* port #1...changes need to be done in firmware to indicate port
* number as part of the descriptor. This way we will be able to get
* the netdev which is associated with that device.
*/

consumer = le32_to_cpu(*(adapter->cmd_consumer));
if (last_consumer == consumer) { /* Ring is empty */
DPRINTK(INFO, "last_consumer %d == consumer %d\n",
last_consumer, consumer);
spin_unlock(&adapter->tx_lock);
return 1;
}

adapter->proc_cmd_buf_counter++;
/*
* Not needed - does not seem to be used anywhere.
* adapter->cmd_consumer = consumer;
*/
spin_unlock(&adapter->tx_lock);

while ((last_consumer != consumer) && (count1 < MAX_STATUS_HANDLE)) {
while (last_consumer != consumer) {
buffer = &adapter->cmd_buf_arr[last_consumer];
pdev = adapter->pdev;
if (buffer->skb) {
frag = &buffer->frag_array[0];
pci_unmap_single(pdev, frag->dma, frag->length,
PCI_DMA_TODEVICE);
frag->dma = 0ULL;
for (i = 1; i < buffer->frag_count; i++) {
DPRINTK(INFO, "getting fragment no %d\n", i);
frag++; /* Get the next frag */
pci_unmap_page(pdev, frag->dma, frag->length,
PCI_DMA_TODEVICE);
frag->dma = 0ULL;
}

adapter->stats.skbfreed++;
adapter->stats.xmitfinished++;
dev_kfree_skb_any(buffer->skb);
buffer->skb = NULL;
} else if (adapter->proc_cmd_buf_counter == 1) {
adapter->stats.txnullskb++;
}
if (unlikely(netif_queue_stopped(adapter->netdev)
&& netif_carrier_ok(adapter->netdev))
&& ((jiffies - adapter->netdev->trans_start) >
adapter->netdev->watchdog_timeo)) {
SCHEDULE_WORK(&adapter->tx_timeout_task);
}

last_consumer = get_next_index(last_consumer,
adapter->max_tx_desc_count);
count1++;
if (++count >= MAX_STATUS_HANDLE)
break;
}

count2 = 0;
spin_lock(&adapter->tx_lock);
if ((--adapter->proc_cmd_buf_counter) == 0) {
if (count) {
adapter->last_cmd_consumer = last_consumer;
while ((adapter->last_cmd_consumer != consumer)
&& (count2 < MAX_STATUS_HANDLE)) {
buffer =
&adapter->cmd_buf_arr[adapter->last_cmd_consumer];
count2++;
if (buffer->skb)
break;
else
adapter->last_cmd_consumer =
get_next_index(adapter->last_cmd_consumer,
adapter->max_tx_desc_count);
}
}
if (count1 || count2) {
if (netif_queue_stopped(adapter->netdev)
&& (adapter->flags & NETXEN_NETDEV_STATUS)) {
netif_wake_queue(adapter->netdev);
adapter->flags &= ~NETXEN_NETDEV_STATUS;
smp_mb();
if (netif_queue_stopped(netdev) && netif_running(netdev)) {
netif_tx_lock(netdev);
netif_wake_queue(netdev);
smp_mb();
netif_tx_unlock(netdev);
}
}
/*
Expand All @@ -1302,16 +1256,9 @@ 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.
*/
if (adapter->last_cmd_consumer == consumer &&
(((adapter->cmd_producer + 1) %
adapter->max_tx_desc_count) == adapter->last_cmd_consumer)) {
consumer = le32_to_cpu(*(adapter->cmd_consumer));
}
done = (adapter->last_cmd_consumer == consumer);
consumer = le32_to_cpu(*(adapter->cmd_consumer));
done = (last_consumer == consumer);

spin_unlock(&adapter->tx_lock);
DPRINTK(INFO, "last consumer is %d in %s\n", last_consumer,
__FUNCTION__);
return (done);
}

Expand Down
95 changes: 22 additions & 73 deletions drivers/net/netxen/netxen_nic_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -317,7 +317,6 @@ netxen_nic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)

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 */
Expand Down Expand Up @@ -533,7 +532,6 @@ netxen_nic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
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 */
Expand Down Expand Up @@ -952,41 +950,17 @@ static int netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
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) {
Expand All @@ -1001,27 +975,16 @@ static int netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
}
}

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));
Expand Down Expand Up @@ -1061,8 +1024,7 @@ static int netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
/* 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];
Expand All @@ -1080,7 +1042,6 @@ static int netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
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);
Expand All @@ -1101,7 +1062,7 @@ static int netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
}
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);
Expand All @@ -1128,7 +1089,7 @@ static int netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
/* 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];
Expand All @@ -1141,35 +1102,19 @@ static int netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
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)
Expand All @@ -1194,9 +1139,13 @@ static void netxen_tx_timeout_task(struct work_struct *work)
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);
}

Expand Down

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