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netxen: fix race in tx stop queue

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There is race between netif_stop_queue and netif_stopped_queue
check.So check once again if buffers are available to avoid race.
With above logic we can also get rid of tx lock in process_cmd_ring.

Signed-off-by: Rajesh Borundia <rajesh.borundia@qlogic.com>
Signed-off-by: Amit Kumar Salecha <amit.salecha@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Rajesh Borundia 2010-10-18 02:03:41 +00:00 committed by David S. Miller
parent 3666e0b04f
commit 7a9905e642
4 changed files with 22 additions and 18 deletions
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5
drivers/net/netxen/netxen_nic.h
View File

@ -175,7 +175,10 @@
#define MAX_NUM_CARDS 4
#define MAX_BUFFERS_PER_CMD 32
#define TX_STOP_THRESH ((MAX_SKB_FRAGS >> 2) + 4)
#define MAX_TSO_HEADER_DESC 2
#define MGMT_CMD_DESC_RESV 4
#define TX_STOP_THRESH ((MAX_SKB_FRAGS >> 2) + MAX_TSO_HEADER_DESC \
+ MGMT_CMD_DESC_RESV)
#define NX_MAX_TX_TIMEOUTS 2
/*

10
drivers/net/netxen/netxen_nic_hw.c
View File

@ -598,8 +598,14 @@ netxen_send_cmd_descs(struct netxen_adapter *adapter,
if (nr_desc >= netxen_tx_avail(tx_ring)) {
netif_tx_stop_queue(tx_ring->txq);
__netif_tx_unlock_bh(tx_ring->txq);
return -EBUSY;
smp_mb();
if (netxen_tx_avail(tx_ring) > nr_desc) {
if (netxen_tx_avail(tx_ring) > TX_STOP_THRESH)
netif_tx_wake_queue(tx_ring->txq);
} else {
__netif_tx_unlock_bh(tx_ring->txq);
return -EBUSY;
}
}
do {

10
drivers/net/netxen/netxen_nic_init.c
View File

@ -1763,14 +1763,10 @@ int netxen_process_cmd_ring(struct netxen_adapter *adapter)
smp_mb();
if (netif_queue_stopped(netdev) && netif_carrier_ok(netdev)) {
__netif_tx_lock(tx_ring->txq, smp_processor_id());
if (netxen_tx_avail(tx_ring) > TX_STOP_THRESH) {
if (netif_queue_stopped(netdev) && netif_carrier_ok(netdev))
if (netxen_tx_avail(tx_ring) > TX_STOP_THRESH)
netif_wake_queue(netdev);
adapter->tx_timeo_cnt = 0;
}
__netif_tx_unlock(tx_ring->txq);
}
adapter->tx_timeo_cnt = 0;
}
/*
* If everything is freed up to consumer then check if the ring is full

15
drivers/net/netxen/netxen_nic_main.c
View File

@ -125,11 +125,6 @@ netxen_nic_update_cmd_producer(struct netxen_adapter *adapter,
struct nx_host_tx_ring *tx_ring)
{
NXWRIO(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] = {
@ -1209,7 +1204,7 @@ netxen_setup_netdev(struct netxen_adapter *adapter,
adapter->max_mc_count = 16;
netdev->netdev_ops = &netxen_netdev_ops;
netdev->watchdog_timeo = 2*HZ;
netdev->watchdog_timeo = 5*HZ;
netxen_nic_change_mtu(netdev, netdev->mtu);
@ -1825,9 +1820,13 @@ netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
/* 4 fragments per cmd des */
no_of_desc = (frag_count + 3) >> 2;
if (unlikely(no_of_desc + 2 > netxen_tx_avail(tx_ring))) {
if (unlikely(netxen_tx_avail(tx_ring) <= TX_STOP_THRESH)) {
netif_stop_queue(netdev);
return NETDEV_TX_BUSY;
smp_mb();
if (netxen_tx_avail(tx_ring) > TX_STOP_THRESH)
netif_start_queue(netdev);
else
return NETDEV_TX_BUSY;
}
producer = tx_ring->producer;