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qlcnic: fix race in tx stop queue

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There is a 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 K 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 K Borundia 2010-06-17 02:56:41 +00:00 committed by David S. Miller
parent 8f891387aa
commit ef71ff833a
4 changed files with 26 additions and 19 deletions
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8
drivers/net/qlcnic/qlcnic.h
View file

@ -113,8 +113,10 @@
#define TX_UDPV6_PKT 0x0c
/* Tx defines */
#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 QLCNIC_MAX_TX_TIMEOUTS 2
/*
@ -369,7 +371,7 @@ struct qlcnic_recv_crb {
*/
struct qlcnic_cmd_buffer {
struct sk_buff *skb;
struct qlcnic_skb_frag frag_array[MAX_BUFFERS_PER_CMD + 1];
struct qlcnic_skb_frag frag_array[MAX_SKB_FRAGS + 1];
u32 frag_count;
};

12
drivers/net/qlcnic/qlcnic_hw.c
View file

@ -338,9 +338,15 @@ qlcnic_send_cmd_descs(struct qlcnic_adapter *adapter,
if (nr_desc >= qlcnic_tx_avail(tx_ring)) {
netif_tx_stop_queue(tx_ring->txq);
__netif_tx_unlock_bh(tx_ring->txq);
adapter->stats.xmit_off++;
return -EBUSY;
smp_mb();
if (qlcnic_tx_avail(tx_ring) > nr_desc) {
if (qlcnic_tx_avail(tx_ring) > TX_STOP_THRESH)
netif_tx_wake_queue(tx_ring->txq);
} else {
adapter->stats.xmit_off++;
__netif_tx_unlock_bh(tx_ring->txq);
return -EBUSY;
}
}
do {

2
drivers/net/qlcnic/qlcnic_init.c
View file

@ -181,7 +181,9 @@ void qlcnic_free_sw_resources(struct qlcnic_adapter *adapter)
tx_ring = adapter->tx_ring;
vfree(tx_ring->cmd_buf_arr);
tx_ring->cmd_buf_arr = NULL;
kfree(adapter->tx_ring);
adapter->tx_ring = NULL;
}
int qlcnic_alloc_sw_resources(struct qlcnic_adapter *adapter)

23
drivers/net/qlcnic/qlcnic_main.c
View file

@ -132,12 +132,6 @@ qlcnic_update_cmd_producer(struct qlcnic_adapter *adapter,
struct qlcnic_host_tx_ring *tx_ring)
{
writel(tx_ring->producer, tx_ring->crb_cmd_producer);
if (qlcnic_tx_avail(tx_ring) <= TX_STOP_THRESH) {
netif_stop_queue(adapter->netdev);
smp_mb();
adapter->stats.xmit_off++;
}
}
static const u32 msi_tgt_status[8] = {
@ -1137,7 +1131,7 @@ qlcnic_setup_netdev(struct qlcnic_adapter *adapter,
adapter->max_mc_count = 38;
netdev->netdev_ops = &qlcnic_netdev_ops;
netdev->watchdog_timeo = 2*HZ;
netdev->watchdog_timeo = 5*HZ;
qlcnic_change_mtu(netdev, netdev->mtu);
@ -1709,10 +1703,15 @@ qlcnic_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 > qlcnic_tx_avail(tx_ring))) {
if (unlikely(qlcnic_tx_avail(tx_ring) <= TX_STOP_THRESH)) {
netif_stop_queue(netdev);
adapter->stats.xmit_off++;
return NETDEV_TX_BUSY;
smp_mb();
if (qlcnic_tx_avail(tx_ring) > TX_STOP_THRESH)
netif_start_queue(netdev);
else {
adapter->stats.xmit_off++;
return NETDEV_TX_BUSY;
}
}
producer = tx_ring->producer;
@ -2018,14 +2017,12 @@ static int qlcnic_process_cmd_ring(struct qlcnic_adapter *adapter)
smp_mb();
if (netif_queue_stopped(netdev) && netif_carrier_ok(netdev)) {
__netif_tx_lock(tx_ring->txq, smp_processor_id());
if (qlcnic_tx_avail(tx_ring) > TX_STOP_THRESH) {
netif_wake_queue(netdev);
adapter->tx_timeo_cnt = 0;
adapter->stats.xmit_on++;
}
__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