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skge: transmit locking improvements 

Don't need to lock when processing transmit complete unless queue fills.
Modeled after tg3.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
This commit is contained in:
Stephen Hemminger 2007-03-16 14:01:30 -07:00 committed by Jeff Garzik
parent 7e0038a414
commit 992c9623b1
1 changed files with 18 additions and 10 deletions
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28
drivers/net/skge.c
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@ -2621,6 +2621,7 @@ static int skge_down(struct net_device *dev)
static inline int skge_avail(const struct skge_ring *ring)
{
smp_mb();
return ((ring->to_clean > ring->to_use) ? 0 : ring->count)
+ (ring->to_clean - ring->to_use) - 1;
}
@ -2709,6 +2710,8 @@ static int skge_xmit_frame(struct sk_buff *skb, struct net_device *dev)
dev->name, e - skge->tx_ring.start, skb->len);
skge->tx_ring.to_use = e->next;
smp_wmb();
if (skge_avail(&skge->tx_ring) <= TX_LOW_WATER) {
pr_debug("%s: transmit queue full\n", dev->name);
netif_stop_queue(dev);
@ -2726,8 +2729,6 @@ static void skge_tx_free(struct skge_port *skge, struct skge_element *e,
{
struct pci_dev *pdev = skge->hw->pdev;
BUG_ON(!e->skb);
/* skb header vs. fragment */
if (control & BMU_STF)
pci_unmap_single(pdev, pci_unmap_addr(e, mapaddr),
@ -2745,7 +2746,6 @@ static void skge_tx_free(struct skge_port *skge, struct skge_element *e,
dev_kfree_skb(e->skb);
}
e->skb = NULL;
}
/* Free all buffers in transmit ring */
@ -3017,21 +3017,29 @@ static void skge_tx_done(struct net_device *dev)
skge_write8(skge->hw, Q_ADDR(txqaddr[skge->port], Q_CSR), CSR_IRQ_CL_F);
netif_tx_lock(dev);
for (e = ring->to_clean; e != ring->to_use; e = e->next) {
struct skge_tx_desc *td = e->desc;
u32 control = ((const struct skge_tx_desc *) e->desc)->control;
if (td->control & BMU_OWN)
if (control & BMU_OWN)
break;
skge_tx_free(skge, e, td->control);
skge_tx_free(skge, e, control);
}
skge->tx_ring.to_clean = e;
if (skge_avail(&skge->tx_ring) > TX_LOW_WATER)
netif_wake_queue(dev);
/* Can run lockless until we need to synchronize to restart queue. */
smp_mb();
netif_tx_unlock(dev);
if (unlikely(netif_queue_stopped(dev) &&
skge_avail(&skge->tx_ring) > TX_LOW_WATER)) {
netif_tx_lock(dev);
if (unlikely(netif_queue_stopped(dev) &&
skge_avail(&skge->tx_ring) > TX_LOW_WATER)) {
netif_wake_queue(dev);
}
netif_tx_unlock(dev);
}
}
static int skge_poll(struct net_device *dev, int *budget)