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authorStephen Hemminger <shemminger@linux-foundation.org>2007-03-16 14:01:30 -0700
committerJeff Garzik <jeff@garzik.org>2007-04-28 11:01:00 -0400
commit992c9623b148ba939e9cdba0d668eedd3af1a5d2 (patch)
tree4593ab3e61d2f58023d4af4397a0b23fefe65abc
parent7e0038a414c38085dfbf352f21006bcca4cd308b (diff)
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>
-rw-r--r--drivers/net/skge.c28
1 files changed, 18 insertions, 10 deletions
diff --git a/drivers/net/skge.c b/drivers/net/skge.c
index f1a0e6c0fbd..bc531fdfc8e 100644
--- a/drivers/net/skge.c
+++ b/drivers/net/skge.c
@@ -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();
+
+ 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);
+ }
+ netif_tx_unlock(dev);
+ }
}
static int skge_poll(struct net_device *dev, int *budget)