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[BNX2]: remove atomics in tx

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Remove atomic operations in the fast tx path. Expensive atomic
operations were used to keep track of the number of available tx
descriptors. The new code uses the difference between the consumer
and producer index to determine the number of free tx descriptors.

As suggested by Jeff Garzik, the name of the inline function is
changed to all lower case.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Michael Chan
2005-08-25 15:36:58 -07:00
committed by David S. Miller
parent cd339a0ed6
commit e89bbf1049
2 changed files with 18 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
drivers/net/bnx2.c
View File

@ -107,6 +107,15 @@ static struct flash_spec flash_table[] =
MODULE_DEVICE_TABLE(pci, bnx2_pci_tbl);
static inline u32 bnx2_tx_avail(struct bnx2 *bp)
{
u32 diff = TX_RING_IDX(bp->tx_prod) - TX_RING_IDX(bp->tx_cons);
if (diff > MAX_TX_DESC_CNT)
diff = (diff & MAX_TX_DESC_CNT) - 1;
return (bp->tx_ring_size - diff);
}
static u32
bnx2_reg_rd_ind(struct bnx2 *bp, u32 offset)
{
@ -1338,22 +1347,19 @@ bnx2_tx_int(struct bnx2 *bp)
}
}
atomic_add(tx_free_bd, &bp->tx_avail_bd);
bp->tx_cons = sw_cons;
if (unlikely(netif_queue_stopped(bp->dev))) {
unsigned long flags;
spin_lock_irqsave(&bp->tx_lock, flags);
if ((netif_queue_stopped(bp->dev)) &&
(atomic_read(&bp->tx_avail_bd) > MAX_SKB_FRAGS)) {
(bnx2_tx_avail(bp) > MAX_SKB_FRAGS)) {
netif_wake_queue(bp->dev);
}
spin_unlock_irqrestore(&bp->tx_lock, flags);
}
bp->tx_cons = sw_cons;
}
static inline void
@ -2971,7 +2977,6 @@ bnx2_init_tx_ring(struct bnx2 *bp)
bp->tx_prod = 0;
bp->tx_cons = 0;
bp->tx_prod_bseq = 0;
atomic_set(&bp->tx_avail_bd, bp->tx_ring_size);
val = BNX2_L2CTX_TYPE_TYPE_L2;
val |= BNX2_L2CTX_TYPE_SIZE_L2;
@ -4057,9 +4062,7 @@ bnx2_start_xmit(struct sk_buff *skb, struct net_device *dev)
u16 prod, ring_prod;
int i;
if (unlikely(atomic_read(&bp->tx_avail_bd) <
(skb_shinfo(skb)->nr_frags + 1))) {
if (unlikely(bnx2_tx_avail(bp) < (skb_shinfo(skb)->nr_frags + 1))) {
netif_stop_queue(dev);
printk(KERN_ERR PFX "%s: BUG! Tx ring full when queue awake!\n",
dev->name);
@ -4156,8 +4159,6 @@ bnx2_start_xmit(struct sk_buff *skb, struct net_device *dev)
prod = NEXT_TX_BD(prod);
bp->tx_prod_bseq += skb->len;
atomic_sub(last_frag + 1, &bp->tx_avail_bd);
REG_WR16(bp, MB_TX_CID_ADDR + BNX2_L2CTX_TX_HOST_BIDX, prod);
REG_WR(bp, MB_TX_CID_ADDR + BNX2_L2CTX_TX_HOST_BSEQ, bp->tx_prod_bseq);
@ -4166,16 +4167,14 @@ bnx2_start_xmit(struct sk_buff *skb, struct net_device *dev)
bp->tx_prod = prod;
dev->trans_start = jiffies;
if (unlikely(atomic_read(&bp->tx_avail_bd) <= MAX_SKB_FRAGS)) {
if (unlikely(bnx2_tx_avail(bp) <= MAX_SKB_FRAGS)) {
unsigned long flags;
spin_lock_irqsave(&bp->tx_lock, flags);
if (atomic_read(&bp->tx_avail_bd) <= MAX_SKB_FRAGS) {
netif_stop_queue(dev);
if (atomic_read(&bp->tx_avail_bd) > MAX_SKB_FRAGS)
netif_wake_queue(dev);
}
netif_stop_queue(dev);
if (bnx2_tx_avail(bp) > MAX_SKB_FRAGS)
netif_wake_queue(dev);
spin_unlock_irqrestore(&bp->tx_lock, flags);
}