[BNX2]: remove atomics in tx
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>
diff --git a/drivers/net/bnx2.c b/drivers/net/bnx2.c
index 015ff79..da903b3 100644
--- a/drivers/net/bnx2.c
+++ b/drivers/net/bnx2.c
@@ -107,6 +107,15 @@
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 @@
}
}
- 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 @@
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 @@
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 @@
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 @@
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);
}