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authorMichael Chan <mchan@broadcom.com>2005-08-26 02:36:58 +0400
committerDavid S. Miller <davem@sunset.davemloft.net>2005-08-30 03:10:38 +0400
commite89bbf1049aac3625fdafe3657ed8d7d5373d351 (patch)
tree15e0fc01d553ce5bc38de546d80f5f2e3736b0bf
parentcd339a0ed61097d92ce03b6d1042b1e4d58535e7 (diff)
downloadlinux-e89bbf1049aac3625fdafe3657ed8d7d5373d351.tar.xz
[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>
-rw-r--r--drivers/net/bnx2.c35
-rw-r--r--drivers/net/bnx2.h3
2 files changed, 18 insertions, 20 deletions
diff --git a/drivers/net/bnx2.c b/drivers/net/bnx2.c
index 015ff7906601..da903b3ebfb0 100644
--- a/drivers/net/bnx2.c
+++ b/drivers/net/bnx2.c
@@ -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);
}
diff --git a/drivers/net/bnx2.h b/drivers/net/bnx2.h
index e1fb099acbf2..9ad3f5740cd8 100644
--- a/drivers/net/bnx2.h
+++ b/drivers/net/bnx2.h
@@ -3841,12 +3841,12 @@ struct bnx2 {
struct status_block *status_blk;
u32 last_status_idx;
- atomic_t tx_avail_bd;
struct tx_bd *tx_desc_ring;
struct sw_bd *tx_buf_ring;
u32 tx_prod_bseq;
u16 tx_prod;
u16 tx_cons;
+ int tx_ring_size;
#ifdef BCM_VLAN
struct vlan_group *vlgrp;
@@ -3929,7 +3929,6 @@ struct bnx2 {
u16 fw_wr_seq;
u16 fw_drv_pulse_wr_seq;
- int tx_ring_size;
dma_addr_t tx_desc_mapping;