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Commit cabdfb37 authored by Stephen Hemminger's avatar Stephen Hemminger Committed by Jeff Garzik
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[PATCH] chelesio: transmit locking (plus bug fix). 



If transmit lock is contended on, then push return code back
and retry at higher level.

Bugfix: If buffer is reallocated because of lack of headroom
and the send is blocked, then drop packet. This is necessary
because caller would end up requeuing a freed skb.

Signed-off-by: default avatarStephen Hemminger <shemminger@osdl.org>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 56f643c2

drivers/net/chelsio/sge.c

+15 −4
Original line number Diff line number Diff line
@@ -1778,7 +1778,9 @@ static int t1_sge_tx(struct sk_buff *skb, struct adapter *adapter, 
	struct cmdQ *q = &sge->cmdQ[qid];

	unsigned int credits, pidx, genbit, count, use_sched_skb = 0;



	spin_lock(&q->lock);

	if (!spin_trylock(&q->lock))

		return NETDEV_TX_LOCKED;



	reclaim_completed_tx(sge, q);



	pidx = q->pidx;
@@ -1887,6 +1889,8 @@ int t1_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	struct sge *sge = adapter->sge;

	struct sge_port_stats *st = per_cpu_ptr(sge->port_stats[dev->if_port], smp_processor_id());

	struct cpl_tx_pkt *cpl;

	struct sk_buff *orig_skb = skb;

	int ret;



	if (skb->protocol == htons(ETH_P_CPL5))

		goto send;
@@ -1930,8 +1934,6 @@ int t1_start_xmit(struct sk_buff *skb, struct net_device *dev) 
		 * Complain when this happens but try to fix things up.

		 */

		if (unlikely(skb_headroom(skb) < dev->hard_header_len - ETH_HLEN)) {

			struct sk_buff *orig_skb = skb;



			pr_debug("%s: headroom %d header_len %d\n", dev->name,

				 skb_headroom(skb), dev->hard_header_len);
@@ -1991,7 +1993,16 @@ int t1_start_xmit(struct sk_buff *skb, struct net_device *dev) 
send:

	st->tx_packets++;

	dev->trans_start = jiffies;

	return t1_sge_tx(skb, adapter, 0, dev);

	ret = t1_sge_tx(skb, adapter, 0, dev);



	/* If transmit busy, and we reallocated skb's due to headroom limit,

	 * then silently discard to avoid leak.

	 */

	if (unlikely(ret != NETDEV_TX_OK && skb != orig_skb)) {

 		dev_kfree_skb_any(skb);

		ret = NETDEV_TX_OK;

 	}

	return ret;

}



/*