From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: [PATCH 10/10] chelesio: transmit locking (plus bug fix). Date: Fri, 01 Dec 2006 16:36:22 -0800 Message-ID: <20061202003707.873200000@osdl.org> References: <20061202003612.573260000@osdl.org> Cc: netdev@vger.kernel.org Return-path: Received: from smtp.osdl.org ([65.172.181.25]:35812 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1162439AbWLBApB (ORCPT ); Fri, 1 Dec 2006 19:45:01 -0500 To: Jeff Garzik Content-Disposition: inline; filename=chelsio-tx-lock.patch Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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: Stephen Hemminger --- drivers/net/chelsio/sge.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) --- chelsio.orig/drivers/net/chelsio/sge.c +++ chelsio/drivers/net/chelsio/sge.c @@ -1778,7 +1778,9 @@ static int t1_sge_tx(struct sk_buff *skb 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, s 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, s * 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, s 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; } /* --