Stephen,
On 12/2/06, Stephen Hemminger <[EMAIL PROTECTED]> wrote:
If transmit lock is contended on, then push return code back
and retry at higher level.
Looking at qdisc_restart, it seems to me that the NETDEV_TX_LOCKED
return code must only be used if the device features LLTX. With your
patch, if q->lock is already grabbed, qdisc_restart is going to
requeue skb without going through the collision section of
qdisc_restart.
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 <[EMAIL PROTECTED]>
---
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;
}
/*
--
-
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--
Eric
-
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