[ofa-general] Re: [PATCH] IB/ipoib: fix thinko in packet length checks

[Roland Dreier]

This definitely looks like a problem, but I'm confused by this:

 > --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c
 > +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
 > @@ -452,7 +452,7 @@ void ipoib_cm_send(struct net_device *dev, struct sk_buff *skb, struct ipoib_cm_
 >  			   skb->len, tx->mtu);
 >  		++priv->stats.tx_dropped;
 >  		++priv->stats.tx_errors;
 > -		ipoib_cm_skb_too_long(dev, skb, tx->mtu - INFINIBAND_ALEN);
 > +		ipoib_cm_skb_too_long(dev, skb, tx->mtu - IPOIB_ENCAP_LEN);
 >  		return;
 >  	}

After this change, the code looks like:

	if (unlikely(skb->len > tx->mtu)) {
		ipoib_warn(priv, "packet len %d (> %d) too long to send, dropping\n",
			   skb->len, tx->mtu);
		++priv->stats.tx_dropped;
		++priv->stats.tx_errors;
		ipoib_cm_skb_too_long(dev, skb, tx->mtu - IPOIB_ENCAP_LEN);
		return;
	}

so why is the test against just tx->mtu, while ipoib_cm_skb_too_long()
is passed an mtu of tx->mtu - IPOIB_ENCAP_LEN?

 - R.