On Thu, 26 Aug 2010, Jason Gunthorpe wrote: > I think doing the memcmp only in the multicast path should be > reasonable overhead wise.
Ok the dgid is only 8 bytes not the whole 40 bytes.... Here is the patch somewhat cleaned up with PACKET_BROADCAST. Subject: [IPoIB] Identify multicast packets and fix IGMP breakage V3 IGMP processing is broken because the IPOIB does not set the skb->pkt_type the right way for Multicast traffic. All incoming packets are set to PACKET_HOST which means that the igmp_recv() function will ignore the IGMP broadcasts/multicasts. This in turn means that the IGMP timers are firing and are sending information about multicast subscriptions unnecessarily. In a large private network this can cause traffic spikes. Signed-off-by: Christoph Lameter <c...@linux.com> --- Index: linux-2.6/drivers/infiniband/ulp/ipoib/ipoib_ib.c =================================================================== --- linux-2.6.orig/drivers/infiniband/ulp/ipoib/ipoib_ib.c 2010-08-26 18:24:07.842079559 -0500 +++ linux-2.6/drivers/infiniband/ulp/ipoib/ipoib_ib.c 2010-08-27 08:26:37.929641162 -0500 @@ -223,6 +223,7 @@ unsigned int wr_id = wc->wr_id & ~IPOIB_OP_RECV; struct sk_buff *skb; u64 mapping[IPOIB_UD_RX_SG]; + union ib_gid *dgid; ipoib_dbg_data(priv, "recv completion: id %d, status: %d\n", wr_id, wc->status); @@ -271,6 +272,21 @@ ipoib_ud_dma_unmap_rx(priv, mapping); ipoib_ud_skb_put_frags(priv, skb, wc->byte_len); + /* First byte of dgid signals multicast when 0xff */ + dgid = &((struct ib_grh *)skb->data)->dgid; + + if (!(wc->wc_flags & IB_WC_GRH) || dgid->raw[0] != 0xff) + + skb->pkt_type = PACKET_HOST; + + else if (memcmp(dgid, dev->broadcast + 4, sizeof(union ib_gid)) == 0) + + skb->pkt_type = PACKET_BROADCAST; + + else + + skb->pkt_type = PACKET_MULTICAST; + skb_pull(skb, IB_GRH_BYTES); skb->protocol = ((struct ipoib_header *) skb->data)->proto; @@ -281,9 +297,6 @@ dev->stats.rx_bytes += skb->len; skb->dev = dev; - /* XXX get correct PACKET_ type here */ - skb->pkt_type = PACKET_HOST; - if (test_bit(IPOIB_FLAG_CSUM, &priv->flags) && likely(wc->csum_ok)) skb->ip_summed = CHECKSUM_UNNECESSARY; -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html