IB/mthca: Implement query_ah method

Implement query_ah (except for AVs which are in HCA memory).  This is
needed to implement RMPP duplicate session detection on sending side
(extraction of DGID/DLID and GRH flag from address handle).
Signed-off-by: Jack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/mthca/mthca_av.c

@@ -193,6 +193,37 @@ int mthca_read_ah(struct mthca_dev *dev, struct mthca_ah *ah,
 	return 0;
 }
 
+int mthca_ah_query(struct ib_ah *ibah, struct ib_ah_attr *attr)
+{
+	struct mthca_ah *ah   = to_mah(ibah);
+	struct mthca_dev *dev = to_mdev(ibah->device);
+
+	/* Only implement for MAD and memfree ah for now. */
+	if (ah->type == MTHCA_AH_ON_HCA)
+		return -ENOSYS;
+
+	memset(attr, 0, sizeof *attr);
+	attr->dlid          = be16_to_cpu(ah->av->dlid);
+	attr->sl            = be32_to_cpu(ah->av->sl_tclass_flowlabel) >> 28;
+	attr->static_rate   = ah->av->msg_sr & 0x7;
+	attr->src_path_bits = ah->av->g_slid & 0x7F;
+	attr->port_num      = be32_to_cpu(ah->av->port_pd) >> 24;
+	attr->ah_flags      = mthca_ah_grh_present(ah) ? IB_AH_GRH : 0;
+
+	if (attr->ah_flags) {
+		attr->grh.traffic_class =
+			be32_to_cpu(ah->av->sl_tclass_flowlabel) >> 20;
+		attr->grh.flow_label =
+			be32_to_cpu(ah->av->sl_tclass_flowlabel) & 0xfffff;
+		attr->grh.hop_limit  = ah->av->hop_limit;
+		attr->grh.sgid_index = ah->av->gid_index &
+				       (dev->limits.gid_table_len - 1);
+		memcpy(attr->grh.dgid.raw, ah->av->dgid, 16);
+	}
+
+	return 0;
+}
+
 int __devinit mthca_init_av_table(struct mthca_dev *dev)
 {
 	int err;

drivers/infiniband/hw/mthca/mthca_dev.h

@@ -539,6 +539,7 @@ int mthca_create_ah(struct mthca_dev *dev,
 int mthca_destroy_ah(struct mthca_dev *dev, struct mthca_ah *ah);
 int mthca_read_ah(struct mthca_dev *dev, struct mthca_ah *ah,
 		  struct ib_ud_header *header);
+int mthca_ah_query(struct ib_ah *ibah, struct ib_ah_attr *attr);
 int mthca_ah_grh_present(struct mthca_ah *ah);
 
 int mthca_multicast_attach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid);

drivers/infiniband/hw/mthca/mthca_provider.c

@@ -1289,6 +1289,7 @@ int mthca_register_device(struct mthca_dev *dev)
 	dev->ib_dev.alloc_pd             = mthca_alloc_pd;
 	dev->ib_dev.dealloc_pd           = mthca_dealloc_pd;
 	dev->ib_dev.create_ah            = mthca_ah_create;
+	dev->ib_dev.query_ah             = mthca_ah_query;
 	dev->ib_dev.destroy_ah           = mthca_ah_destroy;
 
 	if (dev->mthca_flags & MTHCA_FLAG_SRQ) {