IB/mthca: Initialize grh_present before using it

build_mlx_header() was using sqp->ud_header.grh_present before it was
initialized by mthca_read_ah(). Furthermore, header->grh_present is
set by ib_ud_header_init, so there's no need to set it again in
mthca_read_ah().

Signed-off-by: Michael S. Tsirkin <[e-mail]>
Signed-off-by: Roland Dreier <[e-mail]>

drivers/infiniband/hw/mthca/mthca_av.c

···
 	return 0;
 }
 
+int mthca_ah_grh_present(struct mthca_ah *ah)
+{
+	return !!(ah->av->g_slid & 0x80);
+}
+
 int mthca_read_ah(struct mthca_dev *dev, struct mthca_ah *ah,
 		  struct ib_ud_header *header)
 {
···
 	header->lrh.service_level   = be32_to_cpu(ah->av->sl_tclass_flowlabel) >> 28;
 	header->lrh.destination_lid = ah->av->dlid;
 	header->lrh.source_lid      = cpu_to_be16(ah->av->g_slid & 0x7f);
-	if (ah->av->g_slid & 0x80) {
-		header->grh_present = 1;
+	if (mthca_ah_grh_present(ah)) {
 		header->grh.traffic_class =
 			(be32_to_cpu(ah->av->sl_tclass_flowlabel) >> 20) & 0xff;
 		header->grh.flow_label    =
···
 				  &header->grh.source_gid);
 		memcpy(header->grh.destination_gid.raw,
 		       ah->av->dgid, 16);
-	} else {
-		header->grh_present = 0;
 	}
 
 	return 0;

drivers/infiniband/hw/mthca/mthca_dev.h

···
 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_grh_present(struct mthca_ah *ah);
 
 int mthca_multicast_attach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid);
 int mthca_multicast_detach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid);

drivers/infiniband/hw/mthca/mthca_qp.c

···
 	u16 pkey;
 
 	ib_ud_header_init(256, /* assume a MAD */
-			  sqp->ud_header.grh_present,
+			  mthca_ah_grh_present(to_mah(wr->wr.ud.ah)),
 			  &sqp->ud_header);
 
 	err = mthca_read_ah(dev, to_mah(wr->wr.ud.ah), &sqp->ud_header);