RDMA/mana_ib: Fix DSCP value in modify QP

JIRA: https://issues.redhat.com/browse/RHEL-109583

commit 62de0e6
Author: Shiraz Saleem <shirazsaleem@microsoft.com>
Date:   Thu Jul 10 03:24:45 2025 -0700

    RDMA/mana_ib: Fix DSCP value in modify QP

    Convert the traffic_class in GRH to a DSCP value as required by the HW.

    Fixes: e095405 ("RDMA/mana_ib: Modify QP state")
    Signed-off-by: Shiraz Saleem <shirazsaleem@microsoft.com>
    Signed-off-by: Konstantin Taranov <kotaranov@microsoft.com>
    Link: https://patch.msgid.link/1752143085-4169-1-git-send-email-kotaranov@linux.microsoft.com
    Reviewed-by: Long Li <longli@microsoft.com>
    Signed-off-by: Leon Romanovsky <leon@kernel.org>

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>

Author: Maxim Levitsky

drivers/infiniband/hw/mana/qp.c

@@ -772,7 +772,7 @@ static int mana_ib_gd_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
 		req.ah_attr.dest_port = ROCE_V2_UDP_DPORT;
 		req.ah_attr.src_port = rdma_get_udp_sport(attr->ah_attr.grh.flow_label,
 							  ibqp->qp_num, attr->dest_qp_num);
-		req.ah_attr.traffic_class = attr->ah_attr.grh.traffic_class;
+		req.ah_attr.traffic_class = attr->ah_attr.grh.traffic_class >> 2;
 		req.ah_attr.hop_limit = attr->ah_attr.grh.hop_limit;
 	}