IB/cma: Set default gid type to RoCEv2

RoCEv2 is the preferred RDMA protocol for Ethernet link layer because
of its advantages over RoCEv1. For better user experience make it the
default choice for RDMA_CM connections if device/port support it.
Signed-off-by: Moni Shoua <monis@mellanox.com>
Reviewed-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/core/cma.c

@@ -72,6 +72,7 @@ MODULE_LICENSE("Dual BSD/GPL");
 #define CMA_MAX_CM_RETRIES 15
 #define CMA_CM_MRA_SETTING (IB_CM_MRA_FLAG_DELAY | 24)
 #define CMA_IBOE_PACKET_LIFETIME 18
+#define CMA_PREFERRED_ROCE_GID_TYPE IB_GID_TYPE_ROCE_UDP_ENCAP
 
 static const char * const cma_events[] = {
 	[RDMA_CM_EVENT_ADDR_RESOLVED]	 = "address resolved",
@@ -4280,8 +4281,12 @@ static void cma_add_one(struct ib_device *device)
 	for (i = rdma_start_port(device); i <= rdma_end_port(device); i++) {
 		supported_gids = roce_gid_type_mask_support(device, i);
 		WARN_ON(!supported_gids);
-		cma_dev->default_gid_type[i - rdma_start_port(device)] =
-			find_first_bit(&supported_gids, BITS_PER_LONG);
+		if (supported_gids & CMA_PREFERRED_ROCE_GID_TYPE)
+			cma_dev->default_gid_type[i - rdma_start_port(device)] =
+				CMA_PREFERRED_ROCE_GID_TYPE;
+		else
+			cma_dev->default_gid_type[i - rdma_start_port(device)] =
+				find_first_bit(&supported_gids, BITS_PER_LONG);
 		cma_dev->default_roce_tos[i - rdma_start_port(device)] = 0;
 	}