RDMA/cxgb4: Fix RDMA_CM_EVENT_UNREACHABLE error for iWARP

ip_dev_find() always returns real net_device address, whether traffic is
running on a vlan or real device, if traffic is over vlan, filling
endpoint struture with real ndev and an attempt to send a connect request
will results in RDMA_CM_EVENT_UNREACHABLE error.  This patch fixes the
issue by using vlan_dev_real_dev().

Fixes: 830662f6 ("RDMA/cxgb4: Add support for active and passive open connection with IPv6 address")
Link: https://patch.msgid.link/r/20241007132311.70593-1-anumula@chelsio.comSigned-off-by: Anumula Murali Mohan Reddy <anumula@chelsio.com>
Signed-off-by: Potnuri Bharat Teja <bharat@chelsio.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/cxgb4/cm.c

@@ -2086,7 +2086,7 @@ static int import_ep(struct c4iw_ep *ep, int iptype, __u8 *peer_ip,
 	err = -ENOMEM;
 	if (n->dev->flags & IFF_LOOPBACK) {
 		if (iptype == 4)
-			pdev = ip_dev_find(&init_net, *(__be32 *)peer_ip);
+			pdev = __ip_dev_find(&init_net, *(__be32 *)peer_ip, false);
 		else if (IS_ENABLED(CONFIG_IPV6))
 			for_each_netdev(&init_net, pdev) {
 				if (ipv6_chk_addr(&init_net,
@@ -2101,12 +2101,12 @@ static int import_ep(struct c4iw_ep *ep, int iptype, __u8 *peer_ip,
 			err = -ENODEV;
 			goto out;
 		}
+		if (is_vlan_dev(pdev))
+			pdev = vlan_dev_real_dev(pdev);
 		ep->l2t = cxgb4_l2t_get(cdev->rdev.lldi.l2t,
 					n, pdev, rt_tos2priority(tos));
-		if (!ep->l2t) {
-			dev_put(pdev);
+		if (!ep->l2t)
 			goto out;
-		}
 		ep->mtu = pdev->mtu;
 		ep->tx_chan = cxgb4_port_chan(pdev);
 		ep->smac_idx = ((struct port_info *)netdev_priv(pdev))->smt_idx;
@@ -2119,7 +2119,6 @@ static int import_ep(struct c4iw_ep *ep, int iptype, __u8 *peer_ip,
 		ep->rss_qid = cdev->rdev.lldi.rxq_ids[
 			cxgb4_port_idx(pdev) * step];
 		set_tcp_window(ep, (struct port_info *)netdev_priv(pdev));
-		dev_put(pdev);
 	} else {
 		pdev = get_real_dev(n->dev);
 		ep->l2t = cxgb4_l2t_get(cdev->rdev.lldi.l2t,