RDMA/srpt: Fix handling of iWARP logins

The path_rec pointer is NULL set for IB and RoCE logins but not for iWARP
logins. Hence check the path_rec pointer before dereferencing it.

Link: https://lore.kernel.org/r/20190930231707.48259-11-bvanassche@acm.org
Cc: Honggang LI <honli@redhat.com>
Cc: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/ulp/srpt/ib_srpt.c

@@ -2502,6 +2502,7 @@ static int srpt_rdma_cm_req_recv(struct rdma_cm_id *cm_id,
 	struct srpt_device *sdev;
 	struct srp_login_req req;
 	const struct srp_login_req_rdma *req_rdma;
+	struct sa_path_rec *path_rec = cm_id->route.path_rec;
 	char src_addr[40];
 
 	sdev = ib_get_client_data(cm_id->device, &srpt_client);
@@ -2527,7 +2528,7 @@ static int srpt_rdma_cm_req_recv(struct rdma_cm_id *cm_id,
 		 &cm_id->route.addr.src_addr);
 
 	return srpt_cm_req_recv(sdev, NULL, cm_id, cm_id->port_num,
-				cm_id->route.path_rec->pkey, &req, src_addr);
+				path_rec ? path_rec->pkey : 0, &req, src_addr);
 }
 
 static void srpt_cm_rej_recv(struct srpt_rdma_ch *ch,