Return-Path: Received: from aserp1040.oracle.com ([141.146.126.69]:36663 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753522AbcHCP2B convert rfc822-to-8bit (ORCPT ); Wed, 3 Aug 2016 11:28:01 -0400 From: Chuck Lever Content-Type: text/plain; charset=us-ascii Subject: WARN_ON added to rpc_create() Date: Wed, 3 Aug 2016 11:27:47 -0400 Message-Id: <42D0C152-58F9-4467-B86D-2A7A25544CE4@oracle.com> Cc: Linux NFS Mailing List To: Bruce Fields Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Sender: linux-nfs-owner@vger.kernel.org List-ID: Hi Bruce- I see that commit 39a9beab5acb83176e8b9a4f0778749a09341f1f Author: J. Bruce Fields AuthorDate: Tue May 17 12:38:21 2016 -0400 rpc: share one xps between all backchannels has added this piece of code: @@ -452,10 +452,20 @@ static struct rpc_clnt *rpc_create_xprt(struct rpc_create_args *args, struct rpc_clnt *clnt = NULL; struct rpc_xprt_switch *xps; - xps = xprt_switch_alloc(xprt, GFP_KERNEL); - if (xps == NULL) { - xprt_put(xprt); - return ERR_PTR(-ENOMEM); + if (args->bc_xprt && args->bc_xprt->xpt_bc_xps) { + WARN_ON(args->protocol != XPRT_TRANSPORT_BC_TCP); + xps = args->bc_xprt->xpt_bc_xps; + xprt_switch_get(xps); + } else { the WARN_ON here fires on the server whenever I use NFSv4.1 on RDMA. Can you say why it was added? Is there something RPC/RDMA needs to do to make the code safe? -- Chuck Lever