From patchwork Wed May 26 19:35:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever III X-Patchwork-Id: 12282633 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 64569C47088 for ; Wed, 26 May 2021 19:35:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 34435613D3 for ; Wed, 26 May 2021 19:35:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233378AbhEZTgx (ORCPT ); Wed, 26 May 2021 15:36:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:51452 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232812AbhEZTgx (ORCPT ); Wed, 26 May 2021 15:36:53 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8AEDB613CD; Wed, 26 May 2021 19:35:21 +0000 (UTC) Subject: [PATCH v1] xprtrdma: Revert 586a0787ce35 From: Chuck Lever To: trondmy@hammerspace.com, anna.schumaker@netapp.com Cc: linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org Date: Wed, 26 May 2021 15:35:20 -0400 Message-ID: <162205747766.515075.15998908898996547188.stgit@manet.1015granger.net> User-Agent: StGit/1.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org Commit 9ed5af268e88 ("SUNRPC: Clean up the handling of page padding in rpc_prepare_reply_pages()") [Dec 2020] affects RPC Replies that have a data payload (i.e., Write chunks). rpcrdma_prepare_readch(), as its name suggests, sets up Read chunks which are data payloads within RPC Calls. Those payloads are constructed by xdr_write_pages(), which continues to stuff the call buffer's tail kvec with the payload's XDR roundup. Thus removing the tail buffer logic in rpcrdma_prepare_readch() was the wrong thing to do. Fixes: 586a0787ce35 ("xprtrdma: Clean up rpcrdma_prepare_readch()") Signed-off-by: Chuck Lever --- net/sunrpc/xprtrdma/rpc_rdma.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) I'm not sure how this got by initial testing. However, the issue came up when I started testing internally against Solaris NFS servers. diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c index 649f7d8b9733..c335c1361564 100644 --- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -628,8 +628,9 @@ static bool rpcrdma_prepare_pagelist(struct rpcrdma_req *req, return false; } -/* The tail iovec might not reside in the same page as the - * head iovec. +/* The tail iovec may include an XDR pad for the page list, + * as well as additional content, and may not reside in the + * same page as the head iovec. */ static bool rpcrdma_prepare_tail_iov(struct rpcrdma_req *req, struct xdr_buf *xdr, @@ -747,19 +748,27 @@ static bool rpcrdma_prepare_readch(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req, struct xdr_buf *xdr) { - struct kvec *tail = &xdr->tail[0]; - if (!rpcrdma_prepare_head_iov(r_xprt, req, xdr->head[0].iov_len)) return false; - /* If there is a Read chunk, the page list is handled + /* If there is a Read chunk, the page list is being handled * via explicit RDMA, and thus is skipped here. */ - if (tail->iov_len) { - if (!rpcrdma_prepare_tail_iov(req, xdr, - offset_in_page(tail->iov_base), - tail->iov_len)) + /* Do not include the tail if it is only an XDR pad */ + if (xdr->tail[0].iov_len > 3) { + unsigned int page_base, len; + + /* If the content in the page list is an odd length, + * xdr_write_pages() adds a pad at the beginning of + * the tail iovec. Force the tail's non-pad content to + * land at the next XDR position in the Send message. + */ + page_base = offset_in_page(xdr->tail[0].iov_base); + len = xdr->tail[0].iov_len; + page_base += len & 3; + len -= len & 3; + if (!rpcrdma_prepare_tail_iov(req, xdr, page_base, len)) return false; kref_get(&req->rl_kref); }