From mboxrd@z Thu Jan 1 00:00:00 1970 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,URIBL_BLOCKED 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 AED62C433B4 for ; Mon, 19 Apr 2021 18:02:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D725611F2 for ; Mon, 19 Apr 2021 18:02:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240481AbhDSSCl (ORCPT ); Mon, 19 Apr 2021 14:02:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:40892 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240433AbhDSSCl (ORCPT ); Mon, 19 Apr 2021 14:02:41 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C49C861107; Mon, 19 Apr 2021 18:02:10 +0000 (UTC) Subject: [PATCH v3 05/26] xprtrdma: Do not refresh Receive Queue while it is draining From: Chuck Lever To: trondmy@hammerspace.com Cc: linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org Date: Mon, 19 Apr 2021 14:02:09 -0400 Message-ID: <161885532997.38598.5957438962258396970.stgit@manet.1015granger.net> In-Reply-To: <161885481568.38598.16682844600209775665.stgit@manet.1015granger.net> References: <161885481568.38598.16682844600209775665.stgit@manet.1015granger.net> User-Agent: StGit/0.23-29-ga622f1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Currently the Receive completion handler refreshes the Receive Queue whenever a successful Receive completion occurs. On disconnect, xprtrdma drains the Receive Queue. The first few Receive completions after a disconnect are typically successful, until the first flushed Receive. This means the Receive completion handler continues to post more Receive WRs after the drain sentinel has been posted. The late- posted Receives flush after the drain sentinel has completed, leading to a crash later in rpcrdma_xprt_disconnect(). To prevent this crash, xprtrdma has to ensure that the Receive handler stops posting Receives before ib_drain_rq() posts its drain sentinel. Suggested-by: Tom Talpey Signed-off-by: Chuck Lever --- net/sunrpc/xprtrdma/verbs.c | 13 +++++++++++++ net/sunrpc/xprtrdma/xprt_rdma.h | 1 + 2 files changed, 14 insertions(+) diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index ec912cf9c618..d8ed69442219 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -101,6 +101,12 @@ static void rpcrdma_xprt_drain(struct rpcrdma_xprt *r_xprt) struct rpcrdma_ep *ep = r_xprt->rx_ep; struct rdma_cm_id *id = ep->re_id; + /* Wait for rpcrdma_post_recvs() to leave its critical + * section. + */ + if (atomic_inc_return(&ep->re_receiving) > 1) + wait_for_completion(&ep->re_done); + /* Flush Receives, then wait for deferred Reply work * to complete. */ @@ -414,6 +420,7 @@ static int rpcrdma_ep_create(struct rpcrdma_xprt *r_xprt) __module_get(THIS_MODULE); device = id->device; ep->re_id = id; + reinit_completion(&ep->re_done); ep->re_max_requests = r_xprt->rx_xprt.max_reqs; ep->re_inline_send = xprt_rdma_max_inline_write; @@ -1385,6 +1392,9 @@ void rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, bool temp) if (!temp) needed += RPCRDMA_MAX_RECV_BATCH; + if (atomic_inc_return(&ep->re_receiving) > 1) + goto out; + /* fast path: all needed reps can be found on the free list */ wr = NULL; while (needed) { @@ -1410,6 +1420,9 @@ void rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, bool temp) rc = ib_post_recv(ep->re_id->qp, wr, (const struct ib_recv_wr **)&bad_wr); + if (atomic_dec_return(&ep->re_receiving) > 0) + complete(&ep->re_done); + out: trace_xprtrdma_post_recvs(r_xprt, count, rc); if (rc) { diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h index fe3be985e239..31404326f29f 100644 --- a/net/sunrpc/xprtrdma/xprt_rdma.h +++ b/net/sunrpc/xprtrdma/xprt_rdma.h @@ -83,6 +83,7 @@ struct rpcrdma_ep { unsigned int re_max_inline_recv; int re_async_rc; int re_connect_status; + atomic_t re_receiving; atomic_t re_force_disconnect; struct ib_qp_init_attr re_attr; wait_queue_head_t re_connect_wait;