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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 27F31C433F5 for ; Fri, 10 Sep 2021 01:05:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 11B1161132 for ; Fri, 10 Sep 2021 01:05:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343880AbhIJBFk (ORCPT ); Thu, 9 Sep 2021 21:05:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:50084 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234888AbhIJAZF (ORCPT ); Thu, 9 Sep 2021 20:25:05 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id BEDA160FDA; Fri, 10 Sep 2021 00:23:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631233435; bh=zX8ccth7cdh1jMEabccqhWrDi2S6TfLeO1fIqGPTdWw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LsWNwePf3Nu4AeaLpatTNbjIUUUMtwaiaBHcoQ15Sca4AOoHL6N0Fx5fm81oKb3EP W1o6pEpEwmU6tS4QmbimnGr3lZbgxAtOhfUvcbDcEeW0u8jLAFTd5s4gN7D3yXV5is h8dIJanW+ELLks9p2aoJ5NXYUEl77DZFCq3XD02Iyi5eA/Vbe6PQvw97VBj1R8f7Si LY9gbVMYi9QZUjRvC1ABafnvrjNmALD80hutzmW97004mDU4Qg4oBBdYOHl6W92dTl fZdH+aW7quKugOR+Nx5KGtHHoaXGcJm/MU3Y6MW+y9byfcF9FMPJ59A9MaXblULb7E o5Z6ULVjyVJQg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: =?UTF-8?q?H=C3=A5kon=20Bugge?= , Jason Gunthorpe , Sasha Levin , linux-rdma@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 12/17] RDMA/core/sa_query: Retry SA queries Date: Thu, 9 Sep 2021 20:23:33 -0400 Message-Id: <20210910002338.176677-12-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210910002338.176677-1-sashal@kernel.org> References: <20210910002338.176677-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Håkon Bugge [ Upstream commit 5f5a650999d5718af766fc70a120230b04235a6f ] A MAD packet is sent as an unreliable datagram (UD). SA requests are sent as MAD packets. As such, SA requests or responses may be silently dropped. IB Core's MAD layer has a timeout and retry mechanism, which amongst other, is used by RDMA CM. But it is not used by SA queries. The lack of retries of SA queries leads to long specified timeout, and error being returned in case of packet loss. The ULP or user-land process has to perform the retry. Fix this by taking advantage of the MAD layer's retry mechanism. First, a check against a zero timeout is added in rdma_resolve_route(). In send_mad(), we set the MAD layer timeout to one tenth of the specified timeout and the number of retries to 10. The special case when timeout is less than 10 is handled. With this fix: # ucmatose -c 1000 -S 1024 -C 1 runs stable on an Infiniband fabric. Without this fix, we see an intermittent behavior and it errors out with: cmatose: event: RDMA_CM_EVENT_ROUTE_ERROR, error: -110 (110 is ETIMEDOUT) Link: https://lore.kernel.org/r/1628784755-28316-1-git-send-email-haakon.bugge@oracle.com Signed-off-by: Håkon Bugge Signed-off-by: Jason Gunthorpe Signed-off-by: Sasha Levin --- drivers/infiniband/core/cma.c | 3 +++ drivers/infiniband/core/sa_query.c | 9 ++++++++- 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c index 149d210c68ab..9f8b58bb5fb8 100644 --- a/drivers/infiniband/core/cma.c +++ b/drivers/infiniband/core/cma.c @@ -2580,6 +2580,9 @@ int rdma_resolve_route(struct rdma_cm_id *id, int timeout_ms) struct rdma_id_private *id_priv; int ret; + if (!timeout_ms) + return -EINVAL; + id_priv = container_of(id, struct rdma_id_private, id); if (!cma_comp_exch(id_priv, RDMA_CM_ADDR_RESOLVED, RDMA_CM_ROUTE_QUERY)) return -EINVAL; diff --git a/drivers/infiniband/core/sa_query.c b/drivers/infiniband/core/sa_query.c index 1c459725d64e..5b4d1b7d9bad 100644 --- a/drivers/infiniband/core/sa_query.c +++ b/drivers/infiniband/core/sa_query.c @@ -1240,6 +1240,7 @@ static int send_mad(struct ib_sa_query *query, int timeout_ms, gfp_t gfp_mask) bool preload = gfpflags_allow_blocking(gfp_mask); unsigned long flags; int ret, id; + const int nmbr_sa_query_retries = 10; if (preload) idr_preload(gfp_mask); @@ -1253,7 +1254,13 @@ static int send_mad(struct ib_sa_query *query, int timeout_ms, gfp_t gfp_mask) if (id < 0) return id; - query->mad_buf->timeout_ms = timeout_ms; + query->mad_buf->timeout_ms = timeout_ms / nmbr_sa_query_retries; + query->mad_buf->retries = nmbr_sa_query_retries; + if (!query->mad_buf->timeout_ms) { + /* Special case, very small timeout_ms */ + query->mad_buf->timeout_ms = 1; + query->mad_buf->retries = timeout_ms; + } query->mad_buf->context[0] = query; query->id = id; -- 2.30.2