From patchwork Wed Mar 2 13:25:11 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "D. Wythe" X-Patchwork-Id: 12766012 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37C1DC43217 for ; Wed, 2 Mar 2022 13:25:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242183AbiCBN0B (ORCPT ); Wed, 2 Mar 2022 08:26:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234478AbiCBN0A (ORCPT ); Wed, 2 Mar 2022 08:26:00 -0500 Received: from out30-57.freemail.mail.aliyun.com (out30-57.freemail.mail.aliyun.com [115.124.30.57]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1604727FE0; Wed, 2 Mar 2022 05:25:16 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R201e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04395;MF=alibuda@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0V636-KF_1646227513; Received: from localhost(mailfrom:alibuda@linux.alibaba.com fp:SMTPD_---0V636-KF_1646227513) by smtp.aliyun-inc.com(127.0.0.1); Wed, 02 Mar 2022 21:25:14 +0800 From: "D. Wythe" To: kgraul@linux.ibm.com Cc: kuba@kernel.org, davem@davemloft.net, netdev@vger.kernel.org, linux-s390@vger.kernel.org, linux-rdma@vger.kernel.org Subject: [PATCH net v3 1/2] net/smc: fix unexpected SMC_CLC_DECL_ERR_REGRMB error generated by client Date: Wed, 2 Mar 2022 21:25:11 +0800 Message-Id: <92d003a2abfabd714a29be89c3c407f5d75b9c06.1646227183.git.alibuda@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: References: Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org From: "D. Wythe" The main reason for this unexpected SMC_CLC_DECL_ERR_REGRMB in client dues to following execution sequence: Server Conn A: Server Conn B: Client Conn B: smc_lgr_unregister_conn smc_lgr_register_conn smc_clc_send_accept -> smc_rtoken_add smcr_buf_unuse -> Client Conn A: smc_rtoken_delete smc_lgr_unregister_conn() makes current link available to assigned to new incoming connection, while smcr_buf_unuse() has not executed yet, which means that smc_rtoken_add may fail because of insufficient rtoken_entry, reversing their execution order will avoid this problem. Fixes: 3e034725c0d8 ("net/smc: common functions for RMBs and send buffers") Signed-off-by: D. Wythe --- net/smc/smc_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index 29525d0..f8c9675 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -1161,8 +1161,8 @@ void smc_conn_free(struct smc_connection *conn) cancel_work_sync(&conn->abort_work); } if (!list_empty(&lgr->list)) { - smc_lgr_unregister_conn(conn); smc_buf_unuse(conn, lgr); /* allow buffer reuse */ + smc_lgr_unregister_conn(conn); } if (!lgr->conns_num) From patchwork Wed Mar 2 13:25:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "D. Wythe" X-Patchwork-Id: 12766013 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 05A93C433EF for ; Wed, 2 Mar 2022 13:25:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242198AbiCBN0J (ORCPT ); Wed, 2 Mar 2022 08:26:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242180AbiCBN0B (ORCPT ); Wed, 2 Mar 2022 08:26:01 -0500 Received: from out30-54.freemail.mail.aliyun.com (out30-54.freemail.mail.aliyun.com [115.124.30.54]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE6222DE7; Wed, 2 Mar 2022 05:25:17 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R481e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=alibuda@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0V631sQn_1646227514; Received: from localhost(mailfrom:alibuda@linux.alibaba.com fp:SMTPD_---0V631sQn_1646227514) by smtp.aliyun-inc.com(127.0.0.1); Wed, 02 Mar 2022 21:25:15 +0800 From: "D. Wythe" To: kgraul@linux.ibm.com Cc: kuba@kernel.org, davem@davemloft.net, netdev@vger.kernel.org, linux-s390@vger.kernel.org, linux-rdma@vger.kernel.org Subject: [PATCH net v3 2/2] net/smc: fix unexpected SMC_CLC_DECL_ERR_REGRMB error cause by server Date: Wed, 2 Mar 2022 21:25:12 +0800 Message-Id: X-Mailer: git-send-email 1.8.3.1 In-Reply-To: References: Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org From: "D. Wythe" The problem of SMC_CLC_DECL_ERR_REGRMB on the server is very clear. Based on the fact that whether a new SMC connection can be accepted or not depends on not only the limit of conn nums, but also the available entries of rtoken. Since the rtoken release is trigger by peer, while the conn nums is decrease by local, tons of thing can happen in this time difference. This only thing that needs to be mentioned is that now all connection creations are completely protected by smc_server_lgr_pending lock, it's enough to check only the available entries in rtokens_used_mask. Fixes: cd6851f30386 ("smc: remote memory buffers (RMBs)") Signed-off-by: D. Wythe --- net/smc/smc_core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index f8c9675..be7d704 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -1864,7 +1864,8 @@ int smc_conn_create(struct smc_sock *smc, struct smc_init_info *ini) (ini->smcd_version == SMC_V2 || lgr->vlan_id == ini->vlan_id) && (role == SMC_CLNT || ini->is_smcd || - lgr->conns_num < SMC_RMBS_PER_LGR_MAX)) { + (lgr->conns_num < SMC_RMBS_PER_LGR_MAX && + !bitmap_full(lgr->rtokens_used_mask, SMC_RMBS_PER_LGR_MAX)))) { /* link group found */ ini->first_contact_local = 0; conn->lgr = lgr;