From patchwork Fri Aug 26 09:51:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "D. Wythe" X-Patchwork-Id: 12955783 X-Patchwork-Delegate: kuba@kernel.org 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 DF185ECAAD9 for ; Fri, 26 Aug 2022 09:52:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344137AbiHZJwT (ORCPT ); Fri, 26 Aug 2022 05:52:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57090 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344115AbiHZJwF (ORCPT ); Fri, 26 Aug 2022 05:52:05 -0400 Received: from out30-44.freemail.mail.aliyun.com (out30-44.freemail.mail.aliyun.com [115.124.30.44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8A80FD87D5; Fri, 26 Aug 2022 02:51:58 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R181e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045192;MF=alibuda@linux.alibaba.com;NM=1;PH=DS;RN=8;SR=0;TI=SMTPD_---0VNIZf1-_1661507515; Received: from localhost(mailfrom:alibuda@linux.alibaba.com fp:SMTPD_---0VNIZf1-_1661507515) by smtp.aliyun-inc.com; Fri, 26 Aug 2022 17:51:56 +0800 From: "D. Wythe" To: kgraul@linux.ibm.com, wenjia@linux.ibm.com Cc: kuba@kernel.org, davem@davemloft.net, netdev@vger.kernel.org, linux-s390@vger.kernel.org, linux-rdma@vger.kernel.org, "D. Wythe" Subject: [PATCH net-next v2 05/10] net/smc: llc_conf_mutex refactor, replace it with rw_semaphore Date: Fri, 26 Aug 2022 17:51:32 +0800 Message-Id: <183da1da00e0a104af0a8482016e12e2d92fe3ea.1661407821.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: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: "D. Wythe" llc_conf_mutex was used to protect links and link related configurations in the same link group, for example, add or delete links. However, in most cases, the protected critical area has only read semantics and with no write semantics at all, such as obtaining a usable link or an available rmb_desc. This patch do simply code refactoring, replace mutex with rw_semaphore, replace mutex_lock with down_write and replace mutex_unlock with up_write. Theoretically, this replacement is equivalent, but after this patch, we can distinguish lock granularity according to different semantics of critical areas. Signed-off-by: D. Wythe --- net/smc/af_smc.c | 8 ++++---- net/smc/smc_core.c | 20 ++++++++++---------- net/smc/smc_core.h | 2 +- net/smc/smc_llc.c | 18 +++++++++--------- 4 files changed, 24 insertions(+), 24 deletions(-) diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index ddca170..04d79d1 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -498,7 +498,7 @@ static int smcr_lgr_reg_sndbufs(struct smc_link *link, return -EINVAL; /* protect against parallel smcr_link_reg_buf() */ - mutex_lock(&lgr->llc_conf_mutex); + down_write(&lgr->llc_conf_mutex); for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) { if (!smc_link_active(&lgr->lnk[i])) continue; @@ -506,7 +506,7 @@ static int smcr_lgr_reg_sndbufs(struct smc_link *link, if (rc) break; } - mutex_unlock(&lgr->llc_conf_mutex); + up_write(&lgr->llc_conf_mutex); return rc; } @@ -523,7 +523,7 @@ static int smcr_lgr_reg_rmbs(struct smc_link *link, /* protect against parallel smc_llc_cli_rkey_exchange() and * parallel smcr_link_reg_buf() */ - mutex_lock(&lgr->llc_conf_mutex); + down_write(&lgr->llc_conf_mutex); for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) { if (!smc_link_active(&lgr->lnk[i])) continue; @@ -540,7 +540,7 @@ static int smcr_lgr_reg_rmbs(struct smc_link *link, } rmb_desc->is_conf_rkey = true; out: - mutex_unlock(&lgr->llc_conf_mutex); + up_write(&lgr->llc_conf_mutex); smc_llc_flow_stop(lgr, &lgr->llc_flow_lcl); return rc; } diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index f93c69f..95d8438 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -1362,10 +1362,10 @@ static void smcr_buf_unuse(struct smc_buf_desc *buf_desc, bool is_rmb, rc = smc_llc_flow_initiate(lgr, SMC_LLC_FLOW_RKEY); if (!rc) { /* protect against smc_llc_cli_rkey_exchange() */ - mutex_lock(&lgr->llc_conf_mutex); + down_write(&lgr->llc_conf_mutex); smc_llc_do_delete_rkey(lgr, buf_desc); buf_desc->is_conf_rkey = false; - mutex_unlock(&lgr->llc_conf_mutex); + up_write(&lgr->llc_conf_mutex); smc_llc_flow_stop(lgr, &lgr->llc_flow_lcl); } } @@ -1635,12 +1635,12 @@ static void smc_lgr_free(struct smc_link_group *lgr) int i; if (!lgr->is_smcd) { - mutex_lock(&lgr->llc_conf_mutex); + down_write(&lgr->llc_conf_mutex); for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) { if (lgr->lnk[i].state != SMC_LNK_UNUSED) smcr_link_clear(&lgr->lnk[i], false); } - mutex_unlock(&lgr->llc_conf_mutex); + up_write(&lgr->llc_conf_mutex); smc_llc_lgr_clear(lgr); } @@ -1954,12 +1954,12 @@ static void smcr_link_down(struct smc_link *lnk) } else { if (lgr->llc_flow_lcl.type != SMC_LLC_FLOW_NONE) { /* another llc task is ongoing */ - mutex_unlock(&lgr->llc_conf_mutex); + up_write(&lgr->llc_conf_mutex); wait_event_timeout(lgr->llc_flow_waiter, (list_empty(&lgr->list) || lgr->llc_flow_lcl.type == SMC_LLC_FLOW_NONE), SMC_LLC_WAIT_TIME); - mutex_lock(&lgr->llc_conf_mutex); + down_write(&lgr->llc_conf_mutex); } if (!list_empty(&lgr->list)) { smc_llc_send_delete_link(to_lnk, del_link_id, @@ -2021,9 +2021,9 @@ static void smc_link_down_work(struct work_struct *work) if (list_empty(&lgr->list)) return; wake_up_all(&lgr->llc_msg_waiter); - mutex_lock(&lgr->llc_conf_mutex); + down_write(&lgr->llc_conf_mutex); smcr_link_down(link); - mutex_unlock(&lgr->llc_conf_mutex); + up_write(&lgr->llc_conf_mutex); } static int smc_vlan_by_tcpsk_walk(struct net_device *lower_dev, @@ -2567,7 +2567,7 @@ static int smcr_buf_map_usable_links(struct smc_link_group *lgr, int i, rc = 0; /* protect against parallel link reconfiguration */ - mutex_lock(&lgr->llc_conf_mutex); + down_write(&lgr->llc_conf_mutex); for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) { struct smc_link *lnk = &lgr->lnk[i]; @@ -2579,7 +2579,7 @@ static int smcr_buf_map_usable_links(struct smc_link_group *lgr, } } out: - mutex_unlock(&lgr->llc_conf_mutex); + up_write(&lgr->llc_conf_mutex); return rc; } diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h index 65f9460..3035ddb 100644 --- a/net/smc/smc_core.h +++ b/net/smc/smc_core.h @@ -351,7 +351,7 @@ struct smc_link_group { /* queue for llc events */ spinlock_t llc_event_q_lock; /* protects llc_event_q */ - struct mutex llc_conf_mutex; + struct rw_semaphore llc_conf_mutex; /* protects lgr reconfig. */ struct work_struct llc_add_link_work; struct work_struct llc_del_link_work; diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c index 49d92e6..f563f95 100644 --- a/net/smc/smc_llc.c +++ b/net/smc/smc_llc.c @@ -1237,12 +1237,12 @@ static void smc_llc_process_cli_add_link(struct smc_link_group *lgr) qentry = smc_llc_flow_qentry_clr(&lgr->llc_flow_lcl); - mutex_lock(&lgr->llc_conf_mutex); + down_write(&lgr->llc_conf_mutex); if (smc_llc_is_local_add_link(&qentry->msg)) smc_llc_cli_add_link_invite(qentry->link, qentry); else smc_llc_cli_add_link(qentry->link, qentry); - mutex_unlock(&lgr->llc_conf_mutex); + up_write(&lgr->llc_conf_mutex); } static int smc_llc_active_link_count(struct smc_link_group *lgr) @@ -1546,13 +1546,13 @@ static void smc_llc_process_srv_add_link(struct smc_link_group *lgr) qentry = smc_llc_flow_qentry_clr(&lgr->llc_flow_lcl); - mutex_lock(&lgr->llc_conf_mutex); + down_write(&lgr->llc_conf_mutex); rc = smc_llc_srv_add_link(link, qentry); if (!rc && lgr->type == SMC_LGR_SYMMETRIC) { /* delete any asymmetric link */ smc_llc_delete_asym_link(lgr); } - mutex_unlock(&lgr->llc_conf_mutex); + up_write(&lgr->llc_conf_mutex); kfree(qentry); } @@ -1619,7 +1619,7 @@ static void smc_llc_process_cli_delete_link(struct smc_link_group *lgr) smc_lgr_terminate_sched(lgr); goto out; } - mutex_lock(&lgr->llc_conf_mutex); + down_write(&lgr->llc_conf_mutex); /* delete single link */ for (lnk_idx = 0; lnk_idx < SMC_LINKS_PER_LGR_MAX; lnk_idx++) { if (lgr->lnk[lnk_idx].link_id != del_llc->link_num) @@ -1655,7 +1655,7 @@ static void smc_llc_process_cli_delete_link(struct smc_link_group *lgr) smc_lgr_terminate_sched(lgr); } out_unlock: - mutex_unlock(&lgr->llc_conf_mutex); + up_write(&lgr->llc_conf_mutex); out: kfree(qentry); } @@ -1691,7 +1691,7 @@ static void smc_llc_process_srv_delete_link(struct smc_link_group *lgr) int active_links; int i; - mutex_lock(&lgr->llc_conf_mutex); + down_write(&lgr->llc_conf_mutex); qentry = smc_llc_flow_qentry_clr(&lgr->llc_flow_lcl); lnk = qentry->link; del_llc = &qentry->msg.delete_link; @@ -1748,7 +1748,7 @@ static void smc_llc_process_srv_delete_link(struct smc_link_group *lgr) smc_llc_add_link_local(lnk); } out: - mutex_unlock(&lgr->llc_conf_mutex); + up_write(&lgr->llc_conf_mutex); kfree(qentry); } @@ -2162,7 +2162,7 @@ void smc_llc_lgr_init(struct smc_link_group *lgr, struct smc_sock *smc) spin_lock_init(&lgr->llc_flow_lock); init_waitqueue_head(&lgr->llc_flow_waiter); init_waitqueue_head(&lgr->llc_msg_waiter); - mutex_init(&lgr->llc_conf_mutex); + init_rwsem(&lgr->llc_conf_mutex); lgr->llc_testlink_time = READ_ONCE(net->ipv4.sysctl_tcp_keepalive_time); }