From patchwork Wed Nov 17 00:46:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 12623349 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42974C433F5 for ; Wed, 17 Nov 2021 00:48:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2B17A619FA for ; Wed, 17 Nov 2021 00:48:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232350AbhKQAvD (ORCPT ); Tue, 16 Nov 2021 19:51:03 -0500 Received: from smtp-out2.suse.de ([195.135.220.29]:43446 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232241AbhKQAvA (ORCPT ); Tue, 16 Nov 2021 19:51:00 -0500 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 8B0261FCA3; Wed, 17 Nov 2021 00:48:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1637110082; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SRODYG02CzjFzQL4XDmO8VeXkSyZ3ESGsTuHgv14Ty8=; b=RXfSsCdks+WF0ekdLEbw10UWBIBUPVyunaz8slSnFBTUz0JwY/710+aYkbu1FYsHFjq3is LpYrBUOU348zrWbr8zYec3qZkBqYQ9Y88CDLF4vcevlfwazWLXWMm56V/+p2ssIuhLUOEy qqeS6ubBcz8kbNBjO2OaMNqTFeIi5ys= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1637110082; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SRODYG02CzjFzQL4XDmO8VeXkSyZ3ESGsTuHgv14Ty8=; b=/ExewyL1CMgasjh9Cp+KvFBSImgdNm39Z+z3dZO/9kWA43IFevohafhELpUjQoHqlh1bNN hXg6atogeM93ejBg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 7985313BC1; Wed, 17 Nov 2021 00:48:01 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id QiNfDkFRlGFzWgAAMHmgww (envelope-from ); Wed, 17 Nov 2021 00:48:01 +0000 Subject: [PATCH 09/14] lockd: simplify management of network status notifiers From: NeilBrown To: "J. Bruce Fields" , Chuck Lever Cc: linux-nfs@vger.kernel.org Date: Wed, 17 Nov 2021 11:46:50 +1100 Message-ID: <163711001006.5485.14296843136583855733.stgit@noble.brown> In-Reply-To: <163710954700.5485.5622638225352156964.stgit@noble.brown> References: <163710954700.5485.5622638225352156964.stgit@noble.brown> User-Agent: StGit/0.23 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Now that the network status notifiers use nlmsvc_serv rather then nlmsvc_rqst the management can be simplified. Notifier unregistration synchronises with any pending notifications so providing we unregister before nlm_serv is freed no further interlock is required. So we move the unregister call to just before the thread is killed (which destroys the service) and just before the service is destroyed in the failure-path of lockd_up(). Then nlm_ntf_refcnt and nlm_ntf_wq can be removed. Signed-off-by: NeilBrown --- fs/lockd/svc.c | 35 +++++++++-------------------------- 1 file changed, 9 insertions(+), 26 deletions(-) diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c index 83874878f41d..20cebb191350 100644 --- a/fs/lockd/svc.c +++ b/fs/lockd/svc.c @@ -59,9 +59,6 @@ static struct task_struct *nlmsvc_task; static struct svc_rqst *nlmsvc_rqst; unsigned long nlmsvc_timeout; -static atomic_t nlm_ntf_refcnt = ATOMIC_INIT(0); -static DECLARE_WAIT_QUEUE_HEAD(nlm_ntf_wq); - unsigned int lockd_net_id; /* @@ -303,8 +300,7 @@ static int lockd_inetaddr_event(struct notifier_block *this, struct in_ifaddr *ifa = (struct in_ifaddr *)ptr; struct sockaddr_in sin; - if ((event != NETDEV_DOWN) || - !atomic_inc_not_zero(&nlm_ntf_refcnt)) + if (event != NETDEV_DOWN) goto out; if (nlmsvc_serv) { @@ -314,8 +310,6 @@ static int lockd_inetaddr_event(struct notifier_block *this, sin.sin_addr.s_addr = ifa->ifa_local; svc_age_temp_xprts_now(nlmsvc_serv, (struct sockaddr *)&sin); } - atomic_dec(&nlm_ntf_refcnt); - wake_up(&nlm_ntf_wq); out: return NOTIFY_DONE; @@ -332,8 +326,7 @@ static int lockd_inet6addr_event(struct notifier_block *this, struct inet6_ifaddr *ifa = (struct inet6_ifaddr *)ptr; struct sockaddr_in6 sin6; - if ((event != NETDEV_DOWN) || - !atomic_inc_not_zero(&nlm_ntf_refcnt)) + if (event != NETDEV_DOWN) goto out; if (nlmsvc_serv) { @@ -344,8 +337,6 @@ static int lockd_inet6addr_event(struct notifier_block *this, sin6.sin6_scope_id = ifa->idev->dev->ifindex; svc_age_temp_xprts_now(nlmsvc_serv, (struct sockaddr *)&sin6); } - atomic_dec(&nlm_ntf_refcnt); - wake_up(&nlm_ntf_wq); out: return NOTIFY_DONE; @@ -362,14 +353,6 @@ static void lockd_unregister_notifiers(void) #if IS_ENABLED(CONFIG_IPV6) unregister_inet6addr_notifier(&lockd_inet6addr_notifier); #endif - wait_event(nlm_ntf_wq, atomic_read(&nlm_ntf_refcnt) == 0); -} - -static void lockd_svc_exit_thread(void) -{ - atomic_dec(&nlm_ntf_refcnt); - lockd_unregister_notifiers(); - svc_exit_thread(nlmsvc_rqst); } static int lockd_start_svc(struct svc_serv *serv) @@ -388,11 +371,9 @@ static int lockd_start_svc(struct svc_serv *serv) printk(KERN_WARNING "lockd_up: svc_rqst allocation failed, error=%d\n", error); - lockd_unregister_notifiers(); goto out_rqst; } - atomic_inc(&nlm_ntf_refcnt); svc_sock_update_bufs(serv); serv->sv_maxconn = nlm_max_connections; @@ -410,7 +391,7 @@ static int lockd_start_svc(struct svc_serv *serv) return 0; out_task: - lockd_svc_exit_thread(); + svc_exit_thread(nlmsvc_rqst); nlmsvc_task = NULL; out_rqst: nlmsvc_rqst = NULL; @@ -477,7 +458,6 @@ int lockd_up(struct net *net, const struct cred *cred) error = lockd_up_net(serv, net, cred); if (error < 0) { - lockd_unregister_notifiers(); goto err_put; } @@ -488,8 +468,10 @@ int lockd_up(struct net *net, const struct cred *cred) } nlmsvc_users++; err_put: - if (nlmsvc_users == 0) + if (nlmsvc_users == 0) { + lockd_unregister_notifiers(); nlmsvc_serv = NULL; + } svc_put(serv); err_create: mutex_unlock(&nlmsvc_mutex); @@ -518,13 +500,14 @@ lockd_down(struct net *net) printk(KERN_ERR "lockd_down: no lockd running.\n"); BUG(); } + lockd_unregister_notifiers(); kthread_stop(nlmsvc_task); dprintk("lockd_down: service stopped\n"); - lockd_svc_exit_thread(); + svc_exit_thread(nlmsvc_rqst); + nlmsvc_rqst = NULL; dprintk("lockd_down: service destroyed\n"); nlmsvc_serv = NULL; nlmsvc_task = NULL; - nlmsvc_rqst = NULL; out: mutex_unlock(&nlmsvc_mutex); }