From patchwork Tue Nov 23 01:29:35 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 12633309 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 62448C433EF for ; Tue, 23 Nov 2021 01:31:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231451AbhKWBea (ORCPT ); Mon, 22 Nov 2021 20:34:30 -0500 Received: from smtp-out1.suse.de ([195.135.220.28]:57876 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229484AbhKWBea (ORCPT ); Mon, 22 Nov 2021 20:34:30 -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-out1.suse.de (Postfix) with ESMTPS id 7B069218B0; Tue, 23 Nov 2021 01:31:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1637631082; 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=pn9gDOrq59XoNH0HG8W4Dfcs8NF+/Kq6he69YY+ziro=; b=NovLVDQ6qHI1YuqsJ1lJtJe1fjleI2xkuQ1+BeUFq4c6k2kxgC3QiesUzioeBFIFN73AWk 4sPvWAEWu8JU+wdka2bm9jP3OkGJzI5YoJn6QoV1av3URI7jBXGKjsuH1A6n385tK9CKqz IsqCoWZ3S1ZVROasPTL/OzlumE/L6Dc= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1637631082; 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=pn9gDOrq59XoNH0HG8W4Dfcs8NF+/Kq6he69YY+ziro=; b=+NBpqDZYYfONXuBtvSO/JBiMyDW6XUFJ87174N4ERZYLb49ldxblYZtchAADvbzQynW/C3 aa3nrxKiv0k21fCw== 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 6CA6313BD4; Tue, 23 Nov 2021 01:31:21 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id yuTtCmlEnGHOcwAAMHmgww (envelope-from ); Tue, 23 Nov 2021 01:31:21 +0000 Subject: [PATCH 05/19] SUNRPC: use sv_lock to protect updates to sv_nrthreads. From: NeilBrown To: "J. Bruce Fields" , Chuck Lever Cc: linux-nfs@vger.kernel.org Date: Tue, 23 Nov 2021 12:29:35 +1100 Message-ID: <163763097544.7284.15751243743215653521.stgit@noble.brown> In-Reply-To: <163763078330.7284.10141477742275086758.stgit@noble.brown> References: <163763078330.7284.10141477742275086758.stgit@noble.brown> User-Agent: StGit/0.23 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Using sv_lock means we don't need to hold the service mutex over these updates. In particular, svc_exit_thread() no longer requires synchronisation, so threads can exit asynchronously. Signed-off-by: NeilBrown --- fs/nfsd/nfssvc.c | 5 ++--- net/sunrpc/svc.c | 9 +++++++-- 2 files changed, 9 insertions(+), 5 deletions(-) diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c index fc5899502a83..e9c9fa820b17 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -55,9 +55,8 @@ static __be32 nfsd_init_request(struct svc_rqst *, struct svc_process_info *); /* - * nfsd_mutex protects nn->nfsd_serv -- both the pointer itself and the members - * of the svc_serv struct. In particular, ->sv_nrthreads but also to some - * extent ->sv_temp_socks and ->sv_permsocks. + * nfsd_mutex protects nn->nfsd_serv -- both the pointer itself and some members + * of the svc_serv struct such as ->sv_temp_socks and ->sv_permsocks. * * If (out side the lock) nn->nfsd_serv is non-NULL, then it must point to a * properly initialised 'struct svc_serv' with ->sv_nrthreads > 0 (unless diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index acddc6e12e9e..2b2042234e4b 100644 --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -523,7 +523,7 @@ EXPORT_SYMBOL_GPL(svc_shutdown_net); /* * Destroy an RPC service. Should be called with appropriate locking to - * protect the sv_nrthreads, sv_permsocks and sv_tempsocks. + * protect sv_permsocks and sv_tempsocks. */ void svc_destroy(struct kref *ref) @@ -639,7 +639,10 @@ svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node) return ERR_PTR(-ENOMEM); svc_get(serv); - serv->sv_nrthreads++; + spin_lock_bh(&serv->sv_lock); + serv->sv_nrthreads += 1; + spin_unlock_bh(&serv->sv_lock); + spin_lock_bh(&pool->sp_lock); pool->sp_nrthreads++; list_add_rcu(&rqstp->rq_all, &pool->sp_all_threads); @@ -880,7 +883,9 @@ svc_exit_thread(struct svc_rqst *rqstp) list_del_rcu(&rqstp->rq_all); spin_unlock_bh(&pool->sp_lock); + spin_lock_bh(&serv->sv_lock); serv->sv_nrthreads -= 1; + spin_unlock_bh(&serv->sv_lock); svc_sock_update_bufs(serv); svc_rqst_free(rqstp);