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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 09A15C433E1 for ; Tue, 19 May 2020 21:48:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D8BAB205CB for ; Tue, 19 May 2020 21:48:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728584AbgESVr4 (ORCPT ); Tue, 19 May 2020 17:47:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726723AbgESVru (ORCPT ); Tue, 19 May 2020 17:47:50 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BAD11C08C5C0; Tue, 19 May 2020 14:47:50 -0700 (PDT) Received: from [5.158.153.53] (helo=debian-buster-darwi.lab.linutronix.de.) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.80) (envelope-from ) id 1jbA5M-0002x0-BK; Tue, 19 May 2020 23:47:40 +0200 From: "Ahmed S. Darwish" To: Peter Zijlstra , Ingo Molnar , Will Deacon Cc: Thomas Gleixner , "Paul E. McKenney" , "Sebastian A. Siewior" , Steven Rostedt , LKML , "Ahmed S. Darwish" , Trond Myklebust , Anna Schumaker , linux-nfs@vger.kernel.org Subject: [PATCH v1 22/25] NFSv4: Use sequence counter with associated spinlock Date: Tue, 19 May 2020 23:45:44 +0200 Message-Id: <20200519214547.352050-23-a.darwish@linutronix.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200519214547.352050-1-a.darwish@linutronix.de> References: <20200519214547.352050-1-a.darwish@linutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A sequence counter write side critical section must be protected by some form of locking to serialize writers. A plain seqcount_t does not contain the information of which lock must be held when entering a write side critical section. Use the new seqcount_spinlock_t data type, which allows to associate a spinlock with the sequence counter. This enables lockdep to verify that the spinlock used for writer serialization is held when the write side critical section is entered. If lockdep is disabled this lock association is compiled out and has neither storage size nor runtime overhead. Signed-off-by: Ahmed S. Darwish --- fs/nfs/nfs4_fs.h | 2 +- fs/nfs/nfs4state.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h index 2b7f6dcd2eb8..210e590e1f71 100644 --- a/fs/nfs/nfs4_fs.h +++ b/fs/nfs/nfs4_fs.h @@ -117,7 +117,7 @@ struct nfs4_state_owner { unsigned long so_flags; struct list_head so_states; struct nfs_seqid_counter so_seqid; - seqcount_t so_reclaim_seqcount; + seqcount_spinlock_t so_reclaim_seqcount; struct mutex so_delegreturn_mutex; }; diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index ac93715c05a4..9b2bad35ad24 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -509,7 +509,7 @@ nfs4_alloc_state_owner(struct nfs_server *server, nfs4_init_seqid_counter(&sp->so_seqid); atomic_set(&sp->so_count, 1); INIT_LIST_HEAD(&sp->so_lru); - seqcount_init(&sp->so_reclaim_seqcount); + seqcount_spinlock_init(&sp->so_reclaim_seqcount, &sp->so_lock); mutex_init(&sp->so_delegreturn_mutex); return sp; } -- 2.20.1