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=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 A0A6AC4361A for ; Thu, 3 Dec 2020 20:12:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 50093207B8 for ; Thu, 3 Dec 2020 20:12:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729789AbgLCUM2 (ORCPT ); Thu, 3 Dec 2020 15:12:28 -0500 Received: from out01.mta.xmission.com ([166.70.13.231]:47842 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726681AbgLCUM2 (ORCPT ); Thu, 3 Dec 2020 15:12:28 -0500 Received: from in01.mta.xmission.com ([166.70.13.51]) by out01.mta.xmission.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1kkux8-00BSIe-Ol; Thu, 03 Dec 2020 13:11:46 -0700 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in01.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1kkux7-0002Ss-ST; Thu, 03 Dec 2020 13:11:46 -0700 From: ebiederm@xmission.com (Eric W. Biederman) To: Cc: Linus Torvalds , Peter Zijlstra , Ingo Molnar , Will Deacon , Jann Horn , Vasiliy Kulikov , Al Viro , Bernd Edlinger , Oleg Nesterov , Christopher Yeoh , Cyrill Gorcunov , Sargun Dhillon , Christian Brauner , Arnd Bergmann , Arnaldo Carvalho de Melo References: <87tut2bqik.fsf@x220.int.ebiederm.org> Date: Thu, 03 Dec 2020 14:11:13 -0600 In-Reply-To: <87tut2bqik.fsf@x220.int.ebiederm.org> (Eric W. Biederman's message of "Thu, 03 Dec 2020 14:09:39 -0600") Message-ID: <87k0tybqfy.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1kkux7-0002Ss-ST;;;mid=<87k0tybqfy.fsf@x220.int.ebiederm.org>;;;hst=in01.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18X/lTXMU47KKi3VPZMth1CqPtHxJtVd1c= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH 2/3] rwsem: Implement down_read_interruptible X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In preparation for converting exec_update_mutex to a rwsem so that multiple readers can execute in parallel and not deadlock, add down_read_interruptible. This is needed for perf_event_open to be converted (with no semantic changes) from working on a mutex to wroking on a rwsem. Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Will Deacon Signed-off-by: Eric W. Biederman --- include/linux/rwsem.h | 1 + kernel/locking/rwsem.c | 26 ++++++++++++++++++++++++++ 2 files changed, 27 insertions(+) diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 13021b08b2ed..4c715be48717 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -123,6 +123,7 @@ static inline int rwsem_is_contended(struct rw_semaphore *sem) * lock for reading */ extern void down_read(struct rw_semaphore *sem); +extern int __must_check down_read_interruptible(struct rw_semaphore *sem); extern int __must_check down_read_killable(struct rw_semaphore *sem); /* diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 54d11cb97551..a163542d178e 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -1345,6 +1345,18 @@ static inline void __down_read(struct rw_semaphore *sem) } } +static inline int __down_read_interruptible(struct rw_semaphore *sem) +{ + if (!rwsem_read_trylock(sem)) { + if (IS_ERR(rwsem_down_read_slowpath(sem, TASK_INTERRUPTIBLE))) + return -EINTR; + DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem); + } else { + rwsem_set_reader_owned(sem); + } + return 0; +} + static inline int __down_read_killable(struct rw_semaphore *sem) { if (!rwsem_read_trylock(sem)) { @@ -1495,6 +1507,20 @@ void __sched down_read(struct rw_semaphore *sem) } EXPORT_SYMBOL(down_read); +int __sched down_read_interruptible(struct rw_semaphore *sem) +{ + might_sleep(); + rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_); + + if (LOCK_CONTENDED_RETURN(sem, __down_read_trylock, __down_read_interruptible)) { + rwsem_release(&sem->dep_map, _RET_IP_); + return -EINTR; + } + + return 0; +} +EXPORT_SYMBOL(down_read_interruptible); + int __sched down_read_killable(struct rw_semaphore *sem) { might_sleep(); -- 2.25.0