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 BDCA8C4361A for ; Thu, 3 Dec 2020 20:12:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 66721207B8 for ; Thu, 3 Dec 2020 20:12:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731311AbgLCULt (ORCPT ); Thu, 3 Dec 2020 15:11:49 -0500 Received: from out01.mta.xmission.com ([166.70.13.231]:47680 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729071AbgLCULs (ORCPT ); Thu, 3 Dec 2020 15:11:48 -0500 Received: from in02.mta.xmission.com ([166.70.13.52]) by out01.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1kkuwU-00BS9Z-Hs; Thu, 03 Dec 2020 13:11:06 -0700 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1kkuwT-00B38k-2w; Thu, 03 Dec 2020 13:11:06 -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 14:10:32 -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: <87o8jabqh3.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=1kkuwT-00B38k-2w;;;mid=<87o8jabqh3.fsf@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18vkmZsHEZxXZ0gWrolGwg6cT1OeuUlaFQ= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH 1/3] rwsem: Implement down_read_killable_nested X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in02.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_killable_nested. This is needed so that kcmp_lock can be converted from working on a mutexes to working on rw_semaphores. Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Will Deacon Signed-off-by: Eric W. Biederman --- include/linux/rwsem.h | 2 ++ kernel/locking/rwsem.c | 14 ++++++++++++++ 2 files changed, 16 insertions(+) diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 25e3fde85617..13021b08b2ed 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -171,6 +171,7 @@ extern void downgrade_write(struct rw_semaphore *sem); * See Documentation/locking/lockdep-design.rst for more details.) */ extern void down_read_nested(struct rw_semaphore *sem, int subclass); +extern int __must_check down_read_killable_nested(struct rw_semaphore *sem, int subclass); extern void down_write_nested(struct rw_semaphore *sem, int subclass); extern int down_write_killable_nested(struct rw_semaphore *sem, int subclass); extern void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest_lock); @@ -191,6 +192,7 @@ extern void down_read_non_owner(struct rw_semaphore *sem); extern void up_read_non_owner(struct rw_semaphore *sem); #else # define down_read_nested(sem, subclass) down_read(sem) +# define down_read_killable_nested(sem, subclass) down_read_killable(sem) # define down_write_nest_lock(sem, nest_lock) down_write(sem) # define down_write_nested(sem, subclass) down_write(sem) # define down_write_killable_nested(sem, subclass) down_write_killable(sem) diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index f11b9bd3431d..54d11cb97551 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -1605,6 +1605,20 @@ void down_read_nested(struct rw_semaphore *sem, int subclass) } EXPORT_SYMBOL(down_read_nested); +int down_read_killable_nested(struct rw_semaphore *sem, int subclass) +{ + might_sleep(); + rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_); + + if (LOCK_CONTENDED_RETURN(sem, __down_read_trylock, __down_read_killable)) { + rwsem_release(&sem->dep_map, _RET_IP_); + return -EINTR; + } + + return 0; +} +EXPORT_SYMBOL(down_read_killable_nested); + void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest) { might_sleep(); -- 2.25.0