From patchwork Thu Jan 7 14:34:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 358862 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, 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 28E86C433E9 for ; Thu, 7 Jan 2021 14:35:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 089D323383 for ; Thu, 7 Jan 2021 14:35:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729605AbhAGOdd (ORCPT ); Thu, 7 Jan 2021 09:33:33 -0500 Received: from mail.kernel.org ([198.145.29.99]:47182 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729600AbhAGOdc (ORCPT ); Thu, 7 Jan 2021 09:33:32 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id C188B22EBF; Thu, 7 Jan 2021 14:33:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610029997; bh=wtAM82iXgMoyxDh/Ji0NKnDig34WfzmB6eoRobblbSM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aT1c2j+I+1tjh/RQ3Tc9gLzmMG4cMi1zNjhLcoRlgN2nQcCDhOCaZul0R4I+SKmoP wfuDQcnqg4f8KMUpTOps9ViUesx7ulEiOd6jOhY4zrkojckbD62+/zawCzm+G6txna 7Air+P/3/g0qUEEAhwf6/zEVVN5YFrkYq50B06QQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Eric W. Biederman" , "Peter Zijlstra (Intel)" , Sasha Levin Subject: [PATCH 5.10 17/20] rwsem: Implement down_read_killable_nested Date: Thu, 7 Jan 2021 15:34:12 +0100 Message-Id: <20210107143054.781425623@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210107143052.392839477@linuxfoundation.org> References: <20210107143052.392839477@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eric W. Biederman [ Upstream commit 0f9368b5bf6db0c04afc5454b1be79022a681615 ] 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. Signed-off-by: Eric W. Biederman Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/87o8jabqh3.fsf@x220.int.ebiederm.org Signed-off-by: Sasha Levin --- 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 25e3fde856178..13021b08b2ed6 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 f11b9bd3431d2..54d11cb975510 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();