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=-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=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 B1C01C4332B for ; Thu, 7 Jan 2021 14:33:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 83B6423372 for ; Thu, 7 Jan 2021 14:33:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729580AbhAGOdX (ORCPT ); Thu, 7 Jan 2021 09:33:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:47240 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729532AbhAGOdS (ORCPT ); Thu, 7 Jan 2021 09:33:18 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 168E12336D; Thu, 7 Jan 2021 14:32:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610029958; bh=Kga/4gP3btIfsllJyQ5qKksgwH9GjlUV7ZHTymD/SgY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PhHO972qlXaazF1kmOZjEgcO5AKxPyrx/MlVDdTeZcRdUCQeoSux0zawXNQ7ybS3A Y2v2DiT1tJ3tswEbI5KP39SXZTNOSYeCzeTC2UWxtLynyMgsM3e+DrkG03ln/eWA26 xrvWs086gToFIzg4tyC1wvHxk/uhZENDAI4ogkRs= 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 5.4 10/13] rwsem: Implement down_read_killable_nested Date: Thu, 7 Jan 2021 15:33:29 +0100 Message-Id: <20210107143051.339142973@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210107143049.929352526@linuxfoundation.org> References: <20210107143049.929352526@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 00d6054687dd2..c91ac00d1ff8c 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -173,6 +173,7 @@ 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); @@ -193,6 +194,7 @@ 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 baafa1dd9fcc4..2ce13f9585779 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -1608,6 +1608,20 @@ 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(); -- 2.27.0