From patchwork Thu Jan 7 14:33:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 359680 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 94BF7C43332 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 7BD3223355 for ; Thu, 7 Jan 2021 14:35:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728948AbhAGOfb (ORCPT ); Thu, 7 Jan 2021 09:35:31 -0500 Received: from mail.kernel.org ([198.145.29.99]:47262 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729565AbhAGOdV (ORCPT ); Thu, 7 Jan 2021 09:33:21 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 45D322311E; Thu, 7 Jan 2021 14:32:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610029960; bh=07H55USeSn93ZqRjF/TaBFzUhTUO066N9IvQn5RjYao=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jTRVVoaiFbNhyWwYigNla7sBicVY9pO/uxaiqojZkhvLGBaFxgNkppaVHoPm20BPR NLH5U+svwdderIE/Zzas1Vvq4mtGFrnUU+kDicXArL0HtB0zcSt2qNGdzoeyK9vxem NlH2i1gOZX0Vt9CT2Cx8gCgdZODY6B9q9+7NVZFA= 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 11/13] rwsem: Implement down_read_interruptible Date: Thu, 7 Jan 2021 15:33:30 +0100 Message-Id: <20210107143051.459159924@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 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eric W. Biederman [ Upstream commit 31784cff7ee073b34d6eddabb95e3be2880a425c ] 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. Signed-off-by: Eric W. Biederman Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/87k0tybqfy.fsf@x220.int.ebiederm.org Signed-off-by: Sasha Levin --- 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 c91ac00d1ff8c..8a3606372abc8 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -125,6 +125,7 @@ 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 2ce13f9585779..a5eb87f2c5816 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -1348,6 +1348,18 @@ 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)) { @@ -1498,6 +1510,20 @@ 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();