From patchwork Thu Jul 25 21:24:59 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Jordan X-Patchwork-Id: 11059667 X-Patchwork-Delegate: herbert@gondor.apana.org.au Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C1BFF1399 for ; Thu, 25 Jul 2019 21:25:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B1A5928A78 for ; Thu, 25 Jul 2019 21:25:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A3CD628A7C; Thu, 25 Jul 2019 21:25:48 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4BE3A28866 for ; Thu, 25 Jul 2019 21:25:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726803AbfGYVZq (ORCPT ); Thu, 25 Jul 2019 17:25:46 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:54622 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726674AbfGYVZq (ORCPT ); Thu, 25 Jul 2019 17:25:46 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x6PLNQux028419; Thu, 25 Jul 2019 21:25:24 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=corp-2018-07-02; bh=0FHLYwXChjiQiSvTSooHeQULBjqit8SM8K4FegGSKjQ=; b=VJDvALEbh2WRLgJ51/lOw+GuVaIChEtBFMVzz7/5m656+BbbSE1Pp93KOvuF/C9ekWGj dRTl9WLuZV5CDpXGZPAIvVQIanEfDbADCQtquO4r6a4kijH7FHN4mdsfHRNdAcmN/SyY iAUdHLkgTOLPp+dw7pcsoqLcqDtM8HW1m5AK0hPrktlIXx9cJb9gb+XHAvJ9XOnlNETz x98DDCPF+9KKnhwoM6sFxrZjjhTiQPMXXVexeW1kesJ3oiq3Y2mbg/791zkvye+8vGye JXMNb8mz+FngZZpNyO5x0kK4FUZuuSHC9HGxI6HJwXTpSFJ5jrj37e00K8NGyhu4T7bn dg== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2130.oracle.com with ESMTP id 2tx61c6mev-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 25 Jul 2019 21:25:24 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x6PLNIT3066990; Thu, 25 Jul 2019 21:25:24 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3030.oracle.com with ESMTP id 2tx60yj90c-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 25 Jul 2019 21:25:24 +0000 Received: from abhmp0015.oracle.com (abhmp0015.oracle.com [141.146.116.21]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x6PLPKx1030875; Thu, 25 Jul 2019 21:25:22 GMT Received: from localhost.localdomain (/73.60.114.248) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 25 Jul 2019 14:25:19 -0700 From: Daniel Jordan To: Steffen Klassert , Herbert Xu Cc: Tejun Heo , Lai Jiangshan , Peter Zijlstra , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, Daniel Jordan Subject: [RFC 3/9] workqueue: require CPU hotplug read exclusion for apply_workqueue_attrs Date: Thu, 25 Jul 2019 17:24:59 -0400 Message-Id: <20190725212505.15055-4-daniel.m.jordan@oracle.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190725212505.15055-1-daniel.m.jordan@oracle.com> References: <20190725212505.15055-1-daniel.m.jordan@oracle.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9329 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=914 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1907250257 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9329 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=956 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1907250257 Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Change the calling convention for apply_workqueue_attrs to require CPU hotplug read exclusion. Avoids lockdep complaints about nested calls to get_online_cpus in a future patch where padata calls apply_workqueue_attrs when changing other CPU-hotplug-sensitive data structures with the CPU read lock already held. Signed-off-by: Daniel Jordan Acked-by: Tejun Heo --- kernel/workqueue.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index f53705ff3ff1..bc2e09a8ea61 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -4030,6 +4030,8 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq, * * Performs GFP_KERNEL allocations. * + * Assumes caller has CPU hotplug read exclusion, i.e. get_online_cpus(). + * * Return: 0 on success and -errno on failure. */ int apply_workqueue_attrs(struct workqueue_struct *wq, @@ -4037,9 +4039,11 @@ int apply_workqueue_attrs(struct workqueue_struct *wq, { int ret; - apply_wqattrs_lock(); + lockdep_assert_cpus_held(); + + mutex_lock(&wq_pool_mutex); ret = apply_workqueue_attrs_locked(wq, attrs); - apply_wqattrs_unlock(); + mutex_unlock(&wq_pool_mutex); return ret; } @@ -4152,16 +4156,21 @@ static int alloc_and_link_pwqs(struct workqueue_struct *wq) mutex_unlock(&wq->mutex); } return 0; - } else if (wq->flags & __WQ_ORDERED) { + } + + get_online_cpus(); + if (wq->flags & __WQ_ORDERED) { ret = apply_workqueue_attrs(wq, ordered_wq_attrs[highpri]); /* there should only be single pwq for ordering guarantee */ WARN(!ret && (wq->pwqs.next != &wq->dfl_pwq->pwqs_node || wq->pwqs.prev != &wq->dfl_pwq->pwqs_node), "ordering guarantee broken for workqueue %s\n", wq->name); - return ret; } else { - return apply_workqueue_attrs(wq, unbound_std_wq_attrs[highpri]); + ret = apply_workqueue_attrs(wq, unbound_std_wq_attrs[highpri]); } + put_online_cpus(); + + return ret; } static int wq_clamp_max_active(int max_active, unsigned int flags,