Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967781AbdDSRFh (ORCPT ); Wed, 19 Apr 2017 13:05:37 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:37285 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967226AbdDSQ6t (ORCPT ); Wed, 19 Apr 2017 12:58:49 -0400 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com, "Paul E. McKenney" Subject: [PATCH v3 tip/core/rcu 15/40] srcu: Allow early boot use of synchronize_srcu() Date: Wed, 19 Apr 2017 09:58:12 -0700 X-Mailer: git-send-email 2.5.2 In-Reply-To: <20170419165805.GB10874@linux.vnet.ibm.com> References: <20170419165805.GB10874@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17041916-0044-0000-0000-0000030C78F6 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006939; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000208; SDB=6.00849683; UDB=6.00419583; IPR=6.00628316; BA=6.00005304; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00015095; XFM=3.00000013; UTC=2017-04-19 16:58:42 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17041916-0045-0000-0000-0000073A7F0F Message-Id: <1492621117-13939-15-git-send-email-paulmck@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-04-19_15:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1704190140 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 745 Lines: 23 This commit checks for pre-scheduler state, and if that early in the boot process, synchronize_srcu() and friends are no-ops. Signed-off-by: Paul E. McKenney --- kernel/rcu/srcu.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c index e6da9fc1f0e9..7e7ecaa50dc5 100644 --- a/kernel/rcu/srcu.c +++ b/kernel/rcu/srcu.c @@ -417,6 +417,8 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount) lock_is_held(&rcu_sched_lock_map), "Illegal synchronize_srcu() in same-type SRCU (or in RCU) read-side critical section"); + if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE) + return; might_sleep(); init_completion(&rcu.completion); -- 2.5.2