Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755765AbdDLRqX (ORCPT ); Wed, 12 Apr 2017 13:46:23 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:59239 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754767AbdDLRkg (ORCPT ); Wed, 12 Apr 2017 13:40:36 -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 tip/core/rcu 18/40] srcu: Allow early boot use of synchronize_srcu() Date: Wed, 12 Apr 2017 10:40:03 -0700 X-Mailer: git-send-email 2.5.2 In-Reply-To: <20170412174003.GA23207@linux.vnet.ibm.com> References: <20170412174003.GA23207@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17041217-0056-0000-0000-0000033A3507 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006924; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000208; SDB=6.00846603; UDB=6.00417608; IPR=6.00625041; BA=6.00005286; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00015023; XFM=3.00000013; UTC=2017-04-12 17:40:33 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17041217-0057-0000-0000-000007703E4B Message-Id: <1492018825-25634-18-git-send-email-paulmck@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-04-12_13:,, 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=8.0.1-1702020001 definitions=main-1704120145 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 6beeba7b0b67..1026ce24922f 100644 --- a/kernel/rcu/srcu.c +++ b/kernel/rcu/srcu.c @@ -411,6 +411,8 @@ 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