From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755969AbdJJAZJ (ORCPT ); Mon, 9 Oct 2017 20:25:09 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:57898 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755826AbdJJAW4 (ORCPT ); Mon, 9 Oct 2017 20:22:56 -0400 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, torvalds@linux-foundation.org, mark.rutland@arm.com, dhowells@redhat.com, linux-arch@vger.kernel.org, peterz@infradead.org, will.deacon@arm.com, "Paul E. McKenney" , Ingo Molnar Subject: [PATCH RFC tip/core/rcu 08/15] seqlock: Remove now-redundant smp_read_barrier_depends() Date: Mon, 9 Oct 2017 17:22:42 -0700 X-Mailer: git-send-email 2.5.2 In-Reply-To: <20171010001951.GA6476@linux.vnet.ibm.com> References: <20171010001951.GA6476@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17101000-0056-0000-0000-000003D72E6E X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007870; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000235; SDB=6.00928858; UDB=6.00467488; IPR=6.00709129; BA=6.00005631; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00017467; XFM=3.00000015; UTC=2017-10-10 00:22:53 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17101000-0057-0000-0000-0000080E2E84 Message-Id: <1507594969-8347-8-git-send-email-paulmck@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-10-09_07:,, 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=8.0.1-1707230000 definitions=main-1710100003 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org READ_ONCE() now implies smp_read_barrier_depends(), so this patch removes the now-redundant smp_read_barrier_depends() from raw_read_seqcount_latch(). Signed-off-by: Paul E. McKenney Cc: Peter Zijlstra Cc: Ingo Molnar --- include/linux/seqlock.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h index ead97654c4e9..27364347ff68 100644 --- a/include/linux/seqlock.h +++ b/include/linux/seqlock.h @@ -277,9 +277,8 @@ static inline void raw_write_seqcount_barrier(seqcount_t *s) static inline int raw_read_seqcount_latch(seqcount_t *s) { - int seq = READ_ONCE(s->sequence); /* Pairs with the first smp_wmb() in raw_write_seqcount_latch() */ - smp_read_barrier_depends(); + int seq = READ_ONCE(s->sequence); /* ^^^ */ return seq; } -- 2.5.2