From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752568AbbGKXhr (ORCPT ); Sat, 11 Jul 2015 19:37:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49458 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752351AbbGKXhq (ORCPT ); Sat, 11 Jul 2015 19:37:46 -0400 Date: Sun, 12 Jul 2015 01:36:07 +0200 From: Oleg Nesterov To: Linus Torvalds , Paul McKenney , Peter Zijlstra Cc: Daniel Wagner , Davidlohr Bueso , Ingo Molnar , Tejun Heo , linux-kernel@vger.kernel.org Subject: [PATCH 7/7] percpu-rwsem: cleanup the lockdep annotations in percpu_down_read() Message-ID: <20150711233607.GA873@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150711233535.GA829@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Stolen from Peter's patch. Change percpu_down_read() to use __down_read(), this way we can do rwsem_acquire_read() unconditionally at the start to make this code more symmetric and clean. Signed-off-by: Oleg Nesterov --- kernel/locking/percpu-rwsem.c | 10 +++++----- 1 files changed, 5 insertions(+), 5 deletions(-) diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c index 705aefd..2c54c64 100644 --- a/kernel/locking/percpu-rwsem.c +++ b/kernel/locking/percpu-rwsem.c @@ -62,14 +62,14 @@ static bool update_fast_ctr(struct percpu_rw_semaphore *brw, unsigned int val) void percpu_down_read(struct percpu_rw_semaphore *brw) { might_sleep(); - if (likely(update_fast_ctr(brw, +1))) { - rwsem_acquire_read(&brw->rw_sem.dep_map, 0, 0, _RET_IP_); + rwsem_acquire_read(&brw->rw_sem.dep_map, 0, 0, _RET_IP_); + + if (likely(update_fast_ctr(brw, +1))) return; - } - down_read(&brw->rw_sem); + /* Avoid rwsem_acquire_read() and rwsem_release() */ + __down_read(&brw->rw_sem); atomic_inc(&brw->slow_read_ctr); - /* avoid up_read()->rwsem_release() */ __up_read(&brw->rw_sem); } -- 1.5.5.1