From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2447EC38A30 for ; Wed, 22 Apr 2020 04:11:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 09BC22075A for ; Wed, 22 Apr 2020 04:11:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726502AbgDVELy (ORCPT ); Wed, 22 Apr 2020 00:11:54 -0400 Received: from mx2.suse.de ([195.135.220.15]:60088 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726466AbgDVELw (ORCPT ); Wed, 22 Apr 2020 00:11:52 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 850FFADE1; Wed, 22 Apr 2020 04:11:49 +0000 (UTC) From: Davidlohr Bueso To: tglx@linutronix.de, pbonzini@redhat.com Cc: bigeasy@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, torvalds@linux-foundation.org, will@kernel.org, joel@joelfernandes.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, dave@stgolabs.net, Davidlohr Bueso Subject: [PATCH 3/5] rcuwait: Introduce prepare_to and finish_rcuwait Date: Tue, 21 Apr 2020 21:07:37 -0700 Message-Id: <20200422040739.18601-4-dave@stgolabs.net> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200422040739.18601-1-dave@stgolabs.net> References: <20200422040739.18601-1-dave@stgolabs.net> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This allows further flexibility for some callers to implement ad-hoc versions of the generic rcuwait_wait_event(). For example, kvm will need this to maintain tracing semantics. The naming is of course similar to what waitqueue apis offer. Signed-off-by: Davidlohr Bueso --- include/linux/rcuwait.h | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/include/linux/rcuwait.h b/include/linux/rcuwait.h index 6ebb23258a27..0c6a3d0d25ab 100644 --- a/include/linux/rcuwait.h +++ b/include/linux/rcuwait.h @@ -29,12 +29,25 @@ extern int rcuwait_wake_up(struct rcuwait *w); /* * The caller is responsible for locking around rcuwait_wait_event(), - * such that writes to @task are properly serialized. + * and prepare_to_rcuwait() such that writes to @task are properly + * serialized. */ + +static inline void prepare_to_rcuwait(struct rcuwait *w) +{ + rcu_assign_pointer(w->task, current); +} + +static inline void finish_rcuwait(struct rcuwait *w) +{ + WRITE_ONCE(w->task, NULL); + __set_current_state(TASK_RUNNING); +} + #define rcuwait_wait_event(w, condition, state) \ ({ \ int __ret = 0; \ - rcu_assign_pointer((w)->task, current); \ + prepare_to_rcuwait(w); \ for (;;) { \ /* \ * Implicit barrier (A) pairs with (B) in \ @@ -51,9 +64,7 @@ extern int rcuwait_wake_up(struct rcuwait *w); \ schedule(); \ } \ - \ - WRITE_ONCE((w)->task, NULL); \ - __set_current_state(TASK_RUNNING); \ + finish_rcuwait(w); \ __ret; \ }) -- 2.16.4