From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1755012Ab3JCSkb (ORCPT <rfc822;w@1wt.eu>);
	Thu, 3 Oct 2013 14:40:31 -0400
Received: from merlin.infradead.org ([205.233.59.134]:55213 "EHLO
	merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1754969Ab3JCSk1 (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Thu, 3 Oct 2013 14:40:27 -0400
Date: Thu, 3 Oct 2013 20:40:01 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>, Mel Gorman <mgorman@suse.de>,
        Rik van Riel <riel@redhat.com>,
        Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
        Ingo Molnar <mingo@kernel.org>, Andrea Arcangeli <aarcange@redhat.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Steven Rostedt <rostedt@goodmis.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] rcu: Create rcu_sync infrastructure
Message-ID: <20131003184001.GM28601@twins.programming.kicks-ass.net>
References: <20131002145655.361606532@infradead.org>
 <20131002150518.675931976@infradead.org>
 <20131003164117.GD5790@linux.vnet.ibm.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20131003164117.GD5790@linux.vnet.ibm.com>
User-Agent: Mutt/1.5.21 (2012-12-30)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, Oct 03, 2013 at 09:41:17AM -0700, Paul E. McKenney wrote:
> On Wed, Oct 02, 2013 at 04:56:57PM +0200, Peter Zijlstra wrote:
> #ifdef CONFIG_PROVE_RCU
> #define rcu_sync_is_idle_check(rss) BUG_ON(!rss->read_side_check())
> #else
> #define rcu_sync_is_idle_check(rss) do { } while (0)
> #endif
> 
> 	rcu_sync_is_idle_check(rss);

The below actually seems to build, although I didn't test the config
permutations, only defconfig.

---
--- a/include/linux/rcusync.h
+++ b/include/linux/rcusync.h
@@ -14,6 +14,7 @@ struct rcu_sync_struct {
 
 	void (*sync)(void);
 	void (*call)(struct rcu_head *, void (*)(struct rcu_head *));
+	int  (*held)(void);
 };
 
 #define ___RCU_SYNC_INIT(name)						\
@@ -26,18 +27,21 @@ struct rcu_sync_struct {
 	___RCU_SYNC_INIT(name),						\
 	.sync = synchronize_sched,					\
 	.call = call_rcu_sched,						\
+	.held = rcu_read_lock_sched_held,				\
 }
 
 #define __RCU_BH_SYNC_INIT(name) {					\
 	___RCU_SYNC_INIT(name),						\
 	.sync = synchronize_rcu_bh,					\
 	.call = call_rcu_bh,						\
+	.held = rcu_read_lock_bh_held,					\
 }
 
 #define __RCU_SYNC_INIT(name) {						\
 	___RCU_SYNC_INIT(name),						\
 	.sync = synchronize_rcu,					\
 	.call = call_rcu,						\
+	.held = rcu_read_lock_held,					\
 }
 
 #define DEFINE_RCU_SCHED_SYNC(name)					\
@@ -51,6 +55,9 @@ struct rcu_sync_struct {
 
 static inline bool rcu_sync_is_idle(struct rcu_sync_struct *rss)
 {
+#ifdef CONFIG_PROVE_RCU
+	BUG_ON(!rss->held());
+#endif
 	return !rss->gp_state; /* GP_IDLE */
 }