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 S965309AbdKPQcs (ORCPT <rfc822;w@1wt.eu>);
        Thu, 16 Nov 2017 11:32:48 -0500
Received: from merlin.infradead.org ([205.233.59.134]:34576 "EHLO
        merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S933993AbdKPQcl (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 16 Nov 2017 11:32:41 -0500
Date: Thu, 16 Nov 2017 17:32:18 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Dave Watson <davejwatson@fb.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-api <linux-api@vger.kernel.org>, Paul Turner <pjt@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Russell King <linux@arm.linux.org.uk>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Andrew Hunter <ahh@google.com>,
        Andi Kleen <andi@firstfloor.org>, Chris Lameter <cl@linux.com>,
        Ben Maurer <bmaurer@fb.com>, rostedt <rostedt@goodmis.org>,
        Josh Triplett <josh@joshtriplett.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>
Subject: Re: [RFC PATCH v11 for 4.15 01/24] Restartable sequences system call
Message-ID: <20171116163218.fg4u4bbzfrbxatvz@hirez.programming.kicks-ass.net>
References: <20171114200414.2188-1-mathieu.desnoyers@efficios.com>
 <20171114200414.2188-2-mathieu.desnoyers@efficios.com>
 <20171116161815.dg4hi2z35rkh4u4s@hirez.programming.kicks-ass.net>
 <438349693.16595.1510849627973.JavaMail.zimbra@efficios.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <438349693.16595.1510849627973.JavaMail.zimbra@efficios.com>
User-Agent: NeoMutt/20170609 (1.8.3)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, Nov 16, 2017 at 04:27:07PM +0000, Mathieu Desnoyers wrote:
> ----- On Nov 16, 2017, at 11:18 AM, Peter Zijlstra peterz@infradead.org wrote:
> 
> > On Tue, Nov 14, 2017 at 03:03:51PM -0500, Mathieu Desnoyers wrote:
> >> @@ -977,6 +978,13 @@ struct task_struct {
> >>  	unsigned long			numa_pages_migrated;
> >>  #endif /* CONFIG_NUMA_BALANCING */
> >>  
> >> +#ifdef CONFIG_RSEQ
> >> +	struct rseq __user *rseq;
> >> +	u32 rseq_len;
> >> +	u32 rseq_sig;
> >> +	bool rseq_preempt, rseq_signal, rseq_migrate;
> > 
> > No bool please. Use something that has a defined size in ILP32/LP64.
> > _Bool makes it absolutely impossible to speculate on structure layout
> > across architectures.
> 
> I should as well make all those a bitmask within a "u32 rseq_event_mask" then,
> sounds fair ?

Sure, whatever works and isn't _Bool ;-)