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 S1754486AbcGVOJJ (ORCPT <rfc822;w@1wt.eu>);
	Fri, 22 Jul 2016 10:09:09 -0400
Received: from mx1.redhat.com ([209.132.183.28]:39652 "EHLO mx1.redhat.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1754390AbcGVOJH (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Fri, 22 Jul 2016 10:09:07 -0400
Subject: Re: [PATCH v11 06/10] genirq/msi-doorbell: msi_doorbell_safe
To: Thomas Gleixner <tglx@linutronix.de>
References: <1468933367-23159-1-git-send-email-eric.auger@redhat.com>
 <1468933367-23159-7-git-send-email-eric.auger@redhat.com>
 <alpine.DEB.2.11.1607201010350.3564@nanos>
 <3f188661-1d68-199b-3fcc-4da432bae633@redhat.com>
 <alpine.DEB.2.11.1607221443090.3906@nanos>
Cc: eric.auger.pro@gmail.com, marc.zyngier@arm.com,
        christoffer.dall@linaro.org, andre.przywara@arm.com,
        robin.murphy@arm.com, alex.williamson@redhat.com, will.deacon@arm.com,
        joro@8bytes.org, jason@lakedaemon.net,
        linux-arm-kernel@lists.infradead.org, drjones@redhat.com,
        kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, pbonzini@redhat.com,
        linux-kernel@vger.kernel.org, Bharat.Bhushan@freescale.com,
        pranav.sawargaonkar@gmail.com, p.fedin@samsung.com,
        iommu@lists.linux-foundation.org, Jean-Philippe.Brucker@arm.com,
        yehuday@marvell.com, Manish.Jaggi@caviumnetworks.com,
        robert.richter@caviumnetworks.com
From: Auger Eric <eric.auger@redhat.com>
Message-ID: <20646d2e-b75f-b088-3ead-2aca039cde79@redhat.com>
Date: Fri, 22 Jul 2016 16:08:57 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
 Thunderbird/45.1.0
MIME-Version: 1.0
In-Reply-To: <alpine.DEB.2.11.1607221443090.3906@nanos>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Fri, 22 Jul 2016 14:09:06 +0000 (UTC)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Hi Thomas,
On 22/07/2016 14:44, Thomas Gleixner wrote:
> On Thu, 21 Jul 2016, Auger Eric wrote:
>> On 20/07/2016 10:12, Thomas Gleixner wrote:
>>> On Tue, 19 Jul 2016, Eric Auger wrote:
>>>> +bool msi_doorbell_safe(void)
>>>> +{
>>>> +	struct irqchip_doorbell *db;
>>>> +	bool irq_remapping = true;
>>>> +
>>>> +	mutex_lock(&irqchip_doorbell_mutex);
>>>> +	list_for_each_entry(db, &irqchip_doorbell_list, next) {
>>>> +		irq_remapping &= db->info.irq_remapping;
>>>
>>> db->info.irq_remapping is set in msi_doorbell_register(). So you can keep book
>>> about that there. No need to iterate here.
>> Yes makes sense to store the info at registration time. Currently this
>> function is not in any fast path but that's cleaner from a general
>> perspective. I will need to do such iteration at un-registration though.
> 
> Two simple counter should be sufficient.
> 
>   nr_registered_bells;
>   nr_remapped_bells;

Yes definitively smarter to use counters! mental viscosity.

Thanks

Eric
> 
> ....
> 
> Thanks,
> 
> 	tglx
>