netdev - Re: [PATCH v6 net-next 07/19] ionic: Add basic adminq support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190830.151711.704306282464276122.davem@davemloft.net>
Date:   Fri, 30 Aug 2019 15:17:11 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     jakub.kicinski@...ronome.com
Cc:     snelson@...sando.io, netdev@...r.kernel.org
Subject: Re: [PATCH v6 net-next 07/19] ionic: Add basic adminq support

From: Jakub Kicinski <jakub.kicinski@...ronome.com>
Date: Fri, 30 Aug 2019 15:16:04 -0700

> On Fri, 30 Aug 2019 12:31:07 -0700, Shannon Nelson wrote:
>> On 8/29/19 3:52 PM, Jakub Kicinski wrote:
>> > On Thu, 29 Aug 2019 11:27:08 -0700, Shannon Nelson wrote:  
>> >> +static void ionic_lif_qcq_deinit(struct ionic_lif *lif, struct ionic_qcq *qcq)
>> >> +{
>> >> +	struct ionic_dev *idev = &lif->ionic->idev;
>> >> +	struct device *dev = lif->ionic->dev;
>> >> +
>> >> +	if (!qcq)
>> >> +		return;
>> >> +
>> >> +	ionic_debugfs_del_qcq(qcq);
>> >> +
>> >> +	if (!(qcq->flags & IONIC_QCQ_F_INITED))
>> >> +		return;
>> >> +
>> >> +	if (qcq->flags & IONIC_QCQ_F_INTR) {
>> >> +		ionic_intr_mask(idev->intr_ctrl, qcq->intr.index,
>> >> +				IONIC_INTR_MASK_SET);
>> >> +		synchronize_irq(qcq->intr.vector);
>> >> +		devm_free_irq(dev, qcq->intr.vector, &qcq->napi);  
>> > Doesn't free_irq() basically imply synchronize_irq()?  
>> 
>> The synchronize_irq() waits for any threaded handlers to finish, while 
>> free_irq() only waits for HW handling.  This helps makes sure we don't 
>> have anything still running before we remove resources.
> 
> mm.. I'm no IRQ expert but it strikes me as surprising as that'd mean
> every single driver would always have to run synchronize_irq() on
> module exit, no?
> 
> I see there is a kthread_stop() in __free_irq(), you sure it doesn't
> wait for threaded IRQs?

I'm pretty sure it does.