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From: John Garry <john.garry@huawei.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	<gregkh@linuxfoundation.org>, <rafael@kernel.org>,
	<martin.petersen@oracle.com>, <jejb@linux.ibm.com>
Cc: <linuxarm@huawei.com>, <linux-scsi@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <maz@kernel.org>
Subject: Re: [PATCH v2 1/3] genirq/affinity: Add irq_update_affinity_desc()
Date: Mon, 2 Nov 2020 17:32:32 +0000	[thread overview]
Message-ID: <ce13a36e-967c-c7ec-fd34-d53262313a5d@huawei.com> (raw)
In-Reply-To: <87eelifbx6.fsf@nanos.tec.linutronix.de>

On 28/10/2020 18:22, Thomas Gleixner wrote:
> On Wed, Oct 28 2020 at 20:33, John Garry wrote:

Hi Thomas,

>>   
>> +int irq_update_affinity_desc(unsigned int irq,
>> +			     struct irq_affinity_desc *affinity)
>> +{
>> +	unsigned long flags;
>> +	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
>> +
>> +	if (!desc)
>> +		return -EINVAL;
> Just looking at it some more. This needs a check whether the interrupt
> is actually shut down. Otherwise the update will corrupt
> state. Something like this:
> 
>          if (irqd_is_started(&desc->irq_data))
>          	return -EBUSY;
> 
> But all of this can't work on x86 due to the way how vector allocation
> works. Let me think about that.
> 

Is the problem that we reserve per-cpu managed interrupt space when 
allocated irq vectors on x86, and so later changing managed vs 
non-managed setting for irqs messes up this accounting somehow?

Cheers,
John

  reply	other threads:[~2020-11-02 17:36 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-28 12:33 [PATCH v2 0/3] Support managed interrupts for platform devices John Garry
2020-10-28 12:33 ` [PATCH v2 1/3] genirq/affinity: Add irq_update_affinity_desc() John Garry
2020-10-28 18:22   ` Thomas Gleixner
2020-11-02 17:32     ` John Garry [this message]
2020-11-02 20:35       ` Thomas Gleixner
2020-11-17 21:28         ` Thomas Gleixner
2020-11-18 11:34           ` John Garry
2020-11-18 20:38             ` Thomas Gleixner
2020-11-19  9:31               ` John Garry
2020-11-19 18:09                 ` Thomas Gleixner
2020-11-19 19:56                   ` John Garry
2020-11-19 21:03                     ` Thomas Gleixner
2020-11-20 11:52                       ` John Garry
2020-11-22 13:38                         ` Marc Zyngier
2020-11-23 12:54                           ` John Garry
2020-11-23 13:26                             ` Marc Zyngier
2020-11-23 15:45                               ` John Garry
2020-11-24 16:51                                 ` Marc Zyngier
2020-11-24 17:38                                   ` John Garry
2020-11-25 18:35                                     ` Marc Zyngier
2020-11-26 10:47                                       ` John Garry
2020-11-26 11:08                                         ` Marc Zyngier
2020-11-26 11:29                                           ` John Garry
2020-11-26 16:52                                             ` John Garry
2020-11-27  9:57                                               ` Marc Zyngier
2020-11-27 12:45                                                 ` John Garry
2020-11-27 12:49                                                   ` Marc Zyngier
2020-10-28 12:33 ` [PATCH v2 2/3] Driver core: platform: Add platform_get_irqs_affinity() John Garry
2020-10-28 12:33 ` [PATCH v2 3/3] scsi: hisi_sas: Expose HW queues for v2 hw John Garry

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