linux-kernel - Re: [patch V3 16/22] genirq/msi: Provide new domain id based interfaces for freeing interrupts

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Date:   Mon, 16 Jan 2023 17:35:16 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     David Woodhouse <dwmw2@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Juergen Gross <jgross@...e.com>,
        xen-devel <xen-devel@...ts.xen.org>
Cc:     x86@...nel.org, Joerg Roedel <joro@...tes.org>,
        Will Deacon <will@...nel.org>, linux-pci@...r.kernel.org,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Marc Zyngier <maz@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jason Gunthorpe <jgg@...lanox.com>,
        Dave Jiang <dave.jiang@...el.com>,
        Alex Williamson <alex.williamson@...hat.com>,
        Kevin Tian <kevin.tian@...el.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Logan Gunthorpe <logang@...tatee.com>,
        Ashok Raj <ashok.raj@...el.com>, Jon Mason <jdmason@...zu.us>,
        Allen Hubbe <allenbh@...il.com>
Subject: Re: [patch V3 16/22] genirq/msi: Provide new domain id based
 interfaces for freeing interrupts

David!

On Mon, Jan 16 2023 at 09:56, David Woodhouse wrote:
> On Fri, 2022-11-25 at 00:24 +0100, Thomas Gleixner wrote:
>> +
>> +       if (ops->domain_free_irqs)
>> +               ops->domain_free_irqs(domain, dev);
>
> Do you want a call to msi_free_dev_descs(dev) here? In the case where
> the core code calls ops->domain_alloc_irqs() it *has* allocated the
> descriptors first... but it's expecting the irqdomain to free them?

No. Let me stare at it.

> However, it's not quite as simple as adding msi_free_dev_descs()...

Correct.

> diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
> index 955267bbc2be..812e1ec1a633 100644
> --- a/kernel/irq/msi.c
> +++ b/kernel/irq/msi.c
> @@ -1533,9 +1533,10 @@ static void msi_domain_free_locked(struct device *dev, struct msi_ctrl *ctrl)
>  	info = domain->host_data;
>  	ops = info->ops;
>  
> -	if (ops->domain_free_irqs)
> +	if (ops->domain_free_irqs) {
>  		ops->domain_free_irqs(domain, dev);
> -	else
> +		msi_free_msi_descs(dev);

This is just wrong. I need to taxi my grandson. Will have a look
afterwards.

Thanks,

        tglx