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Date: Mon, 10 Jan 2022 19:15:03 +0100
From: Borislav Petkov <bp@alien8.de>
Subject: Re: [patch] genirq/msi: Populate sysfs entry only once
Message-ID: <Ydx3p35NW6Y9tDvO@zn.tnic>
References: <20211206210600.123171746@linutronix.de>
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 <87leznqx2a.ffs@tglx>
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To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>, Bjorn Helgaas <helgaas@kernel.org>, Marc Zygnier <maz@kernel.org>, Alex Williamson <alex.williamson@redhat.com>, Kevin Tian <kevin.tian@intel.com>, Jason Gunthorpe <jgg@nvidia.com>, Megha Dey <megha.dey@intel.com>, Ashok Raj <ashok.raj@intel.com>, linux-pci@vger.kernel.org, Cedric Le Goater <clg@kaod.org>, xen-devel@lists.xenproject.org, Juergen Gross <jgross@suse.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Niklas Schnelle <schnelle@linux.ibm.com>, linux-s390@vger.kernel.org, Heiko Carstens <hca@linux.ibm.com>, Christian Borntraeger <borntraeger@de.ibm.com>, Logan Gunthorpe <logang@deltatee.com>, Jon Mason <jdmason@kudzu.us>, Dave Jiang <dave.jiang@intel.com>, Allen Hubbe <allenbh@gmail.com>, linux-ntb@googlegroups.com
List-ID: <linux-ntb.googlegroups.com>

On Mon, Jan 10, 2022 at 07:12:45PM +0100, Thomas Gleixner wrote:
> The MSI entries for multi-MSI are populated en bloc for the MSI descriptor,
> but the current code invokes the population inside the per interrupt loop
> which triggers a warning in the sysfs code and causes the interrupt
> allocation to fail.
> 
> Move it outside of the loop so it works correctly for single and multi-MSI.
> 
> Fixes: bf5e758f02fc ("genirq/msi: Simplify sysfs handling")
> Reported-by: Borislav Petkov <bp@alien8.de>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
>  kernel/irq/msi.c |   11 +++++------
>  1 file changed, 5 insertions(+), 6 deletions(-)
> 
> --- a/kernel/irq/msi.c
> +++ b/kernel/irq/msi.c
> @@ -887,12 +887,11 @@ int __msi_domain_alloc_irqs(struct irq_d
>  			ret = msi_init_virq(domain, virq + i, vflags);
>  			if (ret)
>  				return ret;
> -
> -			if (info->flags & MSI_FLAG_DEV_SYSFS) {
> -				ret = msi_sysfs_populate_desc(dev, desc);
> -				if (ret)
> -					return ret;
> -			}
> +		}
> +		if (info->flags & MSI_FLAG_DEV_SYSFS) {
> +			ret = msi_sysfs_populate_desc(dev, desc);
> +			if (ret)
> +				return ret;
>  		}
>  		allocated++;
>  	}

Yap, works.

Tested-by: Borislav Petkov <bp@suse.de>

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette