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Date:   Fri, 21 Feb 2020 10:13:58 +0000
From:   Marc Zyngier <maz@kernel.org>
To:     Zenghui Yu <yuzenghui@huawei.com>
Cc:     linux-kernel@vger.kernel.org, tglx@linutronix.de,
        wanghaibin.wang@huawei.com
Subject: Re: [PATCH] genirq/irqdomain: Make sure all irq domain flags are
 distinct
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References: <20200221020725.2038-1-yuzenghui@huawei.com>
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On 2020-02-21 02:07, Zenghui Yu wrote:
> This was noticed when printing debugfs for MSIs on my ARM64 server.
> The new dstate IRQD_MSI_NOMASK_QUIRK came out surprisingly while it
> should only be the x86 stuff for the time being...
> 
> It's the overlap in irqdomain flags which leads to this confusion.
> (1 << 1) might be a good choice for old IRQ_DOMAIN_NAME_ALLOCATED,
> use it to avoid this overlap.
> 
> Fixes: 6f1a4891a592 ("x86/apic/msi: Plug non-maskable MSI affinity 
> race")

To be fair, the real source of the bug is this:

6a6544e520abe ("genirq/irqdomain: Remove auto-recursive hierarchy 
support")

> Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
> ---
>  include/linux/irqdomain.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
> index b2d47571ab67..8d062e86d954 100644
> --- a/include/linux/irqdomain.h
> +++ b/include/linux/irqdomain.h
> @@ -192,7 +192,7 @@ enum {
>  	IRQ_DOMAIN_FLAG_HIERARCHY	= (1 << 0),
> 
>  	/* Irq domain name was allocated in __irq_domain_add() */
> -	IRQ_DOMAIN_NAME_ALLOCATED	= (1 << 6),
> +	IRQ_DOMAIN_NAME_ALLOCATED	= (1 << 1),
> 
>  	/* Irq domain is an IPI domain with virq per cpu */
>  	IRQ_DOMAIN_FLAG_IPI_PER_CPU	= (1 << 2),

Acked-by: Marc Zyngier <maz@kernel.org>

Thomas, do you mind picking this one up, as I don't have anything
else for the time being?


         M.
-- 
Jazz is not dead. It just smells funny...