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Subject: Re: [PATCH kernel v4 1/8] genirq/ipi: Simplify irq_reserve_ipi
To:     Alexey Kardashevskiy <aik@ozlabs.ru>,
        <linux-kernel@vger.kernel.org>
CC:     Marc Zyngier <maz@kernel.org>, <x86@kernel.org>,
        <linux-gpio@vger.kernel.org>, Oliver O'Halloran <oohall@gmail.com>,
        Frederic Barrat <fbarrat@linux.ibm.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        =?UTF-8?Q?Michal_Such=c3=a1nek?= <msuchanek@suse.de>,
        <linuxppc-dev@lists.ozlabs.org>,
        <linux-arm-kernel@lists.infradead.org>,
        Matt Redfearn <matt.redfearn@mips.com>,
        Qais Yousef <qsyousef@gmail.com>, <linux-mips@linux-mips.org>
References: <20201124061720.86766-1-aik@ozlabs.ru>
 <20201124061720.86766-2-aik@ozlabs.ru>
From:   =?UTF-8?Q?C=c3=a9dric_Le_Goater?= <clg@kaod.org>
Message-ID: <d12fcee6-f83a-5b09-6208-face2ea5ec39@kaod.org>
Date:   Tue, 24 Nov 2020 17:54:16 +0100
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On 11/24/20 7:17 AM, Alexey Kardashevskiy wrote:
> __irq_domain_alloc_irqs() can already handle virq==-1 and free
> descriptors if it failed allocating hardware interrupts so let's skip
> this extra step.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

LGTM,

Reviewed-by: Cédric Le Goater <clg@kaod.org>

Copying the MIPS folks since the IPI interface is only used under arch/mips.

C.
 
> ---
>  kernel/irq/ipi.c | 16 +++-------------
>  1 file changed, 3 insertions(+), 13 deletions(-)
> 
> diff --git a/kernel/irq/ipi.c b/kernel/irq/ipi.c
> index 43e3d1be622c..1b2807318ea9 100644
> --- a/kernel/irq/ipi.c
> +++ b/kernel/irq/ipi.c
> @@ -75,18 +75,12 @@ int irq_reserve_ipi(struct irq_domain *domain,
>  		}
>  	}
>  
> -	virq = irq_domain_alloc_descs(-1, nr_irqs, 0, NUMA_NO_NODE, NULL);
> -	if (virq <= 0) {
> -		pr_warn("Can't reserve IPI, failed to alloc descs\n");
> -		return -ENOMEM;
> -	}
> -
> -	virq = __irq_domain_alloc_irqs(domain, virq, nr_irqs, NUMA_NO_NODE,
> -				       (void *) dest, true, NULL);
> +	virq = __irq_domain_alloc_irqs(domain, -1, nr_irqs, NUMA_NO_NODE,
> +				       (void *) dest, false, NULL);
>  
>  	if (virq <= 0) {
>  		pr_warn("Can't reserve IPI, failed to alloc hw irqs\n");
> -		goto free_descs;
> +		return -EBUSY;
>  	}
>  
>  	for (i = 0; i < nr_irqs; i++) {
> @@ -96,10 +90,6 @@ int irq_reserve_ipi(struct irq_domain *domain,
>  		irq_set_status_flags(virq + i, IRQ_NO_BALANCING);
>  	}
>  	return virq;
> -
> -free_descs:
> -	irq_free_descs(virq, nr_irqs);
> -	return -EBUSY;
>  }
>  
>  /**
>