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Date:   Fri, 24 Mar 2023 15:34:05 +0000
Message-ID: <87ileqgo42.wl-maz@kernel.org>
From:   Marc Zyngier <maz@kernel.org>
To:     Jianmin Lv <lvjianmin@loongson.cn>
Cc:     Thomas Gleixner <tglx@linutronix.de>, linux-kernel@vger.kernel.org,
        loongarch@lists.linux.dev,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Huacai Chen <chenhuacai@loongson.cn>,
        loongson-kernel@lists.loongnix.cn
Subject: Re: [PATCH V1 2/5] irqchip/loongson-eiointc: Fix incorrect use of acpi_get_vec_parent
In-Reply-To: <20230324060854.29375-3-lvjianmin@loongson.cn>
References: <20230324060854.29375-1-lvjianmin@loongson.cn>
        <20230324060854.29375-3-lvjianmin@loongson.cn>
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On Fri, 24 Mar 2023 06:08:51 +0000,
Jianmin Lv <lvjianmin@loongson.cn> wrote:
> 
> In eiointc_acpi_init(), a *eiointc* node is passed into
> acpi_get_vec_parent() instead of a required *NUMA* node (on some chip
> like 3C5000L, a *NUMA* node means a *eiointc* node, but on some chip
> like 3C5000, a *NUMA* node contains 4 *eiointc* nodes), and node in
> struct acpi_vector_group is essentially a *NUMA* node, which will
> lead to no parent matched for passed *eiointc* node. so the patch
> adjusts code to use *NUMA* node for parameter node of
> acpi_set_vec_parent/acpi_get_vec_parent.
> 
> Change-Id: Iddd8423f9694cadc1ce28ee290c2e98ca17dfccc
> Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
> ---
>  drivers/irqchip/irq-loongson-eiointc.c | 17 +++++++++++------
>  1 file changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-loongson-eiointc.c b/drivers/irqchip/irq-loongson-eiointc.c
> index 62a632d73991..b165c27a3609 100644
> --- a/drivers/irqchip/irq-loongson-eiointc.c
> +++ b/drivers/irqchip/irq-loongson-eiointc.c
> @@ -280,9 +280,6 @@ static void acpi_set_vec_parent(int node, struct irq_domain *parent, struct acpi
>  {
>  	int i;
>  
> -	if (cpu_has_flatmode)
> -		node = cpu_to_node(node * CORES_PER_EIO_NODE);
> -
>  	for (i = 0; i < MAX_IO_PICS; i++) {
>  		if (node == vec_group[i].node) {
>  			vec_group[i].parent = parent;
> @@ -349,8 +346,13 @@ static int __init pch_pic_parse_madt(union acpi_subtable_headers *header,
>  static int __init pch_msi_parse_madt(union acpi_subtable_headers *header,
>  					const unsigned long end)
>  {
> +	struct irq_domain *parent;
>  	struct acpi_madt_msi_pic *pchmsi_entry = (struct acpi_madt_msi_pic *)header;
> -	struct irq_domain *parent = acpi_get_vec_parent(eiointc_priv[nr_pics - 1]->node, msi_group);
> +	int node = eiointc_priv[nr_pics - 1]->node;
> +
> +	if (cpu_has_flatmode)
> +		node = cpu_to_node(node * CORES_PER_EIO_NODE);

This is a bit unreadable. I'd rather see:

	int node;

	if (cpu_has_flatmode)
		node = ....;
	else
		node = ....;

which makes it easy to detect the use of an uninitialised 'node'
rather than using the wrong default variable.

> +	parent = acpi_get_vec_parent(node, msi_group);
>  
>  	if (parent)
>  		return pch_msi_acpi_init(parent, pchmsi_entry);
> @@ -379,6 +381,7 @@ int __init eiointc_acpi_init(struct irq_domain *parent,
>  	int i, ret, parent_irq;
>  	unsigned long node_map;
>  	struct eiointc_priv *priv;
> +	int node = acpi_eiointc->node;
>  
>  	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
>  	if (!priv)
> @@ -421,8 +424,10 @@ int __init eiointc_acpi_init(struct irq_domain *parent,
>  				  "irqchip/loongarch/intc:starting",
>  				  eiointc_router_init, NULL);
>  
> -	acpi_set_vec_parent(acpi_eiointc->node, priv->eiointc_domain, pch_group);
> -	acpi_set_vec_parent(acpi_eiointc->node, priv->eiointc_domain, msi_group);
> +	if (cpu_has_flatmode)
> +		node = cpu_to_node(node * CORES_PER_EIO_NODE);
> +	acpi_set_vec_parent(node, priv->eiointc_domain, pch_group);
> +	acpi_set_vec_parent(node, priv->eiointc_domain, msi_group);
>  	ret = acpi_cascade_irqdomain_init();
>  
>  	return ret;

Same thing here.

	M.

-- 
Without deviation from the norm, progress is not possible.