linux-kernel - Re: [PATCH v2 2/2] irq/irq-loongarch-ir:Add Redirect irqchip support

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Message-ID: <87ldskwdyb.ffs@tglx>
Date: Tue, 01 Apr 2025 09:14:36 +0200
From: Thomas Gleixner <tglx@...utronix.de>
To: Tianyang Zhang <zhangtianyang@...ngson.cn>, chenhuacai@...nel.org,
 kernel@...0n.name, corbet@....net, alexs@...nel.org, si.yanteng@...ux.dev,
 jiaxun.yang@...goat.com, peterz@...radead.org, wangliupu@...ngson.cn,
 lvjianmin@...ngson.cn, maobibo@...ngson.cn, siyanteng@...oftware.com.cn,
 gaosong@...ngson.cn, yangtiezhu@...ngson.cn
Cc: loongarch@...ts.linux.dev, linux-doc@...r.kernel.org,
 linux-kernel@...r.kernel.org, Tianyang Zhang <zhangtianyang@...ngson.cn>
Subject: Re: [PATCH v2 2/2] irq/irq-loongarch-ir:Add Redirect irqchip support

On Mon, Mar 31 2025 at 14:41, Tianyang Zhang wrote:
>  	irq_data_update_effective_affinity(data, cpumask_of(cpu));
> @@ -242,6 +233,7 @@ static void avecintc_irq_dispatch(struct irq_desc *desc)
>  		d = this_cpu_read(irq_map[vector]);
>  		if (d) {
>  			generic_handle_irq_desc(d);
> +

Stray newline.

>  		} else {

> +
> +static void invalid_enqueue(struct redirect_queue *rqueue, struct irde_inv_cmd *cmd)
> +{
> +	struct irde_inv_cmd *inv_addr;
> +	u32 tail;
> +
> +	guard(raw_spinlock_irqsave)(&rqueue->lock);
> +
> +	while (invalid_queue_is_full(rqueue->node, &tail))
> +		cpu_relax();
> +
> +	inv_addr = (struct irde_inv_cmd *)(rqueue->base + tail * sizeof(struct irde_inv_cmd));
> +	memcpy(inv_addr, cmd, sizeof(struct irde_inv_cmd));
> +	tail = (tail + 1) % INVALID_QUEUE_SIZE;
> +
> +	wmb();

Undocumented memory barrier.

> +
> +	iocsr_write32(tail, LOONGARCH_IOCSR_REDIRECT_CQT);
> +}
> +
> +static void smp_call_invalid_enqueue(void *arg)
> +{
> +	struct smp_invalid_arg *s_arg = (struct smp_invalid_arg *)arg;
> +
> +	invalid_enqueue(s_arg->queue, s_arg->cmd);
> +}
> +
> +static void irde_invlid_entry_node(struct redirect_item *item)
> +{
> +	struct redirect_queue *rqueue;
> +	struct smp_invalid_arg arg;
> +	struct irde_inv_cmd cmd;
> +	volatile u64 raddr = 0;
> +	int node = item->table->node, cpu;
> +
> +	rqueue = &(irde_descs[node].inv_queue);
> +	cmd.cmd_info = 0;
> +	cmd.index.type = INVALID_INDEX;
> +	cmd.index.need_notice = 1;
> +	cmd.index.index = item->index;
> +	cmd.notice_addr = (u64)(__pa(&raddr));
> +
> +	if (cpu_to_node(smp_processor_id()) == node)
> +		invalid_enqueue(rqueue, &cmd);
> +	else {

if () lacks brackets

> +		for_each_cpu(cpu, cpumask_of_node(node)) {
> +			if (cpu_online(cpu))
> +				break;
> +		}
> +		arg.queue = rqueue;
> +		arg.cmd = &cmd;
> +		smp_call_function_single(cpu, smp_call_invalid_enqueue, &arg, 0);
> +	}
> +
> +	while (!raddr)
> +		cpu_relax();
> +
> +}


> +static int redirect_table_free(struct redirect_item *item)
> +{
> +	struct redirect_table *ird_table;
> +	struct redirect_entry *entry;
> +	unsigned long flags;
> +
> +	ird_table = item->table;
> +
> +	entry = item->entry;
> +	memset(entry, 0, sizeof(struct redirect_entry));
> +
> +	raw_spin_lock_irqsave(&ird_table->lock, flags);
> +	bitmap_release_region(ird_table->bitmap, item->index, 0);
> +	raw_spin_unlock_irqrestore(&ird_table->lock, flags);

	scoped_guard(raw_spinlock_irqsave, &ird_table->lock)
		bitmap_release_region(ird_table->bitmap, item->index, 0);

> +static int redirect_set_affinity(struct irq_data *data, const struct cpumask *dest, bool force)
> +{
> +	struct redirect_item *item = data->chip_data;
> +	struct avecintc_data *adata;
> +	int ret;
> +
> +	ret = irq_chip_set_affinity_parent(data, dest, force);
> +	if (ret == IRQ_SET_MASK_OK_DONE)
> +		return IRQ_SET_MASK_OK;

Again bracket rules. Also what is this return value translation about?

> +	else if (ret) {
> +		pr_err("IRDE:set_affinity error %d\n", ret);
> +		return ret;
> +	}
> +
> +	adata = irq_data_get_avec_data(data);
> +
> +	redirect_domain_prepare_entry(item, adata);
> +
> +	irde_invlid_entry_node(item);

This cannot work when irde_invlid_entry_node() goes into the SMP
function call path, because smp_call_function_single() cannot be invoked
with interrupts disabled.

> +
> +static void redirect_free_resources(struct irq_domain *domain,
> +						unsigned int virq, unsigned int nr_irqs)

Please align the arguments as documented.

> +{
> +	struct irq_data *irq_data;
> +	struct redirect_item *item;
> +

Please move the variables into the scope where they are used

> +	for (int i = 0; i < nr_irqs; i++) {
> +		irq_data = irq_domain_get_irq_data(domain, virq  + i);
> +		if (irq_data && irq_data->chip_data) {
> +			item = irq_data->chip_data;
> +			redirect_table_free(item);
> +			kfree(item);
> +		}
> +	}
> +}
> +
> +static int redirect_alloc(struct irq_domain *domain,
> +					unsigned int virq, unsigned int nr_irqs,
> +					 void *arg)

More random coding style

> +{
> +	struct redirect_table *ird_table;
> +	struct avecintc_data *avec_data;
> +	struct irq_data *irq_data;
> +	int ret, i, node;
> +
> +#ifdef CONFIG_NUMA
> +	node = ((msi_alloc_info_t *)arg)->desc->dev->numa_node;

Bah.

> +#else
> +	node = 0;
> +#endif

        msi_alloc_info_t *info = arg;

        node = dev_to_node(info->desc->dev);

> +static int redirect_table_init(int node)
> +{
> +	struct redirect_table *ird_table = &(irde_descs[node].ird_table);
> +	struct page *pages;
> +	unsigned long *bitmap;

Use proper reverse fir tree ordering

Thanks,

        tglx