Re: [PATCH net-next v3 1/4] net: rnpgbe: Add interrupt handling

[Vadim Fedorenko <vadim.fedorenko@linux.dev>]

On 07/05/2026 09:15, Dong Yibo wrote:
> Add comprehensive interrupt handling for the RNPGBE driver:
> - Implement msi-x/msi interrupt configuration and management
> - Create library functions for interrupt registration and cleanup
> 
> This infrastructure enables proper interrupt handling for the
> RNPGBE driver.
> 

[...]

> +/**
> + * rnpgbe_set_interrupt_capability - Set MSI-X or MSI if supported
> + * @mucse: pointer to private structure
> + *
> + * Attempt to configure the interrupts using the best available
> + * capabilities of the hardware.
> + *
> + * @return: 0 on success, negative on failure
> + **/
> +static int rnpgbe_set_interrupt_capability(struct mucse *mucse)
> +{
> +	int v_budget;
> +
> +	v_budget = min_t(int, mucse->num_tx_queues, mucse->num_rx_queues);
> +	v_budget = min_t(int, v_budget, MAX_Q_VECTORS);

these 2 lines can be simplified to

min3(mucse->num_tx_queues, mucse->num_rx_queues, MAX_Q_VECTORS);

> +	v_budget = min_t(int, v_budget, num_online_cpus());
 > +	/* add one vector for mbx */> +	v_budget += 1;
> +	v_budget = pci_alloc_irq_vectors(mucse->pdev, 1, v_budget,
> +					 PCI_IRQ_MSI | PCI_IRQ_MSIX);
> +	if (v_budget < 0)
> +		return v_budget;
> +
> +	if (mucse->pdev->msix_enabled) {
> +		/* q_vector not include mbx */
> +		if (v_budget > 1) {
> +			mucse->flags |= M_FLAG_MSIX_EN;
> +			mucse->num_q_vectors = v_budget - 1;
> +		} else {
> +			mucse->flags |= M_FLAG_MSIX_SINGLE_EN;
> +			mucse->num_q_vectors = 1;
> +		}
> +	} else {
> +		/* msi use only 1 irq */
> +		mucse->num_q_vectors = 1;
> +		mucse->flags |= M_FLAG_MSI_EN;
> +	}

How will it work in case it's only 1 vector allocated? AFAIU, you need 
at least 2 irq vectors - 1 for queue processing, another one for mbx.

> +
> +	return 0;
> +}