Re: [patch 28/39] PCI/MSI: Move pci_irq_get_affinity() to api.c

[Bjorn Helgaas]

On Fri, Nov 11, 2022 at 02:54:59PM +0100, Thomas Gleixner wrote:
> From: Ahmed S. Darwish <darwi@xxxxxxxxxxxxx>
> 
> To distangle the maze in msi.c, all exported device-driver MSI APIs are
> now to be grouped in one file, api.c.
> 
> Move pci_irq_get_affinity() and let its kernel-doc match rest of the
> file.
> 
> Signed-off-by: Ahmed S. Darwish <darwi@xxxxxxxxxxxxx>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

One nit below.

> ---
>  drivers/pci/msi/api.c | 43 +++++++++++++++++++++++++++++++++++++++++++
>  drivers/pci/msi/msi.c | 38 --------------------------------------
>  2 files changed, 43 insertions(+), 38 deletions(-)
> ---
> diff --git a/drivers/pci/msi/api.c b/drivers/pci/msi/api.c
> index 653a61868ae6..473df7ba0584 100644
> --- a/drivers/pci/msi/api.c
> +++ b/drivers/pci/msi/api.c
> @@ -9,6 +9,7 @@
>   */
>  
>  #include <linux/export.h>
> +#include <linux/irq.h>
>  
>  #include "msi.h"
>  
> @@ -251,6 +252,48 @@ int pci_irq_vector(struct pci_dev *dev, unsigned int nr)
>  EXPORT_SYMBOL(pci_irq_vector);
>  
>  /**
> + * pci_irq_get_affinity() - Get a device interrupt vector affinity
> + * @dev: the PCI device to operate on
> + * @nr:  device-relative interrupt vector index (0-based); has different
> + *       meanings, depending on interrupt mode
> + *         MSI-X        the index in the MSI-X vector table
> + *         MSI          the index of the enabled MSI vectors
> + *         INTx         must be 0
> + *
> + * Return: MSI/MSI-X vector affinity, NULL if @nr is out of range or if
> + * the MSI(-X) vector was allocated without explicit affinity
> + * requirements (e.g., by pci_enable_msi(), pci_enable_msix_range(), or
> + * pci_alloc_irq_vectors() without the %PCI_IRQ_AFFINITY flag). Return a
> + * generic set of CPU ids representing all possible CPUs available
> + * during system boot if the device is in legacy INTx mode.

s/ids/IDs/

> + */
> +const struct cpumask *pci_irq_get_affinity(struct pci_dev *dev, int nr)
> +{
> +	int idx, irq = pci_irq_vector(dev, nr);
> +	struct msi_desc *desc;
> +
> +	if (WARN_ON_ONCE(irq <= 0))
> +		return NULL;
> +
> +	desc = irq_get_msi_desc(irq);
> +	/* Non-MSI does not have the information handy */
> +	if (!desc)
> +		return cpu_possible_mask;
> +
> +	/* MSI[X] interrupts can be allocated without affinity descriptor */
> +	if (!desc->affinity)
> +		return NULL;
> +
> +	/*
> +	 * MSI has a mask array in the descriptor.
> +	 * MSI-X has a single mask.
> +	 */
> +	idx = dev->msi_enabled ? nr : 0;
> +	return &desc->affinity[idx].mask;
> +}
> +EXPORT_SYMBOL(pci_irq_get_affinity);
> +
> +/**
>   * pci_free_irq_vectors() - Free previously allocated IRQs for a device
>   * @dev: the PCI device to operate on
>   *
> diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
> index 6fa90d07d2e4..d78646d1c116 100644
> --- a/drivers/pci/msi/msi.c
> +++ b/drivers/pci/msi/msi.c
> @@ -854,44 +854,6 @@ int __pci_enable_msix_range(struct pci_dev *dev,
>  	}
>  }
>  
> -/**
> - * pci_irq_get_affinity - return the affinity of a particular MSI vector
> - * @dev:	PCI device to operate on
> - * @nr:		device-relative interrupt vector index (0-based).
> - *
> - * @nr has the following meanings depending on the interrupt mode:
> - *   MSI-X:	The index in the MSI-X vector table
> - *   MSI:	The index of the enabled MSI vectors
> - *   INTx:	Must be 0
> - *
> - * Return: A cpumask pointer or NULL if @nr is out of range
> - */
> -const struct cpumask *pci_irq_get_affinity(struct pci_dev *dev, int nr)
> -{
> -	int idx, irq = pci_irq_vector(dev, nr);
> -	struct msi_desc *desc;
> -
> -	if (WARN_ON_ONCE(irq <= 0))
> -		return NULL;
> -
> -	desc = irq_get_msi_desc(irq);
> -	/* Non-MSI does not have the information handy */
> -	if (!desc)
> -		return cpu_possible_mask;
> -
> -	/* MSI[X] interrupts can be allocated without affinity descriptor */
> -	if (!desc->affinity)
> -		return NULL;
> -
> -	/*
> -	 * MSI has a mask array in the descriptor.
> -	 * MSI-X has a single mask.
> -	 */
> -	idx = dev->msi_enabled ? nr : 0;
> -	return &desc->affinity[idx].mask;
> -}
> -EXPORT_SYMBOL(pci_irq_get_affinity);
> -
>  struct pci_dev *msi_desc_to_pci_dev(struct msi_desc *desc)
>  {
>  	return to_pci_dev(desc->dev);
>