Re: [patch 20/39] PCI/MSI: Move pci_enable_msi() API to api.c

[Bjorn Helgaas]

On Fri, Nov 11, 2022 at 02:54:46PM +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_enable_msi() and make its kernel-doc comprehensive.
> 
> Signed-off-by: Ahmed S. Darwish <darwi@xxxxxxxxxxxxx>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

Nit: suggest "disentangle" or "untangle" for "distangle" here and in
subsequent patches.

> ---
>  drivers/pci/msi/api.c | 23 +++++++++++++++++++++++
>  drivers/pci/msi/msi.c | 14 ++------------
>  drivers/pci/msi/msi.h |  1 +
>  3 files changed, 26 insertions(+), 12 deletions(-)
> ---
> diff --git a/drivers/pci/msi/api.c b/drivers/pci/msi/api.c
> index 7485942cbe5d..63d7f8f6a284 100644
> --- a/drivers/pci/msi/api.c
> +++ b/drivers/pci/msi/api.c
> @@ -13,6 +13,29 @@
>  #include "msi.h"
>  
>  /**
> + * pci_enable_msi() - Enable MSI interrupt mode on device
> + * @dev: the PCI device to operate on
> + *
> + * Legacy device driver API to enable MSI interrupts mode on device and
> + * allocate a single interrupt vector. On success, the allocated vector
> + * Linux IRQ will be saved at @dev->irq. The driver must invoke
> + * pci_disable_msi() on cleanup.
> + *
> + * NOTE: The newer pci_alloc_irq_vectors() / pci_free_irq_vectors() API
> + * pair should, in general, be used instead.
> + *
> + * Return: 0 on success, errno otherwise
> + */
> +int pci_enable_msi(struct pci_dev *dev)
> +{
> +	int rc = __pci_enable_msi_range(dev, 1, 1, NULL);
> +	if (rc < 0)
> +		return rc;
> +	return 0;
> +}
> +EXPORT_SYMBOL(pci_enable_msi);
> +
> +/**
>   * pci_disable_msi() - Disable MSI interrupt mode on device
>   * @dev: the PCI device to operate on
>   *
> diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
> index 4a1300b74518..98f07ad9af62 100644
> --- a/drivers/pci/msi/msi.c
> +++ b/drivers/pci/msi/msi.c
> @@ -790,8 +790,8 @@ void pci_disable_msix(struct pci_dev *dev)
>  }
>  EXPORT_SYMBOL(pci_disable_msix);
>  
> -static int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
> -				  struct irq_affinity *affd)
> +int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
> +			   struct irq_affinity *affd)
>  {
>  	int nvec;
>  	int rc;
> @@ -844,16 +844,6 @@ static int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
>  	}
>  }
>  
> -/* deprecated, don't use */
> -int pci_enable_msi(struct pci_dev *dev)
> -{
> -	int rc = __pci_enable_msi_range(dev, 1, 1, NULL);
> -	if (rc < 0)
> -		return rc;
> -	return 0;
> -}
> -EXPORT_SYMBOL(pci_enable_msi);
> -
>  static int __pci_enable_msix_range(struct pci_dev *dev,
>  				   struct msix_entry *entries, int minvec,
>  				   int maxvec, struct irq_affinity *affd,
> diff --git a/drivers/pci/msi/msi.h b/drivers/pci/msi/msi.h
> index 634879277349..00bb98d5bb0e 100644
> --- a/drivers/pci/msi/msi.h
> +++ b/drivers/pci/msi/msi.h
> @@ -87,6 +87,7 @@ static inline __attribute_const__ u32 msi_multi_mask(struct msi_desc *desc)
>  /* MSI internal functions invoked from the public APIs */
>  void pci_msi_shutdown(struct pci_dev *dev);
>  void pci_free_msi_irqs(struct pci_dev *dev);
> +int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec, struct irq_affinity *affd);
>  
>  /* Legacy (!IRQDOMAIN) fallbacks */
>  #ifdef CONFIG_PCI_MSI_ARCH_FALLBACKS
>