Re: [patch V2 03/36] PCI/MSI: Allocate MSI device data on first use

[Bjorn Helgaas <helgaas@xxxxxxxxxx>]

On Mon, Dec 06, 2021 at 11:39:00PM +0100, Thomas Gleixner wrote:
> Allocate MSI device data on first use, i.e. when a PCI driver invokes one
> of the PCI/MSI enablement functions.
> 
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>

Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

> ---
>  drivers/pci/msi/msi.c |   20 +++++++++++++++-----
>  1 file changed, 15 insertions(+), 5 deletions(-)
> 
> --- a/drivers/pci/msi/msi.c
> +++ b/drivers/pci/msi/msi.c
> @@ -889,10 +889,12 @@ static int __pci_enable_msi_range(struct
>  /* 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;
> +     int rc = msi_setup_device_data(&dev->dev);
> +
> +     if (!rc)
> +             rc = __pci_enable_msi_range(dev, 1, 1, NULL);
> +
> +     return rc < 0 ? rc : 0;
>  }
>  EXPORT_SYMBOL(pci_enable_msi);
>  
> @@ -947,7 +949,11 @@ static int __pci_enable_msix_range(struc
>  int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries,
>               int minvec, int maxvec)
>  {
> -     return __pci_enable_msix_range(dev, entries, minvec, maxvec, NULL, 0);
> +     int ret = msi_setup_device_data(&dev->dev);
> +
> +     if (!ret)
> +             ret = __pci_enable_msix_range(dev, entries, minvec, maxvec, 
> NULL, 0);
> +     return ret;
>  }
>  EXPORT_SYMBOL(pci_enable_msix_range);
>  
> @@ -974,8 +980,12 @@ int pci_alloc_irq_vectors_affinity(struc
>                                  struct irq_affinity *affd)
>  {
>       struct irq_affinity msi_default_affd = {0};
> +     int ret = msi_setup_device_data(&dev->dev);
>       int nvecs = -ENOSPC;
>  
> +     if (ret)
> +             return ret;
> +
>       if (flags & PCI_IRQ_AFFINITY) {
>               if (!affd)
>                       affd = &msi_default_affd;
>