[PATCH RFC 04/17] acpi: Do not return struct iommu_ops from acpi_iommu_configure_id()

[Rafael J. Wysocki]

On Fri, Nov 3, 2023 at 5:45 PM Jason Gunthorpe <jgg at nvidia.com> wrote:
>
> Nothing needs this pointer. Return a normal error code with the usual
> IOMMU semantic that ENODEV means 'there is no IOMMU driver'.
>
> Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>

> ---
>  drivers/acpi/scan.c | 24 +++++++++++++++---------
>  1 file changed, 15 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index a6891ad0ceee2c..fbabde001a23a2 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -1562,8 +1562,7 @@ static inline const struct iommu_ops *acpi_iommu_fwspec_ops(struct device *dev)
>         return fwspec ? fwspec->ops : NULL;
>  }
>
> -static const struct iommu_ops *acpi_iommu_configure_id(struct device *dev,
> -                                                      const u32 *id_in)
> +static int acpi_iommu_configure_id(struct device *dev, const u32 *id_in)
>  {
>         int err;
>         const struct iommu_ops *ops;
> @@ -1574,7 +1573,7 @@ static const struct iommu_ops *acpi_iommu_configure_id(struct device *dev,
>          */
>         ops = acpi_iommu_fwspec_ops(dev);
>         if (ops)
> -               return ops;
> +               return 0;
>
>         err = iort_iommu_configure_id(dev, id_in);
>         if (err && err != -EPROBE_DEFER)
> @@ -1589,12 +1588,14 @@ static const struct iommu_ops *acpi_iommu_configure_id(struct device *dev,
>
>         /* Ignore all other errors apart from EPROBE_DEFER */
>         if (err == -EPROBE_DEFER) {
> -               return ERR_PTR(err);
> +               return err;
>         } else if (err) {
>                 dev_dbg(dev, "Adding to IOMMU failed: %d\n", err);
> -               return NULL;
> +               return -ENODEV;
>         }
> -       return acpi_iommu_fwspec_ops(dev);
> +       if (!acpi_iommu_fwspec_ops(dev))
> +               return -ENODEV;
> +       return 0;
>  }
>
>  #else /* !CONFIG_IOMMU_API */
> @@ -1623,7 +1624,7 @@ static const struct iommu_ops *acpi_iommu_configure_id(struct device *dev,
>  int acpi_dma_configure_id(struct device *dev, enum dev_dma_attr attr,
>                           const u32 *input_id)
>  {
> -       const struct iommu_ops *iommu;
> +       int ret;
>
>         if (attr == DEV_DMA_NOT_SUPPORTED) {
>                 set_dma_ops(dev, &dma_dummy_ops);
> @@ -1632,10 +1633,15 @@ int acpi_dma_configure_id(struct device *dev, enum dev_dma_attr attr,
>
>         acpi_arch_dma_setup(dev);
>
> -       iommu = acpi_iommu_configure_id(dev, input_id);
> -       if (PTR_ERR(iommu) == -EPROBE_DEFER)
> +       ret = acpi_iommu_configure_id(dev, input_id);
> +       if (ret == -EPROBE_DEFER)
>                 return -EPROBE_DEFER;
>
> +       /*
> +        * Historically this routine doesn't fail driver probing due to errors
> +        * in acpi_iommu_configure()
> +        */
> +
>         arch_setup_dma_ops(dev, 0, U64_MAX, attr == DEV_DMA_COHERENT);
>
>         return 0;
> --
> 2.42.0
>