diff mbox series

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

Message ID 4-v1-5f734af130a3+34f-iommu_fwspec_jgg@nvidia.com (mailing list archive)
State Superseded
Headers show
Series Solve iommu probe races around iommu_fwspec | expand

Commit Message

Jason Gunthorpe Nov. 3, 2023, 4:44 p.m. UTC 
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@nvidia.com>
---
 drivers/acpi/scan.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

Comments

Jerry Snitselaar Nov. 4, 2023, 12:48 a.m. UTC | #1 
On Fri, Nov 03, 2023 at 01:44:49PM -0300, Jason Gunthorpe 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@nvidia.com>
> ---
>  drivers/acpi/scan.c | 24 +++++++++++++++---------
>  1 file changed, 15 insertions(+), 9 deletions(-)
> 

...

>  #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;
>  
                return ret; ?

> +	/*
> +	 * Historically this routine doesn't fail driver probing due to errors
> +	 * in acpi_iommu_configure()

              acpi_iommu_configure_id()

> +	 */
> +
>  	arch_setup_dma_ops(dev, 0, U64_MAX, attr == DEV_DMA_COHERENT);
>  
>  	return 0;
> -- 
> 2.42.0
>
Jason Gunthorpe Nov. 5, 2023, 1:24 p.m. UTC | #2 
On Fri, Nov 03, 2023 at 05:48:01PM -0700, Jerry Snitselaar wrote:
> > @@ -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;
> >  
>                 return ret; ?

Maybe? Like this seemed to be a pattern in this code so I left it

> > +	/*
> > +	 * Historically this routine doesn't fail driver probing due to errors
> > +	 * in acpi_iommu_configure()
> 
>               acpi_iommu_configure_id()

Thanks

Jason
Jerry Snitselaar Nov. 5, 2023, 5:55 p.m. UTC | #3 
On Sun, Nov 05, 2023 at 09:24:09AM -0400, Jason Gunthorpe wrote:
> On Fri, Nov 03, 2023 at 05:48:01PM -0700, Jerry Snitselaar wrote:
> > > @@ -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;
> > >  
> >                 return ret; ?
> 
> Maybe? Like this seemed to be a pattern in this code so I left it

Yeah, it is fine. I think it just caught my eye, because of this earlier
bit in the patch:

        if (err == -EPROBE_DEFER) {
-               return ERR_PTR(err);
+               return err;

which needed to get rid of the ERR_PTR.

Regards,
Jerry

> 
> > > +	/*
> > > +	 * Historically this routine doesn't fail driver probing due to errors
> > > +	 * in acpi_iommu_configure()
> > 
> >               acpi_iommu_configure_id()
> 
> Thanks
> 
> Jason
Rafael J. Wysocki Nov. 6, 2023, 2:32 p.m. UTC | #4 
On Fri, Nov 3, 2023 at 5:45 PM Jason Gunthorpe <jgg@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@nvidia.com>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@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
>
diff mbox series

Patch

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;