[PATCH] iommu: Check for iommu_ops == NULL in iommu_probe_device()

[PATCH] iommu: Check for iommu_ops == NULL in iommu_probe_device()

[Joerg Roedel]

From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>

This check needs to be there and got lost at some point
during development. Add it again.

Fixes: 641fb0efbff0 ('iommu/of: Don't call iommu_ops->add_device directly')
Reported-by: Marek Szyprowski <m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
Reported-by: kernelci.org bot <bot-ssFOTAMYnuFg9hUCZPvPmw@public.gmane.org>
Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
---
 drivers/iommu/iommu.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index a2131751dcff..3ed4db334341 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -114,10 +114,14 @@ void iommu_device_unregister(struct iommu_device *iommu)
 int iommu_probe_device(struct device *dev)
 {
 	const struct iommu_ops *ops = dev->bus->iommu_ops;
+	int ret = -EINVAL;
 
 	WARN_ON(dev->iommu_group);
 
-	return ops->add_device(dev);
+	if (ops)
+		ret = ops->add_device(dev);
+
+	return ret;
 }
 
 void iommu_release_device(struct device *dev)
-- 
2.13.7

Re: [PATCH] iommu: Check for iommu_ops == NULL in iommu_probe_device()

[Auger Eric]

Hi Joerg,

On 12/20/18 10:08 AM, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
> 
> This check needs to be there and got lost at some point
> during development. Add it again.
> 
> Fixes: 641fb0efbff0 ('iommu/of: Don't call iommu_ops->add_device directly')
I experience a regression with those 2 patches. I have virtio-pci device
protected by virtual smmuv3 and in that case I get err = -EPROBE_DEFER
after pci_for_each_dma_alias() in of_iommu_configure(). When
iommu_probe_device is called, ops = NULL so it returns -EINVAL and err
is overwritten. So there is no deferred probing while it happened before.

Thanks

Eric
> Reported-by: Marek Szyprowski <m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> Reported-by: kernelci.org bot <bot-ssFOTAMYnuFg9hUCZPvPmw@public.gmane.org>
> Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
> ---
>  drivers/iommu/iommu.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index a2131751dcff..3ed4db334341 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -114,10 +114,14 @@ void iommu_device_unregister(struct iommu_device *iommu)
>  int iommu_probe_device(struct device *dev)
>  {
>  	const struct iommu_ops *ops = dev->bus->iommu_ops;
> +	int ret = -EINVAL;
>  
>  	WARN_ON(dev->iommu_group);
>  
> -	return ops->add_device(dev);
> +	if (ops)
> +		ret = ops->add_device(dev);
> +
> +	return ret;
>  }
>  
>  void iommu_release_device(struct device *dev)
> 

Re: [PATCH] iommu: Check for iommu_ops == NULL in iommu_probe_device()

[Jean-Philippe Brucker]

On 16/01/2019 15:27, Auger Eric wrote:
> Hi Joerg,
> 
> On 12/20/18 10:08 AM, Joerg Roedel wrote:
>> From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
>>
>> This check needs to be there and got lost at some point
>> during development. Add it again.
>>
>> Fixes: 641fb0efbff0 ('iommu/of: Don't call iommu_ops->add_device directly')
> I experience a regression with those 2 patches. I have virtio-pci device
> protected by virtual smmuv3 and in that case I get err = -EPROBE_DEFER
> after pci_for_each_dma_alias() in of_iommu_configure(). When
> iommu_probe_device is called, ops = NULL so it returns -EINVAL and err
> is overwritten. So there is no deferred probing while it happened before.

There is a fix on the list:
https://www.spinics.net/lists/arm-kernel/msg698371.html

Thanks,
Jean

Re: [PATCH] iommu: Check for iommu_ops == NULL in iommu_probe_device()

[Joerg Roedel]

On Wed, Jan 16, 2019 at 04:33:51PM +0000, Jean-Philippe Brucker wrote:
> There is a fix on the list:
> https://www.spinics.net/lists/arm-kernel/msg698371.html

It is also in my tree already, I will send it upstream this week.

Regards,

	Joerg

Re: [PATCH] iommu: Check for iommu_ops == NULL in iommu_probe_device()

[Auger Eric]

Hi Jean, Joerg,

On 1/16/19 5:43 PM, Joerg Roedel wrote:
> On Wed, Jan 16, 2019 at 04:33:51PM +0000, Jean-Philippe Brucker wrote:
>> There is a fix on the list:
>> https://www.spinics.net/lists/arm-kernel/msg698371.html
> 
> It is also in my tree already, I will send it upstream this week.

OK thanks!

Eric
> 
> Regards,
> 
> 	Joerg
>