Re: [PATCH v3 1/5] iommu/amd: Refactor device probe and capability initialization

[Pranjal Shrivastava <praan@google.com>]

On Tue, Aug 25, 2026 at 12:29:35PM +0530, Vasant Hegde wrote:
> 
> 
> On 8/24/2026 5:53 PM, Pranjal Shrivastava wrote:
> > Restructure the device probe path to improve readability and prepare for
> > cleaner error handling. Refactor check_device() into iommu_lookup_device
> > to explicitly validate and return the amd_iommu ptr & devid. Refactor
> > iommu_init_device() to return the allocated dev_data. Consolidate all
> > PCI cap inits (MSI domains, PASID, ATS) into a new helper:
> > iommu_init_device_caps().
> > 
> > Suggested-by: Vasant Hegde <vasant.hegde@amd.com>
> > Signed-off-by: Pranjal Shrivastava <praan@google.com>
> 
> One minor nit. Otherwise patch looks good.
> 
> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
> 
> 
> 
> > ---
> >  drivers/iommu/amd/iommu.c | 117 +++++++++++++++++++-------------------
> >  1 file changed, 60 insertions(+), 57 deletions(-)
> > 
> > diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
> > index 4c31294fabc5..e1f9fbb63837 100644
> > --- a/drivers/iommu/amd/iommu.c
> > +++ b/drivers/iommu/amd/iommu.c
> > @@ -675,7 +675,8 @@ static void pdev_disable_caps(struct pci_dev *pdev)
> 
> 
> .../...
> 
> >  static struct iommu_device *amd_iommu_probe_device(struct device *dev)
> >  {
> >  	struct iommu_device *iommu_dev;
> >  	struct amd_iommu *iommu;
> >  	struct iommu_dev_data *dev_data;
> >  	int ret;
> > +	u16 devid;
> >  
> > -	if (!check_device(dev))
> > -		return ERR_PTR(-ENODEV);
> > -
> > -	iommu = rlookup_amd_iommu(dev);
> > -	if (!iommu)
> > -		return ERR_PTR(-ENODEV);
> > -
> > -	/* Not registered yet? */
> > -	if (!iommu->iommu.ops)
> > +	if (!iommu_lookup_device(dev, &iommu, &devid))
> >  		return ERR_PTR(-ENODEV);
> >  
> >  	if (dev_iommu_priv_get(dev))
> >  		return &iommu->iommu;
> >  
> > -	ret = iommu_init_device(iommu, dev);
> > -	if (ret) {
> > +	dev_data = iommu_init_device(iommu, dev, devid);
> > +	if (IS_ERR(dev_data)) {
> > +		ret = PTR_ERR(dev_data);
> 
> Instead of this, you can change below iommu_Dev assignment directly.

Ack, I'll change iommu_dev assignment directly.

> 
> -Vasant
> 
> >  		dev_err(dev, "Failed to initialize - trying to proceed anyway\n");
> >  		iommu_dev = ERR_PTR(ret);
> >  		iommu_ignore_device(iommu, dev);
> >  		goto out_err;
> >  	}
> >  

Thanks,
Praan