Re: [PATCH v2 11/14] iommu: Consolidate the code to calculate the target default domain type

[Jason Gunthorpe <jgg@nvidia.com>]

On Tue, Apr 04, 2023 at 09:39:08AM +0000, Tian, Kevin wrote:
> > From: Jason Gunthorpe <jgg@nvidia.com>
> > Sent: Thursday, March 30, 2023 7:41 AM
> >
> > +	for_each_group_device(group, gdev) {
> > +		unsigned int type = iommu_get_def_domain_type(gdev-
> > >dev);
> > +
> > +		if (best_type && type && best_type != type) {
> > +			if (target_type) {
> > +				dev_err_ratelimited(
> > +					gdev->dev,
> > +					"Device cannot be in %s domain\n",
> > +
> > 	iommu_domain_type_str(target_type));
> > +				return -1;
> > +			}
> > +
> > +			dev_warn(
> > +				gdev->dev,
> > +				"Device needs domain type %s, but device %s
> > in the same iommu group requires type %s - using default\n",
> > +				iommu_domain_type_str(type),
> > dev_name(last_dev),
> > +				iommu_domain_type_str(best_type));
> > +			best_type = 0;
> 
> well, in this case best_type is immediately overridden by following lines
> then "- using default" in the warning message doesn't hold.

Ah... Yes based on the original code this should just be return 0.

It was:

       unsigned int type = iommu_get_def_domain_type(dev);

        if (type) {
                if (gtype->type && gtype->type != type) {
                        dev_warn(dev, "Device needs domain type %s, but device %s in the same iommu group requires type %s - using default\n",
                                 iommu_domain_type_str(type),
                                 dev_name(gtype->dev),
                                 iommu_domain_type_str(gtype->type));
                        gtype->type = 0;
                }

                if (!gtype->dev) {
                        gtype->dev  = dev;
                        gtype->type = type;
                }
        }

So if dev is not set then we can't get a type conflict and once dev is
set then it sticks at 0

Thanks,
Jason