RE: [PATCH v3 04/15] iommu: Move bus setup to IOMMU device registration

From: "Tian, Kevin" <kevin.tian@intel.com>
To: Robin Murphy <robin.murphy@arm.com>, "joro@8bytes.org" <joro@8bytes.org>
Cc: "will@kernel.org" <will@kernel.org>,
	"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"baolu.lu@linux.intel.com" <baolu.lu@linux.intel.com>,
	"suravee.suthikulpanit@amd.com" <suravee.suthikulpanit@amd.com>,
	"vasant.hegde@amd.com" <vasant.hegde@amd.com>,
	"mjrosato@linux.ibm.com" <mjrosato@linux.ibm.com>,
	"gerald.schaefer@linux.ibm.com" <gerald.schaefer@linux.ibm.com>,
	"schnelle@linux.ibm.com" <schnelle@linux.ibm.com>,
	"linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v3 04/15] iommu: Move bus setup to IOMMU device registration
Date: Thu, 7 Jul 2022 06:51:17 +0000	[thread overview]
Message-ID: <BN9PR11MB5276ECD0D25C09D6A3686A3B8C839@BN9PR11MB5276.namprd11.prod.outlook.com> (raw)
In-Reply-To: <5b9b608af21b3c4353af042355973bac55397962.1657034828.git.robin.murphy@arm.com>

> From: Robin Murphy <robin.murphy@arm.com>
> Sent: Wednesday, July 6, 2022 1:08 AM
> 
> @@ -202,12 +210,32 @@ int iommu_device_register(struct iommu_device
> *iommu,
>  	spin_lock(&iommu_device_lock);
>  	list_add_tail(&iommu->list, &iommu_device_list);
>  	spin_unlock(&iommu_device_lock);
> +
> +	for (int i = 0; i < ARRAY_SIZE(iommu_buses); i++) {
> +		struct bus_type *bus = iommu_buses[i];
> +		int err;
> +
> +		if (bus->iommu_ops && bus->iommu_ops != ops) {
> +			err = -EBUSY;
> +		} else {
> +			bus->iommu_ops = ops;
> +			err = bus_iommu_probe(bus);
> +		}
> +		if (err) {
> +			iommu_device_unregister(iommu);
> +			return err;
> +		}
> +	}
> +

Probably move above into a new function bus_iommu_probe_all():

	/* probe all buses for devices associated with this iommu */
	err = bus_iommu_probe_all();
	if (err) {
		iommu_device_unregister(iommu);
		return err;
	}

Just  my personal preference on leaving logic in iommu_device_register()
more relevant to the iommu instance itself.

Apart from that:

Reviewed-by: Kevin Tian <kevin.tian@intel.com>