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: Fri, 8 Jul 2022 05:52:32 +0000 [thread overview]
Message-ID: <BN9PR11MB5276C1C35BB1E22D68C3E2A08C829@BN9PR11MB5276.namprd11.prod.outlook.com> (raw)
In-Reply-To: <569e97f6-f78c-1eae-1023-2d5e2df2d40f@arm.com>
> From: Robin Murphy <robin.murphy@arm.com>
> Sent: Thursday, July 7, 2022 6:58 PM
>
> On 2022-07-07 07:51, Tian, Kevin wrote:
> >> 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.
>
> On reflection I think it makes sense to pull the
> iommu_device_unregister() out of the loop anyway - I think that's really
> a left-over from between v1 and v2 when that error case briefly jumped
> to another cleanup loop, before I realised it was actually trivial for
> iommu_device_unregister() to clean up for itself.
>
> However I now see I've also missed another opportunity, and the -EBUSY
> case should be hoisted out of the loop as well, since checking
> iommu_buses[0] is sufficient. Then it's hopefully much clearer that once
> the bus ops go away we'll be left with just a single extra line for the
> loop, as in iommu_device_unregister(). Does that sound reasonable?
>
Yes, sounds good to me.
next prev parent reply other threads:[~2022-07-08 5:53 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-05 17:08 [PATCH v3 00/15] iommu: Retire bus_set_iommu() Robin Murphy
2022-07-05 17:08 ` [PATCH v3 01/15] iommu/vt-d: Handle race between registration and device probe Robin Murphy
2022-07-06 1:39 ` Baolu Lu
2022-07-07 6:51 ` Tian, Kevin
2022-07-08 7:52 ` Baolu Lu
2022-07-15 12:37 ` Robin Murphy
2022-07-19 0:06 ` Lu Baolu
2022-07-05 17:08 ` [PATCH v3 02/15] iommu/amd: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 03/15] iommu: Always register bus notifiers Robin Murphy
2022-07-06 1:53 ` Baolu Lu
2022-07-06 13:43 ` Robin Murphy
2022-07-07 0:20 ` Baolu Lu
2022-07-07 6:34 ` Tian, Kevin
2022-07-07 9:38 ` Robin Murphy
2022-07-07 6:31 ` Tian, Kevin
2022-07-07 9:58 ` Robin Murphy
2022-07-08 5:50 ` Tian, Kevin
2022-07-05 17:08 ` [PATCH v3 04/15] iommu: Move bus setup to IOMMU device registration Robin Murphy
2022-07-06 2:35 ` Baolu Lu
2022-07-06 14:37 ` Robin Murphy
2022-07-07 1:19 ` Baolu Lu
2022-07-07 6:51 ` Tian, Kevin
2022-07-07 10:58 ` Robin Murphy
2022-07-08 5:52 ` Tian, Kevin [this message]
2022-07-05 17:08 ` [PATCH v3 05/15] iommu/amd: Clean up bus_set_iommu() Robin Murphy
2022-07-05 17:08 ` [PATCH v3 06/15] iommu/arm-smmu: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 07/15] iommu/arm-smmu-v3: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 08/15] iommu/dart: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 09/15] iommu/exynos: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 10/15] iommu/ipmmu-vmsa: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 11/15] iommu/mtk: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 12/15] iommu/omap: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 13/15] iommu/tegra-smmu: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 14/15] iommu/virtio: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 15/15] iommu: " Robin Murphy
2022-07-07 7:45 ` Tian, Kevin
2022-07-07 12:49 ` Matthew Rosato
2022-07-07 12:54 ` Matthew Rosato
2022-07-07 14:58 ` Robin Murphy
2022-07-07 16:42 ` Matthew Rosato
2022-07-08 8:14 ` [PATCH] iommu/s390: fail probe for non-pci device Niklas Schnelle
2022-07-08 8:17 ` [PATCH v3 00/15] iommu: Retire bus_set_iommu() Niklas Schnelle
2022-07-15 13:12 ` Robin Murphy
2022-07-21 7:17 ` Tian, Kevin
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