From: Nicolin Chen <nicoleotsuka@gmail.com>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: thierry.reding@gmail.com, joro@8bytes.org, krzk@kernel.org,
vdumpa@nvidia.com, jonathanh@nvidia.com,
linux-tegra@vger.kernel.org, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] iommu/tegra-smmu: Rework .probe_device and .attach_dev
Date: Tue, 29 Sep 2020 23:19:35 -0700 [thread overview]
Message-ID: <20200930061935.GB16460@Asurada-Nvidia> (raw)
In-Reply-To: <68c13611-bc3d-5ba6-70ec-29786d69ff9a@gmail.com>
On Wed, Sep 30, 2020 at 08:59:45AM +0300, Dmitry Osipenko wrote:
> 30.09.2020 08:41, Nicolin Chen пишет:
> > On Wed, Sep 30, 2020 at 08:39:54AM +0300, Dmitry Osipenko wrote:
> >> 30.09.2020 03:30, Nicolin Chen пишет:
> >>> static int tegra_smmu_attach_dev(struct iommu_domain *domain,
> >>> struct device *dev)
> >>> {
> >>> + struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> >>> struct tegra_smmu *smmu = dev_iommu_priv_get(dev);
> >>> struct tegra_smmu_as *as = to_smmu_as(domain);
> >>> - struct device_node *np = dev->of_node;
> >>> - struct of_phandle_args args;
> >>> unsigned int index = 0;
> >>> int err = 0;
> >>>
> >>> - while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
> >>> - &args)) {
> >>> - unsigned int swgroup = args.args[0];
> >>> -
> >>> - if (args.np != smmu->dev->of_node) {
> >>> - of_node_put(args.np);
> >>> - continue;
> >>> - }
> >>> -
> >>> - of_node_put(args.np);
> >>> + if (!fwspec || fwspec->ops != &tegra_smmu_ops)
> >>> + return -ENOENT;
> >>
> >> s/&tegra_smmu_ops/smmu->iommu.ops/
> >>
> >> Secondly, is it even possible that fwspec could be NULL here or that
> >> fwspec->ops != smmu->ops?
> >
> > I am following what's in the arm-smmu driver, as I think it'd be
> > a common practice to do such a check in such a way.
> >
>
> Please check whether it's really needed. It looks like it was needed
> sometime ago, but that's not true anymore.
Given that most iommu drivers have ->ops check, I'd like to
have it also for safety. If someday that's not true anymore,
I'd expect someone to update all existing drivers.
next prev parent reply other threads:[~2020-09-30 6:25 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-30 0:30 [PATCH v2 0/3] iommu/tegra-smmu: Add PCI support Nicolin Chen
2020-09-30 0:30 ` [PATCH v2 1/3] memory: tegra: Add helper function tegra_get_memory_controller Nicolin Chen
2020-09-30 5:12 ` Dmitry Osipenko
2020-09-30 5:44 ` Nicolin Chen
2020-09-30 6:32 ` Dmitry Osipenko
2020-09-30 6:38 ` Nicolin Chen
2020-09-30 7:31 ` Dmitry Osipenko
2020-09-30 7:21 ` Krzysztof Kozlowski
2020-09-30 7:25 ` Nicolin Chen
2020-09-30 7:50 ` Krzysztof Kozlowski
2020-09-30 0:30 ` [PATCH v2 2/3] iommu/tegra-smmu: Rework .probe_device and .attach_dev Nicolin Chen
2020-09-30 5:10 ` Dmitry Osipenko
2020-09-30 5:20 ` Dmitry Osipenko
2020-09-30 5:50 ` Nicolin Chen
2020-09-30 6:34 ` Nicolin Chen
2020-09-30 5:11 ` Dmitry Osipenko
2020-09-30 5:49 ` Nicolin Chen
2020-09-30 6:10 ` Dmitry Osipenko
2020-09-30 6:13 ` Nicolin Chen
2020-09-30 6:33 ` Dmitry Osipenko
2020-09-30 5:24 ` Dmitry Osipenko
2020-09-30 5:39 ` Nicolin Chen
2020-09-30 5:48 ` Dmitry Osipenko
2020-09-30 5:39 ` Dmitry Osipenko
2020-09-30 5:41 ` Nicolin Chen
2020-09-30 5:59 ` Dmitry Osipenko
2020-09-30 6:19 ` Nicolin Chen [this message]
2020-09-30 0:30 ` [PATCH v2 3/3] iommu/tegra-smmu: Add PCI support Nicolin Chen
2020-09-30 5:10 ` Dmitry Osipenko
2020-09-30 5:28 ` Nicolin Chen
2020-09-30 5:10 ` Dmitry Osipenko
2020-09-30 5:29 ` Nicolin Chen
2020-09-30 5:58 ` Dmitry Osipenko
2020-09-30 7:16 ` Nicolin Chen
2020-09-30 5:10 ` Dmitry Osipenko
2020-09-30 5:34 ` Nicolin Chen
2020-09-30 6:01 ` Dmitry Osipenko
2020-09-30 7:12 ` Nicolin Chen
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