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.
