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iommu/tegra-smmu: Unwrap tegra_smmu_group_get

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The tegra_smmu_group_get was added to group devices in different
SWGROUPs and it'd return a NULL group pointer upon a mismatch at
tegra_smmu_find_group(), so for most of clients/devices, it very
likely would mismatch and need a fallback generic_device_group().

But now tegra_smmu_group_get handles devices in same SWGROUP too,
which means that it would allocate a group for every new SWGROUP
or would directly return an existing one upon matching a SWGROUP,
i.e. any device will go through this function.

So possibility of having a NULL group pointer in device_group()
is upon failure of either devm_kzalloc() or iommu_group_alloc().
In either case, calling generic_device_group() no longer makes a
sense. Especially for devm_kzalloc() failing case, it'd cause a
problem if it fails at devm_kzalloc() yet succeeds at a fallback
generic_device_group(), because it does not create a group->list
for other devices to match.

This patch simply unwraps the function to clean it up.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20201125101013.14953-2-nicoleotsuka@gmail.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Nicolin Chen 2020-11-25 02:10:09 -08:00 committed by Will Deacon
parent f8394f232b
commit cf910f61af
1 changed files with 4 additions and 15 deletions
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19
drivers/iommu/tegra-smmu.c
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@ -903,10 +903,12 @@ static void tegra_smmu_group_release(void *iommu_data)
mutex_unlock(&smmu->lock);
}
static struct iommu_group *tegra_smmu_group_get(struct tegra_smmu *smmu,
unsigned int swgroup)
static struct iommu_group *tegra_smmu_device_group(struct device *dev)
{
struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
struct tegra_smmu *smmu = dev_iommu_priv_get(dev);
const struct tegra_smmu_group_soc *soc;
unsigned int swgroup = fwspec->ids[0];
struct tegra_smmu_group *group;
struct iommu_group *grp;
@ -950,19 +952,6 @@ static struct iommu_group *tegra_smmu_group_get(struct tegra_smmu *smmu,
return group->group;
}
static struct iommu_group *tegra_smmu_device_group(struct device *dev)
{
struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
struct tegra_smmu *smmu = dev_iommu_priv_get(dev);
struct iommu_group *group;
group = tegra_smmu_group_get(smmu, fwspec->ids[0]);
if (!group)
group = generic_device_group(dev);
return group;
}
static int tegra_smmu_of_xlate(struct device *dev,
struct of_phandle_args *args)
{