Re: [PATCH v4 1/2] iommu/tegra-smmu: Unwrap tegra_smmu_group_get
On Mon, Sep 28, 2020 at 11:13:24PM -0700, Nicolin Chen wrote: > 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 > --- > > Changelog > v2->v4: > * N/A > v1->v2: > * Changed type of swgroup to "unsigned int", following Thierry's >commnets. > > drivers/iommu/tegra-smmu.c | 19 --- > 1 file changed, 4 insertions(+), 15 deletions(-) Acked-by: Thierry Reding signature.asc Description: PGP signature ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [PATCH v4 1/2] iommu/tegra-smmu: Unwrap tegra_smmu_group_get
29.09.2020 20:41, Dmitry Osipenko пишет: > 29.09.2020 09:13, Nicolin Chen пишет: >> 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 >> --- > > Reviewed-by: Dmitry Osipenko > Tested-by: Dmitry Osipenko ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [PATCH v4 1/2] iommu/tegra-smmu: Unwrap tegra_smmu_group_get
29.09.2020 09:13, Nicolin Chen пишет: > 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 > --- Reviewed-by: Dmitry Osipenko ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
[PATCH v4 1/2] iommu/tegra-smmu: Unwrap tegra_smmu_group_get
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
---
Changelog
v2->v4:
* N/A
v1->v2:
* Changed type of swgroup to "unsigned int", following Thierry's
commnets.
drivers/iommu/tegra-smmu.c | 19 ---
1 file changed, 4 insertions(+), 15 deletions(-)
diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 0becdbfea306..ec4c9dafff95 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -903,10 +903,12 @@ static void tegra_smmu_group_release(void *iommu_data)
mutex_unlock(>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)
{
--
2.17.1
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