| Message ID | 20200929061325.10197-2-nicoleotsuka@gmail.com |
|---|---|
| State | Deferred |
| Headers | show |
| Series | iommu/tegra-smmu: Two followup changes | expand |
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 <nicoleotsuka@gmail.com> > --- Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
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 <nicoleotsuka@gmail.com> >> --- > > Reviewed-by: Dmitry Osipenko <digetx@gmail.com> > Tested-by: Dmitry Osipenko <digetx@gmail.com>
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 <nicoleotsuka@gmail.com> > --- > > 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 <treding@nvidia.com>
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(&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) {
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> --- 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(-)