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@xxxxxxxxx> > --- > > 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@xxxxxxxxxx>
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