From: Nicolin Chen <nicoleotsuka@gmail.com>
To: thierry.reding@gmail.com, joro@8bytes.org
Cc: vdumpa@nvidia.com, jonathanh@nvidia.com, digetx@gmail.com,
linux-tegra@vger.kernel.org, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v3 1/2] iommu/tegra-smmu: Unwrap tegra_smmu_group_get
Date: Mon, 28 Sep 2020 21:52:46 -0700 [thread overview]
Message-ID: <20200929045247.15596-2-nicoleotsuka@gmail.com> (raw)
In-Reply-To: <20200929045247.15596-1-nicoleotsuka@gmail.com>
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->v3:
* 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(&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)
{
--
2.17.1
next prev parent reply other threads:[~2020-09-29 4:58 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-29 4:52 [PATCH v3 0/2] iommu/tegra-smmu: Two followup changes Nicolin Chen
2020-09-29 4:52 ` Nicolin Chen [this message]
2020-09-29 4:52 ` [PATCH v3 2/2] iommu/tegra-smmu: Expend mutex protection range Nicolin Chen
2020-09-29 6:03 ` Christoph Hellwig
2020-09-29 6:02 ` Nicolin Chen
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