LinuxLists.cc - [PATCH] iommu/tegra-smmu: Fix missing put_device() call in tegra_smmu

2022-01-07 08:09:28

Subject: [PATCH] iommu/tegra-smmu: Fix missing put_device() call in tegra_smmu_find

The reference taken by 'of_find_device_by_node()' must be released when
not needed anymore.
Add the corresponding 'put_device()' in the error handling path.

Fixes: 765a9d1d02b2 ("iommu/tegra-smmu: Fix mc errors on tegra124-nyan")
Signed-off-by: Miaoqian Lin <[email protected]>
---
drivers/iommu/tegra-smmu.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index e900e3c46903..2561ce8a2ce8 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -808,8 +808,10 @@ static struct tegra_smmu *tegra_smmu_find(struct device_node *np)
return NULL;

mc = platform_get_drvdata(pdev);
- if (!mc)
+ if (!mc) {
+ put_device(&pdev->dev);
return NULL;
+ }

return mc->smmu;
}
--
2.17.1

2022-02-01 20:42:26

by Joerg Roedel

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Subject: Re: [PATCH] iommu/tegra-smmu: Fix missing put_device() call in tegra_smmu_find

Thierry,

does this look correct to you?

Thanks,

Joerg

On Fri, Jan 07, 2022 at 08:09:11AM +0000, Miaoqian Lin wrote:
> The reference taken by 'of_find_device_by_node()' must be released when
> not needed anymore.
> Add the corresponding 'put_device()' in the error handling path.
>
> Fixes: 765a9d1d02b2 ("iommu/tegra-smmu: Fix mc errors on tegra124-nyan")
> Signed-off-by: Miaoqian Lin <[email protected]>
> ---
> drivers/iommu/tegra-smmu.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
> index e900e3c46903..2561ce8a2ce8 100644
> --- a/drivers/iommu/tegra-smmu.c
> +++ b/drivers/iommu/tegra-smmu.c
> @@ -808,8 +808,10 @@ static struct tegra_smmu *tegra_smmu_find(struct device_node *np)
> return NULL;
>
> mc = platform_get_drvdata(pdev);
> - if (!mc)
> + if (!mc) {
> + put_device(&pdev->dev);
> return NULL;
> + }
>
> return mc->smmu;
> }
> --
> 2.17.1

2022-02-16 17:19:07

by Thierry Reding

[permalink] [raw]

Subject: Re: [PATCH] iommu/tegra-smmu: Fix missing put_device() call in tegra_smmu_find

On Fri, Jan 07, 2022 at 08:09:11AM +0000, Miaoqian Lin wrote:
> The reference taken by 'of_find_device_by_node()' must be released when
> not needed anymore.
> Add the corresponding 'put_device()' in the error handling path.
>
> Fixes: 765a9d1d02b2 ("iommu/tegra-smmu: Fix mc errors on tegra124-nyan")
> Signed-off-by: Miaoqian Lin <[email protected]>
> ---
> drivers/iommu/tegra-smmu.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
> index e900e3c46903..2561ce8a2ce8 100644
> --- a/drivers/iommu/tegra-smmu.c
> +++ b/drivers/iommu/tegra-smmu.c
> @@ -808,8 +808,10 @@ static struct tegra_smmu *tegra_smmu_find(struct device_node *np)
> return NULL;
>
> mc = platform_get_drvdata(pdev);
> - if (!mc)
> + if (!mc) {
> + put_device(&pdev->dev);
> return NULL;
> + }
>
> return mc->smmu;
> }

Sorry for the late reply, looks correct. We probably also need a similar
call in ->release_device(). I also wonder if we should be returning an
-EPROBE_DEFER here, which is technically the correct thing to do, though
in practice that will likely never happen because these pointers are set
during an arch_initcall, so should always be available by the time a
driver tries to attach to an IOMMU.

Acked-by: Thierry Reding <[email protected]>

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2022-02-28 17:36:55

by Joerg Roedel

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