From: Thierry Reding <thierry.reding@gmail.com>
To: Miaoqian Lin <linmq006@gmail.com>
Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
Jonathan Hunter <jonathanh@nvidia.com>,
linux-tegra@vger.kernel.org, Will Deacon <will@kernel.org>
Subject: Re: [PATCH] iommu/tegra-smmu: Fix missing put_device() call in tegra_smmu_find
Date: Wed, 16 Feb 2022 14:48:26 +0100 [thread overview]
Message-ID: <Yg0AqkLA7eXQOuh2@orome> (raw)
In-Reply-To: <20220107080915.12686-1-linmq006@gmail.com>
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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 <linmq006@gmail.com>
> ---
> 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 <treding@nvidia.com>
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WARNING: multiple messages have this Message-ID (diff)
From: Thierry Reding <thierry.reding@gmail.com>
To: Miaoqian Lin <linmq006@gmail.com>
Cc: Krishna Reddy <vdumpa@nvidia.com>, Joerg Roedel <joro@8bytes.org>,
Will Deacon <will@kernel.org>,
Jonathan Hunter <jonathanh@nvidia.com>,
Nicolin Chen <nicoleotsuka@gmail.com>,
linux-tegra@vger.kernel.org, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iommu/tegra-smmu: Fix missing put_device() call in tegra_smmu_find
Date: Wed, 16 Feb 2022 14:48:26 +0100 [thread overview]
Message-ID: <Yg0AqkLA7eXQOuh2@orome> (raw)
In-Reply-To: <20220107080915.12686-1-linmq006@gmail.com>
[-- Attachment #1: Type: text/plain, Size: 1373 bytes --]
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 <linmq006@gmail.com>
> ---
> 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 <treding@nvidia.com>
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next prev parent reply other threads:[~2022-02-16 13:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-07 8:09 [PATCH] iommu/tegra-smmu: Fix missing put_device() call in tegra_smmu_find Miaoqian Lin
2022-01-07 8:09 ` Miaoqian Lin
2022-01-31 15:25 ` Joerg Roedel
2022-01-31 15:25 ` Joerg Roedel
2022-02-16 13:48 ` Thierry Reding [this message]
2022-02-16 13:48 ` Thierry Reding
2022-02-28 12:16 ` Joerg Roedel
2022-02-28 12:16 ` Joerg Roedel
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