[PATCH v2] iommu/tegra-smmu: Drop unnecessary error check for for debugfs_create_dir()

[PATCH v2] iommu/tegra-smmu: Drop unnecessary error check for for debugfs_create_dir()

[Jinjie Ruan]

The debugfs_create_dir() function returns error pointers.
It never returns NULL.

As Baolu suggested, this patch removes the error checking for
debugfs_create_dir in tegra-smmu.c. This is because the DebugFS kernel API
is developed in a way that the caller can safely ignore the errors that
occur during the creation of DebugFS nodes. The debugfs APIs have
a IS_ERR() judge in start_creating() which can handle it gracefully. So
these checks are unnecessary.

Fixes: d1313e7896e9 ("iommu/tegra-smmu: Add debugfs support")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Suggested-by: Baolu Lu <baolu.lu@linux.intel.com>
---
v2:
- Remove the err check instead of using IS_ERR to replace NULL check.
- Update the commit message and title.
---
 drivers/iommu/tegra-smmu.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 1cbf063ccf14..2137040b7efa 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -1056,8 +1056,6 @@ DEFINE_SHOW_ATTRIBUTE(tegra_smmu_clients);
 static void tegra_smmu_debugfs_init(struct tegra_smmu *smmu)
 {
 	smmu->debugfs = debugfs_create_dir("smmu", NULL);
-	if (!smmu->debugfs)
-		return;
 
 	debugfs_create_file("swgroups", S_IRUGO, smmu->debugfs, smmu,
 			    &tegra_smmu_swgroups_fops);
-- 
2.34.1

Re: [PATCH v2] iommu/tegra-smmu: Drop unnecessary error check for for debugfs_create_dir()

[Jason Gunthorpe]

On Fri, Sep 01, 2023 at 03:30:56PM +0800, Jinjie Ruan wrote:
> The debugfs_create_dir() function returns error pointers.
> It never returns NULL.
> 
> As Baolu suggested, this patch removes the error checking for
> debugfs_create_dir in tegra-smmu.c. This is because the DebugFS kernel API
> is developed in a way that the caller can safely ignore the errors that
> occur during the creation of DebugFS nodes. The debugfs APIs have
> a IS_ERR() judge in start_creating() which can handle it gracefully. So
> these checks are unnecessary.
> 
> Fixes: d1313e7896e9 ("iommu/tegra-smmu: Add debugfs support")
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
> Suggested-by: Baolu Lu <baolu.lu@linux.intel.com>
> ---
> v2:
> - Remove the err check instead of using IS_ERR to replace NULL check.
> - Update the commit message and title.
> ---
>  drivers/iommu/tegra-smmu.c | 2 --
>  1 file changed, 2 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason

Re: [PATCH v2] iommu/tegra-smmu: Drop unnecessary error check for for debugfs_create_dir()

[Thierry Reding]

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On Fri, Sep 01, 2023 at 03:30:56PM +0800, Jinjie Ruan wrote:
> The debugfs_create_dir() function returns error pointers.
> It never returns NULL.
> 
> As Baolu suggested, this patch removes the error checking for
> debugfs_create_dir in tegra-smmu.c. This is because the DebugFS kernel API
> is developed in a way that the caller can safely ignore the errors that
> occur during the creation of DebugFS nodes. The debugfs APIs have
> a IS_ERR() judge in start_creating() which can handle it gracefully. So
> these checks are unnecessary.
> 
> Fixes: d1313e7896e9 ("iommu/tegra-smmu: Add debugfs support")
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
> Suggested-by: Baolu Lu <baolu.lu@linux.intel.com>
> ---
> v2:
> - Remove the err check instead of using IS_ERR to replace NULL check.
> - Update the commit message and title.
> ---
>  drivers/iommu/tegra-smmu.c | 2 --
>  1 file changed, 2 deletions(-)

Acked-by: Thierry Reding <treding@nvidia.com>

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Re: [PATCH v2] iommu/tegra-smmu: Drop unnecessary error check for for debugfs_create_dir()

[Joerg Roedel]

On Fri, Sep 01, 2023 at 03:30:56PM +0800, Jinjie Ruan wrote:
>  drivers/iommu/tegra-smmu.c | 2 --
>  1 file changed, 2 deletions(-)

Applied, thanks.