[PATCH v2] iommu/tegra-smmu: drop error checking for debugfs_create_dir()

[PATCH v2] iommu/tegra-smmu: drop error checking for debugfs_create_dir()

[Dario Binacchi]

The return value of debugfs_create_dir() should be checked using the
IS_ERR() function. The patch, however, drops the check statement without
fixing it because the subsequent functions (i. e. debugfs_create_file())
can handle the case where `@parent` is an error pointer.

Suggested-by: Baolu Lu <baolu.lu@linux.intel.com>
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>

---

Changes in v2:
 - drop the error checking statement

 drivers/iommu/tegra-smmu.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index e445f80d0226..3e573148d18c 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -1056,9 +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);
 	debugfs_create_file("clients", S_IRUGO, smmu->debugfs, smmu,
-- 
2.42.0

Re: [PATCH v2] iommu/tegra-smmu: drop error checking for debugfs_create_dir()

[Joerg Roedel]

On Wed, Oct 25, 2023 at 05:25:58PM +0200, Dario Binacchi wrote:
> The return value of debugfs_create_dir() should be checked using the
> IS_ERR() function. The patch, however, drops the check statement without
> fixing it because the subsequent functions (i. e. debugfs_create_file())
> can handle the case where `@parent` is an error pointer.

This deserves a comment in the code explaining why no error checking is
needed.

Regards,

	Joerg

Re: [PATCH v2] iommu/tegra-smmu: drop error checking for debugfs_create_dir()

[Thierry Reding]

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On Mon, Nov 27, 2023 at 10:27:40AM +0100, Joerg Roedel wrote:
> On Wed, Oct 25, 2023 at 05:25:58PM +0200, Dario Binacchi wrote:
> > The return value of debugfs_create_dir() should be checked using the
> > IS_ERR() function. The patch, however, drops the check statement without
> > fixing it because the subsequent functions (i. e. debugfs_create_file())
> > can handle the case where `@parent` is an error pointer.
> 
> This deserves a comment in the code explaining why no error checking is
> needed.

This is a duplicate of f7da9c081517 ("iommu/tegra-smmu: Drop unnecessary
error check for for debugfs_create_dir()"), which is already in v6.7-rc1
so I think we can ignore this one.

Thierry

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