On Wed, Oct 25, 2023 at 07:25:50PM +0800, Baolu Lu wrote:
> On 2023/10/25 19:01, Dario Binacchi wrote:
> > The return value of debugfs_create_dir() should be checked using the
> > IS_ERR() function.
> >
> > Signed-off-by: Dario Binacchi <dario.binacchi@xxxxxxxxxxxxxxxxxxxx>
> > ---
> >
> > drivers/iommu/tegra-smmu.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
> > index e445f80d0226..cd1d80c4c673 100644
> > --- a/drivers/iommu/tegra-smmu.c
> > +++ b/drivers/iommu/tegra-smmu.c
> > @@ -1056,7 +1056,7 @@ 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)
> > + if (IS_ERR(smmu->debugfs))
> > return;
>
> This check can be removed, as debugfs_create_file() can handle the case
> where @parent is an error pointer.
A patch for this has been in linux-next for a few weeks, see:
commit f7da9c081517daba70f9f9342e09d7a6322ba323
Author: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
Date: Fri Sep 1 15:30:56 2023 +0800
iommu/tegra-smmu: Drop unnecessary error check for for debugfs_create_dir()
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@xxxxxxxxxx>
Suggested-by: Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>
Acked-by: Thierry Reding <treding@xxxxxxxxxx>
Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230901073056.1364755-1-ruanjinjie@xxxxxxxxxx
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Thierry
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