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References: <20230523171240.12930-1-osmtendev@gmail.com>
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From:   David Rheinsberg <david.rheinsberg@gmail.com>
Date:   Tue, 30 May 2023 12:48:07 +0200
Message-ID: <CADyDSO7Lchnraz8pZJkgDBg=YiEG51kcSd+_yg55GpJOuHk6wg@mail.gmail.com>
Subject: Re: [PATCH] hid-wiimote-debug.c: Fix error checking for debugfs_create_file
To:     Osama Muhammad <osmtendev@gmail.com>
Cc:     benjamin.tissoires@redhat.com, linux-input@vger.kernel.org,
        linux-kernel@vger.kernel.org
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Hi

On Tue, 23 May 2023 at 19:13, Osama Muhammad <osmtendev@gmail.com> wrote:
>
> This patch fixes the error checking in hid-wiimote-debug.c in
> debugfs_create_file. The correct way to check if an error occurred
> is 'IS_ERR' inline function.

Please have a look at fs/debugfs/inode.c, especiall the docs of
debugfs_create_file():

477  * NOTE: it's expected that most callers should _ignore_ the errors returned
478  * by this function. Other debugfs functions handle the fact that
the "dentry"
479  * passed to them could be an error and they don't crash in that case.
480  * Drivers should generally work fine even if debugfs fails to init anyway.

I think the current code is fine. If you feel like adjusting it, I
would rather just remove the NULL-check.

Thanks
David

> Signed-off-by: Osama Muhammad <osmtendev@gmail.com>
> ---
>  drivers/hid/hid-wiimote-debug.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/hid/hid-wiimote-debug.c b/drivers/hid/hid-wiimote-debug.c
> index a99dcca2e099..eddd981fee1a 100644
> --- a/drivers/hid/hid-wiimote-debug.c
> +++ b/drivers/hid/hid-wiimote-debug.c
> @@ -183,12 +183,12 @@ int wiidebug_init(struct wiimote_data *wdata)
>
>         dbg->eeprom = debugfs_create_file("eeprom", S_IRUSR,
>                 dbg->wdata->hdev->debug_dir, dbg, &wiidebug_eeprom_fops);
> -       if (!dbg->eeprom)
> +       if (IS_ERR(dbg->eeprom))
>                 goto err;
>
>         dbg->drm = debugfs_create_file("drm", S_IRUSR,
>                         dbg->wdata->hdev->debug_dir, dbg, &wiidebug_drm_fops);
> -       if (!dbg->drm)
> +       if (IS_ERR(dbg->drm))
>                 goto err_drm;
>
>         spin_lock_irqsave(&wdata->state.lock, flags);
> --
> 2.34.1
>