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Date:   Wed, 26 Feb 2020 09:12:11 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Luigi Rizzo <lrizzo@google.com>
Cc:     linux-kernel@vger.kernel.org, mhiramat@kernel.org,
        akpm@linux-foundation.org, naveen.n.rao@linux.ibm.com,
        changbin.du@intel.com, ardb@kernel.org, rizzo@iet.unipi.it,
        pabeni@redhat.com, toke@redhat.com, hawk@kernel.org
Subject: Re: [PATCH 1/2] quickstats, kernel sample collector
Message-ID: <20200226081211.GD22801@kroah.com>
References: <20200226023027.218365-1-lrizzo@google.com>
 <20200226023027.218365-2-lrizzo@google.com>
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On Tue, Feb 25, 2020 at 06:30:26PM -0800, Luigi Rizzo wrote:
> +static int __init ks_init(void)
> +{
> +	ks_root = debugfs_create_dir("kstats", NULL);
> +	if (IS_ERR_OR_NULL(ks_root)) {
> +		pr_warn("kstats: cannot create debugfs root\n");
> +		return PTR_ERR(ks_root);
> +	}

Do not check debugfs_create_* calls as there is no need to.  Just take
the return value (if you care to use it again) and move on.

Also, the check you made here is incorrect :)

> +	ks_control_dentry = debugfs_create_file("_control", 0644, ks_root,
> +						NULL, &ks_file_ops);
> +	if (IS_ERR_OR_NULL(ks_control_dentry)) {
> +		pr_warn("kstats: cannot create kstats/_control\n");
> +		debugfs_remove_recursive(ks_root);
> +		return PTR_ERR(ks_control_dentry);
> +	}

Same here, just call debugfs_create_file and move on.

You do this same thing in other places too.

thanks,

greg k-h