From: Greg KH <gregkh@linuxfoundation.org>
To: Jonathan Adams <jwadams@google.com>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
netdev@vger.kernel.org, kvm@vger.kernel.org,
Paolo Bonzini <pbonzini@redhat.com>,
Jim Mattson <jmattson@google.com>,
David Rientjes <rientjes@google.com>,
Justin TerAvest <teravest@google.com>
Subject: Re: [RFC PATCH 1/7] core/metricfs: Create metricfs, standardized files under debugfs.
Date: Sat, 8 Aug 2020 07:41:43 +0200 [thread overview]
Message-ID: <20200808054143.GB1037591@kroah.com> (raw)
In-Reply-To: <20200807212916.2883031-2-jwadams@google.com>
debugfs interaction nits:
On Fri, Aug 07, 2020 at 02:29:10PM -0700, Jonathan Adams wrote:
> +static struct dentry *metricfs_init_dentry(void)
> +{
> + static int once;
> +
> + if (d_metricfs)
> + return d_metricfs;
> +
> + if (!debugfs_initialized())
> + return NULL;
> +
> + d_metricfs = debugfs_create_dir("metricfs", NULL);
> +
> + if (!d_metricfs && !once) {
As it is impossible for d_metricfs to ever be NULL, why are you checking
it?
> + once = 1;
> + pr_warn("Could not create debugfs directory 'metricfs'\n");
There is a pr_warn_once I think, but again, how can this ever trigger?
> + return NULL;
> + }
> +
> + return d_metricfs;
> +}
> +
> +/* We always cast in and out to struct dentry. */
> +struct metricfs_subsys {
> + struct dentry dentry;
> +};
> +
> +static struct dentry *metricfs_create_file(const char *name,
> + mode_t mode,
> + struct dentry *parent,
> + void *data,
> + const struct file_operations *fops)
> +{
> + struct dentry *ret;
> +
> + ret = debugfs_create_file(name, mode, parent, data, fops);
> + if (!ret)
> + pr_warn("Could not create debugfs '%s' entry\n", name);
As ret can never be NULL, why check?
There is no need to ever check debugfs return values, just keep on
going, that's the design of it.
thanks,
greg k-h
next prev parent reply other threads:[~2020-08-08 5:41 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-07 21:29 [RFC PATCH 0/7] metricfs metric file system and examples Jonathan Adams
2020-08-07 21:29 ` [RFC PATCH 1/7] core/metricfs: Create metricfs, standardized files under debugfs Jonathan Adams
2020-08-08 5:41 ` Greg KH [this message]
2020-08-07 21:29 ` [RFC PATCH 2/7] core/metricfs: add support for percpu metricfs files Jonathan Adams
2020-08-08 5:43 ` Greg KH
2020-08-07 21:29 ` [RFC PATCH 3/7] core/metricfs: metric for kernel warnings Jonathan Adams
2020-08-08 5:45 ` Greg KH
2020-08-07 21:29 ` [RFC PATCH 4/7] core/metricfs: expose softirq information through metricfs Jonathan Adams
2020-08-08 5:46 ` Greg KH
2020-08-07 21:29 ` [RFC PATCH 5/7] core/metricfs: expose scheduler stat " Jonathan Adams
2020-08-07 21:29 ` [RFC PATCH 6/7] core/metricfs: expose x86-specific irq " Jonathan Adams
2020-08-13 10:11 ` Thomas Gleixner
2020-08-13 11:47 ` Paolo Bonzini
2020-08-13 12:13 ` Thomas Gleixner
2020-08-13 14:10 ` Paolo Bonzini
2020-08-13 14:21 ` Thomas Gleixner
2020-08-07 21:29 ` [RFC PATCH 7/7] net-metricfs: Export /proc/net/dev via metricfs Jonathan Adams
2020-08-08 2:06 ` [RFC PATCH 0/7] metricfs metric file system and examples Andrew Lunn
2020-08-08 15:59 ` David Ahern
2020-08-10 18:20 ` Jakub Kicinski
2020-08-10 9:23 ` Pavel Machek
-- strict thread matches above, loose matches on Subject: below --
2020-08-06 0:14 Jonathan Adams
2020-08-06 0:14 ` [RFC PATCH 1/7] core/metricfs: Create metricfs, standardized files under debugfs Jonathan Adams
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