From: Andrew Morton <akpm@linux-foundation.org>
To: Wanpeng Li <liwp.linux@gmail.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>,
Rob Landley <rob@landley.net>,
Alexander Viro <viro@zeniv.linux.org.uk>,
"Eric W.Biederman" <ebiederm@xmission.com>,
Lucas De Marchi <lucas.demarchi@profusion.mobi>,
"David S. Miller" <davem@davemloft.net>, Jan Kara <jack@suse.cz>,
Mel Gorman <mgorman@suse.de>, Minchan Kim <minchan.kim@gmail.com>,
James Morris <james.l.morris@oracle.com>,
Ingo Molnar <mingo@elte.hu>,
Michel Lespinasse <walken@google.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org,
Gavin Shan <shangw@linux.vnet.ibm.com>,
Wanpeng Li <liwp@linux.vnet.ibm.com>
Subject: Re: [PATCH v4] remove no longer use of pdflush interface
Date: Wed, 6 Jun 2012 15:50:56 -0700 [thread overview]
Message-ID: <20120606155056.72a6a2b5.akpm@linux-foundation.org> (raw)
In-Reply-To: <1338989888-3480-1-git-send-email-liwp.linux@gmail.com>
On Wed, 6 Jun 2012 21:38:08 +0800
Wanpeng Li <liwp.linux@gmail.com> wrote:
> From: Wanpeng Li <liwp@linux.vnet.ibm.com>
>
> Since per-BDI flusher introduced to linux 2.6, pdflush mechanism is not
> used any more. But the old interface of pdflush exported in/proc/sys/vm/
> is still there. In order to take attention to back-compatibility issues,
> printk warning information and return -ENOSYS to notice the users the
> interface is removed.
>
> ...
>
> +/* notice associated proc obsoleted */
This comment is pretty meaningless - I suggest simply removing it.
> +int pdflush_proc_obsolete(struct ctl_table *table, int write,
> + void __user *buffer, size_t *lenp, loff_t *ppos)
> +{
> + printk_once(KERN_WARNING "%s exported in /proc is scheduled for removal\n",
> + table->procname);
> + return -ENOSYS;
> +}
No, this immediately breaks /proc/sys/vm/nr_pdflush_threads users. To
preserve back-compatibility we should copy "0\n" out to userspace and
return 2.
> +EXPORT_SYMBOL(pdflush_proc_obsolete);
This export isn't needed?
prev parent reply other threads:[~2012-06-06 22:50 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-06 13:38 [PATCH v4] remove no longer use of pdflush interface Wanpeng Li
2012-06-06 22:50 ` Andrew Morton [this message]
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