From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wanpeng Li <liwp.linux@gmail.com>
Subject: Re: [PATCH v2] remove no longer use of pdflush interface
Date: Wed, 6 Jun 2012 18:55:52 +0800
Message-ID: <20120606105552.GC10953@kernel>
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Cc: Andrew Morton <akpm@linux-foundation.org>,
	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>,
	David Howells <dhowells@redhat.com>,
	James Morris <james.l.morris@oracle.com>,
	IngoMolnar <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@gmail.com>,
	Wanpeng Li <liwp@linux.vnet.ibm.com>
To: Boaz Harrosh <bharrosh@panasas.com>
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On Wed, Jun 06, 2012 at 10:31:12AM +0300, Boaz Harrosh wrote:
>
>If there are many users than a self made print once is worth it
>we can use the ctl_table->data pointer for this, some thing like:
>
>int nr_pdflush_was_printed;
>
>@@ -1095,11 +1095,9 @@ static struct ctl_table vm_table[] = {
> 		.extra1		= &zero,
> 	},
> 	{
>-		.procname	= "nr_pdflush_threads",
>-		.data		= &nr_pdflush_threads,
>-		.maxlen		= sizeof nr_pdflush_threads,
>-		.mode		= 0444 /* read-only*/,
>-		.proc_handler	= proc_dointvec,
>+		.data		= &nr_pdflush_was_printed,
>+		.procname       = "nr_pdflush_threads",
>+		.mode           = 0444 /* read-only */,
>+		.proc_handler   = proc_obsolete,
> 	},
>
>
>+/* notice associated proc deprecated */
>+int proc_deprecated(struct ctl_table *table, int write,
>+		    void __user *buffer, size_t *lenp, loff_t *ppos, )
>+{
>+	if (*ctl_table->data) {
>+		printk(KERN_WARNING "%s exported in /proc is deprecated\n",
>+			table->procname);
>+		*ctl_table->data = 0;
>+	}
>+	return -ENOSYS;
>+}

But this time you add another variable nr_pdflush_was_printed. 
So remove variable nr_pdflush_threads does not make sense.