From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pavel Emelyanov <xemul@parallels.com>
Subject: Re: [rfc 3/7] procfs: Add ability to plugin auxiliary fdinfo providers
Date: Wed, 04 Jul 2012 11:39:30 +0400
Message-ID: <4FF3F332.5030302@parallels.com>
References: <20120627110116.201735815@openvz.org> <20120627110512.574379921@openvz.org>
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Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	Al Viro <viro@ZenIV.linux.org.uk>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	James Bottomley <jbottomley@parallels.com>
To: Cyrill Gorcunov <gorcunov@openvz.org>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <20120627110512.574379921@openvz.org>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: linux-fsdevel.vger.kernel.org

On 06/27/2012 03:01 PM, Cyrill Gorcunov wrote:
> This patch brings ability to plugin auxiliary fdinfo providers.
> For example in further patches eventfd, evenpoll and fsnotify
> will print out information associated with files.
> 
> This feature is CONFIG_CHECKPOINT_RESTORE guarded to eliminate
> overhead for those who don't need it at all (this
> unfortunately makes patch bigger than I wanted).
> 
> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
> CC: Al Viro <viro@ZenIV.linux.org.uk>
> CC: Alexey Dobriyan <adobriyan@gmail.com>
> CC: Andrew Morton <akpm@linux-foundation.org>
> CC: Pavel Emelyanov <xemul@parallels.com>
> CC: James Bottomley <jbottomley@parallels.com>
> ---
>  fs/proc/fd.c            |  208 ++++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/proc_fs.h |   28 ++++++
>  2 files changed, 236 insertions(+)

How about introducing one more file_operations member and call it in the
seq_show() (if exists)? Only inotify, eventfd and eventpoll will implement
one. This will allow to avoid all this complexity with drivers.