Date: Tue, 7 Apr 2015 14:55:52 +0100
From: Alasdair G Kergon <agk@redhat.com>
To: Pali =?iso-8859-1?Q?Roh=E1r?= <pali.rohar@gmail.com>
Cc: Alasdair Kergon <agk@redhat.com>, Mike Snitzer <snitzer@redhat.com>,
        Neil Brown <neilb@suse.de>, "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
        linux-raid@vger.kernel.org, dm-devel@redhat.com,
        linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
Subject: Re: [dm-devel] [PATCH 3/3] dm-crypt: Adds support for wiping key
	when doing suspend/hibernation
Message-ID: <20150407135552.GA32694@agk-dp.fab.redhat.com>
Mail-Followup-To: Pali =?iso-8859-1?Q?Roh=E1r?= <pali.rohar@gmail.com>,
	Alasdair Kergon <agk@redhat.com>, Mike Snitzer <snitzer@redhat.com>,
	Neil Brown <neilb@suse.de>, "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
	linux-raid@vger.kernel.org, dm-devel@redhat.com,
	linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
References: <1428254419-7334-1-git-send-email-pali.rohar@gmail.com> <1428254419-7334-4-git-send-email-pali.rohar@gmail.com>
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On Sun, Apr 05, 2015 at 07:20:19PM +0200, Pali Roh?r wrote:
> This patch adds dm message commands and option strings to optionally wipe key
> from dm-crypt device before entering suspend or hibernate state.
 
Try to avoid 0/1 - use descriptive options instead. 
E.g. key wipe_on_hibernation / key retain_on_hibernation  (message)
     wipe_key_on_hiberation ('dmsetup table' - don't forget the reporting interface!)

Have you tested against every state the driver might be in at the time of
suspend/hibernation?

> +static void crypt_suspend_and_wipe_key(struct crypt_config *cc)
> +{
> +	dm_suspend_md(dm_table_get_md(cc->ti->table));

I'm not particularly keen on this - silently ignoring expected error states
like -EINVAL rather than checking first and not calling the function at all
when it's known not to be needed.

Alasdair

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