From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: [PATCH v2 1/3] PM suspend/hibernate: Call notifier after freezing processes Date: Wed, 22 Jul 2015 08:08:27 +1000 Message-ID: <20150722080827.5adcf5f1@noble> References: <1428254419-7334-1-git-send-email-pali.rohar@gmail.com> <3179448.TScsKEAuyR@vostro.rjw.lan> <20150720073226.GB25910@pali> <1715416.hWBvT0iLvO@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1715416.hWBvT0iLvO@vostro.rjw.lan> Sender: linux-kernel-owner@vger.kernel.org To: "Rafael J. Wysocki" Cc: Pali =?UTF-8?B?Um9ow6Fy?= , Alasdair Kergon , Mike Snitzer , Neil Brown , Len Brown , Pavel Machek , dm-devel@redhat.com, linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org List-Id: linux-raid.ids On Mon, 20 Jul 2015 23:46:32 +0200 "Rafael J. Wysocki" wrote: > On Monday, July 20, 2015 09:32:26 AM Pali Roh=C3=A1r wrote: > > On Saturday 18 July 2015 01:27:15 Rafael J. Wysocki wrote: > > > On Thursday, July 16, 2015 09:33:02 AM Pali Roh=C3=A1r wrote: > > > > On Thursday 16 July 2015 03:02:03 Rafael J. Wysocki wrote: > > > > > Also, if you're adding AFTER_FREEZE, it would be good to add = BEFORE_THAW too > > > > > for symmetry. > > > > >=20 > > > >=20 > > > > But there is no use case for BEFORE_THAW. At least it is not ne= eded for now. > > >=20 > > > For your use case, a single function pointer would be sufficient = too. > > >=20 > >=20 > > What do you mean by single function pointer? kernel/power is part o= f > > kernel image and dm-crypt is external kernel module. >=20 > Well, if there is a function pointer in the core suspend code initial= ly set to > NULL and exported to modules such that the dm-crypt code can set it t= o > something else, that should be sufficient, shouldn't it? As long as the dm-crypt module is never unloaded. And as long as no other module could very possible want functionality like this. Ever. If a module wants to be notified - the providing a notifier chain really seems like the right thing to do... NeilBrown >=20 > So if you're adding new PM notifier events, that's already more than = *you* need. >=20 > Anyway, I guess the "post freeze" new one should be enough for now, b= ut please > change the name to POST_FREEZE. >=20 > Also I think we don't need separate "post freeze" events for suspend = and > hibernation. >=20 > Thanks, > Rafael