From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933329AbbFWSuL (ORCPT ); Tue, 23 Jun 2015 14:50:11 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:33205 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933336AbbFWSuA (ORCPT ); Tue, 23 Jun 2015 14:50:00 -0400 Date: Tue, 23 Jun 2015 20:49:57 +0200 From: Pavel Machek To: "Theodore Ts'o" , Richard Weinberger , "Enrico Weigelt, metux IT consult" , "Luis R. Rodriguez" , "backports@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Julia Lawall Subject: Re: Uses of Linux backports in the industry Message-ID: <20150623184957.GB26150@amd> References: <55687D72.3070904@melag.de> <20150529173609.GF18540@thunk.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150529173609.GF18540@thunk.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 2015-05-29 13:36:09, Theodore Ts'o wrote: > On Fri, May 29, 2015 at 05:01:00PM +0200, Richard Weinberger wrote: > > On Fri, May 29, 2015 at 4:53 PM, Enrico Weigelt, metux IT consult > > wrote: > > > Am 29.05.2015 um 04:54 schrieb Luis R. Rodriguez: > > > Actually, I really wonder why folks are sticking to ancient kernels on > > > newer hardware. > > > > Enterprise distribution kernels. Or "special" kernels like PREEMPT_RT. > > Sometimes the vendor BSP is that horrid that a customer cannot afford > > to forward port it > > but wants recent stuff. So you need to backport... > > Yep. The technique I used for the backporting ext4 encryption into > the 3.10 android-common git tree in AOSP was to drop in the 3.18 > versions of fs/ext4 and fs/jbd2 into the 3.10 tree (along with the > associaed include files in include/linux and include/trace/events, of > course), and then fix things up until they built correctly (using > cherry-picks and in some cases, reverting some changes in the 3.18 > version of fs/ext4). After I was sure the transplant of the 3.18 > version of ext4 had "taken" correctly, with no test regressions, only > then did I cherry-pick all of the ext4 encryption changes on top of > 3.10. > > The backport of ext4 encryption to the 3.18 version of android-common > should be much easier. :-) Unfortunately, I also have to do a > backport to the 3.14 android-common branch as well. > > Yes, it's ugly, but there still are some SOC and drivers that aren't > available on newer kernels. Basically, the handset vendors need to > lean a lot harder on the SOC and other peripheral (cell radios, GPS, > etc., etc.). :-( Actually, what we really want is chip vendors to clean up the interfaces, and merge their changes upstream... Perhaps we'll be able to install normal distros on cellphones one day... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html