From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC820C4332B for ; Mon, 18 Jan 2021 09:39:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 82F99222B3 for ; Mon, 18 Jan 2021 09:39:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388884AbhARJch (ORCPT ); Mon, 18 Jan 2021 04:32:37 -0500 Received: from mail.kernel.org ([198.145.29.99]:53614 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388619AbhARJWF (ORCPT ); Mon, 18 Jan 2021 04:22:05 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 91C6420829; Mon, 18 Jan 2021 09:21:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610961679; bh=AxtaIOUwBp1fZah3fw/1D/bRwjy4Z75UqBrLW6p6+jM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lUhQKJpuAihyaw+dsZ8nY8IuZKHyajh3Ytr7xKz4+BS0AIo30T9RnsFFp8m4jwpy2 NIedQU5z9cEkRIhYo/5bMeziWqCmV66FbWGxAidMUpkpmcsrKC3UXZ2ihQmXNMvzwp UgXh0tNhpg+HabzEnCHoVAsi8pLtMN6c69GFy6TM= Date: Mon, 18 Jan 2021 10:21:16 +0100 From: Greg KH To: Sasha Levin Cc: masahiroy@kernel.org, michal.lkml@markovi.net, torvalds@linux-foundation.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, stable@kernel.org Subject: Re: [PATCH] kbuild: give SUBLEVEL more room in KERNEL_VERSION Message-ID: References: <20210118014951.250815-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210118014951.250815-1-sashal@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jan 17, 2021 at 08:49:51PM -0500, Sasha Levin wrote: > SUBLEVEL only has 8 bits of space, which means that we'll overflow it > once it reaches 256. > > Few of the stable branches will imminently overflow SUBLEVEL while > there's no risk of overflowing VERSION. > > Thus, give SUBLEVEL 8 more bits which will be stolen from VERSION, this > should create a better balance between the different version numbers we > use. > > The downside here is that Linus will have 8 bits less to play with, but > given our current release cadence (~10 weeks), the number of Linus's > fingers & toes (20), and the current VERSION (5) we can calculate that > VERSION will overflow in just over 1,000 years, so I'm kicking this can > down the road. > > Cc: stable@kernel.org > Signed-off-by: Sasha Levin > --- > Makefile | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/Makefile b/Makefile > index 9e73f82e0d863..dc2bad7a440d8 100644 > --- a/Makefile > +++ b/Makefile > @@ -1252,8 +1252,8 @@ endef > > define filechk_version.h > echo \#define LINUX_VERSION_CODE $(shell \ > - expr $(VERSION) \* 65536 + 0$(PATCHLEVEL) \* 256 + 0$(SUBLEVEL)); \ > - echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))' > + expr $(VERSION) \* 16777216 + 0$(PATCHLEVEL) \* 65536 + 0$(SUBLEVEL)); \ > + echo '#define KERNEL_VERSION(a,b,c) (((a) << 24) + ((b) << 16) + (c))' As much as I agree, this will break in-tree users of LINUX_VERSION_CODE that try to suck out the version/patchlevel number of the kernel release into their own fields. Things like USB host controller strings, v4l ioctl reports, scsi driver ioctls, and other places do fun bit-movements to try to unreverse this bit packing. So how about we just provide a "real" version/subversion/revision #define as well, and clean up all in-kernel users, so we can get this to work, and we can change it in the future more easily. thanks, greg k-h