Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932111AbbLNITe (ORCPT ); Mon, 14 Dec 2015 03:19:34 -0500 Received: from mail-ob0-f178.google.com ([209.85.214.178]:33422 "EHLO mail-ob0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752867AbbLNITb (ORCPT ); Mon, 14 Dec 2015 03:19:31 -0500 MIME-Version: 1.0 In-Reply-To: <1449970917-12633-1-git-send-email-paul.gortmaker@windriver.com> References: <1449970917-12633-1-git-send-email-paul.gortmaker@windriver.com> Date: Mon, 14 Dec 2015 09:19:30 +0100 X-Google-Sender-Auth: mp96vEIAheIkoYZSV5aiBH8gr78 Message-ID: Subject: Re: [PATCH 00/10] drivers/pci: avoid module_init in non-modular host/pci* From: Geert Uytterhoeven To: Paul Gortmaker Cc: "linux-kernel@vger.kernel.org" , Linux-sh list , linux-pci , Thierry Reding , Alexandre Courbot , Pratyush Anand , Michal Simek , Kishon Vijay Abraham I , Murali Karicheri , =?UTF-8?Q?S=C3=B6ren_Brinkmann?= , Jason Cooper , Stephen Warren , Simon Horman , linux-tegra@vger.kernel.org, "linux-omap@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Thomas Petazzoni , Richard Zhu , rfi@lists.rocketboards.org, Ley Foon Tan , Bjorn Helgaas , Lucas Stach Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3242 Lines: 68 Hi Paul, On Sun, Dec 13, 2015 at 2:41 AM, Paul Gortmaker wrote: > This series of commits is a slice of a larger project to ensure > people don't have dead code for module removal in non-modular > drivers. Overall there was roughly 5k lines of dead code in the > kernel due to this. So far we've fixed several areas, like tty, > x86, net, etc. and we continue to work on other areas. > > There are several reasons to not use module_init for code that can > never be built as a module, but the big ones are: > > (1) it is easy to accidentally code up unused module_exit and remove code > (2) it can be misleading when reading the source, thinking it can be > modular when the Makefile and/or Kconfig prohibit it > (3) it requires the include of the module.h header file which in turn > includes nearly everything else. > > Here we convert some module_init() calls into device_initcall() and delete > any module_exit and remove code that gets orphaned in the process, for > an overall net code reduction, which is always welcome. > > The use of device_initcall ensures that the init function ordering > remains unchanged, but one could argue that PCI host code might be more > appropriate to be handled under subsys_initcall. Fortunately we can > revisit making this extra change at a later date if desired; it does > not need to happen now, and we reduce the risk of introducing > regressions at this point in time by separating the two changes. > > Over half of the drivers changed here already explicitly disallowed any > unbind operations. For the rest we make them the same, since there is > not really any sensible use case to unbind any built-in bus support that > I can think of. Personally, I think all of these should become tristate, so distro kernels don't have to build in PCI(e) support for all SoCs. multi_v7_defconfig kernels are becoming too big. That does not preclude making these modules un-unloadable, though. > Paul Gortmaker (10): > drivers/pci: make host/pci-imx6.c driver explicitly non-modular > drivers/pci: make host/pcie-spear13xx.c driver explicitly non-modular > drivers/pci: make host/pci-mvebu.c explicitly non-modular > drivers/pci: make host/pci-dra7xx.c explicitly non-modular > drivers/pci: make host/pci-rcar-gen2.c explicitly non-modular > drivers/pci: make host/pci-tegra.c explicitly non-modular > drivers/pci: make host/pcie-rcar.c explicitly non-modular > drivers/pci: make host/pcie-xilinx.c explicitly non-modular > drivers/pci: make host/pci-keystone.c explicitly non-modular > drivers/pci: make host/pcie-altera.c explicitly non-modular Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/