From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754268Ab3KKPAz (ORCPT ); Mon, 11 Nov 2013 10:00:55 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:48982 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753312Ab3KKPAq (ORCPT ); Mon, 11 Nov 2013 10:00:46 -0500 Date: Mon, 11 Nov 2013 07:03:18 -0800 From: Greg Kroah-Hartman To: "Rafael J. Wysocki" Cc: Lan Tianyu , ACPI Devel Maling List , LKML , Linux PCI , Bjorn Helgaas , Aaron Lu , Jarkko Nikula , Mika Westerberg , "Luck, Tony" Subject: Re: [PATCH] ACPI / driver core: Store a device pointer in struct acpi_dev_node Message-ID: <20131111150318.GB16112@kroah.com> References: <3268437.YsusHvklcv@vostro.rjw.lan> <52803124.7000304@intel.com> <1683079.zjqzsOAjXB@vostro.rjw.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1683079.zjqzsOAjXB@vostro.rjw.lan> User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 11, 2013 at 02:45:39PM +0100, Rafael J. Wysocki wrote: > On Monday, November 11, 2013 09:21:40 AM Lan Tianyu wrote: > > On 2013年11月10日 08:58, Rafael J. Wysocki wrote: > > > From: Rafael J. Wysocki > > > > > > Modify struct acpi_dev_node to contain a pointer to struct device > > > ambedded in the struct acpi_device associated with the given device > > > object (that is, its ACPI companion device) instead of an ACPI handle > > > corresponding to that struct acpi_device. Introduce two new macros > > > for manipulating that pointer in a CONFIG_ACPI-safe way, > > > ACPI_COMPANION() and ACPI_COMPANION_SET(), and rework the > > > ACPI_HANDLE() macro to take the above changes into account. > > > Drop the ACPI_HANDLE_SET() macro entirely and rework its users to > > > use ACPI_COMPANION_SET() instead. For some of them who used to > > > pass the result of acpi_get_child() directly to ACPI_HANDLE_SET() > > > introduce a helper routine acpi_preset_companion() doing an > > > equivalent thing. > > > > > > The rationale for using a struct device pointer instead of a > > > struct acpi_device one as the member of struct acpi_dev_node is > > > that it allows device.h to avoid including linux/acpi.h which would > > > introduce quite a bit of compilation overhead for stuff that doesn't > > > care about ACPI. > > > In turn, moving the macros to linux/acpi.h forces > > > the stuff that does care about ACPI to include that file as > > > appropriate anyway. > > > > How about declaring "struct acpi_device" in the device.h? This can help > > to use struct acpi_device without including linux/acpi.h. > > > > struct iommu_ops and struct iommu_group have been used by the same way > > in the device.h. > > Yes, they are. Well, that appears to work too. > > Updated patch is appended. It also contains some fixes for problems reported > by the auto build system and it's been tested on x86-64 now, so it should be > reasonably close to final. > > Thanks, > Rafael > > > --- > From: Rafael J. Wysocki > Subject: ACPI / driver core: Store an ACPI device pointer in struct acpi_dev_node > > Modify struct acpi_dev_node to contain a pointer to struct acpi_device > associated with the given device object (that is, its ACPI companion > device) instead of an ACPI handle corresponding to it. Introduce two > new macros for manipulating that pointer in a CONFIG_ACPI-safe way, > ACPI_COMPANION() and ACPI_COMPANION_SET(), and rework the > ACPI_HANDLE() macro to take the above changes into account. > Drop the ACPI_HANDLE_SET() macro entirely and rework its users to > use ACPI_COMPANION_SET() instead. For some of them who used to > pass the result of acpi_get_child() directly to ACPI_HANDLE_SET() > introduce a helper routine acpi_preset_companion() doing an > equivalent thing. > > The main motivation for doing this is that there are things > represented by struct acpi_device objects that don't have valid > ACPI handles (so called fixed ACPI hardware features, such as > power and sleep buttons) and we would like to create platform > device objects for them and "glue" them to their ACPI companions > in the usual way (which currently is impossible due to the > lack of valid ACPI handles). However, there are more reasons > why it may be useful. > > First, struct acpi_device pointers allow of much better type checking > than void pointers which are ACPI handles, so it should be more > difficult to write buggy code using modified struct acpi_dev_node > and the new macros. Second, the change should help to reduce (over > time) the number of places in which the result of ACPI_HANDLE() is > passed to acpi_bus_get_device() in order to obtain a pointer to the > struct acpi_device associated with the given "physical" device, > because now that pointer is returned by ACPI_COMPANION() directly. > Finally, the change should make it easier to write generic code that > will build both for CONFIG_ACPI set and unset without adding explicit > compiler directives to it. > > Signed-off-by: Rafael J. Wysocki Acked-by: Greg Kroah-Hartman