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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5174AC43217 for ; Wed, 5 Jan 2022 10:15:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239319AbiAEKPv convert rfc822-to-8bit (ORCPT ); Wed, 5 Jan 2022 05:15:51 -0500 Received: from aposti.net ([89.234.176.197]:48484 "EHLO aposti.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229984AbiAEKPt (ORCPT ); Wed, 5 Jan 2022 05:15:49 -0500 Date: Wed, 05 Jan 2022 10:15:36 +0000 From: Paul Cercueil Subject: Re: [PATCH 3/8] PM: core: Add EXPORT[_GPL]_SIMPLE_DEV_PM_OPS macros To: Jonathan Cameron Cc: "Rafael J . Wysocki" , Ulf Hansson , Jonathan Cameron , Lars-Peter Clausen , Linus Walleij , Arnd Bergmann , Len Brown , Pavel Machek , list@opendingux.net, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-mmc@vger.kernel.org, linux-pm@vger.kernel.org Message-Id: <06F85R.46PNU7YFWD631@crapouillou.net> In-Reply-To: <20220105100332.000001c1@Huawei.com> References: <20220104214214.198843-1-paul@crapouillou.net> <20220104214214.198843-4-paul@crapouillou.net> <20220105100332.000001c1@Huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jonathan, Le mer., janv. 5 2022 at 10:03:32 +0000, Jonathan Cameron a écrit : > On Tue, 4 Jan 2022 21:42:09 +0000 > Paul Cercueil wrote: > >> These macros are defined conditionally, according to CONFIG_PM: >> - if CONFIG_PM is enabled, these macros resolve to >> DEFINE_SIMPLE_DEV_PM_OPS(), and the dev_pm_ops symbol will be >> exported. >> >> - if CONFIG_PM is disabled, these macros will result in a dummy >> static >> dev_pm_ops to be created with the __maybe_unused flag. The >> dev_pm_ops >> will then be discarded by the compiler, along with the provided >> callback functions if they are not used anywhere else. >> >> In the second case, the symbol is not exported, which should be >> perfectly fine - users of the symbol should all use the pm_ptr() or >> pm_sleep_ptr() macro, so the dev_pm_ops marked as "extern" in the >> client's code will never be accessed. >> >> Signed-off-by: Paul Cercueil >> --- >> include/linux/pm.h | 33 ++++++++++++++++++++++++++++++--- >> 1 file changed, 30 insertions(+), 3 deletions(-) >> >> diff --git a/include/linux/pm.h b/include/linux/pm.h >> index 389e600df233..a1ce29566aea 100644 >> --- a/include/linux/pm.h >> +++ b/include/linux/pm.h >> @@ -8,6 +8,7 @@ >> #ifndef _LINUX_PM_H >> #define _LINUX_PM_H >> >> +#include >> #include >> #include >> #include >> @@ -357,14 +358,40 @@ struct dev_pm_ops { >> #define SET_RUNTIME_PM_OPS(suspend_fn, resume_fn, idle_fn) >> #endif >> >> +#define _DEFINE_DEV_PM_OPS(name, \ >> + suspend_fn, resume_fn, \ >> + runtime_suspend_fn, runtime_resume_fn, idle_fn) \ >> +const struct dev_pm_ops name = { \ >> + SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \ >> + RUNTIME_PM_OPS(runtime_suspend_fn, runtime_resume_fn, idle_fn) \ >> +} >> + > > one blank line probably enough. > >> + >> /* >> * Use this if you want to use the same suspend and resume >> callbacks for suspend >> * to RAM and hibernation. >> */ >> #define DEFINE_SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \ >> -const struct dev_pm_ops name = { \ >> - SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \ >> -} >> + _DEFINE_DEV_PM_OPS(name, suspend_fn, resume_fn, NULL, NULL, NULL) >> + >> +#ifdef CONFIG_PM >> +#define _EXPORT_DEV_PM_OPS(name, suspend_fn, resume_fn, >> runtime_suspend_fn, \ >> + runtime_resume_fn, idle_fn, sec) \ >> + _DEFINE_DEV_PM_OPS(name, suspend_fn, resume_fn, >> runtime_suspend_fn, \ >> + runtime_resume_fn, idle_fn); \ >> + _EXPORT_SYMBOL(name, sec) >> +#else >> +#define _EXPORT_DEV_PM_OPS(name, suspend_fn, resume_fn, >> runtime_suspend_fn, \ >> + runtime_resume_fn, idle_fn, sec) \ >> +static __maybe_unused _DEFINE_DEV_PM_OPS(__static_##name, >> suspend_fn, \ >> + resume_fn, runtime_suspend_fn, \ >> + runtime_resume_fn, idle_fn) >> +#endif >> + >> +#define EXPORT_SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \ >> + _EXPORT_DEV_PM_OPS(name, suspend_fn, resume_fn, NULL, NULL, NULL, >> "") >> +#define EXPORT_GPL_SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \ >> + _EXPORT_DEV_PM_OPS(name, suspend_fn, resume_fn, NULL, NULL, NULL, >> "_gpl") > > So you can get away with these two cases because the > SYSTEM_SLEEP_PM_OPS() all have > pm_sleep_ptr() wrappers. However, _EXPORT_DEV_PM_OPS() could be used > directly and > would require __maybe_unused for the RUNTIME_PM_OPS() parameters > which isn't ideal. I don't see why. On both cases (CONFIG_PM enabled/disabled) the runtime-PM callbacks are referenced directly, so at no point do they appear as unused; therefore __maybe_unused is not needed. Cheers, -Paul > Maybe I'm missing some reason that isn't a problem though as easy to > get lost in > these macros. :) > > You could argue that the _ is meant to indicate that macro shouldn't > be used directly > but I'm not that optimistic. > > Jonathan > > > >> >> /* Deprecated. Use DEFINE_SIMPLE_DEV_PM_OPS() instead. */ >> #define SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \ >