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 30E9EC4332F for ; Fri, 2 Dec 2022 17:48:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234174AbiLBRsN (ORCPT ); Fri, 2 Dec 2022 12:48:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39974 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234262AbiLBRsB (ORCPT ); Fri, 2 Dec 2022 12:48:01 -0500 Received: from mail-qt1-f180.google.com (mail-qt1-f180.google.com [209.85.160.180]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 740B27DA74; Fri, 2 Dec 2022 09:47:59 -0800 (PST) Received: by mail-qt1-f180.google.com with SMTP id fp23so5913137qtb.0; Fri, 02 Dec 2022 09:47:59 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=cZkrcSltncE8/ZuZoYv4b2d7hscDOxyl0JUDZPI6liw=; b=RaGlrd0ba8dYvndE1TLtFoQdEVC7LSet9MIgIcBBC4QOcWYtZn5YZZMX4oVb3ThRUK P7pOUy+ubpMKYXE4xbVbUP3qMGQU63s2QguP8LiQRFvoUIZc3yx5iEEgigxGJ7tvZ6DO /WkvDhcRd2BLd+HQdYgX00yWGKScXs/YEtC1FMFqRymib9P72pBI4NkdCZ26D/RbNdiR kew8s4YydKL7s0NcK3x01xRf5oVT9q4GW5ZToewO5ihFa/BkmTHLcsf2QNeENkhqzHs0 Zo1SC5L1St0x0P2F9xBCFl25c+voRlg754QTZylfcFiNot18FmzWtYESxZxH/VkdtRoG gf3A== X-Gm-Message-State: ANoB5pmRqeAPQ7my/7gaqlI+AoY1ZzQLgpPjb0m9rURuk11vM3iAs53B X7b43MyNBs6UtZvLGCyWqHb5AijwJondlfQff20= X-Google-Smtp-Source: AA0mqf51uIOWkjKSwhAqxTpfKMjsu42I0eiMVKrm0VEx7HQYTsVmieNicP3p40lc7YCyIthr+ry0hUYCl4VWsxspqf0= X-Received: by 2002:ac8:7dcb:0:b0:3a6:8dd0:4712 with SMTP id c11-20020ac87dcb000000b003a68dd04712mr11196833qte.411.1670003278849; Fri, 02 Dec 2022 09:47:58 -0800 (PST) MIME-Version: 1.0 References: <20221127-snd-freeze-v8-0-3bc02d09f2ce@chromium.org> <20221127-snd-freeze-v8-2-3bc02d09f2ce@chromium.org> In-Reply-To: <20221127-snd-freeze-v8-2-3bc02d09f2ce@chromium.org> From: "Rafael J. Wysocki" Date: Fri, 2 Dec 2022 18:47:47 +0100 Message-ID: Subject: Re: [PATCH v8 2/3] freezer: refactor pm_freezing into a function. To: Ricardo Ribalda Cc: Juergen Gross , Mark Brown , Chromeos Kdump , Daniel Baluta , Christophe Leroy , Len Brown , Ard Biesheuvel , Ranjani Sridharan , "Rafael J. Wysocki" , Boris Ostrovsky , Nicholas Piggin , Michael Ellerman , Eric Biederman , Dave Hansen , Jaroslav Kysela , Joel Fernandes , Liam Girdwood , Peter Ujfalusi , Pavel Machek , Pierre-Louis Bossart , Kai Vehmanen , Steven Rostedt , "K. Y. Srinivasan" , Ingo Molnar , Bjorn Helgaas , Dexuan Cui , Takashi Iwai , "H. Peter Anvin" , Bard Liao , Haiyang Zhang , Wei Liu , Thomas Gleixner , Borislav Petkov , x86@kernel.org, kexec@lists.infradead.org, alsa-devel@alsa-project.org, stable@vger.kernel.org, sound-open-firmware@alsa-project.org, linuxppc-dev@lists.ozlabs.org, linux-hyperv@vger.kernel.org, linux-pci@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, xen-devel@lists.xenproject.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Thu, Dec 1, 2022 at 12:08 PM Ricardo Ribalda wrote: > > Add a way to let the drivers know if the processes are frozen. > > This is needed by drivers that are waiting for processes to end on their > shutdown path. > > Convert pm_freezing into a function and export it, so it can be used by > drivers that are either built-in or modules. > > Cc: stable@vger.kernel.org > Fixes: 83bfc7e793b5 ("ASoC: SOF: core: unregister clients and machine drivers in .shutdown") > Signed-off-by: Ricardo Ribalda Why can't you export the original pm_freezing variable and why is this fixing anything? > --- > include/linux/freezer.h | 3 ++- > kernel/freezer.c | 3 +-- > kernel/power/process.c | 24 ++++++++++++++++++++---- > 3 files changed, 23 insertions(+), 7 deletions(-) > > diff --git a/include/linux/freezer.h b/include/linux/freezer.h > index b303472255be..3413c869d68b 100644 > --- a/include/linux/freezer.h > +++ b/include/linux/freezer.h > @@ -13,7 +13,7 @@ > #ifdef CONFIG_FREEZER > DECLARE_STATIC_KEY_FALSE(freezer_active); > > -extern bool pm_freezing; /* PM freezing in effect */ > +bool pm_freezing(void); > extern bool pm_nosig_freezing; /* PM nosig freezing in effect */ > > /* > @@ -80,6 +80,7 @@ static inline int freeze_processes(void) { return -ENOSYS; } > static inline int freeze_kernel_threads(void) { return -ENOSYS; } > static inline void thaw_processes(void) {} > static inline void thaw_kernel_threads(void) {} > +static inline bool pm_freezing(void) { return false; } > > static inline bool try_to_freeze(void) { return false; } > > diff --git a/kernel/freezer.c b/kernel/freezer.c > index 4fad0e6fca64..2d3530ebdb7e 100644 > --- a/kernel/freezer.c > +++ b/kernel/freezer.c > @@ -20,7 +20,6 @@ EXPORT_SYMBOL(freezer_active); > * indicate whether PM freezing is in effect, protected by > * system_transition_mutex > */ > -bool pm_freezing; > bool pm_nosig_freezing; > > /* protects freezing and frozen transitions */ > @@ -46,7 +45,7 @@ bool freezing_slow_path(struct task_struct *p) > if (pm_nosig_freezing || cgroup_freezing(p)) > return true; > > - if (pm_freezing && !(p->flags & PF_KTHREAD)) > + if (pm_freezing() && !(p->flags & PF_KTHREAD)) > return true; > > return false; > diff --git a/kernel/power/process.c b/kernel/power/process.c > index ddd9988327fe..8a4d0e2c8c20 100644 > --- a/kernel/power/process.c > +++ b/kernel/power/process.c > @@ -108,6 +108,22 @@ static int try_to_freeze_tasks(bool user_only) > return todo ? -EBUSY : 0; > } > > +/* > + * Indicate whether PM freezing is in effect, protected by > + * system_transition_mutex. > + */ > +static bool pm_freezing_internal; > + > +/** > + * pm_freezing - indicate whether PM freezing is in effect. > + * > + */ > +bool pm_freezing(void) > +{ > + return pm_freezing_internal; > +} > +EXPORT_SYMBOL(pm_freezing); Use EXPORT_SYMBOL_GPL() instead, please. > + > /** > * freeze_processes - Signal user space processes to enter the refrigerator. > * The current thread will not be frozen. The same process that calls > @@ -126,12 +142,12 @@ int freeze_processes(void) > /* Make sure this task doesn't get frozen */ > current->flags |= PF_SUSPEND_TASK; > > - if (!pm_freezing) > + if (!pm_freezing()) > static_branch_inc(&freezer_active); > > pm_wakeup_clear(0); > pr_info("Freezing user space processes ... "); > - pm_freezing = true; > + pm_freezing_internal = true; > error = try_to_freeze_tasks(true); > if (!error) { > __usermodehelper_set_disable_depth(UMH_DISABLED); > @@ -187,9 +203,9 @@ void thaw_processes(void) > struct task_struct *curr = current; > > trace_suspend_resume(TPS("thaw_processes"), 0, true); > - if (pm_freezing) > + if (pm_freezing()) > static_branch_dec(&freezer_active); > - pm_freezing = false; > + pm_freezing_internal = false; > pm_nosig_freezing = false; > > oom_killer_enable(); > > --