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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 BD244C433ED for ; Tue, 13 Apr 2021 15:45:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9387A613B3 for ; Tue, 13 Apr 2021 15:45:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237436AbhDMPqS (ORCPT ); Tue, 13 Apr 2021 11:46:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232006AbhDMPqS (ORCPT ); Tue, 13 Apr 2021 11:46:18 -0400 Received: from mail-ej1-x636.google.com (mail-ej1-x636.google.com [IPv6:2a00:1450:4864:20::636]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0F1AC061574 for ; Tue, 13 Apr 2021 08:45:56 -0700 (PDT) Received: by mail-ej1-x636.google.com with SMTP id r9so26701425ejj.3 for ; Tue, 13 Apr 2021 08:45:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=8Cg7yH5qZaddhcRW67fhSVjpix8T+GjETAHWS1hoQT0=; b=qR/xgK+5Sq4Y8fTf5qgyS9UDjqmn66BXnh0/EhybMKXpUtYwChWcnh5POCn3bCjhfV 4RacQ19vZCg8pN/0V208WTz7DGO+aHr1XwhPhzavJ2yYFeUs96DAQ5Ol3kcd4uk6i4y8 oQFwqbDs06RY5F5qjvNqAWQMPOu6oMIVWT68eVI59yo5gzKD03beOlTpsXSo83FVaEcC ah6VNLhHo+iQ8m6SM4XJrnjPufm1rxxjy5Ds1cKkV9K4Czd3TR/9ztYlboL4coHxUxi8 PNfrx+TLJ5yhWv4vkcoqt+qviiG4SarOtqqeg0AVmTc2OyaXQMwK0NuhwUdZD3crO1Vn DdKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=8Cg7yH5qZaddhcRW67fhSVjpix8T+GjETAHWS1hoQT0=; b=WCGRR/v+38nvy3EIL0LCzah7ekk0wjzcejNebmJRhkqYSlsgeA8m4ql1aLCXrbLv67 86/4qQ3VorUc1n4pGUYAcRBlb6wQSzMh/xBGMdsbOdlNANqu2/6ij87qHI9BoQ55wLfp r8CX2joA1I9/bv9TJk+lGZj4SKoEVszV1kEuNyJnHa0TSBjzH1TBWCf/tolVKkBvwDQ/ RUsEMU3qG9Pr5l0jstsluN+iUDwscHjlaWpbws8vzDLGSQqVkb4M2yuF0TJRVyUKydWA g/Me9UXwiPbfwWR0BFPEPFf8ri1rsJ/sOE/zwOtqoDK/UQocFTDstC5M/wqCGjQJX7gC VQDA== X-Gm-Message-State: AOAM530EFEvTGpoQgEGgq1OnmkxIZ/6mq8feCi8LvNGDgPitg5SH7wNv ml2JeGFSbD7zrgWD5lTY957qgHDpWUIMPQ== X-Google-Smtp-Source: ABdhPJzHbJ3YVCNPGfh1TuLmv010wSpH+EXpvnP3qgOVJctxbs3gdHJbA3g/D+J/H2ea//596cf5Rw== X-Received: by 2002:a17:906:37da:: with SMTP id o26mr14083098ejc.413.1618328755365; Tue, 13 Apr 2021 08:45:55 -0700 (PDT) Received: from eichest-laptop.lan (77-57-203-148.dclient.hispeed.ch. [77.57.203.148]) by smtp.gmail.com with ESMTPSA id y7sm9822721edq.88.2021.04.13.08.45.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Apr 2021 08:45:54 -0700 (PDT) From: Stefan Eichenberger To: linux-watchdog@vger.kernel.org Cc: Guenter Roeck , Wim Van Sebroeck Subject: [RFC] watchdog: pretimeout: add a notifier call chain governor Date: Tue, 13 Apr 2021 17:45:53 +0200 Message-Id: <20210413154553.1968039-1-eichest@gmail.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org Add a governor which calls a notifier call chain. This allows the registration of custom functions to the watchdog pretimeout. This is useful when writing out-of-tree kernel modules and it is more similar to the register_reboot_notifier or register_oom_notifier API. Signed-off-by: Stefan Eichenberger --- drivers/watchdog/Kconfig | 16 ++++++ drivers/watchdog/Makefile | 1 + drivers/watchdog/pretimeout_notifier.c | 73 ++++++++++++++++++++++++++ drivers/watchdog/watchdog_pretimeout.h | 2 + include/linux/watchdog.h | 5 ++ 5 files changed, 97 insertions(+) create mode 100644 drivers/watchdog/pretimeout_notifier.c diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 355100dad60a..ec019120effc 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -105,6 +105,14 @@ config WATCHDOG_PRETIMEOUT_GOV_PANIC Panic watchdog pretimeout governor, on watchdog pretimeout event put the kernel into panic. +config WATCHDOG_PRETIMEOUT_GOV_NOTIFIER + tristate "Notifier watchdog pretimeout governor" + depends on WATCHDOG_CORE + default WATCHDOG_CORE + help + Notifier watchdog pretimeout governor, on watchdog pretimeout + event call a notifier call chain. + choice prompt "Default Watchdog Pretimeout Governor" default WATCHDOG_PRETIMEOUT_DEFAULT_GOV_PANIC @@ -129,6 +137,14 @@ config WATCHDOG_PRETIMEOUT_DEFAULT_GOV_PANIC a watchdog pretimeout event happens, consider that a watchdog feeder is dead and reboot is unavoidable. +config WATCHDOG_PRETIMEOUT_DEFAULT_GOV_NOTIFIER + bool "notifier" + depends on WATCHDOG_PRETIMEOUT_GOV_NOTIFIER + help + Use notifier watchdog pretimeout governor by default, + if a watchdog pretiemout event happens, a notifier + call chain is called. + endchoice endif # WATCHDOG_PRETIMEOUT_GOV diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index a7eade8b4d45..cb63f4eb89bf 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -12,6 +12,7 @@ watchdog-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV) += watchdog_pretimeout.o obj-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV_NOOP) += pretimeout_noop.o obj-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV_PANIC) += pretimeout_panic.o +obj-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV_NOTIFIER) += pretimeout_notifier.o # Only one watchdog can succeed. We probe the ISA/PCI/USB based # watchdog-cards first, then the architecture specific watchdog diff --git a/drivers/watchdog/pretimeout_notifier.c b/drivers/watchdog/pretimeout_notifier.c new file mode 100644 index 000000000000..3f845c77ec44 --- /dev/null +++ b/drivers/watchdog/pretimeout_notifier.c @@ -0,0 +1,73 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2021 Stefan Eichenberger + */ + +#include +#include +#include + +#include "watchdog_pretimeout.h" + +BLOCKING_NOTIFIER_HEAD(watchdog_pretimeout_notifier_list); + +/** + * register_watchdog_pretimeout_notifier - Register function to be called on pretimeout + * @nb: Info about notifier function to be called + * + * Registers a function with the list of functions to be called when a watchdog pretimeout occurs. + * + * Currently always returns zero, as blocking_notifier_chain_register() + * always returns zero. + */ +int register_watchdog_pretimeout_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&watchdog_pretimeout_notifier_list, nb); +} +EXPORT_SYMBOL(register_watchdog_pretimeout_notifier); + +/** + * unregister_watchdog_pretimeout_notifier - Unregister previously registered pretimeout notifier + * @nb: Hook to be unregistered + * + * Unregisters a previously registered watchdog pretimeout notifier function. + * + * Returns zero on success, or %-ENOENT on failure. + */ +int unregister_watchdog_pretimeout_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&watchdog_pretimeout_notifier_list, nb); +} +EXPORT_SYMBOL(unregister_watchdog_pretimeout_notifier); + +/** + * pretimeout_notifier - Notify registred methods on pretimeout + * @wdd - watchdog_device + * + * Notify, watchdog has not been fed till pretimeout event. + */ +static void pretimeout_notifier(struct watchdog_device *wdd) +{ + blocking_notifier_call_chain(&watchdog_pretimeout_notifier_list, 0, wdd); +} + +static struct watchdog_governor watchdog_gov_notifier = { + .name = "notifier", + .pretimeout = pretimeout_notifier, +}; + +static int __init watchdog_gov_notifier_register(void) +{ + return watchdog_register_governor(&watchdog_gov_notifier); +} + +static void __exit watchdog_gov_notifier_unregister(void) +{ + watchdog_unregister_governor(&watchdog_gov_notifier); +} +module_init(watchdog_gov_notifier_register); +module_exit(watchdog_gov_notifier_unregister); + +MODULE_AUTHOR("Stefan Eichenberger "); +MODULE_DESCRIPTION("Notifier watchdog pretimeout governor"); +MODULE_LICENSE("GPL"); diff --git a/drivers/watchdog/watchdog_pretimeout.h b/drivers/watchdog/watchdog_pretimeout.h index a3f1abc68839..bb00ca1fcadd 100644 --- a/drivers/watchdog/watchdog_pretimeout.h +++ b/drivers/watchdog/watchdog_pretimeout.h @@ -28,6 +28,8 @@ int watchdog_pretimeout_governor_set(struct watchdog_device *wdd, #define WATCHDOG_PRETIMEOUT_DEFAULT_GOV "noop" #elif IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_DEFAULT_GOV_PANIC) #define WATCHDOG_PRETIMEOUT_DEFAULT_GOV "panic" +#elif IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_DEFAULT_GOV_NOTIFIER) +#define WATCHDOG_PRETIMEOUT_DEFAULT_GOV "notifier" #endif #else diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h index 9b19e6bb68b5..760beab1007f 100644 --- a/include/linux/watchdog.h +++ b/include/linux/watchdog.h @@ -215,4 +215,9 @@ int watchdog_set_last_hw_keepalive(struct watchdog_device *, unsigned int); /* devres register variant */ int devm_watchdog_register_device(struct device *dev, struct watchdog_device *); +#if IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV_NOTIFIER) +int register_watchdog_pretimeout_notifier(struct notifier_block *nb); +int unregister_watchdog_pretimeout_notifier(struct notifier_block *nb); +#endif + #endif /* ifndef _LINUX_WATCHDOG_H */ -- 2.27.0