From patchwork Wed Oct 27 21:16:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Osipenko X-Patchwork-Id: 12588213 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2895BC433EF for ; Wed, 27 Oct 2021 21:18:19 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CEBFF6112F for ; Wed, 27 Oct 2021 21:18:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org CEBFF6112F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.217215.377137 (Exim 4.92) (envelope-from ) id 1mfqJC-0001Ti-L1; Wed, 27 Oct 2021 21:18:06 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 217215.377137; Wed, 27 Oct 2021 21:18:06 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mfqJC-0001TX-Gg; Wed, 27 Oct 2021 21:18:06 +0000 Received: by outflank-mailman (input) for mailman id 217215; Wed, 27 Oct 2021 21:18:05 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mfqJB-0000sJ-8S for xen-devel@lists.xenproject.org; Wed, 27 Oct 2021 21:18:05 +0000 Received: from mail-lf1-x132.google.com (unknown [2a00:1450:4864:20::132]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 69deffbd-45dd-4bf9-95f2-79beb43a3f9b; Wed, 27 Oct 2021 21:17:57 +0000 (UTC) Received: by mail-lf1-x132.google.com with SMTP id u11so9038212lfs.1 for ; Wed, 27 Oct 2021 14:17:57 -0700 (PDT) Received: from localhost.localdomain (46-138-41-28.dynamic.spd-mgts.ru. [46.138.41.28]) by smtp.gmail.com with ESMTPSA id d7sm104336ljl.18.2021.10.27.14.17.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 27 Oct 2021 14:17:56 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 69deffbd-45dd-4bf9-95f2-79beb43a3f9b DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=4OzDm5Q6AH2k+PTLkkEFou1ZT7VKkxRv+kE3WUpAOf8=; b=UQ/1aCiL3zbAzp7+64ENWMFEP+bdpmbq+KH3NTi7hX2kN+fFVrO8S32QtOPwQfMxxS B4dmeXUf/BzuJhhzqG8VnHaUgY25bdcGnTrwxpDILzBPa9fYkIseD/FA90YqGQJP6GXZ PaIGof4Fo+LwMmngjVzKDktvBb6N6F/Oq7yFljDHwAcSrBHnke6Ooi6gGMrQtQGLY6gt DkEqtfwDzQkavBqxwLa+DWQ8L/Pn42h6a2KO1Y5kAXNNdt6/bA2gpVm767XfMu2cU+ZD 8088MqymRILm5tETDMubwXrrDQl/PbR2eeFdMLFjmwWobAMprcx5uRuWc88/LBbNkX13 zK7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=4OzDm5Q6AH2k+PTLkkEFou1ZT7VKkxRv+kE3WUpAOf8=; b=7j3IyY68TzNv5tdjXXE7+W/Y4efqcM8OnXKuAUH0Z8HvLDEFMXzNPu6dQHlZM2Bq4k 2XMmCYgN/gKzXFUHPrldfDTGKZfnHbhr9hkuOvMqN6WIf3IGmqiT+weFsFjAhHr/EKvs aOuAfgf/EAYRMfyK87S/XfsSkK+h5vEafjKRWEkI16n5T+j5UiJKjopd0y12IxjN1bFc LNFFymRqB48awzR9T/MqGxj019M0ARI67Y+vGa970a8Y8np89rjBXcDs/o8h6tX1eCAE vb28fJJPMuPUFj7NwgvIUhcP9w+C/CrzveBO8k0Gm2p1IaOmQNekmjhxRvAbuLRMrG8T ptBg== X-Gm-Message-State: AOAM532EQOPWywgYQYpDqQupjgGQhMZrohxfLb9FnyAqGCRXduFX+OPy jaESA1jIXeeXUVrpjp2ZHH0= X-Google-Smtp-Source: ABdhPJyeN/kGQE6WfHsDgri2jvM3EdB0FfWjlbwbrCss0fAIUEYOe9Prwt7QavBIliqBuOmpkw05Og== X-Received: by 2002:a05:6512:3f04:: with SMTP id y4mr128266lfa.180.1635369476308; Wed, 27 Oct 2021 14:17:56 -0700 (PDT) From: Dmitry Osipenko To: Thierry Reding , Jonathan Hunter , Lee Jones , "Rafael J . Wysocki" , Mark Brown , Andrew Morton , Guenter Roeck , Russell King , Daniel Lezcano , Andy Shevchenko , Ulf Hansson Cc: Catalin Marinas , Will Deacon , Guo Ren , Geert Uytterhoeven , Greg Ungerer , Joshua Thompson , Thomas Bogendoerfer , Nick Hu , Greentime Hu , Vincent Chen , "James E.J. Bottomley" , Helge Deller , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Paul Walmsley , Palmer Dabbelt , Albert Ou , Yoshinori Sato , Rich Felker , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Boris Ostrovsky , Juergen Gross , Stefano Stabellini , Len Brown , Santosh Shilimkar , Krzysztof Kozlowski , Linus Walleij , Chen-Yu Tsai , =?utf-8?q?Jonathan_Neusch=C3=A4fer?= , Tony Lindgren , Liam Girdwood , Philipp Zabel , Vladimir Zapolskiy , Avi Fishman , Tomer Maimon , Tali Perry , Patrick Venture , Nancy Yuen , Benjamin Fair , Pavel Machek , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-csky@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-sh@vger.kernel.org, xen-devel@lists.xenproject.org, linux-acpi@vger.kernel.org, linux-omap@vger.kernel.org, openbmc@lists.ozlabs.org, linux-tegra@vger.kernel.org, linux-pm@vger.kernel.org Subject: [PATCH v2 02/45] notifier: Add blocking_notifier_call_chain_empty() Date: Thu, 28 Oct 2021 00:16:32 +0300 Message-Id: <20211027211715.12671-3-digetx@gmail.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211027211715.12671-1-digetx@gmail.com> References: <20211027211715.12671-1-digetx@gmail.com> MIME-Version: 1.0 Add blocking_notifier_call_chain_empty() that returns true if call chain is empty. Signed-off-by: Dmitry Osipenko --- include/linux/notifier.h | 2 ++ kernel/notifier.c | 14 ++++++++++++++ 2 files changed, 16 insertions(+) diff --git a/include/linux/notifier.h b/include/linux/notifier.h index 4b80a815b666..054271e9cb20 100644 --- a/include/linux/notifier.h +++ b/include/linux/notifier.h @@ -173,6 +173,8 @@ int blocking_notifier_call_chain_robust(struct blocking_notifier_head *nh, int raw_notifier_call_chain_robust(struct raw_notifier_head *nh, unsigned long val_up, unsigned long val_down, void *v); +bool blocking_notifier_call_chain_empty(struct blocking_notifier_head *nh); + #define NOTIFY_DONE 0x0000 /* Don't care */ #define NOTIFY_OK 0x0001 /* Suits me */ #define NOTIFY_STOP_MASK 0x8000 /* Don't call further */ diff --git a/kernel/notifier.c b/kernel/notifier.c index b8251dc0bc0f..1f7ba8988b90 100644 --- a/kernel/notifier.c +++ b/kernel/notifier.c @@ -322,6 +322,20 @@ int blocking_notifier_call_chain(struct blocking_notifier_head *nh, } EXPORT_SYMBOL_GPL(blocking_notifier_call_chain); +/** + * blocking_notifier_call_chain_empty - Check whether notifier chain is empty + * @nh: Pointer to head of the blocking notifier chain + * + * Checks whether notifier chain is empty. + * + * Returns true is notifier chain is empty, false otherwise. + */ +bool blocking_notifier_call_chain_empty(struct blocking_notifier_head *nh) +{ + return !rcu_access_pointer(nh->head); +} +EXPORT_SYMBOL_GPL(blocking_notifier_call_chain_empty); + /* * Raw notifier chain routines. There is no protection; * the caller must provide it. Use at your own risk!