From patchwork Mon Apr 11 23:38:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Osipenko X-Patchwork-Id: 12809795 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 235E3C43217 for ; Mon, 11 Apr 2022 23:39:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236039AbiDKXlc (ORCPT ); Mon, 11 Apr 2022 19:41:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234381AbiDKXlV (ORCPT ); Mon, 11 Apr 2022 19:41:21 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD5C8E17; Mon, 11 Apr 2022 16:39:04 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: dmitry.osipenko) with ESMTPSA id C52711F42D8A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1649720343; bh=vZl2ZWhj3ebII6Fu4HXosJY7ElBNxPQBVC6ByCiZ1BY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JviWvIvL43QfXlelzChv/e65G8pQVStHm/cjt8S+palR7BBcwJ28HEV3zpH6iZZTv TAwdfm98zB2JhkW2hCsPJU++kmtM1VV3c4q/FAbp1kMxQV66wX4eOP2dzPpxKzrKBh r/GZxCh68qnq8qhz28d+ivGoVY9SXlXFmaOMiSdDnfRi1xFRVYkWEqZNi0hbs2vHRd Dcs5ywFB53D3180fJ8zfDiYmWEkxlPJhV6Jj84tKq7D3RzpHX7l0fPdorLAO9CU7xa bri2qC1nbypivw49u7/3CmwoCU41LCltEdGxoZKNd3lvbfE0eFlmxhLRCcCz+OsT9r V/pa36+mViA/w== From: Dmitry Osipenko To: Thierry Reding , Jonathan Hunter , Russell King , Catalin Marinas , Will Deacon , Guo Ren , Geert Uytterhoeven , Greg Ungerer , Joshua Thompson , Thomas Bogendoerfer , Sebastian Reichel , Linus Walleij , Philipp Zabel , 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 , "Rafael J. Wysocki" , Len Brown , Santosh Shilimkar , Krzysztof Kozlowski , Liam Girdwood , Mark Brown , Pavel Machek , Lee Jones , Andrew Morton , Guenter Roeck , Daniel Lezcano , Andy Shevchenko , Ulf Hansson , =?utf-8?b?TWljaGHFgiBNaXJvc8WCYXc=?= Cc: 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, linux-riscv@lists.infradead.org, linux-sh@vger.kernel.org, xen-devel@lists.xenproject.org, linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org, linux-tegra@vger.kernel.org Subject: [PATCH v7 02/20] notifier: Add atomic/blocking_notifier_chain_register_unique_prio() Date: Tue, 12 Apr 2022 02:38:14 +0300 Message-Id: <20220411233832.391817-3-dmitry.osipenko@collabora.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220411233832.391817-1-dmitry.osipenko@collabora.com> References: <20220411233832.391817-1-dmitry.osipenko@collabora.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Add variant of atomic/blocking_notifier_chain_register() functions that doesn't allow to register notifier using a duplicated priority. The -EBUSY error code is returned in this case by the new API functions. Signed-off-by: Dmitry Osipenko --- include/linux/notifier.h | 5 +++ kernel/notifier.c | 88 +++++++++++++++++++++++++++++++--------- 2 files changed, 74 insertions(+), 19 deletions(-) diff --git a/include/linux/notifier.h b/include/linux/notifier.h index d4717bc0ab85..ccce26197dd2 100644 --- a/include/linux/notifier.h +++ b/include/linux/notifier.h @@ -150,6 +150,11 @@ extern int raw_notifier_chain_register(struct raw_notifier_head *nh, extern int srcu_notifier_chain_register(struct srcu_notifier_head *nh, struct notifier_block *nb); +extern int atomic_notifier_chain_register_unique_prio( + struct atomic_notifier_head *nh, struct notifier_block *nb); +extern int blocking_notifier_chain_register_unique_prio( + struct blocking_notifier_head *nh, struct notifier_block *nb); + extern int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh, struct notifier_block *nb); extern int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh, diff --git a/kernel/notifier.c b/kernel/notifier.c index 4ed6bda8f127..4fc32b1e6cbb 100644 --- a/kernel/notifier.c +++ b/kernel/notifier.c @@ -20,7 +20,8 @@ BLOCKING_NOTIFIER_HEAD(reboot_notifier_list); */ static int notifier_chain_register(struct notifier_block **nl, - struct notifier_block *n) + struct notifier_block *n, + bool unique_priority) { while ((*nl) != NULL) { if (unlikely((*nl) == n)) { @@ -30,6 +31,8 @@ static int notifier_chain_register(struct notifier_block **nl, } if (n->priority > (*nl)->priority) break; + if (n->priority == (*nl)->priority && unique_priority) + return -EBUSY; nl = &((*nl)->next); } n->next = *nl; @@ -144,12 +147,35 @@ int atomic_notifier_chain_register(struct atomic_notifier_head *nh, int ret; spin_lock_irqsave(&nh->lock, flags); - ret = notifier_chain_register(&nh->head, n); + ret = notifier_chain_register(&nh->head, n, false); spin_unlock_irqrestore(&nh->lock, flags); return ret; } EXPORT_SYMBOL_GPL(atomic_notifier_chain_register); +/** + * atomic_notifier_chain_register_unique_prio - Add notifier to an atomic notifier chain + * @nh: Pointer to head of the atomic notifier chain + * @n: New entry in notifier chain + * + * Adds a notifier to an atomic notifier chain if there is no other + * notifier registered using the same priority. + * + * Returns 0 on success, %-EEXIST or %-EBUSY on error. + */ +int atomic_notifier_chain_register_unique_prio(struct atomic_notifier_head *nh, + struct notifier_block *n) +{ + unsigned long flags; + int ret; + + spin_lock_irqsave(&nh->lock, flags); + ret = notifier_chain_register(&nh->head, n, true); + spin_unlock_irqrestore(&nh->lock, flags); + return ret; +} +EXPORT_SYMBOL_GPL(atomic_notifier_chain_register_unique_prio); + /** * atomic_notifier_chain_unregister - Remove notifier from an atomic notifier chain * @nh: Pointer to head of the atomic notifier chain @@ -209,18 +235,9 @@ NOKPROBE_SYMBOL(atomic_notifier_call_chain); * synchronized by an rwsem. */ -/** - * blocking_notifier_chain_register - Add notifier to a blocking notifier chain - * @nh: Pointer to head of the blocking notifier chain - * @n: New entry in notifier chain - * - * Adds a notifier to a blocking notifier chain. - * Must be called in process context. - * - * Returns 0 on success, %-EEXIST on error. - */ -int blocking_notifier_chain_register(struct blocking_notifier_head *nh, - struct notifier_block *n) +static int __blocking_notifier_chain_register(struct blocking_notifier_head *nh, + struct notifier_block *n, + bool unique_priority) { int ret; @@ -230,15 +247,48 @@ int blocking_notifier_chain_register(struct blocking_notifier_head *nh, * such times we must not call down_write(). */ if (unlikely(system_state == SYSTEM_BOOTING)) - return notifier_chain_register(&nh->head, n); + return notifier_chain_register(&nh->head, n, unique_priority); down_write(&nh->rwsem); - ret = notifier_chain_register(&nh->head, n); + ret = notifier_chain_register(&nh->head, n, unique_priority); up_write(&nh->rwsem); return ret; } + +/** + * blocking_notifier_chain_register - Add notifier to a blocking notifier chain + * @nh: Pointer to head of the blocking notifier chain + * @n: New entry in notifier chain + * + * Adds a notifier to a blocking notifier chain. + * Must be called in process context. + * + * Returns 0 on success, %-EEXIST on error. + */ +int blocking_notifier_chain_register(struct blocking_notifier_head *nh, + struct notifier_block *n) +{ + return __blocking_notifier_chain_register(nh, n, false); +} EXPORT_SYMBOL_GPL(blocking_notifier_chain_register); +/** + * blocking_notifier_chain_register_unique_prio - Add notifier to a blocking notifier chain + * @nh: Pointer to head of the blocking notifier chain + * @n: New entry in notifier chain + * + * Adds a notifier to an blocking notifier chain if there is no other + * notifier registered using the same priority. + * + * Returns 0 on success, %-EEXIST or %-EBUSY on error. + */ +int blocking_notifier_chain_register_unique_prio(struct blocking_notifier_head *nh, + struct notifier_block *n) +{ + return __blocking_notifier_chain_register(nh, n, true); +} +EXPORT_SYMBOL_GPL(blocking_notifier_chain_register_unique_prio); + /** * blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain * @nh: Pointer to head of the blocking notifier chain @@ -354,7 +404,7 @@ bool blocking_notifier_call_chain_is_empty(struct blocking_notifier_head *nh) int raw_notifier_chain_register(struct raw_notifier_head *nh, struct notifier_block *n) { - return notifier_chain_register(&nh->head, n); + return notifier_chain_register(&nh->head, n, false); } EXPORT_SYMBOL_GPL(raw_notifier_chain_register); @@ -433,10 +483,10 @@ int srcu_notifier_chain_register(struct srcu_notifier_head *nh, * such times we must not call mutex_lock(). */ if (unlikely(system_state == SYSTEM_BOOTING)) - return notifier_chain_register(&nh->head, n); + return notifier_chain_register(&nh->head, n, false); mutex_lock(&nh->mutex); - ret = notifier_chain_register(&nh->head, n); + ret = notifier_chain_register(&nh->head, n, false); mutex_unlock(&nh->mutex); return ret; }