From patchwork Fri Dec 15 06:22:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 754742 Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DE798DDBA; Fri, 15 Dec 2023 06:50:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=csgroup.eu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=csgroup.eu Received: from localhost (mailhub3.si.c-s.fr [192.168.12.233]) by localhost (Postfix) with ESMTP id 4Srzfz2LKqz9tNC; Fri, 15 Dec 2023 07:23:07 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id MrLiEn9V7Nq8; Fri, 15 Dec 2023 07:23:07 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 4Srzfz1R30z9tMd; Fri, 15 Dec 2023 07:23:07 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 2B2898B779; Fri, 15 Dec 2023 07:23:07 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id 1waOS0s7MwND; Fri, 15 Dec 2023 07:23:07 +0100 (CET) Received: from PO20335.idsi0.si.c-s.fr (PO24393.IDSI0.si.c-s.fr [192.168.232.43]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 43B508B767; Fri, 15 Dec 2023 07:23:06 +0100 (CET) From: Christophe Leroy To: andy.shevchenko@gmail.com, pavel@ucw.cz, lee@kernel.org, vadimp@nvidia.com, mpe@ellerman.id.au, npiggin@gmail.com, christophe.leroy@csgroup.eu, hdegoede@redhat.com, mazziesaccount@gmail.com, peterz@infradead.org, mingo@redhat.com, will@kernel.org, longman@redhat.com, boqun.feng@gmail.com, nikitos.tr@gmail.com, George Stark Cc: kernel@salutedevices.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org Subject: [PATCH RFC v4-bis] locking: introduce devm_mutex_init Date: Fri, 15 Dec 2023 07:22:57 +0100 Message-ID: X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231214173614.2820929-3-gnstark@salutedevices.com> References: <20231214173614.2820929-3-gnstark@salutedevices.com> Precedence: bulk X-Mailing-List: linux-leds@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1702621376; l=3497; i=christophe.leroy@csgroup.eu; s=20211009; h=from:subject:message-id; bh=knrBp746sRirj9OKdUXZaiSIemnmdrXDctpOz0/Uwjo=; b=+opv6gcWbrLeFdYYfVWPIrvouBaqSluxG3A/gtkg5iBiHt+lU0qsRcFaFbwopezLi3Az4FikW sty92y+bjXNA4nO2gBMv0UQcdmKg/7LcnOWvyLu+jdlkCo/JKXNtSMh X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= From: George Stark Using of devm API leads to a certain order of releasing resources. So all dependent resources which are not devm-wrapped should be deleted with respect to devm-release order. Mutex is one of such objects that often is bound to other resources and has no own devm wrapping. Since mutex_destroy() actually does nothing in non-debug builds frequently calling mutex_destroy() is just ignored which is safe for now but wrong formally and can lead to a problem if mutex_destroy() will be extended so introduce devm_mutex_init() Signed-off-by: George Stark Signed-off-by: Christophe Leroy --- include/linux/mutex.h | 28 ++++++++++++++++++++++------ kernel/locking/mutex-debug.c | 22 ++++++++++++++++++++++ 2 files changed, 44 insertions(+), 6 deletions(-) diff --git a/include/linux/mutex.h b/include/linux/mutex.h index a33aa9eb9fc3..db847220ef44 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -81,14 +81,10 @@ struct mutex { #define __DEBUG_MUTEX_INITIALIZER(lockname) \ , .magic = &lockname -extern void mutex_destroy(struct mutex *lock); - #else # define __DEBUG_MUTEX_INITIALIZER(lockname) -static inline void mutex_destroy(struct mutex *lock) {} - #endif /** @@ -153,8 +149,6 @@ extern void __mutex_rt_init(struct mutex *lock, const char *name, struct lock_class_key *key); extern int mutex_trylock(struct mutex *lock); -static inline void mutex_destroy(struct mutex *lock) { } - #define mutex_is_locked(l) rt_mutex_base_is_locked(&(l)->rtmutex) #define __mutex_init(mutex, name, key) \ @@ -171,6 +165,28 @@ do { \ } while (0) #endif /* CONFIG_PREEMPT_RT */ +struct device; + +/* + * devm_mutex_init() registers a function that calls mutex_destroy() + * when the ressource is released. + * + * When mutex_destroy() is a not, there is no need to register that + * function. + */ +#ifdef CONFIG_DEBUG_MUTEXES +void mutex_destroy(struct mutex *lock); +int devm_mutex_init(struct device *dev, struct mutex *lock); +#else +static inline void mutex_destroy(struct mutex *lock) {} + +static inline int devm_mutex_init(struct device *dev, struct mutex *lock) +{ + mutex_init(lock); + return 0; +} +#endif + /* * See kernel/locking/mutex.c for detailed documentation of these APIs. * Also see Documentation/locking/mutex-design.rst. diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c index bc8abb8549d2..c9efab1a8026 100644 --- a/kernel/locking/mutex-debug.c +++ b/kernel/locking/mutex-debug.c @@ -19,6 +19,7 @@ #include #include #include +#include #include "mutex.h" @@ -104,3 +105,24 @@ void mutex_destroy(struct mutex *lock) } EXPORT_SYMBOL_GPL(mutex_destroy); + +static void devm_mutex_release(void *res) +{ + mutex_destroy(res); +} + +/** + * devm_mutex_init - Resource-managed mutex initialization + * @dev: Device which lifetime mutex is bound to + * @lock: Pointer to a mutex + * + * Initialize mutex which is automatically destroyed when the driver is detached. + * + * Returns: 0 on success or a negative error code on failure. + */ +int devm_mutex_init(struct device *dev, struct mutex *lock) +{ + mutex_init(lock); + return devm_add_action_or_reset(dev, devm_mutex_release, lock); +} +EXPORT_SYMBOL_GPL(devm_mutex_init);