From nobody Mon Feb 9 03:51:10 2026 Received: from todd.t-8ch.de (todd.t-8ch.de [159.69.126.157]) (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 C82227E0E8 for ; Mon, 2 Dec 2024 17:45:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.69.126.157 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733161547; cv=none; b=PySRSxaR3l+Xo16OX5E4iFBAlNZ7XfZaHrjXHjvbmeG/pr/sHf3zoDXfkVxdiHtFYxccLQ+HZHar/3CSTtnYfZzB44RQClhDrj3C8cAGG1Fmi3JDt2k+1KrfB9B+jQ7QGMYUD6OvYG4cuy7EQR4RJDw48/JU7EqO8LYeWbzknNE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733161547; c=relaxed/simple; bh=z+cHfkEdofAUSDaqIVg0Z1cSdifjauaRlbhZ1WorbtQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=cWm9tsqB+eAna/nwl8fKgXe5eoZ3/hEX143sHLbh+j2ZxWu3wUi9f2VRlcOuhTyo2QM5DvS+GE+RINfGZARHQG1fyaUaH+r7dha0uKc1o8LQ3KATZNtNHtUqBtWLroz6VYy8/wItsNcCwXTvBL823driUDxD8yJfEB05+WQT6wM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=weissschuh.net; spf=pass smtp.mailfrom=weissschuh.net; dkim=pass (1024-bit key) header.d=weissschuh.net header.i=@weissschuh.net header.b=JJaKMh7J; arc=none smtp.client-ip=159.69.126.157 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=weissschuh.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=weissschuh.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=weissschuh.net header.i=@weissschuh.net header.b="JJaKMh7J" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=weissschuh.net; s=mail; t=1733161541; bh=z+cHfkEdofAUSDaqIVg0Z1cSdifjauaRlbhZ1WorbtQ=; h=From:Date:Subject:To:Cc:From; b=JJaKMh7Jonw1++41i7HOnnKyggY2hqY9DPdRG6JTXFQg95+BzTWLVnJRfTpAyD4bV aV6cmgk3thspkV9KFGevc0RqZ/TFgBKi3fKrZg/knEAEyTtsKyFkRLaMwQepTVvSNP XQKqXd//s5Dhb4Ic+N6uZkGq4l7q01ERm6YrGLBI= From: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= Date: Mon, 02 Dec 2024 18:45:41 +0100 Subject: [PATCH] locking/mutex: Mark devm_mutex_init() as __must_check Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20241202-must_check-devm_mutex_init-v1-1-e60eb97b8c72@weissschuh.net> X-B4-Tracking: v=1; b=H4sIAETyTWcC/x3MQQqDMBAF0KvIrA0YrSC9SpEQJ986lERJogji3 Rtcvs27KCEKEr2riyIOSbKGAl1XxIsNXyhxxdQ27Us3nVZ+T9nwAv4ph8Mbv2ecRoJkxZb7oZu cHWZQCbaIWc4n/4z3/QeFX32kbAAAAA== X-Change-ID: 20241031-must_check-devm_mutex_init-cac583bda8fe To: Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long , Boqun Feng Cc: Andy Shevchenko , linux-kernel@vger.kernel.org, =?utf-8?q?Thomas_Wei=C3=9Fschuh?= X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1733161541; l=2236; i=linux@weissschuh.net; s=20221212; h=from:subject:message-id; bh=z+cHfkEdofAUSDaqIVg0Z1cSdifjauaRlbhZ1WorbtQ=; b=o/Dglmg09ww/hRm5ldvVor+HHazQsl/5h+NsLj1zjXAURIWENoCtf4jhZtKMVZg5iCqZLF97E vq55iQmoxr+BMD7R2NG8/bPfW0NFNB7deNNTWaZXj5TDhQMJL0LLmqG X-Developer-Key: i=linux@weissschuh.net; a=ed25519; pk=KcycQgFPX2wGR5azS7RhpBqedglOZVgRPfdFSPB1LNw= Even if it's not critical, the avoidance of checking the error code from devm_mutex_init() call today diminishes the point of using devm variant of it. Tomorrow it may even leak something. Enforce all callers checking the return value through the compiler. As devm_mutex_init() itself is a macro which can not be annotated, annotate __devm_mutex_init() instead. Unfortunately __must_check/warn_unused_result don't propagate through statement expression. To work around this move the statement expression into the argument list of the call to __devm_mutex_init() so devm_mutex_init() directly expands to __devm_mutex_init(). Signed-off-by: Thomas Wei=C3=9Fschuh --- include/linux/mutex.h | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/include/linux/mutex.h b/include/linux/mutex.h index 2bf91b57591b49e4668752e773419ae945f124da..3ab77d0d85bd54a700e99694fd4= bcf1d310175bd 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -126,11 +126,12 @@ do { \ =20 #ifdef CONFIG_DEBUG_MUTEXES =20 -int __devm_mutex_init(struct device *dev, struct mutex *lock); +int __must_check __devm_mutex_init(struct device *dev, struct mutex *lock); =20 #else =20 -static inline int __devm_mutex_init(struct device *dev, struct mutex *lock) +static inline int __must_check __devm_mutex_init(struct device *dev, + struct mutex *lock) { /* * When CONFIG_DEBUG_MUTEXES is off mutex_destroy() is just a nop so @@ -141,13 +142,12 @@ static inline int __devm_mutex_init(struct device *de= v, struct mutex *lock) =20 #endif =20 -#define devm_mutex_init(dev, mutex) \ -({ \ - typeof(mutex) mutex_ =3D (mutex); \ - \ - mutex_init(mutex_); \ - __devm_mutex_init(dev, mutex_); \ -}) +#define devm_mutex_init(dev, mutex) __devm_mutex_init(dev, ({ \ + typeof(mutex) mutex_ =3D (mutex); \ + \ + mutex_init(mutex_); \ + mutex_; \ +})) =20 /* * See kernel/locking/mutex.c for detailed documentation of these APIs. --- base-commit: e70140ba0d2b1a30467d4af6bcfe761327b9ec95 change-id: 20241031-must_check-devm_mutex_init-cac583bda8fe Best regards, --=20 Thomas Wei=C3=9Fschuh