From nobody Sun Dec 14 11:32:39 2025 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 32096137930 for ; Thu, 16 Jan 2025 17:32:31 +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=1737048753; cv=none; b=qCbQo0l34P7vK3KcUI8xe0P9seVAQdtmZ2lDJ6E0qT0GGgdnsmjLzdFke88lIoLmA+N8UIBMX7xUuwuyrjd1r5hLnEZwvF3FDBP3k0DTDLnZL8PUcsKheYT84/NThL90cVeSmpDIyIjmq1Xj7rv2Bg9jdGpolpfHRyQGq4ksqrU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737048753; c=relaxed/simple; bh=ZooFOr+F9P8aM+Or8c2aeQigL8fE9gjVpBNM3E6kQNk=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=L5StiK11k/GDTMJeniExOFYzsKIkLl0oVD5YZPY6G9xCPWce+l6zafZgWJNGncwWfmI25MqOKI+t8hcdczGcXdAikrC/w6lm/+oabmgUkCSF0TmIj/BlLfyfjbCUJ2jC+KqGTJua8O4iR1lwg0In6eOSE5/bPRImkukZURgGM2A= 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=sFWRW/BT; 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="sFWRW/BT" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=weissschuh.net; s=mail; t=1737048750; bh=ZooFOr+F9P8aM+Or8c2aeQigL8fE9gjVpBNM3E6kQNk=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=sFWRW/BTPWBGaxfODEfF5JWLtlduK83UN8rdMtCJZiocG7uKq2GM34ApnVxOIEotG INvlRchIr24zHMdnZtYbwAfuMv2VAwGKqhTIALInsb84vond5gifewXcK44NEE5FWV /orWNbh0GkcrYBFJ3r8xIqtDveME/27aLGKlzXp8= From: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= Date: Thu, 16 Jan 2025 18:32:27 +0100 Subject: [PATCH 1/6] sysfs: attribute_group: allow registration of const attribute 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: <20250116-sysfs-const-attr-prep-v1-1-15e72dba4205@weissschuh.net> References: <20250116-sysfs-const-attr-prep-v1-0-15e72dba4205@weissschuh.net> In-Reply-To: <20250116-sysfs-const-attr-prep-v1-0-15e72dba4205@weissschuh.net> To: Greg Kroah-Hartman , "Rafael J. Wysocki" Cc: 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=1737048749; l=1595; i=linux@weissschuh.net; s=20221212; h=from:subject:message-id; bh=ZooFOr+F9P8aM+Or8c2aeQigL8fE9gjVpBNM3E6kQNk=; b=hZRJOAT+SlgG/5sf/fV/I0blvKHmQgaaXR30LiZV+jrb4YbVYPAqlFH4f71Ra9oIVSF17ModM ljRc3j9VV+ECgn+193o8ileL+ket/Txwsv/89p2kLjjSJVajA0M6Ih1 X-Developer-Key: i=linux@weissschuh.net; a=ed25519; pk=KcycQgFPX2wGR5azS7RhpBqedglOZVgRPfdFSPB1LNw= To be able to constify instances of struct attribute it has to be possible to add them to struct attribute_group. The current type of the attrs member however is not compatible with that. Introduce a union that allows registration of both const and non-const attributes to enable a piecewise transition. As both union member types are compatible no logic needs to be adapted. Technically it is now possible register a const struct attribute and receive it as mutable pointer in the callbacks. This is a soundness issue. But this same soundness issue already exists today in sysfs_create_file(). Also the struct definition and callback implementation are always closely linked and are meant to be moved to const in lockstep. Similar to commit 906c508afdca ("sysfs: attribute_group: allow registration= of const bin_attribute") Signed-off-by: Thomas Wei=C3=9Fschuh --- include/linux/sysfs.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index 0f2fcd244523f050c5286f19d4fe1846506f9214..f5e25bed777a6a6e717f10973f1= abcd12111f5c5 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -105,7 +105,10 @@ struct attribute_group { size_t (*bin_size)(struct kobject *, const struct bin_attribute *, int); - struct attribute **attrs; + union { + struct attribute **attrs; + const struct attribute *const *attrs_new; + }; union { struct bin_attribute **bin_attrs; const struct bin_attribute *const *bin_attrs_new; --=20 2.48.1