From nobody Fri Dec 19 17:18:43 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 548F130AD06 for ; Mon, 13 Oct 2025 15:18:00 +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=1760368681; cv=none; b=IjkG3b3W0ux/50iPYTqi73s45+8Currz0dvHVUc2n9VQyzihZP195+ApSRYGgGub++LUIPGQe7vnL5gq8ZdeFce8pBJqveAm+NyU92GI75u+GiEmxMO2P6YMxqTcljUbib0fA5cAlR7SHSBL8sEb7MBGv4WZJZ35EBhChPrXxWo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760368681; c=relaxed/simple; bh=e2JSNt1oXoBuC8lD+VFhcIHgvuTQyriVtTtr7YhY1Vc=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=R4niVaTpGtNmlZ2vEVPFJ3xwTeD1Fe/yHubCGGaXFPepcuMUTnK46stbIJj2b6i4SSHVwRsby8/3tmzMO7nl6bkLjs7g5jmRytvStkM3eN1NCv/7oUvVlDhjftDXCRfYsbIRlqS2Jk8rQGN0zyPobOrAe5NFB2j2gH5YYMRqmak= 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=o9ZLZVWe; 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="o9ZLZVWe" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=weissschuh.net; s=mail; t=1760368677; bh=e2JSNt1oXoBuC8lD+VFhcIHgvuTQyriVtTtr7YhY1Vc=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=o9ZLZVWexMfJhNKk55vlXeiB66nToOeYajBMQlJ6aB73IkdaTOQov8gLm+kJ8q4/5 6km4m4iKNU7V0+KK454i77ttK6iMjOyQrRBRFqMfT3HWU22j7gZ0AdzXpa5CkkrahS 4fUG6vN2w/KBMExQLhpE/lnY9q3KfV9L4aFNVWZA= From: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= Date: Mon, 13 Oct 2025 17:17:54 +0200 Subject: [PATCH v4 1/7] 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: <20251013-sysfs-const-attr-prep-v4-1-e0d36e828334@weissschuh.net> References: <20251013-sysfs-const-attr-prep-v4-0-e0d36e828334@weissschuh.net> In-Reply-To: <20251013-sysfs-const-attr-prep-v4-0-e0d36e828334@weissschuh.net> To: Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich Cc: linux-kernel@vger.kernel.org, =?utf-8?q?Thomas_Wei=C3=9Fschuh?= X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1760368676; l=1495; i=linux@weissschuh.net; s=20221212; h=from:subject:message-id; bh=e2JSNt1oXoBuC8lD+VFhcIHgvuTQyriVtTtr7YhY1Vc=; b=VSkGZc21lexL4OfqHzIiLkqrvhA6zPcck9sfBEX5qLK/U6SZYmwqiT+JDhETQLtKzUqaRLtRm mwAO5VYsJY5AaEifBLkCRqMB945SGTeezd1iOtwlm5fpbMpV+IYgI4I 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 9a25a2911652..e34d6af96abb 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_const; + }; const struct bin_attribute *const *bin_attrs; }; =20 --=20 2.51.0