From nobody Sun Oct 5 03:40:30 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 AFFE62DCC11 for ; Mon, 11 Aug 2025 09:14:32 +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=1754903675; cv=none; b=Y7fYuhagQ27IxJ0pOUXpgdWGVxggC7rRIsKTL57GQN9lE75K6WFsoGRx53oQb3u570WL5G6gRuit+3+d6NjnjEgOW3FR9YppAY1e3rudnqQuYs0xx+8+5iKldr8i/EbXn1p1O+lJnXavDU6CHIg44GBR6TR03kkzBLBXQPJCymk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754903675; c=relaxed/simple; bh=GRXkHr87sMAwGXVCFiOsZuTbb8axjZTo4vNoebQJmjg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=T3BBxlt8xSqPmcTKQnF6ziqCARTn8uTAEvFQse2uRVHmpulnla4o0usOxZR+tvU4K1wKChuM633gr6bPyRw/178iXonN9N3ouzF/73Jfc63iupZTiIG7PhZ0HpHCq/Ja2MSzFC4pxHmKhHl4qjL/25FslUY5YA/o0sx+f8lfSgo= 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=hbShq/hb; 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="hbShq/hb" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=weissschuh.net; s=mail; t=1754903670; bh=GRXkHr87sMAwGXVCFiOsZuTbb8axjZTo4vNoebQJmjg=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=hbShq/hbT9SaJ5IoYzGUUjJARmQwRNfVufjfd4G9aTvY0KzetVyToRaPBJZ5W80JP Xa/+A/81fV0QM6MJ518gJTYswB2GZ0osPB3LkIv7tkttW44+K6MKdSHk5WFuVM3E9t Ee+FhgVASdu4FKecqV9uE9R3D4PabotVlHCKYzKU= From: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= Date: Mon, 11 Aug 2025 11:14:27 +0200 Subject: [PATCH v3 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: <20250811-sysfs-const-attr-prep-v3-1-0d973ff46afc@weissschuh.net> References: <20250811-sysfs-const-attr-prep-v3-0-0d973ff46afc@weissschuh.net> In-Reply-To: <20250811-sysfs-const-attr-prep-v3-0-0d973ff46afc@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 0.14.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1754903670; l=1606; i=linux@weissschuh.net; s=20221212; h=from:subject:message-id; bh=GRXkHr87sMAwGXVCFiOsZuTbb8axjZTo4vNoebQJmjg=; b=BqLrH4TbeVI5edSMiKvXCLPRUbwZKdFjlY6fb/Jbql32J2K8aVx/Ng49CQjQUcvbrpFP/jF/e J/ySe+J+i7xCZ88RGo5YYRMR8pgB68cyleTMgnK84V0H+GvjVF1IRTu 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 f418aae4f1134f8126783d9e8eb575ba4278e927..a47092e837d9eb014894d1f7e49= f0fd0f9a2e350 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 { const struct bin_attribute *const *bin_attrs; const struct bin_attribute *const *bin_attrs_new; --=20 2.50.1