From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 BE5D01D5154 for ; Sat, 28 Jun 2025 08:30:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751099420; cv=none; b=pnkpArn6m/uB06wI14PUMsYfthEGStf6KnVpXaLixehpRqSFFMaxAJHIKiydhl8vouxeh7nXz7Hau30xN06Wwe717oQL1MNn67UAwemnWE+qO2Iq7hoIzUIaJW6qfZtcDMKAFtxO+Ebg9yA7qhQDzt90B4MAzxV40fWQHkXL0i0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751099420; c=relaxed/simple; bh=4cRj8WS59bxfK6qbay5EitRSd60rIvwt6mbPPYZQ7aQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XxXa+ju1w0vnMaSK3/2ua5N0tmn3PVBc5FtwQgwj4FyOrWZp7BQpcvgNocwLNuVEy6cR76V/ee4b6RmIs0XbPzyZnHaUdGMm3GObdU/nc7vVMTss9uHNE3yypkLk4tpHODPMhldAPN98Az4w1gBJryLUlS6Bk8dCAshIWHszXH8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ZZKNWIK3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ZZKNWIK3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E638EC4CEEA; Sat, 28 Jun 2025 08:30:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1751099419; bh=4cRj8WS59bxfK6qbay5EitRSd60rIvwt6mbPPYZQ7aQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZZKNWIK3l6hFWETu0ye5iCeI5zQv+L39reKD7k/UtoxP3BKsFIqwVT5TwEWjeAzAe nPyu0Qp05y9BOpcd6AEdhpYz7PCogsl7iR1fZDT5vVlfr9fOdItDuwTslw3ncXPtiL +zoJKUW26x+0XFz4r/xUaEG6/no2RAu56nfgjJfQ= Date: Sat, 28 Jun 2025 10:30:16 +0200 From: Greg Kroah-Hartman To: Thomas =?iso-8859-1?Q?Wei=DFschuh?= Cc: "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, Danilo Krummrich Subject: Re: [PATCH 1/6] sysfs: attribute_group: allow registration of const attribute Message-ID: <2025062845-finishing-yeast-313b@gregkh> References: <20250116-sysfs-const-attr-prep-v1-0-15e72dba4205@weissschuh.net> <20250116-sysfs-const-attr-prep-v1-1-15e72dba4205@weissschuh.net> <2025011714-skeleton-bring-3e77@gregkh> <3d4c063e-e56d-466c-a3a7-58566bf1da3c@t-8ch.de> 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=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <3d4c063e-e56d-466c-a3a7-58566bf1da3c@t-8ch.de> On Sat, Jun 28, 2025 at 10:19:07AM +0200, Thomas Weißschuh wrote: > Hi Greg, > > On 2025-01-17 08:01:00+0100, Greg Kroah-Hartman wrote: > > On Thu, Jan 16, 2025 at 06:32:27PM +0100, Thomas Weißschuh wrote: > > > 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 Weißschuh > > > --- > > > 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..f5e25bed777a6a6e717f10973f1abcd12111f5c5 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; > > > + }; > > > > I'm all for the idea, BUT, let's finish up doing this one: > > > > > union { > > > struct bin_attribute **bin_attrs; > > > const struct bin_attribute *const *bin_attrs_new; > > > > first please. > > > > That way we can see just how "easy" the switch from _new to not-new goes :) > > I'd like to resend these preparatory patches so they go into v6.17-rc1 > and I can work on the follow-up changes. > In my opinion the switch from _new will work nicely. There have been no > new users of _new in -next at all. > > Any objections? Sure, please do. greg k-h