linux-kernel - Re: [PATCH 03/10] device property: Add fwnode_property_read_int

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <D8X4ZFQUDX4O.2CUNGWJOG6U59@buenzli.dev>
Date: Thu, 03 Apr 2025 18:15:57 +0200
From: "Remo Senekowitsch" <remo@...nzli.dev>
To: "Rob Herring" <robh@...nel.org>, "Andy Shevchenko"
 <andriy.shevchenko@...ux.intel.com>
Cc: "Daniel Scally" <djrscally@...il.com>, "Heikki Krogerus"
 <heikki.krogerus@...ux.intel.com>, "Sakari Ailus"
 <sakari.ailus@...ux.intel.com>, "Dirk Behme" <dirk.behme@...bosch.com>,
 "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>, "Rafael J. Wysocki"
 <rafael@...nel.org>, "Danilo Krummrich" <dakr@...nel.org>, "Saravana
 Kannan" <saravanak@...gle.com>, "Miguel Ojeda" <ojeda@...nel.org>, "Alex
 Gaynor" <alex.gaynor@...il.com>, "Boqun Feng" <boqun.feng@...il.com>, "Gary
 Guo" <gary@...yguo.net>, Björn Roy Baron
 <bjorn3_gh@...tonmail.com>, "Benno Lossin" <benno.lossin@...ton.me>,
 "Andreas Hindborg" <a.hindborg@...nel.org>, "Alice Ryhl"
 <aliceryhl@...gle.com>, "Trevor Gross" <tmgross@...ch.edu>,
 <linux-kernel@...r.kernel.org>, <linux-acpi@...r.kernel.org>,
 <devicetree@...r.kernel.org>, <rust-for-linux@...r.kernel.org>
Subject: Re: [PATCH 03/10] device property: Add
 fwnode_property_read_int_array()

On Thu Apr 3, 2025 at 6:08 PM CEST, Rob Herring wrote:
> On Thu, Apr 3, 2025 at 8:29 AM Andy Shevchenko
> <andriy.shevchenko@...ux.intel.com> wrote:
>>
>> On Wed, Apr 02, 2025 at 06:04:13PM +0200, Remo Senekowitsch wrote:
>> > On Thu Mar 27, 2025 at 9:41 AM CET, Andy Shevchenko wrote:
>> > > On Wed, Mar 26, 2025 at 06:13:42PM +0100, Remo Senekowitsch wrote:
>> > >> The rust bindings for reading device properties has a single
>> > >> implementation supporting differing sizes of integers. The fwnode C API
>> > >> already has a similar interface, but it is not exposed with the
>> > >> fwnode_property_ API. Add the fwnode_property_read_int_array() wrapper.
>>
>> ...
>>
>> > >> +EXPORT_SYMBOL_GPL(fwnode_property_read_int_array);
>> > >
>> > > I'm not sure about this. We have a lot of assumptions in the code that the
>> > > arrays beneath are only represented by the selected number of integer types.
>> > > This opens a Pandora's box, e.g., reading in u24, which is not supported by
>> > > the upper layers..
>> > >
>> > >> +int fwnode_property_read_int_array(const struct fwnode_handle *fwnode, const char *propname,
>> > >> +                             unsigned int elem_size, void *val, size_t nval);
>> >
>> > Here's an alternative approach using a macro to map each integer type explicitly
>> > to its corresponding read function. There are some additional changes that will
>> > be necessary to make the rest work, but this is the gist of it.
>>
>> I don;'t know Rust to tell anything about this, but at least it feels much
>> better approach.
>
> I know a little Rust and it is much worse. It is implementing the same
> code 8 times instead of 1 time just to work-around the C API.

You mean it's worse because it will generate too much code during compile time?

Remo