Re: [PATCH 0/2] rust: usb: add initial USB abstractions

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Aug 25, 2025 at 03:18:04PM -0300, Daniel Almeida wrote:
> This adds initial support for USB Rust drivers, not only because I see a
> widespread use of module_usb_driver() in media (which is a subsystem I
> aim to support) but also because I want to learn about USB in general
> and this is a nice opportunity to start doing so.
> 
> I tried to keep things as consistent with pci.rs and platform.rs as
> possible and tested it by manually binding a device (i.e.: my Logitech
> mouse) to the sample driver via:
> 
> /sys/bus/usb/drivers/rust_driver_usb/new_id
> 
> This initial patch is therefore comprised of the same patterns that are
> known to work for pci and platform already.
> 
> Physically disconnecting the device also worked, i.e.: nothing bad
> showed up in dmesg.
> 
> Note that I did not touch MAINTAINERS at all. The objective is to
> kickstart the discussion of what to do there here in v1.

Ok, as this seems to now be at least building properly for me, I have
taken it into my char-misc branch for the next -rc1 merge window.

BUT it has shown that it still needs some work to get "correct" and it
really doesn't do much quite yet, so I have applied the patch below to
pretty much just "disable" it entirely from the build at this point in
time.

I'll go and revert this commit after -rc1 is out, in my usb-next branch,
so that we can start to build on top of it and ensure that it doesn't
break, but for 6.18, I don't think it's quite ready to be there.

Yes, this is not a normal way that bindings will probably be merged into
the tree, but as I consulted deeply with the USB maintainer about this
topic while eating some good Paris pizza and French wine this week while
at the Kernel Recipes conference, I think that this deserves an
exception as they agree this can be merged now and they will be
responsible for any fallout.[1]

thanks,

greg k-h

From c1785be6395031f92b62badb27665f80f0a7794c Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Thu, 25 Sep 2025 14:42:40 +0200
Subject: USB: disable rust bindings from the build for now

The rust USB bindings as submitted are a good start, but they don't
really seem to be correct in a number of minor places, so just disable
them from the build entirely at this point in time.  When they are ready
to be re-enabled, this commit can be reverted.

Cc: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 rust/bindings/bindings_helper.h | 1 -
 rust/helpers/helpers.c          | 1 -
 rust/kernel/lib.rs              | 2 --
 samples/rust/Kconfig            | 2 +-
 4 files changed, 1 insertion(+), 5 deletions(-)

diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 41cd42cd286f..9b3a4ab95818 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -74,7 +74,6 @@
 #include <linux/slab.h>
 #include <linux/task_work.h>
 #include <linux/tracepoint.h>
-#include <linux/usb.h>
 #include <linux/wait.h>
 #include <linux/workqueue.h>
 #include <linux/xarray.h>
diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
index 04103ab1a349..8e8277bdddca 100644
--- a/rust/helpers/helpers.c
+++ b/rust/helpers/helpers.c
@@ -48,7 +48,6 @@
 #include "task.c"
 #include "time.c"
 #include "uaccess.c"
-#include "usb.c"
 #include "vmalloc.c"
 #include "wait.c"
 #include "workqueue.c"
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 004ca70b816d..99dbb7b2812e 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -127,8 +127,6 @@
 pub mod tracepoint;
 pub mod transmute;
 pub mod types;
-#[cfg(CONFIG_USB = "y")]
-pub mod usb;
 pub mod uaccess;
 pub mod workqueue;
 pub mod xarray;
diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
index 6d6e4d8c88cb..865a62a93ddc 100644
--- a/samples/rust/Kconfig
+++ b/samples/rust/Kconfig
@@ -85,7 +85,7 @@ config SAMPLE_RUST_DRIVER_PLATFORM
 
 config SAMPLE_RUST_DRIVER_USB
 	tristate "USB Driver"
-	depends on USB = y
+	depends on USB = y && BROKEN
 	help
 	  This option builds the Rust USB driver sample.
 
-- 
2.51.0


[1] For those not getting the sarcasm here, I'm that maintainer, and
    yes, Paris has some very good pizza :)