Re: [PATCH v5 1/1] usb: gadget: add raw-gadget interface

From: Andrey Konovalov <andreyknvl@google.com>
To: Felipe Balbi <balbi@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>,
	Alan Stern <stern@rowland.harvard.edu>,
	Dmitry Vyukov <dvyukov@google.com>,
	Alexander Potapenko <glider@google.com>,
	Marco Elver <elver@google.com>,
	USB list <linux-usb@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v5 1/1] usb: gadget: add raw-gadget interface
Date: Mon, 27 Jan 2020 13:27:57 +0100	[thread overview]
Message-ID: <CAAeHK+xJ_Xhy96vVXQLk2G_DqVtjh+3ivNM=yFVXFPBjZ6P3iA@mail.gmail.com> (raw)
In-Reply-To: <20200122145012.GB59473@kroah.com>

On Wed, Jan 22, 2020 at 3:50 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Wed, Jan 22, 2020 at 03:37:46PM +0100, Andrey Konovalov wrote:
> > On Tue, Jan 14, 2020 at 2:24 PM Andrey Konovalov <andreyknvl@google.com> wrote:
> > >
> > > USB Raw Gadget is a kernel module that provides a userspace interface for
> > > the USB Gadget subsystem. Essentially it allows to emulate USB devices
> > > from userspace. Enabled with CONFIG_USB_RAW_GADGET. Raw Gadget is
> > > currently a strictly debugging feature and shouldn't be used in
> > > production.
> > >
> > > Raw Gadget is similar to GadgetFS, but provides a more low-level and
> > > direct access to the USB Gadget layer for the userspace. The key
> > > differences are:
> > >
> > > 1. Every USB request is passed to the userspace to get a response, while
> > >    GadgetFS responds to some USB requests internally based on the provided
> > >    descriptors. However note, that the UDC driver might respond to some
> > >    requests on its own and never forward them to the Gadget layer.
> > >
> > > 2. GadgetFS performs some sanity checks on the provided USB descriptors,
> > >    while Raw Gadget allows you to provide arbitrary data as responses to
> > >    USB requests.
> > >
> > > 3. Raw Gadget provides a way to select a UDC device/driver to bind to,
> > >    while GadgetFS currently binds to the first available UDC.
> > >
> > > 4. Raw Gadget uses predictable endpoint names (handles) across different
> > >    UDCs (as long as UDCs have enough endpoints of each required transfer
> > >    type).
> > >
> > > 5. Raw Gadget has ioctl-based interface instead of a filesystem-based one.
> > >
> > > Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> > > ---
> > >
> > > Greg, I've assumed your LGTM meant that I can add a Reviewed-by from you.
> > >
> > > Felipe, looking forward to your review, thanks!
> >
> > Hi Greg and Felipe,
> >
> > I was wondering if it's feasible to get this reviewed and merged
> > during the upcoming merge window? This patch is the only piece missing
> > to enable USB fuzzing for Android common kernels on syzbot.
>
> No objection from me, if Felipe acks it I can take it...

Hi Felipe,

Any idea if you'll be able to look at this?

Thanks!