Re: [PATCH v2 1/6] driver core: Move the "authorized" attribute from USB/Thunderbolt to core

From: Dan Williams <dan.j.williams@intel.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Jonathan Corbet <corbet@lwn.net>,
	Kuppuswamy Sathyanarayanan
	<sathyanarayanan.kuppuswamy@linux.intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	"Michael S . Tsirkin" <mst@redhat.com>,
	Michael Jamet <michael.jamet@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	X86 ML <x86@kernel.org>, Yehezkel Bernat <YehezkelShB@gmail.com>,
	Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andreas Noever <andreas.noever@gmail.com>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Linux PCI <linux-pci@vger.kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	virtualization@lists.linux-foundation.org,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	USB list <linux-usb@vger.kernel.org>,
	"Rafael J . Wysocki" <rafael@kernel.org>
Subject: Re: [PATCH v2 1/6] driver core: Move the "authorized" attribute from USB/Thunderbolt to core
Date: Wed, 29 Sep 2021 18:55:12 -0700	[thread overview]
Message-ID: <CAPcyv4iiEC3B2i81evZpLP+XHa8dLkfgWmrY7HocORwP8FMPZQ@mail.gmail.com> (raw)
In-Reply-To: <20210930014229.GA447956@rowland.harvard.edu>

On Wed, Sep 29, 2021 at 6:43 PM Alan Stern <stern@rowland.harvard.edu> wrote:
>
> On Wed, Sep 29, 2021 at 06:05:06PM -0700, Kuppuswamy Sathyanarayanan wrote:
> > Currently bus drivers like "USB" or "Thunderbolt" implement a custom
> > version of device authorization to selectively authorize the driver
> > probes. Since there is a common requirement, move the "authorized"
> > attribute support to the driver core in order to allow it to be used
> > by other subsystems / buses.
> >
> > Similar requirements have been discussed in the PCI [1] community for
> > PCI bus drivers as well.
> >
> > No functional changes are intended. It just converts authorized
> > attribute from int to bool and moves it to the driver core. There
> > should be no user-visible change in the location or semantics of
> > attributes for USB devices.
> >
> > Regarding thunderbolt driver, although it declares sw->authorized as
> > "int" and allows 0,1,2 as valid values for sw->authorized attribute,
> > but within the driver, in all authorized attribute related checks,
> > it is treated as bool value. So when converting the authorized
> > attribute from int to bool value, there should be no functional
> > changes other than value 2 being not visible to the user.
> >
> > [1]: https://lore.kernel.org/all/CACK8Z6E8pjVeC934oFgr=VB3pULx_GyT2NkzAogdRQJ9TKSX9A@mail.gmail.com/
> >
> > Reviewed-by: Dan Williams <dan.j.williams@intel.com>
> > Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>
> Since you're moving the authorized flag from the USB core to the
> driver core, the corresponding sysfs attribute functions should be
> moved as well.

Unlike when 'removable' moved from USB to the driver core there isn't
a common definition for how the 'authorized' sysfs-attribute behaves
across buses. The only common piece is where this flag is stored in
the data structure, i.e. the 'authorized' sysfs interface is
purposefully left bus specific.

> Also, you ignored the usb_[de]authorize_interface() functions and
> their friends.

Ugh, yes.
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization