On Thu, Sep 30, 2021 at 8:00 AM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > On Wed, Sep 29, 2021 at 06:55:12PM -0700, Dan Williams wrote: > > On Wed, Sep 29, 2021 at 6:43 PM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx/ > > > > > > > > Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx> > > > > Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> > > > > > > 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. > > How about implementing "library" versions of show_authorized() and > store_authorized() that the bus-specific attribute routines can call? > These library routines would handle parsing the input values, storing > the new flag, and displaying the stored flag value. That way at > least the common parts of these APIs would be centralized in the > driver core, and any additional functionality could easily be added > by the bus-specific attribute routine. > While show_authorized() seems like it could be standardized, have a look at what the different store_authorized() implementations do. Thunderbolt wants "switch approval" vs "switch challenge" and USB has a bunch of bus-specific work to do when the authorization state changes. I don't see much room for a library to help there as more buses add authorization support. That said I do think it would be useful to have a common implementation available for generic probe authorization to toggle the flag if the bus does not have any authorization work to do, but that seems a follow-on once this core is accepted.
