On Thu, Jun 23, 2022 at 08:59:52AM -0700, Dmitry Torokhov wrote: > On Thu, Jun 23, 2022 at 08:24:46AM +0200, Johan Hovold wrote: > > Add a sanity check on the device id-table driver_info field to make sure > > we never access a type structure (and function pointers) outside of the > > device info array (e.g. if someone fails to ifdef a device-id entry). > > > > Note that this also suppresses a compiler warning with -Warray-bounds > > (gcc-11.3.0) when compile-testing the driver without enabling any of > > the device type Kconfig options: > > > > drivers/input/touchscreen/usbtouchscreen.c: In function 'usbtouch_probe': > > drivers/input/touchscreen/usbtouchscreen.c:1668:16:warning: array subscript <unknown> is outside array bounds of 'struct usbtouch_device_info[0]' [-Warray-bounds] > > 1668 | type = &usbtouch_dev_info[id->driver_info]; > > > > Signed-off-by: Johan Hovold <johan@xxxxxxxxxx> > > --- > > > > Changes in v2 > > - use ARRAY_SIZE() for the sanity check (Dmitry) > > - drop the dummy entry and combine the two patches as the sanity check > > itself is enough to suppress the compiler warning (Dmitry) > > - use -ENODEV instead of -EINVAL even if this means no error will be > > logged in the unlikely event of a future driver bug > > Is this on purpose or because I happened to have used this error code > when I suggested the change? I'm fine with returning -EINVAL there. It was on purpose. Returning -EINVAL (invalid argument) here just doesn't seem quite right. I skimmed the errno list for a better alternative, but decided -ENODEV works as well. If there's ever a driver bug that triggers this, you could say the device isn't supported in that configuration. ;) If you prefer -EINVAL, I'll change it back. Johan
