| Message ID | 20210318155202.22230-8-johan@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | USB: cdc-acm: probe fixes | expand |
Am Donnerstag, den 18.03.2021, 16:52 +0100 schrieb Johan Hovold: > Make sure to always claim the data interface and bail out if it's > already bound to another driver or isn't authorised. Hi, Thanks for the fixes. All previous ones are good work. this one is problematic I am afraid. acm_probe() has a test for the availability of the interface: if (!combined_interfaces && usb_interface_claimed(data_interface)) { /* valid in this context */ dev_dbg(&intf->dev, "The data interface isn't available\n"); return -EBUSY; } That check is ancient. BKL still existed. If you want to remove it and do proper error handling, that would be good. But if you do error handling, the check has to go, too. Regards Oliver
On Mon, Mar 22, 2021 at 11:46:47AM +0100, Oliver Neukum wrote: > Am Donnerstag, den 18.03.2021, 16:52 +0100 schrieb Johan Hovold: > > Make sure to always claim the data interface and bail out if it's > > already bound to another driver or isn't authorised. > > Hi, > > Thanks for the fixes. All previous ones are good work. > this one is problematic I am afraid. > > > acm_probe() has a test for the availability of the interface: > > if (!combined_interfaces && usb_interface_claimed(data_interface)) { > /* valid in this context */ > dev_dbg(&intf->dev, "The data interface isn't available\n"); > return -EBUSY; > } > > That check is ancient. BKL still existed. If you want to remove it > and do proper error handling, that would be good. But if you do > error handling, the check has to go, too. Thanks, this bit can go indeed. But note that it's simply because it's now redundant. I'll send a v2. Johan
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 6991ffd66c5d..58c444f9db5e 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -1486,7 +1486,11 @@ static int acm_probe(struct usb_interface *intf, acm->line.bDataBits = 8; acm_set_line(acm, &acm->line); - usb_driver_claim_interface(&acm_driver, data_interface, acm); + if (!acm->combined_interfaces) { + rv = usb_driver_claim_interface(&acm_driver, data_interface, acm); + if (rv) + goto err_remove_files; + } tty_dev = tty_port_register_device(&acm->port, acm_tty_driver, minor, &control_interface->dev); @@ -1508,6 +1512,7 @@ static int acm_probe(struct usb_interface *intf, usb_set_intfdata(data_interface, NULL); usb_driver_release_interface(&acm_driver, data_interface); } +err_remove_files: if (acm->country_codes) { device_remove_file(&acm->control->dev, &dev_attr_wCountryCodes);
Make sure to always claim the data interface and bail out if it's already bound to another driver or isn't authorised. Signed-off-by: Johan Hovold <johan@kernel.org> --- drivers/usb/class/cdc-acm.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)