If usb_8dev_start() fails to submit urb,
it unanchors the urb but forgets to free it.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: NAlexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

The usb_8dev hardware has problems on some xhci USB hosts. The driver fails to
read the firmware revision in the probe function. This leads to the following
Oops:

    [ 3356.635912] kernel BUG at net/core/dev.c:5701!

The driver tries to free the netdev, which has already been registered, without
unregistering it.

This patch fixes the problem by unregistering the netdev in the error path.
Reported-by: NMichael Olbrich <m.olbrich@pengutronix.de>
Reviewed-by: NBernd Krumboeck <krumboeck@universalnet.at>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

alloc failures already get standardized OOM
messages and a dump_stack.
Signed-off-by: NJoe Perches <joe@perches.com>
Acked-by: NMarc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add support for canbus activity led indicators on usb_8dev devices by
calling appropriate can_led functions.

These are only enabled when CONFIG_CAN_LEDS is Y, becomes no-op
otherwise.
Signed-off-by: NBernd Krumboeck <krumboeck@universalnet.at>
Signed-off-by: NFabio Baltieri <fabio.baltieri@gmail.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

Add device driver for USB2CAN interface from "8 devices" (http://www.8devices.com).

changes since v10:
* small cleanups

changes since v9:
* fixed syslog messages
* fixed crc error number
* increased MAX_RX_URBS and MAX_TX_URBS

changes since v8:
* remove all sysfs files

changes since v7:
* add sysfs documentation
* fix minor styling issue
* fixed can state for passive mode
* changed handling for crc errors

changes since v6:
* changed some variable types to big endian equivalent
* small cleanups

changes since v5:
* unlock mutex on error

changes since v4:
* removed FSF address
* renamed struct usb_8dev
* removed unused variable free_slots
* replaced some _to_cpu functions with pointer equivalent
* fix return value for usb_8dev_set_mode
* handle can errors with separate function
* fix overrun error handling
* rewrite error handling for usb_8dev_start_xmit
* fix urb submit in usb_8dev_start
* various small fixes
Acked-by: NWolfgang Grandegger <wg@grandegger.com>
Tested-by: NOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: NBernd Krumboeck <krumboeck@universalnet.at>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>