The CAN_RAW socket can set multiple CAN identifier specific filters that lead
to multiple filters in the af_can.c filter processing. These filters are
indenpendent from each other which leads to logical OR'ed filters when applied.

This patch makes sure that every CAN frame which is filtered for a specific
socket is only delivered once to the user space. This is independent from the
number of matching CAN filters of this socket.

As the raw_rcv() function is executed from NET_RX softirq the introduced
variables are implemented as per-CPU variables to avoid extensive locking at
CAN frame reception time.
Signed-off-by: NOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>