The dvb core only uses the big kernel lock in the open
and ioctl functions, which means it can be replaced with
a dvb specific mutex. Fortunately, all the ioctl functions
go through dvb_usercopy, so we can move the serialization
in there.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>