This is effectively the closure of the ioctl handler table in
radeon_cp.c. That ioctl table is unused (we use the radeon_kms ioctl
table instead), so there is no way for any of the functions referenced
by the table to be called.
This was motivated by a report of an integer overflow vulnerability in
r600_cp_dispatch_texture() (the multiplication of tex->height and
tex->pitch, which are user-controlled). However, I believe the code
in question cannot get invoked.