vcos_verify() returns an rvalue which the compiler expects to be
used and warns about.
In this usage of vcos_verify() it looks like vcos_assert()
would be better, since this code path should never be taken.
PID namespacing breaks VCHIQ as it uses PIDs as unique identifiers for VCHIQ
services, meaning messages sent from userland will contain a different ID than
the one expected by the GPU.
This patch addresses the problem uses the existing GET_CLIENT_ID ioctl to
retrieve the global PID as seen by the kernel rather than using the process's
reported PID.
