powerpc/cell/oprofile: fix mutex locking for spu-oprofile

[Arnd Bergmann]

On Wednesday 20 August 2008, Robert Richter wrote:
> I am fine with the changes with the exception of removing
> add_event_entry() from include/linux/oprofile.h. Though there is no
> usage of the function also in other architectures anymore, this change
> in the API should be discussed on the oprofile mailing list. Please
> separate the change in a different patch and submit it to the mailing
> list. If there are no objections then, this change can go upstream as
> well.

As an explanation, the removal of add_event_entry is the whole point
of this patch. add_event_entry must only be called with buffer_mutex
held, but buffer_mutex itself is not exported.
I'm pretty sure that no other user of add_event_entry exists, as it
was exported specifically for the SPU support and that never worked.
Any other (theoretical) code using it would be broken in the same way
and need a corresponding fix.

We can easily leave the declaration in place, but I'd recommend removing
it eventually. If you prefer to keep it, how about marking it as
__deprecated?

	Arnd <><