drivers/block/rbd.c: atomic_inc_return_safe() & atomic_dec_return_safe()

[Shuah Khan]

All,

I came across these atomic_inc_return_safe() & atomic_dec_return_safe()
functions that hold the counters at safe values.

atomic_inc_return_safe()

If the counter is already 0 it will not be incremented.
If the counter is already at its maximum value returns
-EINVAL without updating it.

atomic_dec_return_safe()

Decrement the counter.  Return the resulting value, or -EINVAL

These two routines are static and only used in rbd.c.

Can these become part of atomic_t ops?

thanks,
-- Shuah