On Thu, 17 Mar 2011, David Miller wrote:

I had been meaning to bring this up from another perspective.

In networking, we often only ever access objects in base or
BH context.  Therefore in BH context cases we can do just
normal counter bumps without any of the special atomic or
IRQ disabling code at all.

We have the __ functions for that purpose. __this_cpu_inc f.e. falls back
to a simply ++ operation if the arch cannot provide something better.
irqsafe_xx are only used if the context does not provide any protection
and if there is the potential of the counter being incremented from an
interrupt context.