[dm-devel] Proposed changes to the dm_target interface

[Joe Thornber <joe fib011235813 fsnet co uk>]

These patches contain some proposed changes to the dm_target
interface, as such they will effect anyone writing their own targets.
Could people take a look at them and give me feedback please ?

The first change adds an endio method, if this method is defined it
will be called whenever the mapped io has completed.

The second change allows the map() method to optionally pass a void *
through to the endio() method.  This is a little bit ugly, but I think
the benefits justify it.

Thoughts ?

- Joe