Some messing with error codes to return 0 on out id's and match

Some messing with error codes to return 0 on out id's and match
current situation.  Is this necessary? Looks a touch 'interesting'.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>