[openib-general] error return values from userspace calls

[Sean Hefty]

Pete Wyckoff wrote:
> Maybe some of this is bugs.  Any general consensus on what the
> official pattern should be?  It would make coders' lives easier if
> there were a single error-reporting style.

We should have a single error-reporting style.

> The RDMA CM functions follow a different convention pretty
> consistently.  They return negative errnos like -EINVAL on error.
> Except they do not interpret system call return values that show up
> in errno:

Michael or someone pointed this out to me a while ago.  I just haven't had time 
to correct this yet.

- Sean