[openib-general] Different low level drivers returns different return values incase of an error

[Michael S. Tsirkin]

> Anyway we should use same error
> codes for both kernel and user space verbs.

This actually does not sound like a good idea.
In particular returning -<errno> values, or incoding them in pointers
by means of PTR_ERR is the standard in linux kernel but seems quite
nonstandard for a userspace library.

-- 
MST