[ofa-general] Re: [PATCHv4 RFC] Scalable Reliable Connection: API and documentation

[Michael S. Tsirkin]

> Quoting Roland Dreier <rdreier at cisco.com>:
> Subject: Re: [PATCHv4 RFC] Scalable Reliable Connection: API and documentation
> 
>  > I actually took pains to avoid breaking the ABI, so I think we won't
>  > need to change the version and/or create compat wrappers. No?
> 
> It doesn't seem so to me -- for example
> 
>  > @@ -408,6 +415,7 @@ struct ibv_qp_init_attr {
>  >  	struct ibv_qp_cap	cap;
>  >  	enum ibv_qp_type	qp_type;
>  >  	int			sq_sig_all;
>  > +	struct ibv_src_domain  *src_domain;
>  >  };
> 
> so struct ibv_qp_init_attr gets bigger, and an app built against the
> old header but run against a new library will end up passing garbage
> in the src_domain field.  Or maybe that's OK -- an app built against
> the old header will never use the SRC qp type, is that the idea?

Exactly.

> Actually looking again, that may be the only glitch, although I'm not
> positive there aren't other problems -- lots of other structures
> change size so there may be other things I'm missing right now.

I think it's OK.
I did take pains to avoid breaking the ABI.

> But definitely the symbols should go into the IBVERBS_1.1 ABI at
> least, since they're not in libibverbs 1.0.

Sure. Thanks for pointing it out.

-- 
MST