linux-kernel - Re: [PATCH v2 8/8] ib_uverbs: Support for kernel implementation of XRC

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1474055349.20134.39.camel@oracle.com>
Date:   Fri, 16 Sep 2016 21:49:09 +0200
From:   Knut Omang <knut.omang@...cle.com>
To:     Jason Gunthorpe <jgunthorpe@...idianresearch.com>
Cc:     Doug Ledford <dledford@...hat.com>, linux-rdma@...r.kernel.org,
        linux-kernel@...r.kernel.org, Sean Hefty <sean.hefty@...el.com>,
        Hal Rosenstock <hal.rosenstock@...il.com>,
        Matan Barak <matanb@...lanox.com>,
        Sagi Grimberg <sagi@...mberg.me>,
        Leon Romanovsky <leonro@...lanox.com>,
        Yishai Hadas <yishaih@...lanox.com>,
        Majd Dibbiny <majd@...lanox.com>,
        Eran Ben Elisha <eranbe@...lanox.com>,
        Or Gerlitz <ogerlitz@...lanox.com>
Subject: Re: [PATCH v2 8/8] ib_uverbs: Support for kernel implementation of
 XRC

On Fri, 2016-09-16 at 13:31 -0600, Jason Gunthorpe wrote:
> On Fri, Sep 16, 2016 at 08:31:19PM +0200, Knut Omang wrote:
> > +++ b/include/uapi/rdma/ib_user_verbs.h
> > @@ -725,6 +725,8 @@ struct ib_uverbs_send_wr {
> >  			__u32 reserved;
> >  		} ud;
> >  	} wr;
> > +	__u32 xrc_remote_srq_num;
> > +	__u32 reserved;
> >  };
> 
> You still need to discuss why this is OK...
> 
> Are you doing all this just to be able to use the existing post_send user
> space path in the common code? Is there a kernel XRC user planned?

Yes, with this patch, the SIF user level provider library is able to 
use either kernel verbs or user verbs on a per QP basis. This is a
very useful capability that the verbs API neatly lends itself almost 
completely to, except for this particular missing piece.

> Another approach would be to implement post_send in your driver and
> not rely on this common code path.

I agree this would be possible, but that would have been
to implement a generic feature which seems a natural completion
of what is already in there in provider specific code, something 
I would have thought from other discussions here is considered bad 
practice?

Thanks,
Knut

> 
> Jason