From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 10/11] IB: only keep a single key in struct ib_mr Date: Tue, 22 Dec 2015 14:13:27 +0100 Message-ID: <20151222131326.GA25267@lst.de> References: <1448214409-7729-1-git-send-email-hch@lst.de> <1448214409-7729-11-git-send-email-hch@lst.de> <56791542.6020604@dev.mellanox.co.il> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <56791542.6020604-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Sagi Grimberg Cc: Christoph Hellwig , dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Liran Liss List-Id: linux-rdma@vger.kernel.org On Tue, Dec 22, 2015 at 11:17:54AM +0200, Sagi Grimberg wrote: > What makes me worried here is that the IB/RoCE specification really > defines different keys for local and remote access. I'm less concerned > about our consumers but more about our providers. We keep seeing new > providers come along and its not impossible that a specific HW will > *rely* on this distinction. In such a case we'd need to revert this > patch altogether in that very moment. > > I think we're better off working on proper abstractions to help ULPs > get it right (and simple!), without risking future devices support. With the new API in the next patch ULPs simply can't request an lkey and a rkey at the same time, so for kernel use it's not a problmblem at all. That leaves my favourite nightmare: uverbs, which of course allows for everything under the sun, just because we can. I guess the right answer to that problem is to first split the data structures for kernel and user MRs, which we probably should have done much earlier. Not just because of this but also because of other issues like all the fields your FR API changs added to ib_mr that aren't needed for user MRs, or becaue the user MR structure should reallbe be merged with struct ib_umem. > > Sagi. ---end quoted text--- -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html