From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matan Barak Subject: Re: [PATCH V1 for-next 1/2] IB/core: Report LSO capabilities when querying device Date: Thu, 28 Apr 2016 11:02:53 +0300 Message-ID: <5721C3AD.8050407@mellanox.com> References: <1461765892-1285-1-git-send-email-matanb@mellanox.com> <1461765892-1285-2-git-send-email-matanb@mellanox.com> <1828884A29C6694DAF28B7E6B8A82373AB046AB1@ORSMSX109.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1828884A29C6694DAF28B7E6B8A82373AB046AB1-P5GAC/sN6hkd3b2yrw5b5LfspsVTdybXVpNB7YpNyf8@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Hefty, Sean" , Christoph Lameter Cc: Doug Ledford , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Majd Dibbiny , Bodong Wang List-Id: linux-rdma@vger.kernel.org On 28/04/2016 00:54, Hefty, Sean wrote: >>> +struct ib_lso_caps { >>> + u32 max_lso; >>> + u32 supported_qpts; /* Use enum ib_qp_type */ >> >> So this is a bitmap of the qps supported? And thus we have a limit now of >> 32 QP types. That needs to be documented and you need a BUILD_BUG_ON >> somewhere in case IB_QPT_MAX becomes larger than 32. Also needs to be >> better commented so we know this is a bitmap. > > I think it would make more sense to indicate what protocol, or specific aspect of a protocol, are being offloaded. Some qp types support LSO as a matter of practice. > For a lot of applications, we want to hide the lower level protocol. For example, we try hard to hide whether IB/RoCE is used by an application. Thus, is it wise to expose this thing in API? A user creates a UD QP, he doesn't know or care whether the lower layer is Ethernet (RoCE v1/V2) or IB. I agree that the max_lso could be different for various QP types and maybe probing a QP type would be favorable that getting this information in a generic query_device. -- 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