From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer Subject: Re: [RFC PATCH v2 2/5] net: add ndo to set bpf prog in adapter rx Date: Fri, 8 Apr 2016 11:38:58 +0200 Message-ID: <20160408113858.4d39b274@redhat.com> References: <1460090930-11219-1-git-send-email-bblanco@plumgrid.com> <1460090930-11219-2-git-send-email-bblanco@plumgrid.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: davem@davemloft.net, netdev@vger.kernel.org, tom@herbertland.com, alexei.starovoitov@gmail.com, ogerlitz@mellanox.com, daniel@iogearbox.net, eric.dumazet@gmail.com, ecree@solarflare.com, john.fastabend@gmail.com, tgraf@suug.ch, johannes@sipsolutions.net, eranlinuxmellanox@gmail.com, lorenzo@google.com, brouer@redhat.com To: Brenden Blanco Return-path: Received: from mx1.redhat.com ([209.132.183.28]:56138 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758004AbcDHJjV (ORCPT ); Fri, 8 Apr 2016 05:39:21 -0400 In-Reply-To: <1460090930-11219-2-git-send-email-bblanco@plumgrid.com> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 7 Apr 2016 21:48:47 -0700 Brenden Blanco wrote: > Add two new set/get netdev ops for drivers implementing the > BPF_PROG_TYPE_PHYS_DEV filter. > > Signed-off-by: Brenden Blanco [...] > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index cb4e508..3acf732 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h [...] > @@ -1102,6 +1103,14 @@ struct tc_to_netdev { > * appropriate rx headroom value allows avoiding skb head copy on > * forward. Setting a negative value resets the rx headroom to the > * default value. > + * int (*ndo_bpf_set)(struct net_device *dev, struct bpf_prog *prog); > + * This function is used to set or clear a bpf program used in the > + * earliest stages of packet rx. The prog will have been loaded as > + * BPF_PROG_TYPE_PHYS_DEV. The callee is responsible for calling > + * bpf_prog_put on any old progs that are stored, but not on the passed > + * in prog. > + * bool (*ndo_bpf_get)(struct net_device *dev); > + * This function is used to check if a bpf program is set on the device. > * This interface for the entire device, right. I can imagine that users want to attach a eBPF program per RX queue. Can we adapt the interface to support this? (could default to adding it all queues) I'm also wondering if we should add a "flags" parameter. Or maybe we can extend 'struct bpf_prog' with I have in mind. When the eBPF program is attached to a RX queue, I want to know if the program want to modify packet-data, up-front. The problem is that most drivers use dma_sync, which means that data is considered 'read-only' (the "considered" part depend on DMA engine, and we might find a DMA loop-hole for some configs). If the program want to write, the driver have the option of reconfiguring the driver routine to use dma_unmap, before handing over the page. Or driver can also choose to realloc the specific RX ring queue pages as single pages (using dma_map/unmap consistently). This also allow us to give a return code indicating given driver does not support writable packet-pages (rejecting program). -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer