From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9ECE4C3A5A7 for ; Thu, 8 Dec 2022 08:25:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229517AbiLHIZq (ORCPT ); Thu, 8 Dec 2022 03:25:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34174 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229675AbiLHIZf (ORCPT ); Thu, 8 Dec 2022 03:25:35 -0500 Received: from out199-8.us.a.mail.aliyun.com (out199-8.us.a.mail.aliyun.com [47.90.199.8]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4CD595E3DC; Thu, 8 Dec 2022 00:25:22 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R131e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045176;MF=hengqi@linux.alibaba.com;NM=0;PH=DS;RN=11;SR=0;TI=SMTPD_---0VWpUtXs_1670487916; Received: from 30.221.147.145(mailfrom:hengqi@linux.alibaba.com fp:SMTPD_---0VWpUtXs_1670487916) by smtp.aliyun-inc.com; Thu, 08 Dec 2022 16:25:17 +0800 Message-ID: Date: Thu, 8 Dec 2022 16:25:15 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:108.0) Gecko/20100101 Thunderbird/108.0 Subject: Re: [RFC PATCH 5/9] virtio_net: build xdp_buff with multi buffers To: Jason Wang Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, "Michael S. Tsirkin" , Paolo Abeni , Jakub Kicinski , John Fastabend , "David S. Miller" , Daniel Borkmann , Alexei Starovoitov , Eric Dumazet References: <20221122074348.88601-1-hengqi@linux.alibaba.com> <20221122074348.88601-6-hengqi@linux.alibaba.com> From: Heng Qi In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org 在 2022/12/6 下午2:14, Jason Wang 写道: > On Tue, Nov 22, 2022 at 3:44 PM Heng Qi wrote: >> Support xdp for multi buffer packets. >> >> Putting the first buffer as the linear part for xdp_buff, >> and the rest of the buffers as non-linear fragments to struct >> skb_shared_info in the tailroom belonging to xdp_buff. >> >> Signed-off-by: Heng Qi >> Reviewed-by: Xuan Zhuo >> --- >> drivers/net/virtio_net.c | 74 ++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 74 insertions(+) >> >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >> index cd65f85d5075..20784b1d8236 100644 >> --- a/drivers/net/virtio_net.c >> +++ b/drivers/net/virtio_net.c >> @@ -911,6 +911,80 @@ static struct sk_buff *receive_big(struct net_device *dev, >> return NULL; >> } >> >> +static int virtnet_build_xdp_buff(struct net_device *dev, >> + struct virtnet_info *vi, >> + struct receive_queue *rq, >> + struct xdp_buff *xdp, >> + void *buf, >> + unsigned int len, >> + unsigned int frame_sz, >> + u16 *num_buf, >> + unsigned int *xdp_frags_truesize, >> + struct virtnet_rq_stats *stats) >> +{ >> + unsigned int tailroom = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); >> + struct virtio_net_hdr_mrg_rxbuf *hdr = buf; >> + unsigned int truesize, headroom; >> + struct skb_shared_info *shinfo; >> + unsigned int xdp_frags_truesz = 0; >> + unsigned int cur_frag_size; >> + struct page *page; >> + skb_frag_t *frag; >> + int offset; >> + void *ctx; >> + >> + xdp_init_buff(xdp, frame_sz, &rq->xdp_rxq); >> + xdp_prepare_buff(xdp, buf - VIRTIO_XDP_HEADROOM, >> + VIRTIO_XDP_HEADROOM + vi->hdr_len, len - vi->hdr_len, true); >> + shinfo = xdp_get_shared_info_from_buff(xdp); >> + shinfo->nr_frags = 0; >> + shinfo->xdp_frags_size = 0; >> + >> + if ((*num_buf - 1) > MAX_SKB_FRAGS) >> + return -EINVAL; >> + >> + while ((--*num_buf) >= 1) { >> + buf = virtqueue_get_buf_ctx(rq->vq, &len, &ctx); > So this works only for a mergeable buffer, I wonder if it's worth it > to make it work for big mode as well. Or at least we can mention it as > a TODO somewhere and rename this function (with mergeable suffix). Yes, I'm leaning towards the latter, I'll rename it with a mergeable suffix in the next version. Thanks. > > Others look good. > > Thanks > >> + if (unlikely(!buf)) { >> + pr_debug("%s: rx error: %d buffers out of %d missing\n", >> + dev->name, *num_buf, >> + virtio16_to_cpu(vi->vdev, hdr->num_buffers)); >> + dev->stats.rx_length_errors++; >> + return -EINVAL; >> + } >> + >> + if (!xdp_buff_has_frags(xdp)) >> + xdp_buff_set_frags_flag(xdp); >> + >> + stats->bytes += len; >> + page = virt_to_head_page(buf); >> + offset = buf - page_address(page); >> + truesize = mergeable_ctx_to_truesize(ctx); >> + headroom = mergeable_ctx_to_headroom(ctx); >> + >> + cur_frag_size = truesize + (headroom ? (headroom + tailroom) : 0); >> + xdp_frags_truesz += cur_frag_size; >> + if (unlikely(len > truesize || cur_frag_size > PAGE_SIZE)) { >> + pr_debug("%s: rx error: len %u exceeds truesize %lu\n", >> + dev->name, len, (unsigned long)ctx); >> + dev->stats.rx_length_errors++; >> + return -EINVAL; >> + } >> + >> + frag = &shinfo->frags[shinfo->nr_frags++]; >> + __skb_frag_set_page(frag, page); >> + skb_frag_off_set(frag, offset); >> + skb_frag_size_set(frag, len); >> + if (page_is_pfmemalloc(page)) >> + xdp_buff_set_frag_pfmemalloc(xdp); >> + >> + shinfo->xdp_frags_size += len; >> + } >> + >> + *xdp_frags_truesize = xdp_frags_truesz; >> + return 0; >> +} >> + >> static struct sk_buff *receive_mergeable(struct net_device *dev, >> struct virtnet_info *vi, >> struct receive_queue *rq, >> -- >> 2.19.1.6.gb485710b >>