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 X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56185C43387 for ; Thu, 17 Jan 2019 11:25:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2DFD82054F for ; Thu, 17 Jan 2019 11:25:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728451AbfAQLZV (ORCPT ); Thu, 17 Jan 2019 06:25:21 -0500 Received: from tama50.ecl.ntt.co.jp ([129.60.39.147]:47291 "EHLO tama50.ecl.ntt.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725889AbfAQLZU (ORCPT ); Thu, 17 Jan 2019 06:25:20 -0500 Received: from vc2.ecl.ntt.co.jp (vc2.ecl.ntt.co.jp [129.60.86.154]) by tama50.ecl.ntt.co.jp (8.13.8/8.13.8) with ESMTP id x0HBPEOi021775; Thu, 17 Jan 2019 20:25:14 +0900 Received: from vc2.ecl.ntt.co.jp (localhost [127.0.0.1]) by vc2.ecl.ntt.co.jp (Postfix) with ESMTP id 9B15D639311; Thu, 17 Jan 2019 20:25:14 +0900 (JST) Received: from jcms-pop21.ecl.ntt.co.jp (jcms-pop21.ecl.ntt.co.jp [129.60.87.134]) by vc2.ecl.ntt.co.jp (Postfix) with ESMTP id 8FB8B639309; Thu, 17 Jan 2019 20:25:14 +0900 (JST) Received: from makita-ubuntu.m.ecl.ntt.co.jp (unknown [129.60.241.182]) by jcms-pop21.ecl.ntt.co.jp (Postfix) with ESMTPSA id 88985400B79; Thu, 17 Jan 2019 20:25:14 +0900 (JST) From: Toshiaki Makita Subject: [PATCH net 7/7] virtio_net: Differentiate sk_buff and xdp_frame on freeing Date: Thu, 17 Jan 2019 20:20:45 +0900 Message-Id: <1547724045-2726-8-git-send-email-makita.toshiaki@lab.ntt.co.jp> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1547724045-2726-1-git-send-email-makita.toshiaki@lab.ntt.co.jp> References: <1547724045-2726-1-git-send-email-makita.toshiaki@lab.ntt.co.jp> X-CC-Mail-RelayStamp: 1 To: "David S. Miller" , "Michael S. Tsirkin" , Jason Wang Cc: Toshiaki Makita , netdev@vger.kernel.org, virtualization@lists.linux-foundation.org X-TM-AS-MML: disable Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org We do not reset or free up unused buffers when enabling/disabling XDP, so it can happen that xdp_frames are freed after disabling XDP or sk_buffs are freed after enabling XDP on xdp tx queues. Thus we need to handle both forms (xdp_frames and sk_buffs) regardless of XDP setting. One way to trigger this problem is to disable XDP when napi_tx is enabled. In that case, virtnet_xdp_set() calls virtnet_napi_enable() which kicks NAPI. The NAPI handler will call virtnet_poll_cleantx() which invokes free_old_xmit_skbs() for queues which have been used by XDP. Note that even with this change we need to keep skipping free_old_xmit_skbs() from NAPI handlers when XDP is enabled, because XDP tx queues do not aquire queue locks. Fixes: 4941d472bf95 ("virtio-net: do not reset during XDP set") Signed-off-by: Toshiaki Makita --- drivers/net/virtio_net.c | 54 +++++++++++++++++++++++++++++++++++++----------- 1 file changed, 42 insertions(+), 12 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 996de69..6598c25 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -57,6 +57,8 @@ #define VIRTIO_XDP_TX BIT(0) #define VIRTIO_XDP_REDIR BIT(1) +#define VIRTIO_XDP_FLAG BIT(0) + /* RX packet size EWMA. The average packet size is used to determine the packet * buffer size when refilling RX rings. As the entire RX ring may be refilled * at once, the weight is chosen so that the EWMA will be insensitive to short- @@ -252,6 +254,21 @@ struct padded_vnet_hdr { char padding[4]; }; +static bool is_xdp_frame(void *ptr) +{ + return (unsigned long)ptr & VIRTIO_XDP_FLAG; +} + +static void *xdp_to_ptr(struct xdp_frame *ptr) +{ + return (void *)((unsigned long)ptr | VIRTIO_XDP_FLAG); +} + +static struct xdp_frame *ptr_to_xdp(void *ptr) +{ + return (struct xdp_frame *)((unsigned long)ptr & ~VIRTIO_XDP_FLAG); +} + /* Converting between virtqueue no. and kernel tx/rx queue no. * 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq */ @@ -462,7 +479,8 @@ static int __virtnet_xdp_xmit_one(struct virtnet_info *vi, sg_init_one(sq->sg, xdpf->data, xdpf->len); - err = virtqueue_add_outbuf(sq->vq, sq->sg, 1, xdpf, GFP_ATOMIC); + err = virtqueue_add_outbuf(sq->vq, sq->sg, 1, xdp_to_ptr(xdpf), + GFP_ATOMIC); if (unlikely(err)) return -ENOSPC; /* Caller handle free/refcnt */ @@ -482,13 +500,13 @@ static int virtnet_xdp_xmit(struct net_device *dev, { struct virtnet_info *vi = netdev_priv(dev); struct receive_queue *rq = vi->rq; - struct xdp_frame *xdpf_sent; struct bpf_prog *xdp_prog; struct send_queue *sq; unsigned int len; int drops = 0; int kicks = 0; int ret, err; + void *ptr; int i; /* Only allow ndo_xdp_xmit if XDP is loaded on dev, as this @@ -507,8 +525,12 @@ static int virtnet_xdp_xmit(struct net_device *dev, } /* Free up any pending old buffers before queueing new ones. */ - while ((xdpf_sent = virtqueue_get_buf(sq->vq, &len)) != NULL) - xdp_return_frame(xdpf_sent); + while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) { + if (likely(is_xdp_frame(ptr))) + xdp_return_frame(ptr_to_xdp(ptr)); + else + dev_consume_skb_any(ptr); + } for (i = 0; i < n; i++) { struct xdp_frame *xdpf = frames[i]; @@ -1329,18 +1351,26 @@ static int virtnet_receive(struct receive_queue *rq, int budget, static void free_old_xmit_skbs(struct send_queue *sq) { - struct sk_buff *skb; unsigned int len; unsigned int packets = 0; unsigned int bytes = 0; + void *ptr; - while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) { - pr_debug("Sent skb %p\n", skb); + while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) { + if (likely(!is_xdp_frame(ptr))) { + struct sk_buff *skb = ptr; - bytes += skb->len; - packets++; + pr_debug("Sent skb %p\n", skb); - dev_consume_skb_any(skb); + bytes += skb->len; + dev_consume_skb_any(skb); + } else { + struct xdp_frame *frame = ptr_to_xdp(ptr); + + bytes += frame->len; + xdp_return_frame(frame); + } + packets++; } /* Avoid overhead when no packets have been processed @@ -2665,10 +2695,10 @@ static void free_unused_bufs(struct virtnet_info *vi) for (i = 0; i < vi->max_queue_pairs; i++) { struct virtqueue *vq = vi->sq[i].vq; while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) { - if (!is_xdp_raw_buffer_queue(vi, i)) + if (!is_xdp_frame(buf)) dev_kfree_skb(buf); else - xdp_return_frame(buf); + xdp_return_frame(ptr_to_xdp(buf)); } } -- 1.8.3.1