[PATCH net-next 19/21] virtio-net: don't mix error-caused drops with XDP_DROP cases

From: Alexander Lobakin <alexandr.lobakin@intel.com>
To: "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>,
	Jesse Brandeburg <jesse.brandeburg@intel.com>,
	Lukasz Czapnik <lukasz.czapnik@intel.com>,
	Marcin Kubiak <marcin.kubiak@intel.com>,
	Michal Kubiak <michal.kubiak@intel.com>,
	Michal Swiatkowski <michal.swiatkowski@intel.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Netanel Belgazal <netanel@amazon.com>,
	Arthur Kiyanovski <akiyano@amazon.com>,
	Guy Tzalik <gtzalik@amazon.com>,
	Saeed Bishara <saeedb@amazon.com>,
	Ioana Ciornei <ioana.ciornei@nxp.com>,
	Claudiu Manoil <claudiu.manoil@nxp.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Marcin Wojtas <mw@semihalf.com>,
	Russell King <linux@armlinux.org.uk>,
	Edward Cree <ecree.xilinx@gmail.com>,
	Martin Habets <habetsm.xilinx@gmail.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Jesper Dangaard Brouer <hawk@kernel.org>,
	John Fastabend <john.fastabend@gmail.com>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>, KP Singh <kpsingh@kernel.org>,
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	Sameeh Jubran <sameehj@amazon.com>,
	Alexander Duyck <alexanderduyck@fb.com>,
	Danielle Ratson <danieller@nvidia.com>,
	Ido Schimmel <idosch@nvidia.com>, Andrew Lunn <andrew@lunn.ch>,
	Vladyslav Tarasiuk <vladyslavt@nvidia.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Jian Shen <shenjian15@huawei.com>,
	Petr Vorel <petr.vorel@gmail.com>, Dan Murphy <dmurphy@ti.com>,
	Yangbo Lu <yangbo.lu@nxp.com>, Michal Kubecek <mkubecek@suse.cz>,
	Zheng Yongjun <zhengyongjun3@huawei.com>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	YueHaibing <yuehaibing@huawei.com>,
	Johannes Berg <johannes@sipsolutions.net>,
	netdev@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org, bpf@vger.kernel.org
Subject: [PATCH net-next 19/21] virtio-net: don't mix error-caused drops with XDP_DROP cases
Date: Tue,  3 Aug 2021 18:42:17 +0200	[thread overview]
Message-ID: <20210803164217.4202-1-alexandr.lobakin@intel.com> (raw)
In-Reply-To: <20210803163641.3743-1-alexandr.lobakin@intel.com>

It's pretty confusing to have just one field for tracking both
XDP_DROP cases and various errors which lead to the frame being
dropped.
Add a new field, xdp_errors, to separate error paths, and leave
xdp_drops purely for counting frames with the XDP_DROP verdict.

Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
---
 drivers/net/virtio_net.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 8cbb4651ed75..acad099006cd 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -91,6 +91,7 @@ struct virtnet_rq_stats {
 	u64 xdp_tx;
 	u64 xdp_redirects;
 	u64 xdp_drops;
+	u64 xdp_errors;
 	u64 kicks;
 };
 
@@ -113,6 +114,7 @@ static const struct virtnet_stat_desc virtnet_rq_stats_desc[] = {
 	{ "xdp_tx",		VIRTNET_RQ_STAT(xdp_tx) },
 	{ "xdp_redirects",	VIRTNET_RQ_STAT(xdp_redirects) },
 	{ "xdp_drops",		VIRTNET_RQ_STAT(xdp_drops) },
+	{ "xdp_errors",		VIRTNET_RQ_STAT(xdp_errors) },
 	{ "kicks",		VIRTNET_RQ_STAT(kicks) },
 };
 
@@ -804,7 +806,8 @@ static struct sk_buff *receive_small(struct net_device *dev,
 			trace_xdp_exception(vi->dev, xdp_prog, act);
 			goto err_xdp;
 		case XDP_DROP:
-			goto err_xdp;
+			stats->xdp_drops++;
+			goto xdp_drop;
 		}
 	}
 	rcu_read_unlock();
@@ -828,8 +831,9 @@ static struct sk_buff *receive_small(struct net_device *dev,
 	return skb;
 
 err_xdp:
+	stats->xdp_errors++;
+xdp_drop:
 	rcu_read_unlock();
-	stats->xdp_drops++;
 err_len:
 	stats->drops++;
 	put_page(page);
@@ -1012,7 +1016,12 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 		case XDP_DROP:
 			if (unlikely(xdp_page != page))
 				__free_pages(xdp_page, 0);
-			goto err_xdp;
+
+			if (unlikely(act != XDP_DROP))
+				goto err_xdp;
+
+			stats->xdp_drops++;
+			goto xdp_drop;
 		}
 	}
 	rcu_read_unlock();
@@ -1081,8 +1090,9 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 	return head_skb;
 
 err_xdp:
+	stats->xdp_errors++;
+xdp_drop:
 	rcu_read_unlock();
-	stats->xdp_drops++;
 err_skb:
 	put_page(page);
 	while (num_buf-- > 1) {
-- 
2.31.1

