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From: Yunjian Wang <wangyunjian@huawei.com>
To: <mst@redhat.com>, <willemdebruijn.kernel@gmail.com>,
	<jasowang@redhat.com>, <kuba@kernel.org>, <bjorn@kernel.org>,
	<magnus.karlsson@intel.com>, <maciej.fijalkowski@intel.com>,
	<jonathan.lemon@gmail.com>, <davem@davemloft.net>
CC: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <kvm@vger.kernel.org>,
	<virtualization@lists.linux.dev>, <xudingke@huawei.com>,
	<liwei395@huawei.com>, Yunjian Wang <wangyunjian@huawei.com>
Subject: [PATCH net-next v2 2/3] vhost_net: Call peek_len when using xdp
Date: Wed, 28 Feb 2024 19:05:44 +0800
Message-ID: <1709118344-127812-1-git-send-email-wangyunjian@huawei.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain

If TUN supports AF_XDP TX zero-copy, the XDP program will enqueue
packets to the XDP ring and wake up the vhost worker. This requires
the vhost worker to call peek_len(), which can be used to consume
XDP descriptors.

Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
---
 drivers/vhost/net.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index f2ed7167c848..077e74421558 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -207,6 +207,11 @@ static int vhost_net_buf_peek_len(void *ptr)
 	return __skb_array_len_with_tag(ptr);
 }
 
+static bool vhost_sock_xdp(struct socket *sock)
+{
+	return sock_flag(sock->sk, SOCK_XDP);
+}
+
 static int vhost_net_buf_peek(struct vhost_net_virtqueue *nvq)
 {
 	struct vhost_net_buf *rxq = &nvq->rxq;
@@ -214,6 +219,13 @@ static int vhost_net_buf_peek(struct vhost_net_virtqueue *nvq)
 	if (!vhost_net_buf_is_empty(rxq))
 		goto out;
 
+	if (ptr_ring_empty(nvq->rx_ring)) {
+		struct socket *sock = vhost_vq_get_backend(&nvq->vq);
+		/* Call peek_len to consume XSK descriptors, when using xdp */
+		if (vhost_sock_xdp(sock) && sock->ops->peek_len)
+			sock->ops->peek_len(sock);
+	}
+
 	if (!vhost_net_buf_produce(nvq))
 		return 0;
 
@@ -346,11 +358,6 @@ static bool vhost_sock_zcopy(struct socket *sock)
 		sock_flag(sock->sk, SOCK_ZEROCOPY);
 }
 
-static bool vhost_sock_xdp(struct socket *sock)
-{
-	return sock_flag(sock->sk, SOCK_XDP);
-}
-
 /* In case of DMA done not in order in lower device driver for some reason.
  * upend_idx is used to track end of used idx, done_idx is used to track head
  * of used idx. Once lower device DMA done contiguously, we will signal KVM
-- 
2.41.0