-----Original Message-----
From: Yuanhan Liu [mailto:yuanhan.liu@linux.intel.com]
Sent: Friday, March 17, 2017 4:29 PM
To: Tan, Jianfeng
Cc: dev@dpdk.org; david.marchand@6wind.com
Subject: Re: [PATCH 4/5] net/virtio-user: add lsc support with vhost-user
adapter

On Fri, Mar 03, 2017 at 05:56:42PM +0000, Jianfeng Tan wrote:

quoted

So far, virtio-user with vhost-user as the backend can only support
client mode. So when vhost user backend is down, i.e., unix socket
connection is broken and cannot be re-connected. We will force the
link state to be down.

Signed-off-by: Jianfeng Tan <redacted>
 static void
 virtio_user_read_dev_config(struct virtio_hw *hw, size_t offset,
 		     void *dst, int length)

@@ -63,8 +77,27 @@ virtio_user_read_dev_config(struct virtio_hw *hw,

size_t offset,

quoted

 		return;
 	}

-	if (offset == offsetof(struct virtio_net_config, status))
+	if (offset == offsetof(struct virtio_net_config, status)) {
+		char buf[128];
+
+		if (dev->vhostfd >= 0) {
+			int flags;
+			int r;
+
+			flags = fcntl(dev->vhostfd, F_GETFL);
+			fcntl(dev->vhostfd, F_SETFL, flags | O_NONBLOCK);
+			r = recv(dev->vhostfd, buf, 128, 0);

I think you need specify flag MSG_PEEK, to not consume the data if
there any?

Thanks for catching this issue, I'll fix it in next version.

Thanks,
Jianfeng