[dpdk-dev] [PATCH v2 5/5] net/vhost: add memory checking

[zhiyong.yang@intel.com]

When vhost user PMD works in client mode to connect/reconnect virtio-user
with server mode, new thread sometimes may run to new_device before
queue_setup has been done, So have to wait until memory allocation is
done.

Release note is updated in the patch.

Signed-off-by: Zhiyong Yang <zhiyong.yang@intel.com>
---
 doc/guides/rel_notes/release_18_05.rst | 7 +++++++
 drivers/net/vhost/rte_eth_vhost.c      | 9 +++++++++
 2 files changed, 16 insertions(+)

diff --git a/doc/guides/rel_notes/release_18_05.rst b/doc/guides/rel_notes/release_18_05.rst
index 3923dc253..7b301f021 100644
--- a/doc/guides/rel_notes/release_18_05.rst
+++ b/doc/guides/rel_notes/release_18_05.rst
@@ -41,6 +41,13 @@ New Features
      Also, make sure to start the actual text at the margin.
      =========================================================
 
+* **Added support for virtio-user server mode.**
+
+  In a container environment if the vhost-user backend restarts, there's no way
+  for it to reconnect to virtio-user. To address this, support for server mode
+  is added. In this mode the socket file is created by virtio-user, which the
+  backend then connects to. This means that if the backend restarts, it can
+  reconnect to virtio-user and continue communications.
 
 API Changes
 -----------
diff --git a/drivers/net/vhost/rte_eth_vhost.c b/drivers/net/vhost/rte_eth_vhost.c
index 3aae01c39..2490bad0b 100644
--- a/drivers/net/vhost/rte_eth_vhost.c
+++ b/drivers/net/vhost/rte_eth_vhost.c
@@ -580,6 +580,15 @@ new_device(int vid)
 		eth_dev->data->numa_node = newnode;
 #endif
 
+	/* The thread may run here before eth_dev->data->rx_queues or
+	 * eth_dev->data->tx_queues have gotten valid memory, so have to
+	 * wait until memory allocation is done.
+	 */
+	while (!eth_dev->data->rx_queues ||
+	       !eth_dev->data->tx_queues) {
+		usleep(1);
+	}
+
 	for (i = 0; i < eth_dev->data->nb_rx_queues; i++) {
 		vq = eth_dev->data->rx_queues[i];
 		if (vq == NULL)
-- 
2.14.3