[dpdk-dev] [PATCH] vhost: added user callbacks for socket open/close

[Dariusz Stojaczyk]

When user receives destroy_device signal, he does not know *why* that
event happened. He does not differ between socket shutdown and virtio
processing pause. User could completely delete device during transition
from BIOS to kernel, causing freeze or possibly kernel panic. Instead
of changing new_device/destroy_device callbacks and breaking the ABI,
a set of new functions new_connection/destroy_connection has been added.

Signed-off-by: Dariusz Stojaczyk <dariuszx.stojaczyk at intel.com>
---
 lib/librte_vhost/rte_vhost.h |  5 ++++-
 lib/librte_vhost/socket.c    | 23 +++++++++++++++++++----
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/lib/librte_vhost/rte_vhost.h b/lib/librte_vhost/rte_vhost.h
index 8c974eb..8f86167 100644
--- a/lib/librte_vhost/rte_vhost.h
+++ b/lib/librte_vhost/rte_vhost.h
@@ -107,7 +107,10 @@ struct vhost_device_ops {
 	 */
 	int (*features_changed)(int vid, uint64_t features);
 
-	void *reserved[4]; /**< Reserved for future extension */
+	int (*new_connection)(int vid);		/**< Connect to socket. */
+	void (*destroy_connection)(int vid);	/**< Disconnect from socket */
+
+	void *reserved[2]; /**< Reserved for future extension */
 };
 
 /**
diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
index 41aa3f9..4ab4ff7 100644
--- a/lib/librte_vhost/socket.c
+++ b/lib/librte_vhost/socket.c
@@ -230,24 +230,36 @@ vhost_user_add_connection(int fd, struct vhost_user_socket *vsocket)
 
 	RTE_LOG(INFO, VHOST_CONFIG, "new device, handle is %d\n", vid);
 
+	if (vsocket->notify_ops->new_connection) {
+		ret = vsocket->notify_ops->new_connection(vid);
+		if (ret < 0) {
+			RTE_LOG(ERR, VHOST_CONFIG,
+				"failed to add vhost user connection with fd %d\n",
+				fd);
+			goto err;
+		}
+	}
+
 	conn->connfd = fd;
 	conn->vsocket = vsocket;
 	conn->vid = vid;
 	ret = fdset_add(&vhost_user.fdset, fd, vhost_user_read_cb,
 			NULL, conn);
 	if (ret < 0) {
-		conn->connfd = -1;
-		free(conn);
-		close(fd);
 		RTE_LOG(ERR, VHOST_CONFIG,
 			"failed to add fd %d into vhost server fdset\n",
 			fd);
-		return;
+		goto err;
 	}
 
 	pthread_mutex_lock(&vsocket->conn_mutex);
 	TAILQ_INSERT_TAIL(&vsocket->conn_list, conn, next);
 	pthread_mutex_unlock(&vsocket->conn_mutex);
+	return;
+
+err:
+	free(conn);
+	close(fd);
 }
 
 /* call back when there is new vhost-user connection from client  */
@@ -277,6 +289,9 @@ vhost_user_read_cb(int connfd, void *dat, int *remove)
 		*remove = 1;
 		vhost_destroy_device(conn->vid);
 
+		if (vsocket->notify_ops->destroy_connection)
+			vsocket->notify_ops->destroy_connection(conn->vid);
+
 		pthread_mutex_lock(&vsocket->conn_mutex);
 		TAILQ_REMOVE(&vsocket->conn_list, conn, next);
 		pthread_mutex_unlock(&vsocket->conn_mutex);
-- 
2.7.4