[dpdk-dev] [PATCH v3] vhost: fix driver unregister for client mode

[Ilya Maximets]

Currently while calling of 'rte_vhost_driver_unregister()' connection
to QEMU will not be closed. This leads to inability to register driver
again and reconnect to same virtual machine.

This scenario is reproducible with OVS. While executing of the following
command vhost port will be re-created (will be executed
'rte_vhost_driver_register()' followed by 'rte_vhost_driver_unregister()')
network will be broken and QEMU possibly will crash:

	ovs-vsctl set Interface vhost1 ofport_request=15

Fix this by closing all established connections on driver unregister and
removing of pending connections from reconnection list.

Fixes: 64ab701c3d1e ("vhost: add vhost-user client mode")

Signed-off-by: Ilya Maximets <i.maximets at samsung.com>
---

Version 3:
	* fixed leak of file descriptors by adding of
	  'close(reconn->fd)' to 'vhost_user_remove_reconnect()'

Version 2:
	* style fixes.

 lib/librte_vhost/vhost_user/fd_man.c         | 15 ++++++--
 lib/librte_vhost/vhost_user/fd_man.h         |  2 +-
 lib/librte_vhost/vhost_user/vhost-net-user.c | 57 ++++++++++++++++++++++++----
 3 files changed, 63 insertions(+), 11 deletions(-)

diff --git a/lib/librte_vhost/vhost_user/fd_man.c b/lib/librte_vhost/vhost_user/fd_man.c
index c691339..2d3eeb7 100644
--- a/lib/librte_vhost/vhost_user/fd_man.c
+++ b/lib/librte_vhost/vhost_user/fd_man.c
@@ -132,8 +132,10 @@ fdset_init(struct fdset *pfdset)
 	if (pfdset == NULL)
 		return;
 
-	for (i = 0; i < MAX_FDS; i++)
+	for (i = 0; i < MAX_FDS; i++) {
 		pfdset->fd[i].fd = -1;
+		pfdset->fd[i].dat = NULL;
+	}
 	pfdset->num = 0;
 }
 
@@ -166,14 +168,16 @@ fdset_add(struct fdset *pfdset, int fd, fd_cb rcb, fd_cb wcb, void *dat)
 
 /**
  *  Unregister the fd from the fdset.
+ *  Returns context of a given fd or NULL.
  */
-void
+void *
 fdset_del(struct fdset *pfdset, int fd)
 {
 	int i;
+	void *dat = NULL;
 
 	if (pfdset == NULL || fd == -1)
-		return;
+		return NULL;
 
 	do {
 		pthread_mutex_lock(&pfdset->fd_mutex);
@@ -181,13 +185,17 @@ fdset_del(struct fdset *pfdset, int fd)
 		i = fdset_find_fd(pfdset, fd);
 		if (i != -1 && pfdset->fd[i].busy == 0) {
 			/* busy indicates r/wcb is executing! */
+			dat = pfdset->fd[i].dat;
 			pfdset->fd[i].fd = -1;
 			pfdset->fd[i].rcb = pfdset->fd[i].wcb = NULL;
+			pfdset->fd[i].dat = NULL;
 			pfdset->num--;
 			i = -1;
 		}
 		pthread_mutex_unlock(&pfdset->fd_mutex);
 	} while (i != -1);
+
+	return dat;
 }
 
 /**
@@ -203,6 +211,7 @@ fdset_del_slot(struct fdset *pfdset, int index)
 
 	pfdset->fd[index].fd = -1;
 	pfdset->fd[index].rcb = pfdset->fd[index].wcb = NULL;
+	pfdset->fd[index].dat = NULL;
 	pfdset->num--;
 
 	pthread_mutex_unlock(&pfdset->fd_mutex);
diff --git a/lib/librte_vhost/vhost_user/fd_man.h b/lib/librte_vhost/vhost_user/fd_man.h
index 74ecde2..bd66ed1 100644
--- a/lib/librte_vhost/vhost_user/fd_man.h
+++ b/lib/librte_vhost/vhost_user/fd_man.h
@@ -60,7 +60,7 @@ void fdset_init(struct fdset *pfdset);
 int fdset_add(struct fdset *pfdset, int fd,
 	fd_cb rcb, fd_cb wcb, void *dat);
 
-void fdset_del(struct fdset *pfdset, int fd);
+void *fdset_del(struct fdset *pfdset, int fd);
 
 void fdset_event_dispatch(struct fdset *pfdset);
 
diff --git a/lib/librte_vhost/vhost_user/vhost-net-user.c b/lib/librte_vhost/vhost_user/vhost-net-user.c
index f0ea3a2..62c5ec3 100644
--- a/lib/librte_vhost/vhost_user/vhost-net-user.c
+++ b/lib/librte_vhost/vhost_user/vhost-net-user.c
@@ -60,6 +60,7 @@
 struct vhost_user_socket {
 	char *path;
 	int listenfd;
+	int connfd;
 	bool is_server;
 	bool reconnect;
 };
@@ -277,11 +278,13 @@ vhost_user_add_connection(int fd, struct vhost_user_socket *vsocket)
 
 	RTE_LOG(INFO, VHOST_CONFIG, "new device, handle is %d\n", vid);
 
+	vsocket->connfd = fd;
 	conn->vsocket = vsocket;
 	conn->vid = vid;
 	ret = fdset_add(&vhost_user.fdset, fd, vhost_user_msg_handler,
 			NULL, conn);
 	if (ret < 0) {
+		vsocket->connfd = -1;
 		free(conn);
 		close(fd);
 		RTE_LOG(ERR, VHOST_CONFIG,
@@ -329,6 +332,7 @@ vhost_user_msg_handler(int connfd, void *dat, int *remove)
 			RTE_LOG(ERR, VHOST_CONFIG,
 				"vhost read incorrect message\n");
 
+		vsocket->connfd = -1;
 		close(connfd);
 		*remove = 1;
 		free(conn);
@@ -635,6 +639,7 @@ rte_vhost_driver_register(const char *path, uint64_t flags)
 		goto out;
 	memset(vsocket, 0, sizeof(struct vhost_user_socket));
 	vsocket->path = strdup(path);
+	vsocket->connfd = -1;
 
 	if ((flags & RTE_VHOST_USER_CLIENT) != 0) {
 		vsocket->reconnect = !(flags & RTE_VHOST_USER_NO_RECONNECT);
@@ -664,6 +669,30 @@ out:
 	return ret;
 }
 
+static bool
+vhost_user_remove_reconnect(struct vhost_user_socket *vsocket)
+{
+	int found = false;
+	struct vhost_user_reconnect *reconn, *next;
+
+	pthread_mutex_lock(&reconn_list.mutex);
+
+	for (reconn = TAILQ_FIRST(&reconn_list.head);
+	     reconn != NULL; reconn = next) {
+		next = TAILQ_NEXT(reconn, next);
+
+		if (reconn->vsocket == vsocket) {
+			TAILQ_REMOVE(&reconn_list.head, reconn, next);
+			close(reconn->fd);
+			free(reconn);
+			found = true;
+			break;
+		}
+	}
+	pthread_mutex_unlock(&reconn_list.mutex);
+	return found;
+}
+
 /**
  * Unregister the specified vhost socket
  */
@@ -672,20 +701,34 @@ rte_vhost_driver_unregister(const char *path)
 {
 	int i;
 	int count;
+	struct vhost_user_connection *conn;
 
 	pthread_mutex_lock(&vhost_user.mutex);
 
 	for (i = 0; i < vhost_user.vsocket_cnt; i++) {
-		if (!strcmp(vhost_user.vsockets[i]->path, path)) {
-			if (vhost_user.vsockets[i]->is_server) {
-				fdset_del(&vhost_user.fdset,
-					vhost_user.vsockets[i]->listenfd);
-				close(vhost_user.vsockets[i]->listenfd);
+		struct vhost_user_socket *vsocket = vhost_user.vsockets[i];
+
+		if (!strcmp(vsocket->path, path)) {
+			if (vsocket->is_server) {
+				fdset_del(&vhost_user.fdset, vsocket->listenfd);
+				close(vsocket->listenfd);
 				unlink(path);
+			} else if (vsocket->reconnect) {
+				vhost_user_remove_reconnect(vsocket);
+			}
+
+			conn = fdset_del(&vhost_user.fdset, vsocket->connfd);
+			if (conn) {
+				RTE_LOG(INFO, VHOST_CONFIG,
+					"free connfd = %d for device '%s'\n",
+					vsocket->connfd, path);
+				close(vsocket->connfd);
+				vhost_destroy_device(conn->vid);
+				free(conn);
 			}
 
-			free(vhost_user.vsockets[i]->path);
-			free(vhost_user.vsockets[i]);
+			free(vsocket->path);
+			free(vsocket);
 
 			count = --vhost_user.vsocket_cnt;
 			vhost_user.vsockets[i] = vhost_user.vsockets[count];
-- 
2.7.4