[PATCH v14 10/14] fixup: Adjust conditions under which we quite after completing migration

[David Gibson <david@gibson.dropbear.id.au>]

In order to allow local to local migrations, we want the source passt to
quit once the migration is completed, so that it frees up sockets for the
target passt to reopen.  We use a global variable, quit_on_device_state, to
trigger this behaviour.

We don't need that global: the information we need is in c->migrate_target.
Moreover, we only want to exit on a *successful* migration.  Checking
c->device_state_result == 0 is not a foolproof way to do this, since the
migration could fail due to an unrelated device in the guest, but it's
better than always assuming success.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 vhost_user.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/vhost_user.c b/vhost_user.c
index 9115fb50..7ab13774 100644
--- a/vhost_user.c
+++ b/vhost_user.c
@@ -998,9 +998,6 @@ static bool vu_send_rarp_exec(struct vu_dev *vdev,
 	return false;
 }
 
-/* If set, quit when we get a VHOST_USER_CHECK_DEVICE_STATE, after replying */
-static bool quit_on_device_state = false;
-
 /**
  * vu_set_device_state_fd_exec() - Set the device state migration channel
  * @vdev:	vhost-user device
@@ -1028,9 +1025,6 @@ static bool vu_set_device_state_fd_exec(struct vu_dev *vdev,
 	migrate_request(vdev->context, msg->fds[0],
 			direction == VHOST_USER_TRANSFER_STATE_DIRECTION_LOAD);
 
-	if (direction == VHOST_USER_TRANSFER_STATE_DIRECTION_SAVE)
-		quit_on_device_state = true;
-
 	/* We don't provide a new fd for the data transfer */
 	vmsg_set_reply_u64(msg, VHOST_USER_VRING_NOFD_MASK);
 
@@ -1210,8 +1204,9 @@ void vu_control_handler(struct vu_dev *vdev, int fd, uint32_t events)
 	if (reply_requested)
 		vu_send_reply(fd, &msg);
 
-	if (quit_on_device_state &&
-	    msg.hdr.request == VHOST_USER_CHECK_DEVICE_STATE) {
+	if (msg.hdr.request == VHOST_USER_CHECK_DEVICE_STATE &&
+	    vdev->context->device_state_result == 0 &&
+	    !vdev->context->migrate_target) {
 		info("Migration complete, exiting");
 		_exit(EXIT_SUCCESS);
 	}
-- 
@@ -998,9 +998,6 @@ static bool vu_send_rarp_exec(struct vu_dev *vdev,
 	return false;
 }
 
-/* If set, quit when we get a VHOST_USER_CHECK_DEVICE_STATE, after replying */
-static bool quit_on_device_state = false;
-
 /**
  * vu_set_device_state_fd_exec() - Set the device state migration channel
  * @vdev:	vhost-user device
@@ -1028,9 +1025,6 @@ static bool vu_set_device_state_fd_exec(struct vu_dev *vdev,
 	migrate_request(vdev->context, msg->fds[0],
 			direction == VHOST_USER_TRANSFER_STATE_DIRECTION_LOAD);
 
-	if (direction == VHOST_USER_TRANSFER_STATE_DIRECTION_SAVE)
-		quit_on_device_state = true;
-
 	/* We don't provide a new fd for the data transfer */
 	vmsg_set_reply_u64(msg, VHOST_USER_VRING_NOFD_MASK);
 
@@ -1210,8 +1204,9 @@ void vu_control_handler(struct vu_dev *vdev, int fd, uint32_t events)
 	if (reply_requested)
 		vu_send_reply(fd, &msg);
 
-	if (quit_on_device_state &&
-	    msg.hdr.request == VHOST_USER_CHECK_DEVICE_STATE) {
+	if (msg.hdr.request == VHOST_USER_CHECK_DEVICE_STATE &&
+	    vdev->context->device_state_result == 0 &&
+	    !vdev->context->migrate_target) {
 		info("Migration complete, exiting");
 		_exit(EXIT_SUCCESS);
 	}
-- 
2.48.1