Re: [PATCH v13 4/6] vhost_user: Make source quit after reporting migration state

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

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On Sun, Feb 09, 2025 at 11:20:03PM +0100, Stefano Brivio wrote:
> This will close all the sockets we currently have open in repair mode,
> and completes our migration tasks as source. If the hypervisor wants
> to have us back at this point, somebody needs to restart us.
> 
> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
> ---
>  vhost_user.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/vhost_user.c b/vhost_user.c
> index 256c8ab..9115fb5 100644
> --- a/vhost_user.c
> +++ b/vhost_user.c
> @@ -998,6 +998,9 @@ 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;

We don't actually need this global, because we have c->migrate_target.

> +
>  /**
>   * vu_set_device_state_fd_exec() - Set the device state migration channel
>   * @vdev:	vhost-user device
> @@ -1025,6 +1028,9 @@ 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);
>  
> @@ -1203,4 +1209,10 @@ 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) {

We probably also only want to quit when the migration is successful.
We can't determine that in all cases, but we can at least check
device_state_result.  Patch coming.

> +		info("Migration complete, exiting");
> +		_exit(EXIT_SUCCESS);
> +	}
>  }

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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