Re: [Qemu-devel] [PATCH RFC 3/3] libvhost-user: quit when no more data received

[Maxime Coquelin]

On 07/12/2017 11:41 AM, Jens Freimann wrote:
> From: Jens Freimann<address@hidden>
>
> When recvmsg() returns a message size of zero and
> errno is ENOENT end processing of vhost-user messages.
>
> Without this we run into a vubr_panic() call and get
>       PANIC: Error while recvmsg: No such file or directory
>       Error while dispatching.
>
> Add a switch "quit" to the vhost user device and set true to stop
> processing messages.
>
> Signed-off-by: Jens Freimann<address@hidden>
> ---
>   contrib/libvhost-user/libvhost-user.c | 12 +++++++++++-
>   contrib/libvhost-user/libvhost-user.h |  1 +
>   2 files changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/contrib/libvhost-user/libvhost-user.c 
> b/contrib/libvhost-user/libvhost-user.c
> index 9efb9da..5538859 100644
> --- a/contrib/libvhost-user/libvhost-user.c
> +++ b/contrib/libvhost-user/libvhost-user.c
> @@ -161,7 +161,10 @@ vu_message_read(VuDev *dev, int conn_fd, VhostUserMsg 
> *vmsg)
>           rc = recvmsg(conn_fd, &msg, 0);
>       } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
>   
> -    if (rc <= 0) {
> +    if (rc == 0 && (errno == ENOENT)) {
> +        vmsg->size = 0;
> +        dev->quit = true;
> +    } else if (rc < 0) {
>           vu_panic(dev, "Error while recvmsg: %s", strerror(errno));
>           return false;
>       }
> @@ -755,6 +758,10 @@ vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
>       DPRINT("Flags:   0x%x\n", vmsg->flags);
>       DPRINT("Size:    %d\n", vmsg->size);
>   
> +    if (dev->quit) {
> +        return true;
> +    }
> +

You may want to return false here, as true means a reply is requested?

Maxime