[Libvir] PATCH: Fix compat for Xen 3.2.0

[Jim Meyering]

"Daniel P. Berrange" <berrange at redhat.com> wrote:

> Xen 3.2.0 removed the sockets_per_node field from the nodeinfo data returned
> by XenD. I previously add compat for this, but got it in the wrong place
> so it would most likely end up in a divide-by-zero error. This patch
> re-arranges it to be correct.
>
> diff -rup libvirt-0.4.0.orig/src/xend_internal.c libvirt-0.4.0.new/src/xend_internal.c
> --- libvirt-0.4.0.orig/src/xend_internal.c	2007-12-17 18:05:27.000000000 -0500
> +++ libvirt-0.4.0.new/src/xend_internal.c	2008-01-18 21:13:30.000000000 -0500
> @@ -1907,6 +1907,9 @@ sexpr_to_xend_node_info(struct sexpr *ro
>      info->mhz = sexpr_int(root, "node/cpu_mhz");
>      info->nodes = sexpr_int(root, "node/nr_nodes");
>      info->sockets = sexpr_int(root, "node/sockets_per_node");
> +    info->cores = sexpr_int(root, "node/cores_per_socket");
> +    info->threads = sexpr_int(root, "node/threads_per_core");
> +
>      /* Xen 3.2.0 replaces sockets_per_node with 'nr_cpus'.
>       * Old Xen calculated sockets_per_node using its internal
>       * nr_cpus / (nodes*cores*threads), so fake it ourselves
> @@ -1921,8 +1924,6 @@ sexpr_to_xend_node_info(struct sexpr *ro
>          if (info->sockets == 0)
>              info->sockets = 1;
>      }
> -    info->cores = sexpr_int(root, "node/cores_per_socket");
> -    info->threads = sexpr_int(root, "node/threads_per_core");
>      return (0);
>  }

ACK.

Now that you mention divide-by-zero,
is there something that guarantees none of the
terms in the denominator there is zero?

        info->sockets = nr_cpus / (info->nodes * info->cores * info->threads);