[PATCH 13/21] libxl: Add a gc to libxl_get_cpu_topology

[Ian Jackson <ian.jackson@eu.citrix.com>]

In the next patch we are going to change the definition of NOGC to
require a local variable libxl__gc *gc.

libxl_get_cpu_topology doesn't have one but does use NOGC.
Fix this by:
 - introducing an `out' label
 - replacing the only call to `return' with a suitable assignment
   to ret and a `goto out'.
 - adding uses of GC_INIT and GC_FREE.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
---
 tools/libxl/libxl.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 6ec7471..a259d65 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -3201,6 +3201,7 @@ int libxl_get_physinfo(libxl_ctx *ctx, libxl_physinfo *physinfo)
 
 libxl_cputopology *libxl_get_cpu_topology(libxl_ctx *ctx, int *nr)
 {
+    GC_INIT(ctx);
     xc_topologyinfo_t tinfo;
     DECLARE_HYPERCALL_BUFFER(xc_cpu_to_core_t, coremap);
     DECLARE_HYPERCALL_BUFFER(xc_cpu_to_socket_t, socketmap);
@@ -3213,7 +3214,8 @@ libxl_cputopology *libxl_get_cpu_topology(libxl_ctx *ctx, int *nr)
     if (max_cpus == 0)
     {
         LIBXL__LOG(ctx, XTL_ERROR, "Unable to determine number of CPUS");
-        return NULL;
+        ret = NULL;
+        goto out;
     }
 
     coremap = xc_hypercall_buffer_alloc
@@ -3258,6 +3260,8 @@ fail:
 
     if (ret)
         *nr = max_cpus;
+ out:
+    GC_FREE;
     return ret;
 }
 
-- 
1.7.2.5