xen: Rename the balloon lock

* xen_create_contiguous_region needs access to the balloon lock to
  ensure memory doesn't change under its feet, so expose the balloon
  lock
* Change the name of the lock to xen_reservation_lock, to imply it's
  now less-specific usage.

[ Impact: cleanup ]

Signed-off-by: Alex Nixon <alex.nixon@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h
index af36ead16817..e6adce6bc75c 100644
--- a/include/xen/interface/memory.h
+++ b/include/xen/interface/memory.h
@@ -9,6 +9,8 @@
 #ifndef __XEN_PUBLIC_MEMORY_H__
 #define __XEN_PUBLIC_MEMORY_H__
 
+#include <linux/spinlock.h>
+
 /*
  * Increase or decrease the specified domain's memory reservation. Returns a
  * -ve errcode on failure, or the # extents successfully allocated or freed.
@@ -142,4 +144,10 @@ struct xen_translate_gpfn_list {
 };
 DEFINE_GUEST_HANDLE_STRUCT(xen_translate_gpfn_list);
 
+
+/*
+ * Prevent the balloon driver from changing the memory reservation
+ * during a driver critical region.
+ */
+extern spinlock_t xen_reservation_lock;
 #endif /* __XEN_PUBLIC_MEMORY_H__ */