[PATCH -next] xen/pvcalls: Make pvcalls_back_global static

[YueHaibing]

Fix sparse warning:

drivers/xen/pvcalls-back.c:30:3: warning:
 symbol 'pvcalls_back_global' was not declared. Should it be static?

Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>
---
 drivers/xen/pvcalls-back.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
index cf4ce3e9358d..4807704f8d69 100644
--- a/drivers/xen/pvcalls-back.c
+++ b/drivers/xen/pvcalls-back.c
@@ -24,7 +24,7 @@
 #define PVCALLS_VERSIONS "1"
 #define MAX_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER
 
-struct pvcalls_back_global {
+static struct pvcalls_back_global {
 	struct list_head frontends;
 	struct semaphore frontends_lock;
 } pvcalls_back_global;
-- 
2.17.1