xmem/tmem: fix 'undefined variable' build error.

In the (not so useful) kernel configuration where CONFIG_SWAP
is undefined and CONFIG_XEN_SELFBALLOONING is defined,
xen_tmem_init would use undefined variable 'static bool frontswap'.

Added #else to have #define frontswap (0) in the case where
CONFIG_FRONTSWAP is not defined.

Signed-off-by: Frederico Cadete <frederico@cadete.eu>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
index 18e8bd8fa947..cc072c66c766 100644
--- a/drivers/xen/tmem.c
+++ b/drivers/xen/tmem.c
@@ -41,6 +41,8 @@ module_param(selfballooning, bool, S_IRUGO);
 #ifdef CONFIG_FRONTSWAP
 static bool frontswap __read_mostly = true;
 module_param(frontswap, bool, S_IRUGO);
+#else /* CONFIG_FRONTSWAP */
+#define frontswap (0)
 #endif /* CONFIG_FRONTSWAP */
 
 #ifdef CONFIG_XEN_SELFBALLOONING