datapath: Check for supported kernel versions.

Most of the time kernels older or newer than the ones we support
simply fail to compile.  However, sometimes they appear to succeed
but then cause problems later on.  This explicitly checks for
supported versions at compile time.

Signed-off-by: Jesse Gross <jesse@nicira.com>

diff --git a/datapath/datapath.c b/datapath/datapath.c
index 5ce77cd..d901e6b 100644 (file)
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -54,6 +54,11 @@
 #include "vlan.h"
 #include "vport-internal_dev.h"
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,18) || \
+    LINUX_VERSION_CODE > KERNEL_VERSION(2,6,38)
+#error Kernels before 2.6.18 or after 2.6.38 are not supported by this version of Open vSwitch.
+#endif
+
 int (*dp_ioctl_hook)(struct net_device *dev, struct ifreq *rq, int cmd);
 EXPORT_SYMBOL(dp_ioctl_hook);