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 e2846f2099cea1f9c0dd5f058899f131a6b08f42..534ab9143c866180d9a8807da18894b39dc3e78a 100644 (file)
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -53,6 +53,11 @@
 #include "vlan.h"
 #include "vport-internal_dev.h"
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,18) || \
+    LINUX_VERSION_CODE > KERNEL_VERSION(2,6,39)
+#error Kernels before 2.6.18 or after 2.6.39 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);