[PATCH v2 net-next 1/9] sunvnet: make sunvnet common code dynamically loadable

[Shannon Nelson <shannon.nelson@oracle.com>]

When the sunvnet_common code was split out for use by both sunvnet
and the newer ldmvsw, it was made into a static kernel library, which
limits the usefulness of sunvnet and ldmvsw as loadables, since most
of the real work is being done in the shared code.  Also, this is
simply dead code in kernels that aren't running the LDoms.

This patch makes the sunvnet_common into a dynamically loadable
module and makes sunvnet and ldmvsw dependent on sunvnet_common.

Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
---
 drivers/net/ethernet/sun/Kconfig          |    8 ++++++--
 drivers/net/ethernet/sun/sunvnet_common.c |   29 +++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/sun/Kconfig b/drivers/net/ethernet/sun/Kconfig
index a4b40e3..a7d91da 100644
--- a/drivers/net/ethernet/sun/Kconfig
+++ b/drivers/net/ethernet/sun/Kconfig
@@ -70,19 +70,23 @@ config CASSINI
 	  <http://docs.oracle.com/cd/E19113-01/giga.ether.pci/817-4341-10/817-4341-10.pdf>.
 
 config SUNVNET_COMMON
-	bool
+	tristate "Common routines to support Sun Virtual Networking"
 	depends on SUN_LDOMS
-	default y if SUN_LDOMS
+	default m if SUN_LDOMS
 
 config SUNVNET
 	tristate "Sun Virtual Network support"
+	default m
 	depends on SUN_LDOMS
+	depends on SUNVNET_COMMON
 	---help---
 	  Support for virtual network devices under Sun Logical Domains.
 
 config LDMVSW
 	tristate "Sun4v LDoms Virtual Switch support"
+	default m
 	depends on SUN_LDOMS
+	depends on SUNVNET_COMMON
 	---help---
 	  Support for virtual switch devices under Sun4v Logical Domains.
 	  This driver adds a network interface for every vsw-port node
diff --git a/drivers/net/ethernet/sun/sunvnet_common.c b/drivers/net/ethernet/sun/sunvnet_common.c
index 191c8ad..e03cf13 100644
--- a/drivers/net/ethernet/sun/sunvnet_common.c
+++ b/drivers/net/ethernet/sun/sunvnet_common.c
@@ -37,6 +37,35 @@
  */
 #define	VNET_MAX_RETRIES	10
 
+#define DRV_MODULE_NAME		"sunvnet_common"
+#define DRV_MODULE_VERSION	"1.1"
+#define DRV_MODULE_RELDATE	"February 3, 2017"
+
+static char version[] =
+	DRV_MODULE_NAME " " DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")";
+MODULE_AUTHOR("David S. Miller (davem@davemloft.net)");
+MODULE_DESCRIPTION("Sun LDOM virtual network support library");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_MODULE_VERSION);
+
+static int __init sunvnet_common_init(void)
+{
+	pr_info("%s\n", version);
+	return 0;
+}
+module_init(sunvnet_common_init);
+
+static void __exit sunvnet_common_exit(void)
+{
+	/* Empty function, just here to fill the exit function pointer
+	 * slot.  In some combinations of older gcc and newer kernel,
+	 * leaving this undefined results in the kernel marking it as a
+	 * permanent module; it will show up in lsmod output as [permanent]
+	 * and not be unloadable.
+	 */
+}
+module_exit(sunvnet_common_exit);
+
 static int __vnet_tx_trigger(struct vnet_port *port, u32 start);
 static void vnet_port_reset(struct vnet_port *port);
 
-- 
1.7.1