netlink: Export genl_lock() API for use by modules

This lets kernel modules which use genl netlink APIs serialize netlink
processing.

Signed-off-by: James Chapman <jchapman@katalix.com>
Reviewed-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 12 insertions, 2 deletions

diff --git a/include/linux/genetlink.h b/include/linux/genetlink.h
index b834ef6d59fa..61549b26ad6f 100644
--- a/include/linux/genetlink.h
+++ b/include/linux/genetlink.h
@@ -80,4 +80,12 @@ enum {
 
 #define CTRL_ATTR_MCAST_GRP_MAX (__CTRL_ATTR_MCAST_GRP_MAX - 1)
 
+#ifdef __KERNEL__
+
+/* All generic netlink requests are serialized by a global lock.  */
+extern void genl_lock(void);
+extern void genl_unlock(void);
+
+#endif /* __KERNEL__ */
+
 #endif  /* __LINUX_GENERIC_NETLINK_H */
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index a4b6e148c5de..a28fda7420d9 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -20,15 +20,17 @@
 
 static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
 
-static inline void genl_lock(void)
+void genl_lock(void)
 {
         mutex_lock(&genl_mutex);
 }
+EXPORT_SYMBOL(genl_lock);
 
-static inline void genl_unlock(void)
+void genl_unlock(void)
 {
         mutex_unlock(&genl_mutex);
 }
+EXPORT_SYMBOL(genl_unlock);
 
 #define GENL_FAM_TAB_SIZE       16
 #define GENL_FAM_TAB_MASK       (GENL_FAM_TAB_SIZE - 1)