[PATCH net-next 2/4] genetlink: Add lockdep_genl_is_held().

[Jesse Gross <jesse-l0M0P4e3n4LQT0dZR+AlfA@public.gmane.org>]

From: Pravin B Shelar <pshelar-l0M0P4e3n4LQT0dZR+AlfA@public.gmane.org>

Open vSwitch uses genl_mutex locking to protect datapath
data-structures like flow-table, flow-actions. Following patch adds
lockdep_genl_is_held() which is used for rcu annotation to prove
locking.

Signed-off-by: Pravin B Shelar <pshelar-l0M0P4e3n4LQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Jesse Gross <jesse-l0M0P4e3n4LQT0dZR+AlfA@public.gmane.org>
---
 include/linux/genetlink.h |    3 +++
 net/netlink/genetlink.c   |    8 ++++++++
 2 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/include/linux/genetlink.h b/include/linux/genetlink.h
index 61549b2..59311ad 100644
--- a/include/linux/genetlink.h
+++ b/include/linux/genetlink.h
@@ -85,6 +85,9 @@ enum {
 /* All generic netlink requests are serialized by a global lock.  */
 extern void genl_lock(void);
 extern void genl_unlock(void);
+#ifdef CONFIG_PROVE_LOCKING
+extern int lockdep_genl_is_held(void);
+#endif
 
 #endif /* __KERNEL__ */
 
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 8a36599..28453ae 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -33,6 +33,14 @@ void genl_unlock(void)
 }
 EXPORT_SYMBOL(genl_unlock);
 
+#ifdef CONFIG_PROVE_LOCKING
+int lockdep_genl_is_held(void)
+{
+	return lockdep_is_held(&genl_mutex);
+}
+EXPORT_SYMBOL(lockdep_genl_is_held);
+#endif
+
 #define GENL_FAM_TAB_SIZE	16
 #define GENL_FAM_TAB_MASK	(GENL_FAM_TAB_SIZE - 1)
 
-- 
1.7.5.4