batman-adv: Add lockdep_asserts for documented external locks

Some functions already have documentation about locks they require inside
their kerneldoc header. These can be directly tested during runtime using
the lockdep asserts.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c
index ec5f7bc..700c96c 100644
--- a/net/batman-adv/fragmentation.c
+++ b/net/batman-adv/fragmentation.c
@@ -25,6 +25,7 @@
 #include <linux/if_ether.h>
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
+#include <linux/lockdep.h>
 #include <linux/netdevice.h>
 #include <linux/pkt_sched.h>
 #include <linux/skbuff.h>
@@ -112,6 +113,8 @@
 static bool batadv_frag_init_chain(struct batadv_frag_table_entry *chain,
 				   u16 seqno)
 {
+	lockdep_assert_held(&chain->lock);
+
 	if (chain->seqno == seqno)
 		return false;