lockdep: increase MAX_LOCK_DEPTH

Some code paths exceed the current max lock depth (XFS), so increase
this limit a bit. I looked at making this a dynamic allocated array,
but we should not advocate insane lock depths, so stay with this as
long as it works...

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index e217d18..e3ea124 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1189,7 +1189,7 @@
 	int softirq_context;
 #endif
 #ifdef CONFIG_LOCKDEP
-# define MAX_LOCK_DEPTH 30UL
+# define MAX_LOCK_DEPTH 48UL
 	u64 curr_chain_key;
 	int lockdep_depth;
 	struct held_lock held_locks[MAX_LOCK_DEPTH];