[PATCH] pi-futex: futex_lock_pi/futex_unlock_pi support

This adds the actual pi-futex implementation, based on rt-mutexes.

[dino@in.ibm.com: fix an oops-causing race]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Dinakar Guniguntala <dino@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/fork.c b/kernel/fork.c
index b664a08..628198a 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1092,6 +1092,9 @@
 #ifdef CONFIG_COMPAT
 	p->compat_robust_list = NULL;
 #endif
+	INIT_LIST_HEAD(&p->pi_state_list);
+	p->pi_state_cache = NULL;
+
 	/*
 	 * sigaltstack should be cleared when sharing the same VM
 	 */