[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>

2 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/futex.h b/include/linux/futex.h
index f05a3f469322..34c3a215f2cd 100644
--- a/include/linux/futex.h
+++ b/include/linux/futex.h
@@ -12,6 +12,9 @@
 #define FUTEX_REQUEUE           3
 #define FUTEX_CMP_REQUEUE       4
 #define FUTEX_WAKE_OP           5
+#define FUTEX_LOCK_PI           6
+#define FUTEX_UNLOCK_PI         7
+#define FUTEX_TRYLOCK_PI        8
 
 /*
  * Support for robust futexes: the kernel cleans up held futexes at
@@ -97,10 +100,14 @@ extern int handle_futex_death(u32 __user *uaddr, struct task_struct *curr);
 
 #ifdef CONFIG_FUTEX
 extern void exit_robust_list(struct task_struct *curr);
+extern void exit_pi_state_list(struct task_struct *curr);
 #else
 static inline void exit_robust_list(struct task_struct *curr)
 {
 }
+static inline void exit_pi_state_list(struct task_struct *curr)
+{
+}
 #endif
 
 #define FUTEX_OP_SET            0       /* *(int *)UADDR2 = OPARG; */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index edadd13cf53f..b4e6be7de5ad 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -84,6 +84,7 @@ struct sched_param {
 #include <asm/processor.h>
 
 struct exec_domain;
+struct futex_pi_state;
 
 /*
  * List of flags we want to share for kernel threads,
@@ -915,6 +916,8 @@ struct task_struct {
 #ifdef CONFIG_COMPAT
         struct compat_robust_list_head __user *compat_robust_list;
 #endif
+        struct list_head pi_state_list;
+        struct futex_pi_state *pi_state_cache;
 
         atomic_t fs_excl;       /* holding fs exclusive resources */
         struct rcu_head rcu;