This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / kernel / rtmutex_common.h

diff --git a/kernel/rtmutex_common.h b/kernel/rtmutex_common.h
new file mode 100644 (file)
index 0000000..9c75856
--- /dev/null
+++ b/kernel/rtmutex_common.h
@@ -0,0 +1,123 @@
+/*
+ * RT Mutexes: blocking mutual exclusion locks with PI support
+ *
+ * started by Ingo Molnar and Thomas Gleixner:
+ *
+ *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ *
+ * This file contains the private data structure and API definitions.
+ */
+
+#ifndef __KERNEL_RTMUTEX_COMMON_H
+#define __KERNEL_RTMUTEX_COMMON_H
+
+#include <linux/rtmutex.h>
+
+/*
+ * The rtmutex in kernel tester is independent of rtmutex debugging. We
+ * call schedule_rt_mutex_test() instead of schedule() for the tasks which
+ * belong to the tester. That way we can delay the wakeup path of those
+ * threads to provoke lock stealing and testing of  complex boosting scenarios.
+ */
+#ifdef CONFIG_RT_MUTEX_TESTER
+
+extern void schedule_rt_mutex_test(struct rt_mutex *lock);
+
+#define schedule_rt_mutex(_lock)                               \
+  do {                                                         \
+       if (!(current->flags & PF_MUTEX_TESTER))                \
+               schedule();                                     \
+       else                                                    \
+               schedule_rt_mutex_test(_lock);                  \
+  } while (0)
+
+#else
+# define schedule_rt_mutex(_lock)                      schedule()
+#endif
+
+/*
+ * This is the control structure for tasks blocked on a rt_mutex,
+ * which is allocated on the kernel stack on of the blocked task.
+ *
+ * @list_entry:                pi node to enqueue into the mutex waiters list
+ * @pi_list_entry:     pi node to enqueue into the mutex owner waiters list
+ * @task:              task reference to the blocked task
+ */
+struct rt_mutex_waiter {
+       struct plist_node       list_entry;
+       struct plist_node       pi_list_entry;
+       struct task_struct      *task;
+       struct rt_mutex         *lock;
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+       unsigned long           ip;
+       pid_t                   deadlock_task_pid;
+       struct rt_mutex         *deadlock_lock;
+#endif
+};
+
+/*
+ * Various helpers to access the waiters-plist:
+ */
+static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
+{
+       return !plist_head_empty(&lock->wait_list);
+}
+
+static inline struct rt_mutex_waiter *
+rt_mutex_top_waiter(struct rt_mutex *lock)
+{
+       struct rt_mutex_waiter *w;
+
+       w = plist_first_entry(&lock->wait_list, struct rt_mutex_waiter,
+                              list_entry);
+       BUG_ON(w->lock != lock);
+
+       return w;
+}
+
+static inline int task_has_pi_waiters(struct task_struct *p)
+{
+       return !plist_head_empty(&p->pi_waiters);
+}
+
+static inline struct rt_mutex_waiter *
+task_top_pi_waiter(struct task_struct *p)
+{
+       return plist_first_entry(&p->pi_waiters, struct rt_mutex_waiter,
+                                 pi_list_entry);
+}
+
+/*
+ * lock->owner state tracking:
+ */
+#define RT_MUTEX_OWNER_PENDING 1UL
+#define RT_MUTEX_HAS_WAITERS   2UL
+#define RT_MUTEX_OWNER_MASKALL 3UL
+
+static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
+{
+       return (struct task_struct *)
+               ((unsigned long)lock->owner & ~RT_MUTEX_OWNER_MASKALL);
+}
+
+static inline struct task_struct *rt_mutex_real_owner(struct rt_mutex *lock)
+{
+       return (struct task_struct *)
+               ((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS);
+}
+
+static inline unsigned long rt_mutex_owner_pending(struct rt_mutex *lock)
+{
+       return (unsigned long)lock->owner & RT_MUTEX_OWNER_PENDING;
+}
+
+/*
+ * PI-futex support (proxy locking functions, etc.):
+ */
+extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
+extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
+                                      struct task_struct *proxy_owner);
+extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
+                                 struct task_struct *proxy_owner);
+#endif