[PATCH] pi-futex: rt mutex core

Core functions for the rt-mutex subsystem.

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: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 118 insertions, 0 deletions

diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 678c1a9038..3a256957fb 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -124,6 +124,7 @@ extern struct group_info init_groups;
         .cpu_timers     = INIT_CPU_TIMERS(tsk.cpu_timers),              \
         .fs_excl        = ATOMIC_INIT(0),                               \
         .pi_lock        = SPIN_LOCK_UNLOCKED,                           \
+        INIT_RT_MUTEXES(tsk)                                            \
 }
 
 
diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
new file mode 100644
index 0000000000..12309c916c
--- /dev/null
+++ b/include/linux/rtmutex.h
@@ -0,0 +1,104 @@
+/*
+ * 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 public data structure and API definitions.
+ */
+
+#ifndef __LINUX_RT_MUTEX_H
+#define __LINUX_RT_MUTEX_H
+
+#include <linux/linkage.h>
+#include <linux/plist.h>
+#include <linux/spinlock_types.h>
+
+/*
+ * The rt_mutex structure
+ *
+ * @wait_lock:  spinlock to protect the structure
+ * @wait_list:  pilist head to enqueue waiters in priority order
+ * @owner:      the mutex owner
+ */
+struct rt_mutex {
+        spinlock_t              wait_lock;
+        struct plist_head       wait_list;
+        struct task_struct      *owner;
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+        int                     save_state;
+        struct list_head        held_list_entry;
+        unsigned long           acquire_ip;
+        const char              *name, *file;
+        int                     line;
+        void                    *magic;
+#endif
+};
+
+struct rt_mutex_waiter;
+struct hrtimer_sleeper;
+
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
+        , .name = #mutexname, .file = __FILE__, .line = __LINE__
+# define rt_mutex_init(mutex)                   __rt_mutex_init(mutex, __FUNCTION__)
+ extern void rt_mutex_debug_task_free(struct task_struct *tsk);
+#else
+# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
+# define rt_mutex_init(mutex)                   __rt_mutex_init(mutex, NULL)
+# define rt_mutex_debug_task_free(t)            do { } while (0)
+#endif
+
+#define __RT_MUTEX_INITIALIZER(mutexname) \
+        { .wait_lock = SPIN_LOCK_UNLOCKED \
+        , .wait_list = PLIST_HEAD_INIT(mutexname.wait_list, mutexname.wait_lock) \
+        , .owner = NULL \
+        __DEBUG_RT_MUTEX_INITIALIZER(mutexname)}
+
+#define DEFINE_RT_MUTEX(mutexname) \
+        struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)
+
+/***
+ * rt_mutex_is_locked - is the mutex locked
+ * @lock: the mutex to be queried
+ *
+ * Returns 1 if the mutex is locked, 0 if unlocked.
+ */
+static inline int rt_mutex_is_locked(struct rt_mutex *lock)
+{
+        return lock->owner != NULL;
+}
+
+extern void __rt_mutex_init(struct rt_mutex *lock, const char *name);
+extern void rt_mutex_destroy(struct rt_mutex *lock);
+
+extern void rt_mutex_lock(struct rt_mutex *lock);
+extern int rt_mutex_lock_interruptible(struct rt_mutex *lock,
+                                                int detect_deadlock);
+extern int rt_mutex_timed_lock(struct rt_mutex *lock,
+                                        struct hrtimer_sleeper *timeout,
+                                        int detect_deadlock);
+
+extern int rt_mutex_trylock(struct rt_mutex *lock);
+
+extern void rt_mutex_unlock(struct rt_mutex *lock);
+
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+# define INIT_RT_MUTEX_DEBUG(tsk)                                       \
+        .held_list_head = LIST_HEAD_INIT(tsk.held_list_head),           \
+        .held_list_lock = SPIN_LOCK_UNLOCKED
+#else
+# define INIT_RT_MUTEX_DEBUG(tsk)
+#endif
+
+#ifdef CONFIG_RT_MUTEXES
+# define INIT_RT_MUTEXES(tsk)                                           \
+        .pi_waiters     = PLIST_HEAD_INIT(tsk.pi_waiters, tsk.pi_lock), \
+        INIT_RT_MUTEX_DEBUG(tsk)
+#else
+# define INIT_RT_MUTEXES(tsk)
+#endif
+
+#endif
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6f167645e7..6ea23c9af4 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -73,6 +73,7 @@ struct sched_param {
 #include <linux/seccomp.h>
 #include <linux/rcupdate.h>
 #include <linux/futex.h>
+#include <linux/rtmutex.h>
 
 #include <linux/time.h>
 #include <linux/param.h>
@@ -858,6 +859,17 @@ struct task_struct {
         /* Protection of the PI data structures: */
         spinlock_t pi_lock;
 
+#ifdef CONFIG_RT_MUTEXES
+        /* PI waiters blocked on a rt_mutex held by this task */
+        struct plist_head pi_waiters;
+        /* Deadlock detection and priority inheritance handling */
+        struct rt_mutex_waiter *pi_blocked_on;
+# ifdef CONFIG_DEBUG_RT_MUTEXES
+        spinlock_t held_list_lock;
+        struct list_head held_list_head;
+# endif
+#endif
+
 #ifdef CONFIG_DEBUG_MUTEXES
         /* mutex deadlock detection */
         struct mutex_waiter *blocked_on;
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index bee12a7a05..46e4d8f277 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -149,6 +149,7 @@ enum
         KERN_ACPI_VIDEO_FLAGS=71, /* int: flags for setting up video after ACPI sleep */
         KERN_IA64_UNALIGNED=72, /* int: ia64 unaligned userland trap enable */
         KERN_COMPAT_LOG=73,     /* int: print compat layer  messages */
+        KERN_MAX_LOCK_DEPTH=74,
 };