From 23f78d4a03c53cbd75d87a795378ea540aa08c86 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 27 Jun 2006 02:54:53 -0700 Subject: [PATCH] pi-futex: rt mutex core Core functions for the rt-mutex subsystem. Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Signed-off-by: Arjan van de Ven Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/rtmutex_common.h | 93 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) create mode 100644 kernel/rtmutex_common.h (limited to 'kernel/rtmutex_common.h') diff --git a/kernel/rtmutex_common.h b/kernel/rtmutex_common.h new file mode 100644 index 00000000000..50eed60eb08 --- /dev/null +++ b/kernel/rtmutex_common.h @@ -0,0 +1,93 @@ +/* + * 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 + * Copyright (C) 2006, Timesys Corp., Thomas Gleixner + * + * This file contains the private data structure and API definitions. + */ + +#ifndef __KERNEL_RTMUTEX_COMMON_H +#define __KERNEL_RTMUTEX_COMMON_H + +#include + +/* + * 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; +} + +#endif -- cgit v1.2.3