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[PATCH] pi-futex: rt mutex futex api 

Add proxy-locking rt-mutex functionality needed by pi-futexes.

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>
This commit is contained in:
Ingo Molnar 2006-06-27 02:54:57 -07:00 committed by Linus Torvalds
parent 61a8712286
commit 0cdbee9920
1 changed files with 55 additions and 0 deletions
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55
kernel/rtmutex.c
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@ -903,3 +903,58 @@ void __rt_mutex_init(struct rt_mutex *lock, const char *name)
debug_rt_mutex_init(lock, name);
}
EXPORT_SYMBOL_GPL(__rt_mutex_init);
/**
* rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a
* proxy owner
*
* @lock: the rt_mutex to be locked
* @proxy_owner:the task to set as owner
*
* No locking. Caller has to do serializing itself
* Special API call for PI-futex support
*/
void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
struct task_struct *proxy_owner)
{
__rt_mutex_init(lock, NULL);
debug_rt_mutex_proxy_lock(lock, proxy_owner __RET_IP__);
rt_mutex_set_owner(lock, proxy_owner, 0);
rt_mutex_deadlock_account_lock(lock, proxy_owner);
}
/**
* rt_mutex_proxy_unlock - release a lock on behalf of owner
*
* @lock: the rt_mutex to be locked
*
* No locking. Caller has to do serializing itself
* Special API call for PI-futex support
*/
void rt_mutex_proxy_unlock(struct rt_mutex *lock,
struct task_struct *proxy_owner)
{
debug_rt_mutex_proxy_unlock(lock);
rt_mutex_set_owner(lock, NULL, 0);
rt_mutex_deadlock_account_unlock(proxy_owner);
}
/**
* rt_mutex_next_owner - return the next owner of the lock
*
* @lock: the rt lock query
*
* Returns the next owner of the lock or NULL
*
* Caller has to serialize against other accessors to the lock
* itself.
*
* Special API call for PI-futex support
*/
struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock)
{
if (!rt_mutex_has_waiters(lock))
return NULL;
return rt_mutex_top_waiter(lock)->task;
}