[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>

[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>
Ingo Molnar · Linus Torvalds
1 parent 61a8712286
Showing 1 changed file with 55 additions and 0 deletions Side-by-side Diff
kernel/rtmutex.c
@@ -903,4 +903,59 @@
 	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;
+}
...	...	@@ -903,4 +903,59 @@
903	903	debug_rt_mutex_init(lock, name);
904	904	}
905	905	EXPORT_SYMBOL_GPL(__rt_mutex_init);
	906	+
	907	+/**
	908	+ * rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a
	909	+ * proxy owner
	910	+ *
	911	+ * @lock: the rt_mutex to be locked
	912	+ * @proxy_owner:the task to set as owner
	913	+ *
	914	+ * No locking. Caller has to do serializing itself
	915	+ * Special API call for PI-futex support
	916	+ */
	917	+void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
	918	+ struct task_struct *proxy_owner)
	919	+{
	920	+ __rt_mutex_init(lock, NULL);
	921	+ debug_rt_mutex_proxy_lock(lock, proxy_owner __RET_IP__);
	922	+ rt_mutex_set_owner(lock, proxy_owner, 0);
	923	+ rt_mutex_deadlock_account_lock(lock, proxy_owner);
	924	+}
	925	+
	926	+/**
	927	+ * rt_mutex_proxy_unlock - release a lock on behalf of owner
	928	+ *
	929	+ * @lock: the rt_mutex to be locked
	930	+ *
	931	+ * No locking. Caller has to do serializing itself
	932	+ * Special API call for PI-futex support
	933	+ */
	934	+void rt_mutex_proxy_unlock(struct rt_mutex *lock,
	935	+ struct task_struct *proxy_owner)
	936	+{
	937	+ debug_rt_mutex_proxy_unlock(lock);
	938	+ rt_mutex_set_owner(lock, NULL, 0);
	939	+ rt_mutex_deadlock_account_unlock(proxy_owner);
	940	+}
	941	+
	942	+/**
	943	+ * rt_mutex_next_owner - return the next owner of the lock
	944	+ *
	945	+ * @lock: the rt lock query
	946	+ *
	947	+ * Returns the next owner of the lock or NULL
	948	+ *
	949	+ * Caller has to serialize against other accessors to the lock
	950	+ * itself.
	951	+ *
	952	+ * Special API call for PI-futex support
	953	+ */
	954	+struct task_struct rt_mutex_next_owner(struct rt_mutex lock)
	955	+{
	956	+ if (!rt_mutex_has_waiters(lock))
	957	+ return NULL;
	958	+
	959	+ return rt_mutex_top_waiter(lock)->task;
	960	+}