* Reworked the way sem_undo requests are processed by following

Ingo suggestions: instead of having one global sem_undo list,
  we now have two local list, one per semaphore set and one per team
  which is held in its xsi_sem_context structure, along with a mutex.
  A mutex has also been added to the semaphore set class in order to
  protect the local list, but also in order to (hopefully) improve
  concurrency.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26993 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/posix/xsi_semaphore.h

@@ -17,7 +17,7 @@
 __BEGIN_DECLS
 
 extern void xsi_ipc_init();
-extern void xsi_sem_undo(team_id teamID, int32 numberOfUndos);
+extern void xsi_sem_undo(struct team *team);
 
 /* user calls */
 int _user_xsi_semget(key_t key, int numberOfSemaphores, int flags);

headers/private/kernel/thread_types.h

@@ -67,6 +67,7 @@ struct image;					// defined in image.c
 struct realtime_sem_context;	// defined in realtime_sem.cpp
 struct select_info;
 struct user_thread;				// defined in libroot/user_thread.h
+struct xsi_sem_context;			// defined in xsi_semaphore.cpp
 
 struct death_entry {
 	struct list_link	link;
@@ -183,7 +184,7 @@ struct team {
 	int32			flags;
 	void			*io_context;
 	struct realtime_sem_context	*realtime_sem_context;
-	int32			xsi_sem_undo_requests;
+	struct xsi_sem_context *xsi_sem_context;
 	sem_id			death_sem;		// semaphore to wait on for dying threads
 	struct list		dead_threads;
 	int				dead_threads_count;