Simultaneous exit/thread_destroy working

Reiterating again to simplify:

Working:
 - Pager issues destroy, client also issues exit
   they work in sync.

Missing
 - Pager killing itself
 - Pager killing all children while killing itself
 - Pager waiting on children

conts/test/main.c

@@ -15,6 +15,7 @@
 
 int exit_test_thread(void *arg)
 {
+	l4_thread_switch(0);
 	l4_exit(0);
 	return 0;
 }
@@ -38,11 +39,11 @@ int exit_test(void)
 	/* Kill it */
 	printf("Killing Thread (%d).\n", ids.tid);
 	if ((ret = l4_thread_control(THREAD_DESTROY, &ids)) < 0)
-		printf("Error: Killing Thread (%d)\n", ids.tid);
+		printf("Error: Killing Thread (%d), err = %d\n", ids.tid, ret);
 	else
 		printf("Success: Killed Thread (%d)\n", ids.tid);
 
-
+	return 0;
 
 #if 0
 	/* Wait on it */

include/l4/generic/scheduler.h

@@ -61,7 +61,7 @@ extern struct scheduler scheduler;
 void sched_init_runqueue(struct runqueue *rq);
 void sched_init_task(struct ktcb *task, int priority);
 void sched_prepare_sleep(void);
-void sched_pager_exit(void);
+void sched_exit_pager(void);
 void sched_exit_sync(void);
 void sched_suspend_sync(void);
 void sched_suspend_async(void);

include/l4/generic/tcb.h

@@ -36,6 +36,7 @@ enum task_state {
 	TASK_INACTIVE	= 0,
 	TASK_SLEEPING	= 1,
 	TASK_RUNNABLE	= 2,
+	TASK_DEAD	= 3,
 };
 
 #define TASK_ID_INVALID			-1

src/api/thread.c

@@ -28,8 +28,8 @@ int sys_thread_switch(void)
  * doing, and take action on the signal provided. Currently this
  * may be a suspension or an exit signal.
  */
-int thread_signal_sync(struct ktcb *task, unsigned int flags,
-		       unsigned int task_state)
+int thread_signal(struct ktcb *task, unsigned int flags,
+		  unsigned int task_state)
 {
 	int ret = 0;
 
@@ -42,7 +42,7 @@ int thread_signal_sync(struct ktcb *task, unsigned int flags,
 	/* Wake it up if it's sleeping */
 	wake_up_task(task, WAKEUP_INTERRUPT | WAKEUP_SYNC);
 
-	/* Wait until task suspends itself */
+	/* Wait until task switches to desired state */
 	WAIT_EVENT(&task->wqh_pager,
 		   task->state == task_state, ret);
 
@@ -51,7 +51,36 @@ int thread_signal_sync(struct ktcb *task, unsigned int flags,
 
 int thread_suspend(struct ktcb *task)
 {
-	return thread_signal_sync(task, TASK_SUSPENDING, TASK_INACTIVE);
+	return thread_signal(task, TASK_SUSPENDING, TASK_INACTIVE);
+}
+
+/*
+ * Put them in TASK_DEAD so that a suspended exiting thread
+ * does not run again if issued THREAD_RUN
+ */
+int thread_destroy(struct ktcb *task)
+{
+	if (task == current) {
+		if (current->tid == current->pagerid)
+			sched_exit_pager();
+		else
+			sched_suspend_sync();
+		return 0;
+	}
+
+	thread_suspend(task);
+
+	tcb_remove(task);
+
+	/* Wake up waiters */
+	wake_up_all(&current->wqh_send, 0);
+	wake_up_all(&current->wqh_recv, 0);
+
+	BUG_ON(task->wqh_pager.sleepers > 0);
+	BUG_ON(task->state != TASK_INACTIVE);
+
+	tcb_delete(task);
+	return 0;
 }
 
 int arch_clear_thread(struct ktcb *tcb)
@@ -113,57 +142,6 @@ int thread_recycle(struct ktcb *task)
 	return 0;
 }
 
-int thread_destroy(struct ktcb *task)
-{
-	int ret;
-
-	/* If we're a self-destructing pager */
-	if (task == current &&
-	    current->tid == current->pagerid) {
-		struct ktcb *child, *n;
-
-		/* Make all children exit synchronously */
-		spin_lock(&curcont->ktcb_list.list_lock);
-		list_foreach_removable_struct(child, n,
-					      &curcont->ktcb_list.list,
-					      task_list) {
-			if (child->pagerid == current->tid &&
-			    child != current) {
-				spin_unlock(&curcont->ktcb_list.list_lock);
-
-				/* Its a bug since nobody can interrupt us */
-				BUG_ON(thread_signal_sync(child, TASK_EXITING,
-						   	  TASK_INACTIVE) < 0);
-				spin_lock(&curcont->ktcb_list.list_lock);
-			}
-		}
-		spin_unlock(&curcont->ktcb_list.list_lock);
-
-		/* Delete all exited children */
-		spin_lock(&current->child_exit_list.list_lock);
-		printk("(%d) To delete %d children\n", current->tid, current->child_exit_list.count);
-		list_foreach_removable_struct(child, n,
-					      &current->child_exit_list.list,
-					      task_list) {
-			list_remove(&child->task_list);
-			tcb_delete(child);
-		}
-		spin_unlock(&current->child_exit_list.list_lock);
-
-		/* Destroy yourself */
-		sched_pager_exit();
-		BUG();
-	}
-
-	if ((ret = thread_signal_sync(task, TASK_EXITING, TASK_INACTIVE)) < 0)
-		return ret;
-
-	ktcb_list_remove(task, &current->child_exit_list);
-	tcb_delete(task);
-
-	return 0;
-}
-
 /* Runs a thread for the first time */
 int thread_start(struct ktcb *task)
 {

src/generic/scheduler.c

@@ -229,7 +229,7 @@ void sched_resume_async(struct ktcb *task)
  * A self-paging thread deletes itself,
  * schedules and disappears from the system.
  */
-void sched_pager_exit(void)
+void sched_exit_pager(void)
 {
 	// printk("Pager (%d) Exiting...\n", current->tid);
 	/* Remove from its list, callers get -ESRCH */
@@ -269,13 +269,6 @@ void sched_exit_sync(void)
 {
 	struct ktcb *pager = tcb_find(current->pagerid);
 
-	/* Quit global list */
-	tcb_remove(current);
-
-	/* Wake up waiters */
-	wake_up_all(&current->wqh_send, 0);
-	wake_up_all(&current->wqh_recv, 0);
-
 	/* Go to exit list */
 	ktcb_list_add(current, &pager->child_exit_list);
 
@@ -285,8 +278,8 @@ void sched_exit_sync(void)
 	wake_up(&current->wqh_pager, 0);
 
 	sched_rq_remove_task(current);
-	current->state = TASK_INACTIVE;
-	current->flags &= ~TASK_SUSPENDING;
+	current->state = TASK_DEAD;
+	current->flags &= ~TASK_EXITING;
 	preempt_enable();
 
 	/* Quit */
@@ -294,16 +287,6 @@ void sched_exit_sync(void)
 	BUG();
 }
 
-/*
- * TODO:
- * Instead of sched_suspend_sync()
- * call sched_die_sync() on killer suspends:
- * (e.g. if also kill flag set, call sched_die_sync instead)
- * and handle dying on its own and dying over a pager
- * in there. (e.g. put yourself in a task_dead queue, take
- * care of pager calling destroy on you, calling wait on you etc.)
- */
-
 /*
  * NOTE: Could do these as sched_prepare_suspend()
  * + schedule() or need_resched = 1
@@ -328,12 +311,10 @@ void sched_suspend_async(void)
 	sched_rq_remove_task(current);
 	current->state = TASK_INACTIVE;
 	current->flags &= ~TASK_SUSPENDING;
-
-	/* This will make sure we yield soon */
 	preempt_enable();
 
 	if (current->pagerid != current->tid)
-		wake_up_task(tcb_find(current->pagerid), 0);
+		wake_up(&current->wqh_pager, 0);
 
 	need_resched = 1;
 }