kernel: Remove signal hacks for vhost_tasks

This removes the signal/coredump hacks added for vhost_tasks in:

Commit f9010dbd ("fork, vhost: Use CLONE_THREAD to fix freezer/ps regression")

When that patch was added vhost_tasks did not handle SIGKILL and would
try to ignore/clear the signal and continue on until the device's close
function was called. In the previous patches vhost_tasks and the vhost
drivers were converted to support SIGKILL by cleaning themselves up and
exiting. The hacks are no longer needed so this removes them.
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20240316004707.45557-10-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

fs/coredump.c

@@ -371,8 +371,6 @@ static int zap_process(struct task_struct *start, int exit_code)
 		if (t != current && !(t->flags & PF_POSTCOREDUMP)) {
 			sigaddset(&t->pending.signal, SIGKILL);
 			signal_wake_up(t, 1);
-			/* The vhost_worker does not particpate in coredumps */
-			if ((t->flags & (PF_USER_WORKER | PF_IO_WORKER)) != PF_USER_WORKER)
 			nr++;
 		}
 	}

kernel/exit.c

@@ -414,10 +414,7 @@ static void coredump_task_exit(struct task_struct *tsk)
 	tsk->flags |= PF_POSTCOREDUMP;
 	core_state = tsk->signal->core_state;
 	spin_unlock_irq(&tsk->sighand->siglock);
-
-	/* The vhost_worker does not particpate in coredumps */
-	if (core_state &&
-	    ((tsk->flags & (PF_IO_WORKER | PF_USER_WORKER)) != PF_USER_WORKER)) {
+	if (core_state) {
 		struct core_thread self;
 
 		self.task = current;

kernel/signal.c

@@ -1375,8 +1375,6 @@ int zap_other_threads(struct task_struct *p)
 
 	for_other_threads(p, t) {
 		task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
-		/* Don't require de_thread to wait for the vhost_worker */
-		if ((t->flags & (PF_IO_WORKER | PF_USER_WORKER)) != PF_USER_WORKER)
 		count++;
 
 		/* Don't bother with already dead threads */