IB/ucm: Simplify ib_ucm_event()

Use wait_event_interruptible() instead of a more complicated
open-coded equivalent.
Signed-off-by: Sean Hefty <sean.hefty@intel.com>

drivers/infiniband/core/ucm.c

@@ -407,29 +407,18 @@ static ssize_t ib_ucm_event(struct ib_ucm_file *file,
 
 	mutex_lock(&file->file_mutex);
 	while (list_empty(&file->events)) {
+		mutex_unlock(&file->file_mutex);
 
-		if (file->filp->f_flags & O_NONBLOCK) {
-			result = -EAGAIN;
-			break;
-		}
+		if (file->filp->f_flags & O_NONBLOCK)
+			return -EAGAIN;
 
-		if (signal_pending(current)) {
-			result = -ERESTARTSYS;
-			break;
-		}
+		if (wait_event_interruptible(file->poll_wait,
+					     !list_empty(&file->events)))
+			return -ERESTARTSYS;
 
-		prepare_to_wait(&file->poll_wait, &wait, TASK_INTERRUPTIBLE);
-
-		mutex_unlock(&file->file_mutex);
-		schedule();
 		mutex_lock(&file->file_mutex);
-
-		finish_wait(&file->poll_wait, &wait);
 	}
 
-	if (result)
-		goto done;
-
 	uevent = list_entry(file->events.next, struct ib_ucm_event, file_list);
 
 	if (ib_ucm_new_cm_id(uevent->resp.event)) {