Move the device_delete_all_children() function from usb_util.c

to kern/subr_bus.c. Simplify this function so that it no longer
depends on malloc() to execute. Identify a few other places where
it makes sense to use device_delete_all_children().

MFC after:	1 week

1 files changed, 33 insertions, 0 deletions

diff --git a/sys/kern/subr_bus.c b/sys/kern/subr_bus.c
index 4a36a8bae796..c337c78ace36 100644
--- a/sys/kern/subr_bus.c
+++ b/sys/kern/subr_bus.c
@@ -1881,6 +1881,39 @@ device_delete_child(device_t dev, device_t child)
 }
 
 /**
+ * @brief Delete all children devices of the given device, if any.
+ *
+ * This function deletes all children devices of the given device, if
+ * any, using the device_delete_child() function for each device it
+ * finds. If a child device cannot be deleted, this function will
+ * return an error code.
+ * 
+ * @param dev		the parent device
+ *
+ * @retval 0		success
+ * @retval non-zero	a device would not detach
+ */
+int
+device_delete_all_children(device_t dev)
+{
+	device_t child;
+	int error;
+
+	PDEBUG(("Deleting all children of %s", DEVICENAME(dev)));
+
+	error = 0;
+
+	while ( (child = TAILQ_FIRST(&dev->children)) ) {
+		error = device_delete_child(dev, child);
+		if (error) {
+			PDEBUG(("Failed deleting %s", DEVICENAME(child)));
+			break;
+		}
+	}
+	return (error);
+}
+
+/**
  * @brief Find a device given a unit number
  *
  * This is similar to devclass_get_devices() but only searches for