firewire: cdev: shut down iso context before freeing the buffer

DMA must be halted before we DMA-unmap and free the DMA buffer.  Since
we cannot rely on the client to stop the context before it closes the
fd, we have to reorder fw_iso_buffer_destroy vs. fw_iso_context_destroy.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

drivers/firewire/fw-cdev.c

@@ -1386,12 +1386,12 @@ static int fw_device_op_release(struct inode *inode, struct file *file)
 	list_del(&client->link);
 	mutex_unlock(&client->device->client_list_mutex);
 
-	if (client->buffer.pages)
-		fw_iso_buffer_destroy(&client->buffer, client->device->card);
-
 	if (client->iso_context)
 		fw_iso_context_destroy(client->iso_context);
 
+	if (client->buffer.pages)
+		fw_iso_buffer_destroy(&client->buffer, client->device->card);
+
 	/* Freeze client->resource_idr and client->event_list */
 	spin_lock_irq(&client->lock);
 	client->in_shutdown = true;