[...]

quoted

+	/* Driver set this to memory recycling info. Reset it on recycle.
+	 * This will *not* work for NIC using a split-page memory model.
+	 * The page will be returned to the pool here regardless of the
+	 * 'flipped' fragment being in use or not.
+	 */

I am not sure I understand how does the last part of comment related
to the code below, as there is no driver using split-page memory model
will reach here because those driver will not call skb_mark_for_recycle(),
right?

Yes the comment is there to prohibit people (mlx5 only actually) to add the
recycling bit on their driver.  Because if they do it will *probably* work
but they might get random corrupted packets which will be hard to debug.

quoted

+	page->pp = NULL;
+	page_pool_put_full_page(pp, virt_to_head_page(data), false);
+
+	return true;
+}
+EXPORT_SYMBOL(page_pool_return_skb_page);