On 2024-05-10 16:21, Mina Almasry wrote:

+void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding)
+{
+	struct netdev_rx_queue *rxq;
+	unsigned long xa_idx;
+	unsigned int rxq_idx;
+
+	if (!binding)
+		return;
+
+	if (binding->list.next)
+		list_del(&binding->list);
+
+	xa_for_each(&binding->bound_rxq_list, xa_idx, rxq) {
+		if (rxq->mp_params.mp_priv == binding) {
+			/* We hold the rtnl_lock while binding/unbinding
+			 * dma-buf, so we can't race with another thread that
+			 * is also modifying this value. However, the page_pool
+			 * may read this config while it's creating its
+			 * rx-queues. WRITE_ONCE() here to match the
+			 * READ_ONCE() in the page_pool.
+			 */
+			WRITE_ONCE(rxq->mp_params.mp_ops, NULL);
+			WRITE_ONCE(rxq->mp_params.mp_priv, NULL);
+
+			rxq_idx = get_netdev_rx_queue_index(rxq);
+
+			netdev_rx_queue_restart(binding->dev, rxq_idx);

What if netdev_rx_queue_restart() fails? Depending on where it failed, a
queue might still be filled from struct net_devmem_dmabuf_binding. This
is one downside of the current situation with netdev_rx_queue_restart()
needing to do allocations each time.

Perhaps a full reset if individual queue restart fails?