Re: [PATCH net-next v9 04/14] netdev: support binding dma-buf to netdevice

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?