anchao commented on code in PR #7616:
URL: https://github.com/apache/nuttx/pull/7616#discussion_r1038341235
##########
net/devif/devif_poll.c:
##########
@@ -772,6 +769,217 @@ int devif_poll(FAR struct net_driver_s *dev,
devif_poll_callback_t callback)
return bstop;
}
+/****************************************************************************
+ * Name: devif_poll_callback
+ *
+ * Description:
+ * This function will help us to gather multiple iob memory slices into a
+ * linear device buffer. if devices with small memory, this function will
+ * trigger a memory copy if net device start transmit the iob slices to
+ * flat buffer
+ *
+ ****************************************************************************/
+
+static int devif_poll_callback(FAR struct net_driver_s *dev)
+{
+ if (dev->d_len > 0)
+ {
+ return true;
+ }
+
+ return false;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: devif_iob_poll
+ *
+ * Description:
+ * This function will traverse each active network connection structure and
+ * will perform network polling operations. devif_poll() may be called
+ * asynchronously with the network driver can accept another outgoing
+ * packet.
+ *
+ * This function will call the provided callback function for every active
+ * connection. Polling will continue until all connections have been polled
+ * or until the user-supplied function returns a non-zero value (which it
+ * should do only if it cannot accept further write data).
+ *
+ * When the callback function is called, there may be an outbound packet
+ * waiting for service in the device packet buffer, and if so the d_len
+ * field is set to a value larger than zero. The device driver should then
+ * send out the packet.
+ *
+ * This is the iob buffer version of devif_input(),
+ * this function will support send/receive iob vectors directly between
+ * the driver and l3/l4 stack to avoid unnecessary memory copies,
+ * especially on hardware that supports Scatter/gather, which can
+ * greatly improve performance
+ * this function will uses d_iob as packets input which used by some
+ * NICs such as celluler net driver.
+ *
+ * If NIC hardware support Scatter/gather transfer
+ *
+ * tcp_poll()/udp_poll()/pkt_poll()/...(l3/l4)
+ * / \
+ * / \
+ * devif_poll_[l3|l4]_connections() devif_iob_send() (nocopy:udp/icmp/...)
+ * / \ (copy:tcp)
+ * / \
+ * devif_iob_poll("NIC"_txpoll) callback() // "NIC"_txpoll
+ *
+ *
+ * Assumptions:
+ * This function is called from the MAC device driver with the network
+ * locked.
+ *
+ ****************************************************************************/
+
+int devif_iob_poll(FAR struct net_driver_s *dev,
Review Comment:
Done
##########
drivers/net/loopback.c:
##########
@@ -200,7 +199,7 @@ static void lo_txavail_work(FAR void *arg)
* return stop
*/
- while (devif_poll(&priv->lo_dev, NULL));
+ while (devif_iob_poll(&priv->lo_dev, NULL));
Review Comment:
Done
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