[Qemu-devel] [PATCH v2] net-hub: Drop can_receive

[Fam Zheng]

This moves the semantics from net_hub_port_can_receive to receive
functions, by returning 0 if all receiving ports return 0. Also,
remember to flush the source port's queue in that case.

Signed-off-by: Fam Zheng <address@hidden>
---
 net/hub.c | 54 +++++++++++++++++++++++++++++-------------------------
 1 file changed, 29 insertions(+), 25 deletions(-)

diff --git a/net/hub.c b/net/hub.c
index 3047f12..5697fad 100644
--- a/net/hub.c
+++ b/net/hub.c
@@ -31,6 +31,7 @@ typedef struct NetHubPort {
     QLIST_ENTRY(NetHubPort) next;
     NetHub *hub;
     int id;
+    bool needs_flush;
 } NetHubPort;
 
 struct NetHub {
@@ -42,35 +43,58 @@ struct NetHub {
 
 static QLIST_HEAD(, NetHub) hubs = QLIST_HEAD_INITIALIZER(&hubs);
 
+static void net_hub_port_send_cb(NetClientState *nc, ssize_t ret)
+{
+    NetHubPort *port = DO_UPCAST(NetHubPort, nc, nc);
+    NetHub *hub = port->hub;
+
+    QLIST_FOREACH(port, &hub->ports, next) {
+        if (port->needs_flush) {
+            port->needs_flush = false;
+            qemu_flush_queued_packets(&port->nc);
+        }
+    }
+}
+
 static ssize_t net_hub_receive(NetHub *hub, NetHubPort *source_port,
                                const uint8_t *buf, size_t len)
 {
     NetHubPort *port;
+    ssize_t ret = -1;
 
     QLIST_FOREACH(port, &hub->ports, next) {
+        ssize_t r;
         if (port == source_port) {
             continue;
         }
 
-        qemu_send_packet(&port->nc, buf, len);
+        r = qemu_send_packet_async(&port->nc, buf, len,
+                                   net_hub_port_send_cb);
+        ret = MAX(r, ret);
     }
-    return len;
+    source_port->needs_flush = ret == 0;
+
+    return ret;
 }
 
 static ssize_t net_hub_receive_iov(NetHub *hub, NetHubPort *source_port,
                                    const struct iovec *iov, int iovcnt)
 {
     NetHubPort *port;
-    ssize_t len = iov_size(iov, iovcnt);
+    ssize_t ret = -1;
 
     QLIST_FOREACH(port, &hub->ports, next) {
+        ssize_t r;
         if (port == source_port) {
             continue;
         }
 
-        qemu_sendv_packet(&port->nc, iov, iovcnt);
+        r = qemu_sendv_packet_async(&port->nc, iov,
+                                    iovcnt, net_hub_port_send_cb);
+        ret = MAX(r, ret);
     }
-    return len;
+    source_port->needs_flush = ret == 0;
+    return ret;
 }
 
 static NetHub *net_hub_new(int id)
@@ -87,25 +111,6 @@ static NetHub *net_hub_new(int id)
     return hub;
 }
 
-static int net_hub_port_can_receive(NetClientState *nc)
-{
-    NetHubPort *port;
-    NetHubPort *src_port = DO_UPCAST(NetHubPort, nc, nc);
-    NetHub *hub = src_port->hub;
-
-    QLIST_FOREACH(port, &hub->ports, next) {
-        if (port == src_port) {
-            continue;
-        }
-
-        if (qemu_can_send_packet(&port->nc)) {
-            return 1;
-        }
-    }
-
-    return 0;
-}
-
 static ssize_t net_hub_port_receive(NetClientState *nc,
                                     const uint8_t *buf, size_t len)
 {
@@ -132,7 +137,6 @@ static void net_hub_port_cleanup(NetClientState *nc)
 static NetClientInfo net_hub_port_info = {
     .type = NET_CLIENT_OPTIONS_KIND_HUBPORT,
     .size = sizeof(NetHubPort),
-    .can_receive = net_hub_port_can_receive,
     .receive = net_hub_port_receive,
     .receive_iov = net_hub_port_receive_iov,
     .cleanup = net_hub_port_cleanup,
-- 
2.4.3