net: add qemu_purge_queued_packets()

If net client sends packets asynchronously, it needs to purge its queued
packets in cleanup() so as to prevent sent callbacks being invoked with
a freed client.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

net.c

@@ -439,6 +439,22 @@ qemu_deliver_packet(VLANClientState *sender, const uint8_t *buf, int size)
     return ret;
 }
 
+void qemu_purge_queued_packets(VLANClientState *vc)
+{
+    VLANPacket **pp = &vc->vlan->send_queue;
+
+    while (*pp != NULL) {
+        VLANPacket *packet = *pp;
+
+        if (packet->sender == vc) {
+            *pp = packet->next;
+            qemu_free(packet);
+        } else {
+            pp = &packet->next;
+        }
+    }
+}
+
 void qemu_flush_queued_packets(VLANClientState *vc)
 {
     VLANPacket *packet;

net.h

@@ -70,6 +70,7 @@ ssize_t qemu_sendv_packet_async(VLANClientState *vc, const struct iovec *iov,
 void qemu_send_packet(VLANClientState *vc, const uint8_t *buf, int size);
 ssize_t qemu_send_packet_async(VLANClientState *vc, const uint8_t *buf,
                                int size, NetPacketSent *sent_cb);
+void qemu_purge_queued_packets(VLANClientState *vc);
 void qemu_flush_queued_packets(VLANClientState *vc);
 void qemu_format_nic_info_str(VLANClientState *vc, uint8_t macaddr[6]);
 void qemu_check_nic_model(NICInfo *nd, const char *model);