[PATCH 2/8] net: Define net_client_set_link()

[Laurent Vivier <lvivier@redhat.com>]

The code to set the link status is currently located in
qmp_set_link(). This function identifies the device by name,
searches for the corresponding NetClientState, and then updates
the link status.

In some parts of the code, such as vhost-user.c, the
NetClientState are already available. Calling qmp_set_link()
from these locations leads to a redundant search for the clients.

This patch refactors the logic by introducing a new function,
net_client_set_link(), which accepts a NetClientState array
directly. qmp_set_link() is simplified to be a wrapper that
performs the client search and then calls the new function.
The vhost-user implementation is updated to use net_client_set_link()
directly, thereby eliminating the unnecessary client lookup.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 include/net/net.h |  1 +
 net/net.c         | 32 ++++++++++++++++++++------------
 net/vhost-user.c  |  4 ++--
 3 files changed, 23 insertions(+), 14 deletions(-)

diff --git a/include/net/net.h b/include/net/net.h
index cdd5b109b0d2..ac59b593ba48 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -298,6 +298,7 @@ void net_client_parse(QemuOptsList *opts_list, const char *optstr);
 void show_netdevs(void);
 void net_init_clients(void);
 void net_check_clients(void);
+void net_client_set_link(NetClientState **ncs, int queues, bool up);
 void net_cleanup(void);
 void hmp_host_net_add(Monitor *mon, const QDict *qdict);
 void hmp_host_net_remove(Monitor *mon, const QDict *qdict);
diff --git a/net/net.c b/net/net.c
index 39d6f28158a3..cfa2d8e95827 100644
--- a/net/net.c
+++ b/net/net.c
@@ -1601,21 +1601,11 @@ void colo_notify_filters_event(int event, Error **errp)
     }
 }
 
-void qmp_set_link(const char *name, bool up, Error **errp)
+void net_client_set_link(NetClientState **ncs, int queues, bool up)
 {
-    NetClientState *ncs[MAX_QUEUE_NUM];
     NetClientState *nc;
-    int queues, i;
-
-    queues = qemu_find_net_clients_except(name, ncs,
-                                          NET_CLIENT_DRIVER__MAX,
-                                          MAX_QUEUE_NUM);
+    int i;
 
-    if (queues == 0) {
-        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
-                  "Device '%s' not found", name);
-        return;
-    }
     nc = ncs[0];
 
     for (i = 0; i < queues; i++) {
@@ -1646,6 +1636,24 @@ void qmp_set_link(const char *name, bool up, Error **errp)
     }
 }
 
+void qmp_set_link(const char *name, bool up, Error **errp)
+{
+    NetClientState *ncs[MAX_QUEUE_NUM];
+    int queues;
+
+    queues = qemu_find_net_clients_except(name, ncs,
+                                          NET_CLIENT_DRIVER__MAX,
+                                          MAX_QUEUE_NUM);
+
+    if (queues == 0) {
+        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
+                  "Device '%s' not found", name);
+        return;
+    }
+
+    net_client_set_link(ncs, queues, up);
+}
+
 static void net_vm_change_state_handler(void *opaque, bool running,
                                         RunState state)
 {
diff --git a/net/vhost-user.c b/net/vhost-user.c
index 0b235e50c650..10ac8dc0b3d7 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -264,7 +264,7 @@ static void chr_closed_bh(void *opaque)
         vhost_user_save_acked_features(ncs[i]);
     }
 
-    qmp_set_link(name, false, &err);
+    net_client_set_link(ncs, queues, false);
 
     qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, net_vhost_user_event,
                              NULL, opaque, NULL, true);
@@ -300,7 +300,7 @@ static void net_vhost_user_event(void *opaque, QEMUChrEvent event)
         }
         s->watch = qemu_chr_fe_add_watch(&s->chr, G_IO_HUP,
                                          net_vhost_user_watch, s);
-        qmp_set_link(name, true, &err);
+        net_client_set_link(ncs, queues, true);
         s->started = true;
         qapi_event_send_netdev_vhost_user_connected(name, chr->label);
         break;
-- 
2.49.0