FAILED: patch "[PATCH] usb: gadget: f_ecm: Fix net_device lifecycle with device_move" failed to apply to 5.10-stable tree

index e0c02121374e..e495bac4efeb 100644
@@ -681,6 +681,7 @@ ecm_bind(struct usb_configuration *c, struct usb_function *f)
 	struct usb_ep		*ep;
 
 	struct f_ecm_opts	*ecm_opts;
+	struct net_device	*net __free(detach_gadget) = NULL;
 	struct usb_request	*request __free(free_usb_request) = NULL;
 
 	if (!can_support_ecm(cdev->gadget))

@@ -688,18 +689,18 @@ ecm_bind(struct usb_configuration *c, struct usb_function *f)
 
 	ecm_opts = container_of(f->fi, struct f_ecm_opts, func_inst);
 
-	mutex_lock(&ecm_opts->lock);
+	scoped_guard(mutex, &ecm_opts->lock)
+		if (ecm_opts->bind_count == 0 && !ecm_opts->bound) {
+			if (!device_is_registered(&ecm_opts->net->dev)) {
+				gether_set_gadget(ecm_opts->net, cdev->gadget);
+				status = gether_register_netdev(ecm_opts->net);
+			} else
+				status = gether_attach_gadget(ecm_opts->net, cdev->gadget);
 
-	gether_set_gadget(ecm_opts->net, cdev->gadget);
-
-	if (!ecm_opts->bound) {
-		status = gether_register_netdev(ecm_opts->net);
-		ecm_opts->bound = true;
-	}
-
-	mutex_unlock(&ecm_opts->lock);
-	if (status)
-		return status;
+			if (status)
+				return status;
+			net = ecm_opts->net;
+		}
 
 	ecm_string_defs[1].s = ecm->ethaddr;
 

@@ -790,6 +791,9 @@ ecm_bind(struct usb_configuration *c, struct usb_function *f)
 
 	ecm->notify_req = no_free_ptr(request);
 
+	ecm_opts->bind_count++;
+	retain_and_null_ptr(net);
+
 	DBG(cdev, "CDC Ethernet: IN/%s OUT/%s NOTIFY/%s\n",
 			ecm->port.in_ep->name, ecm->port.out_ep->name,
 			ecm->notify->name);

@@ -836,7 +840,7 @@ static void ecm_free_inst(struct usb_function_instance *f)
 	struct f_ecm_opts *opts;
 
 	opts = container_of(f, struct f_ecm_opts, func_inst);
-	if (opts->bound)
+	if (device_is_registered(&opts->net->dev))
 		gether_cleanup(netdev_priv(opts->net));
 	else
 		free_netdev(opts->net);

@@ -906,9 +910,12 @@ static void ecm_free(struct usb_function *f)
 static void ecm_unbind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct f_ecm		*ecm = func_to_ecm(f);
+	struct f_ecm_opts	*ecm_opts;
 
 	DBG(c->cdev, "ecm unbind\n");
 
+	ecm_opts = container_of(f->fi, struct f_ecm_opts, func_inst);
+
 	usb_free_all_descriptors(f);
 
 	if (atomic_read(&ecm->notify_count)) {

@@ -918,6 +925,10 @@ static void ecm_unbind(struct usb_configuration *c, struct usb_function *f)
 
 	kfree(ecm->notify_req->buf);
 	usb_ep_free_request(ecm->notify, ecm->notify_req);
+
+	ecm_opts->bind_count--;
+	if (ecm_opts->bind_count == 0 && !ecm_opts->bound)
+		gether_detach_gadget(ecm_opts->net);
 }
 
 static struct usb_function *ecm_alloc(struct usb_function_instance *fi)

index 77cfb89932be..7f666b9dea02 100644
@@ -15,17 +15,26 @@
 
 #include <linux/usb/composite.h>
 
+/**
+ * struct f_ecm_opts - ECM function options
+ * @func_inst: USB function instance.
+ * @net: The net_device associated with the ECM function.
+ * @bound: True if the net_device is shared and pre-registered during the
+ *         legacy composite driver's bind phase (e.g., multi.c). If false,
+ *         the ECM function will register the net_device during its own
+ *         bind phase.
+ * @bind_count: Tracks the number of configurations the ECM function is
+ *              bound to, preventing double-registration of the @net device.
+ * @lock: Protects the data from concurrent access by configfs read/write
+ *        and create symlink/remove symlink operations.
+ * @refcnt: Reference counter for the function instance.
+ */
 struct f_ecm_opts {
 	struct usb_function_instance	func_inst;
 	struct net_device		*net;
 	bool				bound;
+	int				bind_count;
 
-	/*
-	 * Read/write access to configfs attributes is handled by configfs.
-	 *
-	 * This is to protect the data from concurrent access by read/write
-	 * and create symlink/remove symlink.
-	 */
 	struct mutex			lock;
 	int				refcnt;
 };