net: wwan: core: split port creation and registration

Upcoming GNSS (NMEA) port type support requires exporting it via the
GNSS subsystem. On another hand, we still need to do basic WWAN core
work: find or allocate the WWAN device, make it the port parent, etc. To
reuse as much code as possible, split the port creation function into
the registration of a regular WWAN port device, and basic port struct
initialization.

To be able to use put_device() uniformly, break the device_register()
call into device_initialize() and device_add() and call device
initialization earlier.

While at it, fix a minor number leak upon WWAN port registration
failure.

Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Link: https://patch.msgid.link/20260126062158.308598-4-slark_xiao@163.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c
index 1da935e84008d39723b0f512440adc501ec7c9bf..76f1d759d2557cef00edc0458c99251604c47a9c 100644 (file)
--- a/drivers/net/wwan/wwan_core.c
+++ b/drivers/net/wwan/wwan_core.c
@@ -357,7 +357,8 @@ static void wwan_port_destroy(struct device *dev)
 {
        struct wwan_port *port = to_wwan_port(dev);
 
-       ida_free(&minors, MINOR(port->dev.devt));
+       if (dev->class == &wwan_class)
+               ida_free(&minors, MINOR(dev->devt));
        mutex_destroy(&port->data_lock);
        mutex_destroy(&port->ops_lock);
        kfree(port);
@@ -436,6 +437,44 @@ static int __wwan_port_dev_assign_name(struct wwan_port *port, const char *fmt)
        return dev_set_name(&port->dev, "%s", buf);
 }
 
+/* Register a regular WWAN port device (e.g. AT, MBIM, etc.) */
+static int wwan_port_register_wwan(struct wwan_port *port)
+{
+       struct wwan_device *wwandev = to_wwan_dev(port->dev.parent);
+       char namefmt[0x20];
+       int minor, err;
+
+       /* A port is exposed as character device, get a minor */
+       minor = ida_alloc_range(&minors, 0, WWAN_MAX_MINORS - 1, GFP_KERNEL);
+       if (minor < 0)
+               return minor;
+
+       port->dev.class = &wwan_class;
+       port->dev.devt = MKDEV(wwan_major, minor);
+
+       /* allocate unique name based on wwan device id, port type and number */
+       snprintf(namefmt, sizeof(namefmt), "wwan%u%s%%d", wwandev->id,
+                wwan_port_types[port->type].devsuf);
+
+       /* Serialize ports registration */
+       mutex_lock(&wwan_register_lock);
+
+       __wwan_port_dev_assign_name(port, namefmt);
+       err = device_add(&port->dev);
+
+       mutex_unlock(&wwan_register_lock);
+
+       if (err) {
+               ida_free(&minors, minor);
+               port->dev.class = NULL;
+               return err;
+       }
+
+       dev_info(&wwandev->dev, "port %s attached\n", dev_name(&port->dev));
+
+       return 0;
+}
+
 struct wwan_port *wwan_create_port(struct device *parent,
                                   enum wwan_port_type type,
                                   const struct wwan_port_ops *ops,
@@ -444,8 +483,7 @@ struct wwan_port *wwan_create_port(struct device *parent,
 {
        struct wwan_device *wwandev;
        struct wwan_port *port;
-       char namefmt[0x20];
-       int minor, err;
+       int err;
 
        if (type > WWAN_PORT_MAX || !ops)
                return ERR_PTR(-EINVAL);
@@ -457,17 +495,9 @@ struct wwan_port *wwan_create_port(struct device *parent,
        if (IS_ERR(wwandev))
                return ERR_CAST(wwandev);
 
-       /* A port is exposed as character device, get a minor */
-       minor = ida_alloc_range(&minors, 0, WWAN_MAX_MINORS - 1, GFP_KERNEL);
-       if (minor < 0) {
-               err = minor;
-               goto error_wwandev_remove;
-       }
-
        port = kzalloc(sizeof(*port), GFP_KERNEL);
        if (!port) {
                err = -ENOMEM;
-               ida_free(&minors, minor);
                goto error_wwandev_remove;
        }
 
@@ -481,27 +511,14 @@ struct wwan_port *wwan_create_port(struct device *parent,
        mutex_init(&port->data_lock);
 
        port->dev.parent = &wwandev->dev;
-       port->dev.class = &wwan_class;
        port->dev.type = &wwan_port_dev_type;
-       port->dev.devt = MKDEV(wwan_major, minor);
        dev_set_drvdata(&port->dev, drvdata);
+       device_initialize(&port->dev);
 
-       /* allocate unique name based on wwan device id, port type and number */
-       snprintf(namefmt, sizeof(namefmt), "wwan%u%s%%d", wwandev->id,
-                wwan_port_types[port->type].devsuf);
-
-       /* Serialize ports registration */
-       mutex_lock(&wwan_register_lock);
-
-       __wwan_port_dev_assign_name(port, namefmt);
-       err = device_register(&port->dev);
-
-       mutex_unlock(&wwan_register_lock);
-
+       err = wwan_port_register_wwan(port);
        if (err)
                goto error_put_device;
 
-       dev_info(&wwandev->dev, "port %s attached\n", dev_name(&port->dev));
        return port;
 
 error_put_device: