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Miller" , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org Subject: [RFC PATCH v5 3/7] net: wwan: core: split port creation and registration Date: Fri, 9 Jan 2026 03:09:05 +0200 Message-ID: <20260109010909.4216-4-ryazanov.s.a@gmail.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260109010909.4216-1-ryazanov.s.a@gmail.com> References: <20260109010909.4216-1-ryazanov.s.a@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- Changes: * RFCv1->RFCv2: break device_register() into device_initialize() and device_add() and use put_device() uniformly. Now, in case of error, memory is released in wwan_create_port(). * RFCv2->RFCv5: became 3/7 (was 2/6); fix a minor number leak on device_add() failure - thanks Sai! --- drivers/net/wwan/wwan_core.c | 68 ++++++++++++++++++++++-------------- 1 file changed, 42 insertions(+), 26 deletions(-) diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c index 33f7a140fba9..4c6d315f4847 100644 --- a/drivers/net/wwan/wwan_core.c +++ b/drivers/net/wwan/wwan_core.c @@ -360,7 +360,8 @@ 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); @@ -439,6 +440,43 @@ 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); + 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, @@ -447,8 +485,7 @@ 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); @@ -460,17 +497,9 @@ 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; } @@ -484,27 +513,14 @@ 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: -- 2.52.0