netdev - [RFC PATCH v2 3/6] net: wwan: core: split port unregister and stop

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Message-ID: <20250624213801.31702-4-ryazanov.s.a@gmail.com>
Date: Wed, 25 Jun 2025 00:37:58 +0300
From: Sergey Ryazanov <ryazanov.s.a@...il.com>
To: Loic Poulain <loic.poulain@....qualcomm.com>,
	Johannes Berg <johannes@...solutions.net>
Cc: Andrew Lunn <andrew+netdev@...n.ch>,
	Eric Dumazet <edumazet@...gle.com>,
	"David S . Miller" <davem@...emloft.net>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	netdev@...r.kernel.org
Subject: [RFC PATCH v2 3/6] net: wwan: core: split port unregister and stop

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: call the port stop operation, purge queues, release the parent
WWAN device, etc. To reuse as much code as possible, split the port
unregistering function into the deregistration of a regular WWAN port
device, and the common port tearing down code.

In order to keep more code generic, break the device_unregister() call
into device_del() and put_device(), which release the port memory
uniformly.

Signed-off-by: Sergey Ryazanov <ryazanov.s.a@...il.com>
---
Changes:
 RFCv1->RFCv2: break device_unregister() into device_del() and
 put_device() to use later uniformly.
---
 drivers/net/wwan/wwan_core.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c
index edee5ff48f28..c735b9830e6e 100644
--- a/drivers/net/wwan/wwan_core.c
+++ b/drivers/net/wwan/wwan_core.c
@@ -476,6 +476,18 @@ static int wwan_port_register_wwan(struct wwan_port *port)
 	return 0;
 }
 
+/* Unregister a regular WWAN port (e.g. AT, MBIM, etc) */
+static void wwan_port_unregister_wwan(struct wwan_port *port)
+{
+	struct wwan_device *wwandev = to_wwan_dev(port->dev.parent);
+
+	dev_set_drvdata(&port->dev, NULL);
+
+	dev_info(&wwandev->dev, "port %s disconnected\n", dev_name(&port->dev));
+
+	device_del(&port->dev);
+}
+
 struct wwan_port *wwan_create_port(struct device *parent,
 				   enum wwan_port_type type,
 				   const struct wwan_port_ops *ops,
@@ -536,18 +548,19 @@ void wwan_remove_port(struct wwan_port *port)
 	struct wwan_device *wwandev = to_wwan_dev(port->dev.parent);
 
 	mutex_lock(&port->ops_lock);
-	if (port->start_count)
+	if (port->start_count) {
 		port->ops->stop(port);
+		port->start_count = 0;
+	}
 	port->ops = NULL; /* Prevent any new port operations (e.g. from fops) */
 	mutex_unlock(&port->ops_lock);
 
 	wake_up_interruptible(&port->waitqueue);
-
 	skb_queue_purge(&port->rxq);
-	dev_set_drvdata(&port->dev, NULL);
 
-	dev_info(&wwandev->dev, "port %s disconnected\n", dev_name(&port->dev));
-	device_unregister(&port->dev);
+	wwan_port_unregister_wwan(port);
+
+	put_device(&port->dev);
 
 	/* Release related wwan device */
 	wwan_remove_dev(wwandev);
-- 
2.49.0