On Thu, Jan 22, 2026 at 3:32 AM Slark Xiao [off-list ref] wrote:

At 2026-01-16 11:24:54, "Slark Xiao" [off-list ref] wrote:

quoted

At 2026-01-16 10:44:35, "Jakub Kicinski" [off-list ref] wrote:

quoted

This is an AI-generated review of your patch. The human sending this
email has considered the AI review valid, or at least plausible.

For local reproduction steps see https://netdev-ai.bots.linux.dev/ai-local.html
---
net: wwan: core: split port creation and registration

This patch splits the port creation function to prepare for upcoming GNSS
port type support. It separates device_register() into device_initialize()
and device_add(), and moves minor number allocation into the new
wwan_port_register_wwan() function.

quoted

diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c
index 1da935e84008..1a9a77d597e6 100644
--- 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);

[ ... ]

quoted

+/* 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);

[ ... ]

quoted

+   err = device_add(&port->dev);
+
+   mutex_unlock(&wwan_register_lock);
+
+   if (err) {
+           ida_free(&minors, minor);

               ^^^^^^^^^^^^^^^^^^^^^^^^

quoted

quoted

Hi Sergey,
Can we modify it like this?

+       if (err) {
+               ida_free(&minors, minor);
+               port->dev.class = NULL;

This shall be able to avoid the double free issue.

I would prefer to let wwan_port_destroy() handle this, meaning we
shouldn’t free the IDA here and should simply return the error code,
but your approach is also acceptable.

Regards,
Loic