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realtek: dsa: rtl83xx: flush scheduled work on removal

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The workqueue items don't need to be processed directly when they are
scheduled. It can happen that they are simply processed at a much later
time. It is therefore necessary to ensure that all workqueue items of a
driver are no longer being processed before the driver (or structures of
this driver) are destroyed.

When skipping this step, the driver driver can cause a kernel Oops on
reboot.

Unfortunately, it is not recommended [1] to flush items out of the system
workqueue - simply because this can cause deadlocks. The driver itself must
have a private workqueue which is then flushed.

[1] https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp

Signed-off-by: Issam Hamdi <ih@simonwunderlich.de>
Signed-off-by: Harshal Gohel <hg@simonwunderlich.de>
Signed-off-by: Sharadanand Karanjkar <sk@simonwunderlich.de>
Link: https://github.com/openwrt/openwrt/pull/19570
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
This commit is contained in:
Issam Hamdi 2025-02-20 16:06:00 +01:00 committed by Hauke Mehrtens
parent 0fa192a3a2
commit feec7cf34d
3 changed files with 39 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/common.c
View File

@ -1330,7 +1330,7 @@ static int rtl83xx_netevent_event(struct notifier_block *this,
pr_debug("%s: updating neighbour on port %d, mac %016llx\n",
__func__, port, net_work->mac);
schedule_work(&net_work->work);
queue_work(priv->wq, &net_work->work);
if (err)
netdev_warn(dev, "failed to handle neigh update (err %d)\n", err);
break;
@ -1452,7 +1452,7 @@ static int rtl83xx_fib_event(struct notifier_block *this, unsigned long event, v
break;
}
schedule_work(&fib_work->work);
queue_work(priv->wq, &fib_work->work);
return NOTIFY_DONE;
}
@ -1486,6 +1486,7 @@ static int __init rtl83xx_sw_probe(struct platform_device *pdev)
priv->ds->ops = &rtl83xx_switch_ops;
priv->ds->needs_standalone_vlan_filtering = true;
priv->dev = dev;
dev_set_drvdata(dev, priv);
err = devm_mutex_init(dev, &priv->reg_mutex);
if (err)
@ -1583,10 +1584,16 @@ static int __init rtl83xx_sw_probe(struct platform_device *pdev)
return err;
}
priv->wq = create_singlethread_workqueue("rtl83xx");
if (!priv->wq) {
dev_err(dev, "Error creating workqueue: %d\n", err);
return -ENOMEM;
}
err = dsa_register_switch(priv->ds);
if (err) {
dev_err(dev, "Error registering switch: %d\n", err);
return err;
goto err_register_switch;
}
/* dsa_to_port returns dsa_port from the port list in
@ -1694,13 +1701,37 @@ err_register_fib_nb:
err_register_ne_nb:
unregister_netdevice_notifier(&priv->nb);
err_register_nb:
dsa_switch_shutdown(priv->ds);
err_register_switch:
destroy_workqueue(priv->wq);
return err;
}
static void rtl83xx_sw_remove(struct platform_device *pdev)
{
struct rtl838x_switch_priv *priv = platform_get_drvdata(pdev);
if (!priv)
return;
/* TODO: */
pr_debug("Removing platform driver for rtl83xx-sw\n");
/* unregister notifiers which will create workqueue entries with
* references to the switch structures. Also stop self-arming delayed
* work items to avoid them still accessing the DSA structures
* when they are getting shut down.
*/
unregister_fib_notifier(&init_net, &priv->fib_nb);
unregister_netevent_notifier(&priv->ne_nb);
cancel_delayed_work_sync(&priv->counters_work);
dsa_switch_shutdown(priv->ds);
destroy_workqueue(priv->wq);
dev_set_drvdata(&pdev->dev, NULL);
}
static const struct of_device_id rtl83xx_switch_of_ids[] = {

6
target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/dsa.c
View File

@ -1236,7 +1236,8 @@ static void rtldsa_poll_counters(struct work_struct *work)
spin_unlock(&counters->lock);
}
schedule_delayed_work(&priv->counters_work, RTLDSA_COUNTERS_POLL_INTERVAL);
queue_delayed_work(priv->wq, &priv->counters_work,
RTLDSA_COUNTERS_POLL_INTERVAL);
}
static void rtldsa_init_counters(struct rtl838x_switch_priv *priv)
@ -1254,7 +1255,8 @@ static void rtldsa_init_counters(struct rtl838x_switch_priv *priv)
}
INIT_DELAYED_WORK(&priv->counters_work, rtldsa_poll_counters);
schedule_delayed_work(&priv->counters_work, RTLDSA_COUNTERS_POLL_INTERVAL);
queue_delayed_work(priv->wq, &priv->counters_work,
RTLDSA_COUNTERS_POLL_INTERVAL);
}
static void rtldsa_get_strings(struct dsa_switch *ds,

1
target/linux/realtek/files-6.12/drivers/net/dsa/rtl83xx/rtl838x.h
View File

@ -1143,6 +1143,7 @@ struct rtl838x_switch_priv {
u32 lag_primary[MAX_LAGS];
u32 is_lagmember[57];
u64 lagmembers;
struct workqueue_struct *wq;
struct notifier_block nb; /* TODO: change to different name */
struct notifier_block ne_nb;
struct notifier_block fib_nb;