From: Reinhard Speyerer <rspmn@arcor.de>
To: "Bjørn Mork" <bjorn@mork.no>
Cc: Daniele Palmas <dnlplm@gmail.com>,
netdev@vger.kernel.org, rspmn@arcor.de
Subject: [PATCH 3/4] qmi_wwan: avoid RCU stalls on device disconnect when in QMAP mode
Date: Wed, 12 Jun 2019 19:03:15 +0200 [thread overview]
Message-ID: <fbb0cab5f36550668dd4dc6ecdb5eafa90a6e655.1560287477.git.rspmn@arcor.de> (raw)
In-Reply-To: <cover.1560287477.git.rspmn@arcor.de>
Switch qmimux_unregister_device() and qmi_wwan_disconnect() to
use unregister_netdevice_queue() and unregister_netdevice_many()
instead of unregister_netdevice(). This avoids RCU stalls which
have been observed on device disconnect in certain setups otherwise.
Fixes: c6adf77953bc ("net: usb: qmi_wwan: add qmap mux protocol support")
Cc: Daniele Palmas <dnlplm@gmail.com>
Signed-off-by: Reinhard Speyerer <rspmn@arcor.de>
---
drivers/net/usb/qmi_wwan.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index b0a96459621f..c6fbc2a2a785 100644
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -312,14 +312,15 @@ static int qmimux_register_device(struct net_device *real_dev, u8 mux_id)
return err;
}
-static void qmimux_unregister_device(struct net_device *dev)
+static void qmimux_unregister_device(struct net_device *dev,
+ struct list_head *head)
{
struct qmimux_priv *priv = netdev_priv(dev);
struct net_device *real_dev = priv->real_dev;
free_percpu(priv->stats64);
netdev_upper_dev_unlink(real_dev, dev);
- unregister_netdevice(dev);
+ unregister_netdevice_queue(dev, head);
/* Get rid of the reference to real_dev */
dev_put(real_dev);
@@ -490,7 +491,7 @@ static ssize_t del_mux_store(struct device *d, struct device_attribute *attr, c
ret = -EINVAL;
goto err;
}
- qmimux_unregister_device(del_dev);
+ qmimux_unregister_device(del_dev, NULL);
if (!qmimux_has_slaves(dev))
info->flags &= ~QMI_WWAN_FLAG_MUX;
@@ -1500,6 +1501,7 @@ static void qmi_wwan_disconnect(struct usb_interface *intf)
struct qmi_wwan_state *info;
struct list_head *iter;
struct net_device *ldev;
+ LIST_HEAD(list);
/* called twice if separate control and data intf */
if (!dev)
@@ -1512,8 +1514,9 @@ static void qmi_wwan_disconnect(struct usb_interface *intf)
}
rcu_read_lock();
netdev_for_each_upper_dev_rcu(dev->net, ldev, iter)
- qmimux_unregister_device(ldev);
+ qmimux_unregister_device(ldev, &list);
rcu_read_unlock();
+ unregister_netdevice_many(&list);
rtnl_unlock();
info->flags &= ~QMI_WWAN_FLAG_MUX;
}
--
2.11.0
next prev parent reply other threads:[~2019-06-12 17:12 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-12 17:01 [PATCH 0/4] qmi_wwan: fix QMAP handling Reinhard Speyerer
2019-06-12 17:02 ` [PATCH 1/4] qmi_wwan: add support for QMAP padding in the RX path Reinhard Speyerer
2019-06-12 17:02 ` [PATCH 2/4] qmi_wwan: add network device usage statistics for qmimux devices Reinhard Speyerer
2019-06-12 17:03 ` Reinhard Speyerer [this message]
2019-06-12 17:03 ` [PATCH 4/4] qmi_wwan: extend permitted QMAP mux_id value range Reinhard Speyerer
2019-06-13 15:14 ` [PATCH 0/4] qmi_wwan: fix QMAP handling Daniele Palmas
2019-06-13 17:54 ` Bjørn Mork
2019-06-15 2:06 ` David Miller
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