From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kurt Van Dijck Subject: [PATCH] can: rename LED trigger name on netdev renames Date: Tue, 4 Sep 2012 11:29:11 +0200 Message-ID: <1346750951-10451-1-git-send-email-kurt.van.dijck@eia.be> References: <20120904071128.GB416@vandijck-laurijssen.be> Return-path: Received: from mailrelay009.isp.belgacom.be ([195.238.6.176]:58919 "EHLO mailrelay009.isp.belgacom.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752178Ab2IDJ3c (ORCPT ); Tue, 4 Sep 2012 05:29:32 -0400 In-Reply-To: <20120904071128.GB416@vandijck-laurijssen.be> Sender: linux-can-owner@vger.kernel.org List-ID: To: Fabio Baltieri , Marc Kleine-Budde , Oliver Hartkopp , Wolfgang Grandegger Cc: linux-kernel@vger.kernel.org, linux-can@vger.kernel.org, Kurt Van Dijck The LED trigger name for CAN devices is based on the initial CAN device name, but does never change. The LED trigger name is not guaranteed to be unique in case of hotplugging CAN devices. This patch tries to address this problem by modifying the LED trigger name according to the CAN device name when the latter changes. This patch is meant as illustration only. In case of VCAN device rename, a segmentation fault will occur. Signed-off-by: Kurt Van Dijck --- drivers/net/can/led.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) diff --git a/drivers/net/can/led.c b/drivers/net/can/led.c index eaa14ac..f62f908 100644 --- a/drivers/net/can/led.c +++ b/drivers/net/can/led.c @@ -12,6 +12,7 @@ #include #include #include +#include #include @@ -87,3 +88,59 @@ void devm_can_led_init(struct net_device *netdev) devres_add(&netdev->dev, res); } EXPORT_SYMBOL_GPL(devm_can_led_init); + +/* + * NETDEV rename notifier to rename the associated led triggers too + */ +static int can_led_notifier(struct notifier_block *nb, unsigned long msg, + void *data) +{ + struct net_device *netdev = (struct net_device *)data; + struct can_priv *priv = netdev_priv(netdev); + int busy = 0; + + if (!net_eq(dev_net(netdev), &init_net)) + return NOTIFY_DONE; + + if (netdev->type != ARPHRD_CAN) + return NOTIFY_DONE; + + if (msg != NETDEV_CHANGENAME) + return NOTIFY_DONE; + + read_lock(&priv->tx_led_trig->leddev_list_lock); + if (!list_empty(&priv->tx_led_trig->led_cdevs)) + ++busy; + read_unlock(&priv->tx_led_trig->leddev_list_lock); + read_lock(&priv->rx_led_trig->leddev_list_lock); + if (!list_empty(&priv->rx_led_trig->led_cdevs)) + ++busy; + read_unlock(&priv->rx_led_trig->leddev_list_lock); + + if (busy) + return notifier_from_errno(-EBUSY); + + snprintf(priv->tx_led_trig_name, sizeof(priv->tx_led_trig_name), + "%s-tx", netdev->name); + snprintf(priv->rx_led_trig_name, sizeof(priv->rx_led_trig_name), + "%s-rx", netdev->name); + return NOTIFY_DONE; +} + +/* notifier block for netdevice event */ +static struct notifier_block can_netdev_notifier __read_mostly = { + .notifier_call = can_led_notifier, +}; + +static __init int can_led_init(void) +{ + return register_netdevice_notifier(&can_netdev_notifier); +} + +static __exit void can_led_exit(void) +{ + unregister_netdevice_notifier(&can_netdev_notifier); +} + +module_init(can_led_init); +module_exit(can_led_exit); -- 1.7.10.4