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Message-Id: <1397632082-18453-1-git-send-email-zhen-hual@hp.com>
Date: Wed, 16 Apr 2014 15:08:02 +0800
From: "Li, Zhen-Hua" <zhen-hual@...com>
To: "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Veaceslav Falico <vfalico@...hat.com>,
Nicolas Dichtel <nicolas.dichtel@...nd.com>,
Jiri Pirko <jiri@...nulli.us>,
stephen hemminger <stephen@...workplumber.org>,
Jerry Chu <hkchu@...gle.com>,
Sathya Perla <sathya.perla@...lex.com>,
Subbu Seetharaman <subbu.seetharaman@...lex.com>,
Ajit Khaparde <ajit.khaparde@...lex.com>,
<netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Cc: "Li, Zhen-Hua" <zhen-hual@...com>
Subject: [PATCH 1/1] net: Add rtnl_lock for netif_device_attach/detach
From: "Li, Zhen-Hua" <zhen-hual@...com>
As netif_running is called in netif_device_attach/detach. There should be
rtnl_lock/unlock called, to avoid dev stat change during netif_device_attach
and detach being called.
I checked NIC some drivers, some of them have netif_device_attach/detach
called between rtnl_lock/unlock, while some drivers do not.
This patch is tring to find a generic way to fix this for all NIC drivers.
Signed-off-by: Li, Zhen-Hua <zhen-hual@...com>
---
net/core/dev.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/net/core/dev.c b/net/core/dev.c
index 5b3042e..795bbc5 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2190,10 +2190,19 @@ EXPORT_SYMBOL(__dev_kfree_skb_any);
*/
void netif_device_detach(struct net_device *dev)
{
+ /**
+ * As netif_running is called , rtnl_lock and unlock are needed to
+ * avoid __LINK_STATE_START bit changes during this function call.
+ */
+ int need_unlock;
+
+ need_unlock = rtnl_trylock();
if (test_and_clear_bit(__LINK_STATE_PRESENT, &dev->state) &&
netif_running(dev)) {
netif_tx_stop_all_queues(dev);
}
+ if (need_unlock)
+ rtnl_unlock();
}
EXPORT_SYMBOL(netif_device_detach);
@@ -2205,11 +2214,20 @@ EXPORT_SYMBOL(netif_device_detach);
*/
void netif_device_attach(struct net_device *dev)
{
+ /**
+ * As netif_running is called , rtnl_lock and unlock are needed to
+ * avoid __LINK_STATE_START bit changes during this function call.
+ */
+ int need_unlock;
+
+ need_unlock = rtnl_trylock();
if (!test_and_set_bit(__LINK_STATE_PRESENT, &dev->state) &&
netif_running(dev)) {
netif_tx_wake_all_queues(dev);
__netdev_watchdog_up(dev);
}
+ if (need_unlock)
+ rtnl_unlock();
}
EXPORT_SYMBOL(netif_device_attach);
--
1.7.10.4
--
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