Hello.
On 04/16/2014 11:08 AM, Li, Zhen-Hua wrote:
From: "Li, Zhen-Hua" <zhen-h...@hp.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-h...@hp.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)
{
+ /**
Hm, why kernel-doc style comment here?
+ * 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)
{
+ /**
... and here?
+ * As netif_running is called , rtnl_lock and unlock are needed to
+ * avoid __LINK_STATE_START bit changes during this function call.
+ */
WBR, Sergei
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