Re: MOD_INC_USE_COUNT

[Stephen Hemminger <shemminger@osdl.org>]

On Thu, 10 Nov 2005 21:14:29 +0800
Tony <tony.uestc@gmail.com> wrote:

> Hello All,
> Usually, when a net_device->open is called, it will MOD_INC_USE_COUNT on 
> success. It is removed since 2.5.x, then should I increase the use 
> count? how? thx.
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Did you read Documentation/network/netdevices.txt?

Networking devices don't do ref counting because they should be removable
at any time! Because of hotplug and failover, it just doesn't work to keep
track of ref counting network devices. 

What happens is that each protocol is notified on module removal of a
network device. The protocol then cleans up all references to that
device. If the protocol is buggy, then you will see the kernel
wait and print a message that ref count is still not correct.


-- 
Stephen Hemminger <shemminger@osdl.org>
OSDL http://developer.osdl.org/~shemminger