Stephen, you're right about the dev->destructor problem.
I misread your postings, and I'm very sorry about that.
We were talking about two different things, and admittedly
I had forgotten how some of this stuff works.
Alexey, currently dev->{open,close} are what does get/put
of device module reference.
However, device unregister can explode if dev->destructor is
present. Unlike in dev->destructor==NULL case, we do not
wait for remnant dev->refcnt to go away. Therefore we could
invoke dev->destructor() after module is unloaded.
I guess there are two ways to address this problem:
1) dev_get() gets module reference and dev_put() puts is.
Ugly, as this means dev_get() can fail, but this does
cover all the possible cases.
2) Make unregister_netdev() wait for refcount to reach 1
regardless of whether dev->destructor is NULL or not.
I don't like #1. Do you see some holes in #2?
As Stephen brought up, this also means we should do something
about that NETDEV_UNREGISTER code in dst_dev_event() :-(
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