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List:       linux-net
Subject:    Re: Serializing hard_start_xmit() (was: 3c509 ethernet going down.)
From:       alan () lxorguk ! ukuu ! org ! uk (Alan Cox)
Date:       1997-01-30 0:23:17
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> (2) In do_dev_queue_xmit(), distinguish normal kernel level and
>     software interrupt level by intr_count. 
> 
>     If it is normal kernel level and dev->tbusy==0, the queue must be
>     empty, so we can send the packet (don't need checking the queue).

Clever

> (3) Guarantee that hard_start_xmit() is called atomically with dev->tbusy==0.
>     (This can make network drivers simple.)
Yes.

I'll apply this when I've been over it. I can see the smp stuff is wrong
at the moment (lock_kernel is handled entirely at syscall level still)

Alan

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