On Tue, 2007-12-06 at 11:19 +0200, Johannes Berg wrote:

On Mon, 2007-06-11 at 08:23 -0400, jamal wrote:

quoted

Sure. Packets stashed on the any DMA ring are considered "gone to the
wire". That is a very valid assumption to make.

Not at all! Packets could be on the DMA queue forever if you're feeding
out more packets. Heck, on most wireless hardware packets can even be
*expired* from the DMA queue and you get an indication that it was
impossible to send them.

The spirit of the discussion you are quoting was much higher level than
that. Yes what you describe can happen on any DMA (to hard-disk etc)
A simpler example, if you tcpdump on an outgoing packet you see it on
its way to the driver - it is accounted for as "gone"[1].
In any case, read the rest of the thread.

cheers,
jamal

[1] Current Linux tcpdumping is not that accurate, but i dont wanna go
into that discussion