- Avoid lock contention in the if_transmit callback by using trylock and
enqueueing the frames when it fails. This way there is some latency
removed from the transmitting path.
- If IFF_DRV_OACTIVE is set (and also if IFF_DRV_RUNNING is not) just
enqueue the desired frames and return successful transmit. This way we
avoid to return errors on transmit side and resulting in
possible out-of-order frames. Please note that IFF_DRV_OACTIVE is set
everytime we get the threshold ring hit, so this can be happening quite
often.
Submitted by: Attilio.Rao@isilon.com
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