Comment 12 for bug 335507

For reference, I've discovered a linux-netdev mailing-list article describing this and an underlying change to the way the IFF_RUNNING flag is used from March 2006.

http://marc.info/?l=linux-netdev&m=122922534630000&w=2

commit b00055aacdb172c05067612278ba27265fcd05ce
Author: Stefan Rompf <email address hidden>
Date: Mon Mar 20 17:09:11 2006 -0800

    [NET] core: add RFC2863 operstate

    this patch adds a dormant flag to network devices, RFC2863 operstate derived
    from these flags and possibility for userspace interaction. It allows drivers
    to signal that a device is unusable for user traffic without disabling
    queueing (and therefore the possibility for protocol establishment traffic to
    flow) and a userspace supplicant (WPA, 802.1X) to mark a device unusable
    without changes to the driver.

    It is the result of our long discussion. However I must admit that it
    represents what Jamal and I agreed on with compromises towards Krzysztof, but
    Thomas and Krzysztof still disagree with some parts. Anyway I think it should
    be applied.

    Signed-off-by: Stefan Rompf <email address hidden>
    Signed-off-by: David S. Miller <email address hidden>

So, on the face of it looks as if no user-space application should rely on IFF_RUNNING.