On Thu, 2016-04-14 at 18:08 +0200, Jiri Kosina wrote: > On Thu, 14 Apr 2016, Phil Sutter wrote: > > > > > I've came across the behavior where adding a child qdisc and then > > > > deleting > > > > it again makes the networking dysfunctional (I guess that's because all > > > > of > > > > a sudden there is absolutely no working qdisc on the device, although > > > > there originally was a default one in the parent). > > > > > > > > In a nutshell, is this expected behavior or bug? > > > > > > This is the expected behavior. > > > > OTOH some qdiscs (CBQ, DRR, DSMARK, HFSC, HTB, QFQ) assign the default > > one upon deletion instead of noop_qdisc, hence I would describe > > the situation using the words 'inconsistent' and 'accident' rather than > > 'expected'. :) > > Would a patch that'd unify this in a sense that all qdiscs would assign > the default one upon deletion acceptable? >
And what would be the chosen behavior ? Relying on TBF installing a bfifo for you at delete would be hazardous. For example CBQ got it differently than HFSC If qdisc_create_dflt() fails in CBQ, we fail the 'delete', while HFSC falls back to noop_qdisc, without warning the user :( At least always using noop_qdisc is consistent. No magic there. Doing 'unification' right now would break existing scripts. This is too late, I am afraid.