drr_change_class lacks a check for NULL of tca[TCA_OPTIONS], so oops
is possible.
Reported-by: NDenys Fedoryschenko <denys@visp.net.lb>
Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The functions gen_new_estimator and gen_replace_estimator can return
errors, but they were being ignored.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Jarek Poplawski points out:

If all child qdiscs of sch_drr are non-work-conserving (e.g. sch_tbf)
drr_dequeue() will busy-loop waiting for skbs instead of leaving the
job for a watchdog. Checking for list_empty() in each loop isn't
necessary either, because this can never be true except the first time.

Using non-work-conserving qdiscs as children of DRR makes no sense,
simply bail out in that case.
Reported-by: NJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NJarek Poplawski <jarkao2@gmail.com>
Acked-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The use of xchg() hasn't been necessary since 2.2.something when proper
locking was added to packet schedulers.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add classful DRR scheduler as a more flexible replacement for SFQ.

The main difference to the algorithm described in "Efficient Fair Queueing
using Deficit Round Robin" is that this implementation doesn't drop packets
from the longest queue on overrun because its classful and limits are
handled by each individual child qdisc.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>