On Tue, Jun 23, 2020 at 05:00:53PM +0200, Toke Høiland-Jørgensen wrote:
> This reverts commit 191cf872190de28a92e1bd2b56d8860e37e07443.
>
> That commit should never have been backported since it relies on a change in
> locking semantics that was introduced in v4.8 and not backported. Because of
> this, the backported commit to sch_fq leads to lockups because of the double
> locking.
>
> Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
> ---
> net/sched/sch_fq.c | 32 ++++++++++++++------------------
> 1 file changed, 14 insertions(+), 18 deletions(-)
>
> diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
> index f4aa2ab4713a..eb814ffc0902 100644
> --- a/net/sched/sch_fq.c
> +++ b/net/sched/sch_fq.c
> @@ -830,24 +830,20 @@ nla_put_failure:
> static int fq_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
> {
> struct fq_sched_data *q = qdisc_priv(sch);
> - struct tc_fq_qd_stats st;
> -
> - sch_tree_lock(sch);
> -
> - st.gc_flows = q->stat_gc_flows;
> - st.highprio_packets = q->stat_internal_packets;
> - st.tcp_retrans = q->stat_tcp_retrans;
> - st.throttled = q->stat_throttled;
> - st.flows_plimit = q->stat_flows_plimit;
> - st.pkts_too_long = q->stat_pkts_too_long;
> - st.allocation_errors = q->stat_allocation_errors;
> - st.time_next_delayed_flow = q->time_next_delayed_flow - ktime_get_ns();
> - st.flows = q->flows;
> - st.inactive_flows = q->inactive_flows;
> - st.throttled_flows = q->throttled_flows;
> - st.pad = 0;
> -
> - sch_tree_unlock(sch);
> + u64 now = ktime_get_ns();
> + struct tc_fq_qd_stats st = {
> + .gc_flows = q->stat_gc_flows,
> + .highprio_packets = q->stat_internal_packets,
> + .tcp_retrans = q->stat_tcp_retrans,
> + .throttled = q->stat_throttled,
> + .flows_plimit = q->stat_flows_plimit,
> + .pkts_too_long = q->stat_pkts_too_long,
> + .allocation_errors = q->stat_allocation_errors,
> + .flows = q->flows,
> + .inactive_flows = q->inactive_flows,
> + .throttled_flows = q->throttled_flows,
> + .time_next_delayed_flow = q->time_next_delayed_flow - now,
> + };
>
> return gnet_stats_copy_app(d, &st, sizeof(st));
> }
> --
> 2.27.0
>
Thanks, now applied.
greg k-h
