tmakin/ack-tegra
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

sch_hfsc: make hfsc_qlen_notify() idempotent

Browse Source 
commit 51eb3b65544c9efd6a1026889ee5fb5aa62da3bb upstream.

hfsc_qlen_notify() is not idempotent either and not friendly
to its callers, like fq_codel_dequeue(). Let's make it idempotent
to ease qdisc_tree_reduce_backlog() callers' life:

1. update_vf() decreases cl->cl_nactive, so we can check whether it is
non-zero before calling it.

2. eltree_remove() always removes RB node cl->el_node, but we can use
   RB_EMPTY_NODE() + RB_CLEAR_NODE() to make it safe.

Reported-by: Gerrard Tai <gerrard.tai@starlabs.sg>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250403211033.166059-4-xiyou.wangcong@gmail.com
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Cong Wang
2025-04-03 14:10:25 -07:00
committed by Greg Kroah-Hartman
parent 353add4cad
commit d06476714d
1 changed files with 6 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
net/sched/sch_hfsc.c
View File

@@ -203,7 +203,10 @@ eltree_insert(struct hfsc_class *cl)
static inline void
eltree_remove(struct hfsc_class *cl)
{
rb_erase(&cl->el_node, &cl->sched->eligible);
if (!RB_EMPTY_NODE(&cl->el_node)) {
rb_erase(&cl->el_node, &cl->sched->eligible);
RB_CLEAR_NODE(&cl->el_node);
}
}
static inline void
@@ -1225,7 +1228,8 @@ hfsc_qlen_notify(struct Qdisc *sch, unsigned long arg)
/* vttree is now handled in update_vf() so that update_vf(cl, 0, 0)
* needs to be called explicitly to remove a class from vttree.
*/
update_vf(cl, 0, 0);
if (cl->cl_nactive)
update_vf(cl, 0, 0);
if (cl->cl_flags & HFSC_RSC)
eltree_remove(cl);
}