Fri, Jun 19, 2020 at 11:41:56AM CEST, satis...@oneconvergence.com wrote:
>A packet reaches OVS user space, only if, either there is no rule in
>datapath/hardware or there is race condition that the flow is added
>to hardware but before it is processed another packet arrives.
>
>It is possible hardware as part of its limitations/optimizations
>remove certain flows. To handle such cases where the hardware lost
>the flows, tc can offload to hardware if it receives a flow for which
>there exists an entry in its flow table. To handle such cases TC when
>it returns EEXIST error, also programs the flow in hardware, if
>hardware offload is enabled.
>
>Signed-off-by: Chandra Kesava <kesa...@gmail.com>
>Signed-off-by: Prathibha Nagooru <prathibha.nago...@oneconvergence.com>
>Signed-off-by: Satish Dhote <satis...@oneconvergence.com>
>---
> net/sched/cls_flower.c | 23 +++++++++++++++++++----
> 1 file changed, 19 insertions(+), 4 deletions(-)
>
>diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
>index f1a5352cbb04..d718233cd5b9 100644
>--- a/net/sched/cls_flower.c
>+++ b/net/sched/cls_flower.c
>@@ -431,7 +431,8 @@ static void fl_hw_destroy_filter(struct tcf_proto *tp,
>struct cls_fl_filter *f,
>
> static int fl_hw_replace_filter(struct tcf_proto *tp,
> struct cls_fl_filter *f, bool rtnl_held,
>- struct netlink_ext_ack *extack)
>+ struct netlink_ext_ack *extack,
>+ unsigned long cookie)
> {
> struct tcf_block *block = tp->chain->block;
> struct flow_cls_offload cls_flower = {};
>@@ -444,7 +445,7 @@ static int fl_hw_replace_filter(struct tcf_proto *tp,
>
> tc_cls_common_offload_init(&cls_flower.common, tp, f->flags, extack);
> cls_flower.command = FLOW_CLS_REPLACE;
>- cls_flower.cookie = (unsigned long) f;
>+ cls_flower.cookie = cookie;
> cls_flower.rule->match.dissector = &f->mask->dissector;
> cls_flower.rule->match.mask = &f->mask->key;
> cls_flower.rule->match.key = &f->mkey;
>@@ -2024,11 +2025,25 @@ static int fl_change(struct net *net, struct sk_buff
>*in_skb,
> fl_init_unmasked_key_dissector(&fnew->unmasked_key_dissector);
>
> err = fl_ht_insert_unique(fnew, fold, &in_ht);
>- if (err)
>+ if (err) {
>+ /* It is possible Hardware lost the flow even though TC has it,
>+ * and flow miss in hardware causes controller to offload flow
>again.
What? Seems that you have a buggy HW what should be fixed...
What is "controller"?
>+ */
>+ if (err == -EEXIST && !tc_skip_hw(fnew->flags)) {
>+ struct cls_fl_filter *f =
>+ __fl_lookup(fnew->mask, &fnew->mkey);
>+
>+ if (f)
>+ fl_hw_replace_filter(tp, fnew, rtnl_held,
>+ extack,
>+ (unsigned long)(f));
>+ }
> goto errout_mask;
>+ }
>
> if (!tc_skip_hw(fnew->flags)) {
>- err = fl_hw_replace_filter(tp, fnew, rtnl_held, extack);
>+ err = fl_hw_replace_filter(tp, fnew, rtnl_held, extack,
>+ (unsigned long)fnew);
> if (err)
> goto errout_ht;
> }
>--
>2.17.1
>
