Thx Pravin, I'll address your comments.
Also, will send the patch for branch-2.0 -> master
On Mon, Jun 30, 2014 at 12:00 PM, Pravin Shelar <pshe...@nicira.com> wrote:
> Good catch.
>
>
> On Mon, Jun 30, 2014 at 10:59 AM, Alex Wang <al...@nicira.com> wrote:
> > Due to the race condition in userspace, there is chance that two
> > overlapping megaflows could be installed in datapath. And this
> > causes userspace unable to delete the less inclusive megaflow flow
> > even after it timeout, since the flow_del logic will stop at the
> > first match of masked flow.
> >
> > This commit fixes the bug by making the kernel flow_del logic check
> > all masks in that case.
> >
> > Signed-off-by: Alex Wang <al...@nicira.com>
> Can you also give specific subject for this patch?
>
> > ---
> > datapath/datapath.c | 4 ++--
> > datapath/flow_table.c | 16 ++++++++++++++++
> > datapath/flow_table.h | 3 +++
> > 3 files changed, 21 insertions(+), 2 deletions(-)
> >
> > diff --git a/datapath/datapath.c b/datapath/datapath.c
> > index c15ded9..cb66ff3 100644
> > --- a/datapath/datapath.c
> > +++ b/datapath/datapath.c
> > @@ -974,8 +974,8 @@ static int ovs_flow_cmd_del(struct sk_buff *skb,
> struct genl_info *info)
> > if (err)
> > goto unlock;
> >
> > - flow = ovs_flow_tbl_lookup(&dp->table, &key);
> > - if (!flow || !ovs_flow_cmp_unmasked_key(flow, &match)) {
> > + flow = ovs_flow_tbl_lookup_exact(&dp->table, &key, &match);
>
> match has ref to key, so you can just pass match as argument to this
> function.
>
> > + if (!flow) {
> > err = -ENOENT;
> > goto unlock;
> > }
>
> > diff --git a/datapath/flow_table.c b/datapath/flow_table.c
> > index fa7ad36..a0d1ea7 100644
> > --- a/datapath/flow_table.c
> > +++ b/datapath/flow_table.c
> > @@ -482,6 +482,22 @@ struct sw_flow *ovs_flow_tbl_lookup(struct
> flow_table *tbl,
> > return ovs_flow_tbl_lookup_stats(tbl, key, &n_mask_hit);
> > }
> >
> > +struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl,
> > + const struct sw_flow_key *key,
> > + struct sw_flow_match *match)
> > +{
> > + struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
> > + struct sw_flow_mask *mask;
> > + struct sw_flow *flow;
> > +
> > + list_for_each_entry_rcu(mask, &tbl->mask_list, list) {
> > + flow = masked_flow_lookup(ti, key, mask);
> > + if (flow && ovs_flow_cmp_unmasked_key(flow, match)) /*
> Found */
> > + return flow;
> > + }
> This function is always called under ovs-mutex, so no need to use rcu
> iterator.
>
> > + return NULL;
> > +}
> > +
> > int ovs_flow_tbl_num_masks(const struct flow_table *table)
> > {
> > struct sw_flow_mask *mask;
> > diff --git a/datapath/flow_table.h b/datapath/flow_table.h
> > index baaeb10..3697427 100644
> > --- a/datapath/flow_table.h
> > +++ b/datapath/flow_table.h
> > @@ -72,6 +72,9 @@ struct sw_flow *ovs_flow_tbl_dump_next(struct
> table_instance *table,
> > struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *,
> > const struct sw_flow_key *,
> > u32 *n_mask_hit);
> > +struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl,
> > + const struct sw_flow_key *key,
> > + struct sw_flow_match *match);
>
> We should use same exact-lookup for flow_get and when we try to modify
> flow.
>
> > struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *,
> > const struct sw_flow_key *);
> >
> > --
> > 1.7.9.5
> >
>
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