The 05/21/2020 11:16, Nikolay Aleksandrov wrote:
> On 20/05/2020 16:09, Horatiu Vultur wrote:
> > It is not allow to have the same net bridge port part of multiple MRP
> > rings. Therefore add a check if the port is used already in a different
> > MRP. In that case return failure.
> >
> > Fixes: 9a9f26e8f7ea ("bridge: mrp: Connect MRP API with the switchdev API")
> > Signed-off-by: Horatiu Vultur <horatiu.vul...@microchip.com>
> > ---
> > net/bridge/br_mrp.c | 31 +++++++++++++++++++++++++++++++
> > 1 file changed, 31 insertions(+)
> >
> > diff --git a/net/bridge/br_mrp.c b/net/bridge/br_mrp.c
> > index d7bc09de4c139..a5a3fa59c078a 100644
> > --- a/net/bridge/br_mrp.c
> > +++ b/net/bridge/br_mrp.c
> > @@ -37,6 +37,32 @@ static struct br_mrp *br_mrp_find_id(struct net_bridge
> > *br, u32 ring_id)
> > return res;
> > }
> >
> > +static bool br_mrp_unique_ifindex(struct net_bridge *br, u32 ifindex)
> > +{
> > + struct br_mrp *mrp;
> > + bool res = true;
> > +
> > + rcu_read_lock();
>
> Why do you need the rcu_read_lock() here when lockdep_rtnl_is_held() is used?
> You should be able to just do rtnl_dereference() below as this is used only
> under rtnl.
Hi Nik,
Also initially I thought that is not needed, but when I enabled all the
RCU debug configs to see if I use correctly the RCU, I got a warning
regarding suspicious RCU usage.
And that is the reason why I have put it.
>
> > + list_for_each_entry_rcu(mrp, &br->mrp_list, list,
> > + lockdep_rtnl_is_held()) {
> > + struct net_bridge_port *p;
> > +
> > + p = rcu_dereference(mrp->p_port);
> > + if (p && p->dev->ifindex == ifindex) {
> > + res = false;
> > + break;
> > + }
> > +
> > + p = rcu_dereference(mrp->s_port);
> > + if (p && p->dev->ifindex == ifindex) {
> > + res = false;
> > + break;
> > + }
> > + }
> > + rcu_read_unlock();
> > + return res;
> > +}
> > +
> > static struct br_mrp *br_mrp_find_port(struct net_bridge *br,
> > struct net_bridge_port *p)
> > {
> > @@ -255,6 +281,11 @@ int br_mrp_add(struct net_bridge *br, struct
> > br_mrp_instance *instance)
> > !br_mrp_get_port(br, instance->s_ifindex))
> > return -EINVAL;
> >
> > + /* It is not possible to have the same port part of multiple rings */
> > + if (!br_mrp_unique_ifindex(br, instance->p_ifindex) ||
> > + !br_mrp_unique_ifindex(br, instance->s_ifindex))
> > + return -EINVAL;
> > +
> > mrp = kzalloc(sizeof(*mrp), GFP_KERNEL);
> > if (!mrp)
> > return -ENOMEM;
> >
>
--
/Horatiu
