The 05/21/2020 19:58, Nikolay Aleksandrov wrote:
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>
> On 21/05/2020 21:49, Horatiu Vultur wrote:
> > 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.vultur@xxxxxxxxxxxxx>
> >>> ---
> >>> 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.
> >
>
> Did you try using rtnl_dereference() instead of rcu_dereference() ?
I have just tried it now and that seems to work fine.
I will redo the patch and send a new patch series.
>
> >>
> >>> + 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
