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.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.
>
Did you try using rtnl_dereference() instead of rcu_dereference() ?
>>
>>> + 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;
>>>
>>
>
