[PATCH 1/3] bridge: mrp: Add br_mrp_unique_ifindex function

[Horatiu Vultur]

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();
+       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;
-- 
2.26.2