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From:   Horatiu Vultur <horatiu.vultur@microchip.com>
To:     <jiri@resnulli.us>, <ivecera@redhat.com>, <davem@davemloft.net>,
        <kuba@kernel.org>, <roopa@cumulusnetworks.com>,
        <nikolay@cumulusnetworks.com>, <andrew@lunn.ch>,
        <UNGLinuxDriver@microchip.com>, <netdev@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <bridge@lists.linux-foundation.org>
CC:     Horatiu Vultur <horatiu.vultur@microchip.com>
Subject: [PATCH 1/3] bridge: mrp: Add br_mrp_unique_ifindex function
Date:   Wed, 20 May 2020 13:09:21 +0000
Message-ID: <20200520130923.3196432-2-horatiu.vultur@microchip.com>
In-Reply-To: <20200520130923.3196432-1-horatiu.vultur@microchip.com>
References: <20200520130923.3196432-1-horatiu.vultur@microchip.com>
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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@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