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From:   Horatiu Vultur <horatiu.vultur@microchip.com>
To:     <nikolay@cumulusnetworks.com>, <roopa@cumulusnetworks.com>,
        <davem@davemloft.net>, <kuba@kernel.org>, <netdev@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <bridge@lists.linux-foundation.org>
CC:     Horatiu Vultur <horatiu.vultur@microchip.com>
Subject: [PATCH net-next v2] bridge: mrp: Extend MRP netlink interface with IFLA_BRIDGE_MRP_CLEAR
Date:   Thu, 25 Jun 2020 09:06:30 +0200
Message-ID: <20200625070630.3267620-1-horatiu.vultur@microchip.com>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

In case the userspace daemon dies, then when is restarted it doesn't
know if there are any MRP instances in the kernel. Therefore extend the
netlink interface to allow the daemon to clear all MRP instances when is
started.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>

---
v2:
  - use list_for_each_entry_safe instead of list_for_each_entry_rcu
    when deleting mrp instances
---
 include/uapi/linux/if_bridge.h |  8 ++++++++
 net/bridge/br_mrp.c            | 15 +++++++++++++++
 net/bridge/br_mrp_netlink.c    | 26 ++++++++++++++++++++++++++
 net/bridge/br_private_mrp.h    |  1 +
 4 files changed, 50 insertions(+)

diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
index caa6914a3e53a..2ae7d0c0d46b8 100644
--- a/include/uapi/linux/if_bridge.h
+++ b/include/uapi/linux/if_bridge.h
@@ -166,6 +166,7 @@ enum {
 	IFLA_BRIDGE_MRP_RING_STATE,
 	IFLA_BRIDGE_MRP_RING_ROLE,
 	IFLA_BRIDGE_MRP_START_TEST,
+	IFLA_BRIDGE_MRP_CLEAR,
 	__IFLA_BRIDGE_MRP_MAX,
 };
 
@@ -228,6 +229,13 @@ enum {
 
 #define IFLA_BRIDGE_MRP_START_TEST_MAX (__IFLA_BRIDGE_MRP_START_TEST_MAX - 1)
 
+enum {
+	IFLA_BRIDGE_MRP_CLEAR_UNSPEC,
+	__IFLA_BRIDGE_MRP_CLEAR_MAX,
+};
+
+#define IFLA_BRIDGE_MRP_CLEAR_MAX (__IFLA_BRIDGE_MRP_CLEAR_MAX - 1)
+
 struct br_mrp_instance {
 	__u32 ring_id;
 	__u32 p_ifindex;
diff --git a/net/bridge/br_mrp.c b/net/bridge/br_mrp.c
index 24986ec7d38cc..02da4e22d277a 100644
--- a/net/bridge/br_mrp.c
+++ b/net/bridge/br_mrp.c
@@ -372,6 +372,21 @@ int br_mrp_del(struct net_bridge *br, struct br_mrp_instance *instance)
 	return 0;
 }
 
+/* Deletes all MRP instances on the bridge
+ * note: called under rtnl_lock
+ */
+int br_mrp_clear(struct net_bridge *br)
+{
+	struct br_mrp *mrp;
+	struct br_mrp *tmp;
+
+	list_for_each_entry_safe(mrp, tmp, &br->mrp_list, list) {
+		br_mrp_del_impl(br, mrp);
+	}
+
+	return 0;
+}
+
 /* Set port state, port state can be forwarding, blocked or disabled
  * note: already called with rtnl_lock
  */
diff --git a/net/bridge/br_mrp_netlink.c b/net/bridge/br_mrp_netlink.c
index 34b3a8776991f..5e743538464f6 100644
--- a/net/bridge/br_mrp_netlink.c
+++ b/net/bridge/br_mrp_netlink.c
@@ -14,6 +14,7 @@ static const struct nla_policy br_mrp_policy[IFLA_BRIDGE_MRP_MAX + 1] = {
 	[IFLA_BRIDGE_MRP_RING_STATE]	= { .type = NLA_NESTED },
 	[IFLA_BRIDGE_MRP_RING_ROLE]	= { .type = NLA_NESTED },
 	[IFLA_BRIDGE_MRP_START_TEST]	= { .type = NLA_NESTED },
+	[IFLA_BRIDGE_MRP_CLEAR]		= { .type = NLA_NESTED },
 };
 
 static const struct nla_policy
@@ -235,6 +236,25 @@ static int br_mrp_start_test_parse(struct net_bridge *br, struct nlattr *attr,
 	return br_mrp_start_test(br, &test);
 }
 
+static const struct nla_policy
+br_mrp_clear_policy[IFLA_BRIDGE_MRP_CLEAR_MAX + 1] = {
+	[IFLA_BRIDGE_MRP_CLEAR_UNSPEC]		= { .type = NLA_REJECT },
+};
+
+static int br_mrp_clear_parse(struct net_bridge *br, struct nlattr *attr,
+			      struct netlink_ext_ack *extack)
+{
+	struct nlattr *tb[IFLA_BRIDGE_MRP_START_TEST_MAX + 1];
+	int err;
+
+	err = nla_parse_nested(tb, IFLA_BRIDGE_MRP_CLEAR_MAX, attr,
+			       br_mrp_clear_policy, extack);
+	if (err)
+		return err;
+
+	return br_mrp_clear(br);
+}
+
 int br_mrp_parse(struct net_bridge *br, struct net_bridge_port *p,
 		 struct nlattr *attr, int cmd, struct netlink_ext_ack *extack)
 {
@@ -301,6 +321,12 @@ int br_mrp_parse(struct net_bridge *br, struct net_bridge_port *p,
 			return err;
 	}
 
+	if (tb[IFLA_BRIDGE_MRP_CLEAR]) {
+		err = br_mrp_clear_parse(br, tb[IFLA_BRIDGE_MRP_CLEAR], extack);
+		if (err)
+			return err;
+	}
+
 	return 0;
 }
 
diff --git a/net/bridge/br_private_mrp.h b/net/bridge/br_private_mrp.h
index 33b255e38ffec..25c3b8596c25b 100644
--- a/net/bridge/br_private_mrp.h
+++ b/net/bridge/br_private_mrp.h
@@ -36,6 +36,7 @@ struct br_mrp {
 /* br_mrp.c */
 int br_mrp_add(struct net_bridge *br, struct br_mrp_instance *instance);
 int br_mrp_del(struct net_bridge *br, struct br_mrp_instance *instance);
+int br_mrp_clear(struct net_bridge *br);
 int br_mrp_set_port_state(struct net_bridge_port *p,
 			  enum br_mrp_port_state_type state);
 int br_mrp_set_port_role(struct net_bridge_port *p,
-- 
2.26.2