[PATCH net-next 10/15] batman-adv: replace non-atomic mesh state with (READ|WRITE)_ONCE

Simon Wunderlich <[email protected]>
Newsgroups org.open-mesh.lists.batman,org.kernel.vger.netdev
Message-ID <[email protected]> 
From: Sven Eckelmann <[email protected]>

The mesh state is only accessed as plain loads/stores and does not require
full atomic_t semantics. Convert to an enum and replace its users with
READ_ONCE()/WRITE_ONCE() to avoid load/store tearing.

Signed-off-by: Sven Eckelmann <[email protected]>
Signed-off-by: Simon Wunderlich <[email protected]>
---
 net/batman-adv/bat_iv_ogm.c     |  2 +-
 net/batman-adv/bat_v_elp.c      |  2 +-
 net/batman-adv/bat_v_ogm.c      |  2 +-
 net/batman-adv/main.c           | 20 ++++++++++----------
 net/batman-adv/mesh-interface.c |  6 +++---
 net/batman-adv/send.c           |  2 +-
 net/batman-adv/tp_meter.c       |  6 +++---
 net/batman-adv/types.h          |  2 +-
 8 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index df8e64588e1e7..c436b77674a56 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -1777,7 +1777,7 @@ static void batadv_iv_send_outstanding_bat_ogm_packet(struct work_struct *work)
 				   delayed_work);
 	bat_priv = netdev_priv(forw_packet->if_incoming->mesh_iface);
 
-	if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING) {
+	if (READ_ONCE(bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING) {
 		dropped = true;
 		goto out;
 	}
diff --git a/net/batman-adv/bat_v_elp.c b/net/batman-adv/bat_v_elp.c
index 0190fafcbed2d..d53485d17220e 100644
--- a/net/batman-adv/bat_v_elp.c
+++ b/net/batman-adv/bat_v_elp.c
@@ -307,7 +307,7 @@ static void batadv_v_elp_periodic_work(struct work_struct *work)
 	hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
 	bat_priv = netdev_priv(hard_iface->mesh_iface);
 
-	if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
+	if (READ_ONCE(bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 		goto out;
 
 	/* we are in the process of shutting this interface down */
diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c
index f4cd8cad97e0c..b337bd8e58e7d 100644
--- a/net/batman-adv/bat_v_ogm.c
+++ b/net/batman-adv/bat_v_ogm.c
@@ -279,7 +279,7 @@ static void batadv_v_ogm_send_meshif(struct batadv_priv *bat_priv)
 
 	lockdep_assert_held(&bat_priv->bat_v.ogm_buff_mutex);
 
-	if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
+	if (READ_ONCE(bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 		goto out;
 
 	ogm_buff = &bat_priv->bat_v.ogm_buff;
diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
index a5398c5df2632..60d4f60066c80 100644
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -200,31 +200,31 @@ int batadv_mesh_init(struct net_device *mesh_iface)
 
 	ret = batadv_originator_init(bat_priv);
 	if (ret < 0) {
-		atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+		WRITE_ONCE(bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
 		goto err_orig;
 	}
 
 	ret = batadv_tt_init(bat_priv);
 	if (ret < 0) {
-		atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+		WRITE_ONCE(bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
 		goto err_tt;
 	}
 
 	ret = batadv_v_mesh_init(bat_priv);
 	if (ret < 0) {
-		atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+		WRITE_ONCE(bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
 		goto err_v;
 	}
 
 	ret = batadv_bla_init(bat_priv);
 	if (ret < 0) {
-		atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+		WRITE_ONCE(bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
 		goto err_bla;
 	}
 
 	ret = batadv_dat_init(bat_priv);
 	if (ret < 0) {
-		atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+		WRITE_ONCE(bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
 		goto err_dat;
 	}
 
@@ -232,7 +232,7 @@ int batadv_mesh_init(struct net_device *mesh_iface)
 	batadv_mcast_init(bat_priv);
 
 	atomic_set(&bat_priv->gw.reselect, 0);
-	atomic_set(&bat_priv->mesh_state, BATADV_MESH_ACTIVE);
+	WRITE_ONCE(bat_priv->mesh_state, BATADV_MESH_ACTIVE);
 
 	return 0;
 
@@ -246,7 +246,7 @@ int batadv_mesh_init(struct net_device *mesh_iface)
 	batadv_originator_free(bat_priv);
 err_orig:
 	batadv_purge_outstanding_packets(bat_priv, NULL);
-	atomic_set(&bat_priv->mesh_state, BATADV_MESH_INACTIVE);
+	WRITE_ONCE(bat_priv->mesh_state, BATADV_MESH_INACTIVE);
 
 	return ret;
 }
@@ -259,7 +259,7 @@ void batadv_mesh_free(struct net_device *mesh_iface)
 {
 	struct batadv_priv *bat_priv = netdev_priv(mesh_iface);
 
-	atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+	WRITE_ONCE(bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
 
 	batadv_purge_outstanding_packets(bat_priv, NULL);
 	batadv_tp_stop_all(bat_priv);
@@ -290,7 +290,7 @@ void batadv_mesh_free(struct net_device *mesh_iface)
 	free_percpu(bat_priv->bat_counters);
 	bat_priv->bat_counters = NULL;
 
-	atomic_set(&bat_priv->mesh_state, BATADV_MESH_INACTIVE);
+	WRITE_ONCE(bat_priv->mesh_state, BATADV_MESH_INACTIVE);
 }
 
 /**
@@ -454,7 +454,7 @@ int batadv_batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
 
 	bat_priv = netdev_priv(hard_iface->mesh_iface);
 
-	if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
+	if (READ_ONCE(bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 		goto err_free;
 
 	/* discard frames on not active interfaces */
diff --git a/net/batman-adv/mesh-interface.c b/net/batman-adv/mesh-interface.c
index 58cbb4f8a5abd..7497f307c10db 100644
--- a/net/batman-adv/mesh-interface.c
+++ b/net/batman-adv/mesh-interface.c
@@ -125,7 +125,7 @@ static int batadv_interface_set_mac_addr(struct net_device *dev, void *p)
 	eth_hw_addr_set(dev, addr->sa_data);
 
 	/* only modify transtable if it has been initialized before */
-	if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
+	if (READ_ONCE(bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 		return 0;
 
 	rcu_read_lock();
@@ -192,7 +192,7 @@ static netdev_tx_t batadv_interface_tx(struct sk_buff *skb,
 	int network_offset = ETH_HLEN;
 	__be16 proto;
 
-	if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
+	if (READ_ONCE(bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 		goto dropped;
 
 	/* reset control block to avoid left overs from previous users */
@@ -783,7 +783,7 @@ static int batadv_meshif_init_late(struct net_device *dev)
 	atomic_set(&bat_priv->bcast_queue_left, BATADV_BCAST_QUEUE_LEN);
 	atomic_set(&bat_priv->batman_queue_left, BATADV_BATMAN_QUEUE_LEN);
 
-	atomic_set(&bat_priv->mesh_state, BATADV_MESH_INACTIVE);
+	WRITE_ONCE(bat_priv->mesh_state, BATADV_MESH_INACTIVE);
 	atomic_set(&bat_priv->bcast_seqno, 1);
 	atomic_set(&bat_priv->tt.vn, 0);
 	atomic_set(&bat_priv->tt.ogm_append_cnt, 0);
diff --git a/net/batman-adv/send.c b/net/batman-adv/send.c
index 62ae98eef81e2..c7e86c83242a2 100644
--- a/net/batman-adv/send.c
+++ b/net/batman-adv/send.c
@@ -1047,7 +1047,7 @@ static void batadv_send_outstanding_bcast_packet(struct work_struct *work)
 				   delayed_work);
 	bat_priv = netdev_priv(forw_packet->if_incoming->mesh_iface);
 
-	if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING) {
+	if (READ_ONCE(bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING) {
 		dropped = true;
 		goto out;
 	}
diff --git a/net/batman-adv/tp_meter.c b/net/batman-adv/tp_meter.c
index 0fc4ca78e84eb..aefe757277b20 100644
--- a/net/batman-adv/tp_meter.c
+++ b/net/batman-adv/tp_meter.c
@@ -999,7 +999,7 @@ void batadv_tp_start(struct batadv_priv *bat_priv, const u8 *dst,
 
 	/* look for an already existing test towards this node */
 	spin_lock_bh(&bat_priv->tp_list_lock);
-	if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE) {
+	if (READ_ONCE(bat_priv->mesh_state) != BATADV_MESH_ACTIVE) {
 		spin_unlock_bh(&bat_priv->tp_list_lock);
 		batadv_tp_batctl_error_notify(BATADV_TP_REASON_DST_UNREACHABLE,
 					      dst, bat_priv, session_cookie);
@@ -1387,7 +1387,7 @@ batadv_tp_init_recv(struct batadv_priv *bat_priv,
 	struct batadv_tp_vars *tp_vars = NULL;
 
 	spin_lock_bh(&bat_priv->tp_list_lock);
-	if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
+	if (READ_ONCE(bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 		goto out_unlock;
 
 	tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig,
@@ -1518,7 +1518,7 @@ void batadv_tp_meter_recv(struct batadv_priv *bat_priv, struct sk_buff *skb)
 {
 	struct batadv_icmp_tp_packet *icmp;
 
-	if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
+	if (READ_ONCE(bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 		goto out;
 
 	icmp = (struct batadv_icmp_tp_packet *)skb->data;
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index cf01a670d8250..58375c0a643b8 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -1504,7 +1504,7 @@ struct batadv_priv {
 	 * @mesh_state: current status of the mesh
 	 *  (inactive/active/deactivating)
 	 */
-	atomic_t mesh_state;
+	enum batadv_mesh_state mesh_state;
 
 	/** @mesh_iface: net device which holds this struct as private data */
 	struct net_device *mesh_iface;
-- 
2.47.3
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