1 files changed, 75 insertions, 42 deletions

diff --git a/net/batman-adv/tp_meter.c b/net/batman-adv/tp_meter.c
index 066c76113fc4..0fc4ca78e84e 100644
--- a/net/batman-adv/tp_meter.c
+++ b/net/batman-adv/tp_meter.c
@@ -8,6 +8,7 @@
 #include "main.h"
 
 #include <linux/atomic.h>
+#include <linux/bug.h>
 #include <linux/build_bug.h>
 #include <linux/byteorder/generic.h>
 #include <linux/cache.h>
@@ -254,6 +255,7 @@ static void batadv_tp_batctl_error_notify(enum batadv_tp_meter_reason reason,
  * batadv_tp_list_find() - find a tp_vars object in the global list
  * @bat_priv: the bat priv with all the mesh interface information
  * @dst: the other endpoint MAC address to look for
+ * @role: role of the session
  *
  * Look for a tp_vars object matching dst as end_point and return it after
  * having increment the refcounter. Return NULL is not found
@@ -261,7 +263,8 @@ static void batadv_tp_batctl_error_notify(enum batadv_tp_meter_reason reason,
  * Return: matching tp_vars or NULL when no tp_vars with @dst was found
  */
 static struct batadv_tp_vars *batadv_tp_list_find(struct batadv_priv *bat_priv,
-						  const u8 *dst)
+						  const u8 *dst,
+						  enum batadv_tp_meter_role role)
 {
 	struct batadv_tp_vars *pos, *tp_vars = NULL;
 
@@ -270,6 +273,9 @@ static struct batadv_tp_vars *batadv_tp_list_find(struct batadv_priv *bat_priv,
 		if (!batadv_compare_eth(pos->other_end, dst))
 			continue;
 
+		if (pos->role != role)
+			continue;
+
 		/* most of the time this function is invoked during the normal
 		 * process..it makes sens to pay more when the session is
 		 * finished and to speed the process up during the measurement
@@ -286,11 +292,32 @@ static struct batadv_tp_vars *batadv_tp_list_find(struct batadv_priv *bat_priv,
 }
 
 /**
+ * batadv_tp_list_active() - check if session from/to destination is ongoing
+ * @bat_priv: the bat priv with all the mesh interface information
+ * @dst: the other endpoint MAC address to look for
+ *
+ * Return: if matching session with @dst was found
+ */
+static bool batadv_tp_list_active(struct batadv_priv *bat_priv, const u8 *dst)
+	__must_hold(&bat_priv->tp_list_lock)
+{
+	struct batadv_tp_vars *tp_vars;
+
+	hlist_for_each_entry_rcu(tp_vars, &bat_priv->tp_list, list) {
+		if (batadv_compare_eth(tp_vars->other_end, dst))
+			return true;
+	}
+
+	return false;
+}
+
+/**
  * batadv_tp_list_find_session() - find tp_vars session object in the global
  *  list
  * @bat_priv: the bat priv with all the mesh interface information
  * @dst: the other endpoint MAC address to look for
  * @session: session identifier
+ * @role: role of the session
  *
  * Look for a tp_vars object matching dst as end_point, session as tp meter
  * session and return it after having increment the refcounter. Return NULL
@@ -300,7 +327,7 @@ static struct batadv_tp_vars *batadv_tp_list_find(struct batadv_priv *bat_priv,
  */
 static struct batadv_tp_vars *
 batadv_tp_list_find_session(struct batadv_priv *bat_priv, const u8 *dst,
-			    const u8 *session)
+			    const u8 *session, enum batadv_tp_meter_role role)
 {
 	struct batadv_tp_vars *pos, *tp_vars = NULL;
 
@@ -312,6 +339,9 @@ batadv_tp_list_find_session(struct batadv_priv *bat_priv, const u8 *dst,
 		if (memcmp(pos->session, session, sizeof(pos->session)) != 0)
 			continue;
 
+		if (pos->role != role)
+			continue;
+
 		/* most of the time this function is invoked during the normal
 		 * process..it makes sense to pay more when the session is
 		 * finished and to speed the process up during the measurement
@@ -400,13 +430,7 @@ static void batadv_tp_sender_cleanup(struct batadv_tp_vars *tp_vars)
 	batadv_tp_list_detach(tp_vars);
 
 	/* kill the timer and remove its reference */
-	timer_delete_sync(&tp_vars->timer);
-	/* the worker might have rearmed itself therefore we kill it again. Note
-	 * that if the worker should run again before invoking the following
-	 * timer_delete(), it would not re-arm itself once again because the status
-	 * is OFF now
-	 */
-	timer_delete(&tp_vars->timer);
+	timer_shutdown_sync(&tp_vars->timer);
 	batadv_tp_vars_put(tp_vars);
 }
 
@@ -418,11 +442,14 @@ static void batadv_tp_sender_cleanup(struct batadv_tp_vars *tp_vars)
 static void batadv_tp_sender_end(struct batadv_priv *bat_priv,
 				 struct batadv_tp_vars *tp_vars)
 {
+	enum batadv_tp_meter_reason reason;
 	u32 session_cookie;
 
+	reason = atomic_read(&tp_vars->send_result);
+
 	batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
 		   "Test towards %pM finished..shutting down (reason=%d)\n",
-		   tp_vars->other_end, tp_vars->reason);
+		   tp_vars->other_end, reason);
 
 	batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
 		   "Last timing stats: SRTT=%ums RTTVAR=%ums RTO=%ums\n",
@@ -435,7 +462,7 @@ static void batadv_tp_sender_end(struct batadv_priv *bat_priv,
 	session_cookie = batadv_tp_session_cookie(tp_vars->session,
 						  tp_vars->icmp_uid);
 
-	batadv_tp_batctl_notify(tp_vars->reason,
+	batadv_tp_batctl_notify(reason,
 				tp_vars->other_end,
 				bat_priv,
 				tp_vars->start_time,
@@ -451,10 +478,18 @@ static void batadv_tp_sender_end(struct batadv_priv *bat_priv,
 static void batadv_tp_sender_shutdown(struct batadv_tp_vars *tp_vars,
 				      enum batadv_tp_meter_reason reason)
 {
-	if (!atomic_dec_and_test(&tp_vars->sending))
-		return;
+	atomic_cmpxchg(&tp_vars->send_result, 0, reason);
+}
 
-	tp_vars->reason = reason;
+/**
+ * batadv_tp_sender_stopped() - check if tp session was stopped with reason
+ * @tp_vars: the private data of the current TP meter session
+ *
+ * Return: whether stop reason was found
+ */
+static bool batadv_tp_sender_stopped(struct batadv_tp_vars *tp_vars)
+{
+	return atomic_read(&tp_vars->send_result) != 0;
 }
 
 /**
@@ -484,7 +519,7 @@ static void batadv_tp_reset_sender_timer(struct batadv_tp_vars *tp_vars)
 	/* most of the time this function is invoked while normal packet
 	 * reception...
 	 */
-	if (unlikely(atomic_read(&tp_vars->sending) == 0))
+	if (unlikely(batadv_tp_sender_stopped(tp_vars)))
 		/* timer ref will be dropped in batadv_tp_sender_cleanup */
 		return;
 
@@ -504,7 +539,7 @@ static void batadv_tp_sender_timeout(struct timer_list *t)
 	struct batadv_tp_vars *tp_vars = timer_container_of(tp_vars, t, timer);
 	struct batadv_priv *bat_priv = tp_vars->bat_priv;
 
-	if (atomic_read(&tp_vars->sending) == 0)
+	if (batadv_tp_sender_stopped(tp_vars))
 		return;
 
 	/* if the user waited long enough...shutdown the test */
@@ -659,11 +694,11 @@ static void batadv_tp_recv_ack(struct batadv_priv *bat_priv,
 
 	/* find the tp_vars */
 	tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig,
-					      icmp->session);
+					      icmp->session, BATADV_TP_SENDER);
 	if (unlikely(!tp_vars))
 		return;
 
-	if (unlikely(atomic_read(&tp_vars->sending) == 0))
+	if (unlikely(batadv_tp_sender_stopped(tp_vars)))
 		goto out;
 
 	/* old ACK? silently drop it.. */
@@ -829,21 +864,21 @@ static int batadv_tp_send(void *arg)
 
 	if (unlikely(tp_vars->role != BATADV_TP_SENDER)) {
 		err = BATADV_TP_REASON_DST_UNREACHABLE;
-		tp_vars->reason = err;
+		batadv_tp_sender_shutdown(tp_vars, err);
 		goto out;
 	}
 
 	orig_node = batadv_orig_hash_find(bat_priv, tp_vars->other_end);
 	if (unlikely(!orig_node)) {
 		err = BATADV_TP_REASON_DST_UNREACHABLE;
-		tp_vars->reason = err;
+		batadv_tp_sender_shutdown(tp_vars, err);
 		goto out;
 	}
 
 	primary_if = batadv_primary_if_get_selected(bat_priv);
 	if (unlikely(!primary_if)) {
 		err = BATADV_TP_REASON_DST_UNREACHABLE;
-		tp_vars->reason = err;
+		batadv_tp_sender_shutdown(tp_vars, err);
 		goto out;
 	}
 
@@ -862,7 +897,7 @@ static int batadv_tp_send(void *arg)
 	queue_delayed_work(batadv_event_workqueue, &tp_vars->finish_work,
 			   msecs_to_jiffies(tp_vars->test_length));
 
-	while (atomic_read(&tp_vars->sending) != 0) {
+	while (!batadv_tp_sender_stopped(tp_vars)) {
 		if (unlikely(!batadv_tp_avail(tp_vars, payload_len))) {
 			batadv_tp_wait_available(tp_vars, payload_len);
 			continue;
@@ -885,8 +920,7 @@ static int batadv_tp_send(void *arg)
 				   "Meter: %s() cannot send packets (%d)\n",
 				   __func__, err);
 			/* ensure nobody else tries to stop the thread now */
-			if (atomic_dec_and_test(&tp_vars->sending))
-				tp_vars->reason = err;
+			batadv_tp_sender_shutdown(tp_vars, err);
 			break;
 		}
 
@@ -972,10 +1006,8 @@ void batadv_tp_start(struct batadv_priv *bat_priv, const u8 *dst,
 		return;
 	}
 
-	tp_vars = batadv_tp_list_find(bat_priv, dst);
-	if (tp_vars) {
+	if (batadv_tp_list_active(bat_priv, dst)) {
 		spin_unlock_bh(&bat_priv->tp_list_lock);
-		batadv_tp_vars_put(tp_vars);
 		batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
 			   "Meter: test to or from the same node already ongoing, aborting\n");
 		batadv_tp_batctl_error_notify(BATADV_TP_REASON_ALREADY_ONGOING,
@@ -1008,7 +1040,7 @@ void batadv_tp_start(struct batadv_priv *bat_priv, const u8 *dst,
 	ether_addr_copy(tp_vars->other_end, dst);
 	kref_init(&tp_vars->refcount);
 	tp_vars->role = BATADV_TP_SENDER;
-	atomic_set(&tp_vars->sending, 1);
+	atomic_set(&tp_vars->send_result, 0);
 	memcpy(tp_vars->session, session_id, sizeof(session_id));
 	tp_vars->icmp_uid = icmp_uid;
 
@@ -1096,16 +1128,16 @@ void batadv_tp_stop(struct batadv_priv *bat_priv, const u8 *dst,
 	if (!orig_node)
 		return;
 
-	tp_vars = batadv_tp_list_find(bat_priv, orig_node->orig);
+	tp_vars = batadv_tp_list_find(bat_priv, orig_node->orig, BATADV_TP_SENDER);
 	if (!tp_vars) {
 		batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
 			   "Meter: trying to interrupt an already over connection\n");
-		goto out;
+		goto out_put_orig_node;
 	}
 
 	batadv_tp_sender_shutdown(tp_vars, return_value);
 	batadv_tp_vars_put(tp_vars);
-out:
+out_put_orig_node:
 	batadv_orig_node_put(orig_node);
 }
 
@@ -1156,6 +1188,9 @@ static void batadv_tp_receiver_shutdown(struct timer_list *t)
 	spin_unlock_bh(&tp_vars->unacked_lock);
 
 	/* drop reference of timer */
+	if (WARN_ON(atomic_xchg(&tp_vars->receiving, 0) != 1))
+		return;
+
 	batadv_tp_vars_put(tp_vars);
 }
 
@@ -1356,7 +1391,7 @@ batadv_tp_init_recv(struct batadv_priv *bat_priv,
 		goto out_unlock;
 
 	tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig,
-					      icmp->session);
+					      icmp->session, BATADV_TP_RECEIVER);
 	if (tp_vars)
 		goto out_unlock;
 
@@ -1374,6 +1409,7 @@ batadv_tp_init_recv(struct batadv_priv *bat_priv,
 
 	ether_addr_copy(tp_vars->other_end, icmp->orig);
 	tp_vars->role = BATADV_TP_RECEIVER;
+	atomic_set(&tp_vars->receiving, 1);
 	memcpy(tp_vars->session, icmp->session, sizeof(tp_vars->session));
 	tp_vars->last_recv = BATADV_TP_FIRST_SEQ;
 	tp_vars->bat_priv = bat_priv;
@@ -1426,7 +1462,7 @@ static void batadv_tp_recv_msg(struct batadv_priv *bat_priv,
 		}
 	} else {
 		tp_vars = batadv_tp_list_find_session(bat_priv, icmp->orig,
-						      icmp->session);
+						      icmp->session, BATADV_TP_RECEIVER);
 		if (!tp_vars) {
 			batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
 				   "Unexpected packet from %pM!\n",
@@ -1435,13 +1471,6 @@ static void batadv_tp_recv_msg(struct batadv_priv *bat_priv,
 		}
 	}
 
-	if (unlikely(tp_vars->role != BATADV_TP_RECEIVER)) {
-		batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
-			   "Meter: dropping packet: not expected (role=%u)\n",
-			   tp_vars->role);
-		goto out;
-	}
-
 	tp_vars->last_recv_time = jiffies;
 
 	/* if the packet is a duplicate, it may be the case that an ACK has been
@@ -1546,8 +1575,12 @@ void batadv_tp_stop_all(struct batadv_priv *bat_priv)
 			break;
 		case BATADV_TP_RECEIVER:
 			batadv_tp_list_detach(tp_var);
-			if (timer_shutdown_sync(&tp_var->timer))
-				batadv_tp_vars_put(tp_var);
+			timer_shutdown_sync(&tp_var->timer);
+
+			if (atomic_xchg(&tp_var->receiving, 0) != 1)
+				break;
+
+			batadv_tp_vars_put(tp_var);
 			break;
 		}