[PATCH net-next 13/15] batman-adv: tp_meter: keep unacked list for receivers

[Simon Wunderlich <sw@simonwunderlich.de>]

From: Sven Eckelmann <sven@narfation.org>

There is no need to share the unacked list between sender and receivers.
Only receivers will ever write to and read from it. The initialization in
batadv_tp_start() was therefore never needed. After its removal, it is
enough to just store it in struct batadv_tp_receiver.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
---
 net/batman-adv/tp_meter.c | 110 +++++++++++++++++++++-----------------
 net/batman-adv/types.h    |  20 +++----
 2 files changed, 71 insertions(+), 59 deletions(-)

diff --git a/net/batman-adv/tp_meter.c b/net/batman-adv/tp_meter.c
index 5cc719c81ea0b..f18ce360839d3 100644
--- a/net/batman-adv/tp_meter.c
+++ b/net/batman-adv/tp_meter.c
@@ -358,28 +358,16 @@ batadv_tp_list_find_sender_session(struct batadv_priv *bat_priv, const u8 *dst,
 }
 
 /**
- * batadv_tp_vars_common_release() - release batadv_tp_vars_common from lists
+ * batadv_tp_sender_release() - release batadv_tp_sender
  *  and queue for free after rcu grace period
- * @ref: kref pointer of the batadv_tp_vars_common
+ * @ref: kref pointer of the batadv_tp_sender
  */
-static void batadv_tp_vars_common_release(struct kref *ref)
+static void batadv_tp_sender_release(struct kref *ref)
 {
-	struct batadv_tp_vars_common *tp_vars;
-	struct batadv_tp_unacked *un, *safe;
-
-	tp_vars = container_of(ref, struct batadv_tp_vars_common, refcount);
-
-	/* lock should not be needed because this object is now out of any
-	 * context!
-	 */
-	spin_lock_bh(&tp_vars->unacked_lock);
-	list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) {
-		list_del(&un->list);
-		kfree(un);
-	}
-	spin_unlock_bh(&tp_vars->unacked_lock);
+	struct batadv_tp_sender *tp_vars;
 
-	kfree_rcu(tp_vars, rcu);
+	tp_vars = container_of(ref, struct batadv_tp_sender, common.refcount);
+	kfree_rcu(tp_vars, common.rcu);
 }
 
 /**
@@ -392,7 +380,7 @@ static void batadv_tp_sender_put(struct batadv_tp_sender *tp_vars)
 	if (!tp_vars)
 		return;
 
-	kref_put(&tp_vars->common.refcount, batadv_tp_vars_common_release);
+	kref_put(&tp_vars->common.refcount, batadv_tp_sender_release);
 }
 
 /**
@@ -1145,9 +1133,6 @@ void batadv_tp_start(struct batadv_priv *bat_priv, const u8 *dst,
 	init_waitqueue_head(&tp_vars->more_bytes);
 	init_completion(&tp_vars->finished);
 
-	spin_lock_init(&tp_vars->common.unacked_lock);
-	INIT_LIST_HEAD(&tp_vars->common.unacked_list);
-
 	spin_lock_init(&tp_vars->cc_lock);
 
 	tp_vars->prerandom_offset = 0;
@@ -1251,6 +1236,33 @@ batadv_tp_list_find_receiver_session(struct batadv_priv *bat_priv, const u8 *dst
 	return tp_vars;
 }
 
+/**
+ * batadv_tp_receiver_release() - release batadv_tp_receiver
+ *  and queue for free after rcu grace period
+ * @ref: kref pointer of the batadv_tp_receiver
+ */
+static void batadv_tp_receiver_release(struct kref *ref)
+{
+	struct batadv_tp_receiver *tp_vars;
+	struct batadv_tp_unacked *safe;
+	struct batadv_tp_unacked *un;
+
+	tp_vars = container_of(ref, struct batadv_tp_receiver, common.refcount);
+
+	/* lock should not be needed because this object is now out of any
+	 * context!
+	 */
+	spin_lock_bh(&tp_vars->unacked_lock);
+	list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) {
+		list_del(&un->list);
+		kfree(un);
+		tp_vars->unacked_count--;
+	}
+	spin_unlock_bh(&tp_vars->unacked_lock);
+
+	kfree_rcu(tp_vars, common.rcu);
+}
+
 /**
  * batadv_tp_receiver_put() - decrement the batadv_tp_receiver
  *  refcounter and possibly release it
@@ -1261,7 +1273,7 @@ static void batadv_tp_receiver_put(struct batadv_tp_receiver *tp_vars)
 	if (!tp_vars)
 		return;
 
-	kref_put(&tp_vars->common.refcount, batadv_tp_vars_common_release);
+	kref_put(&tp_vars->common.refcount, batadv_tp_receiver_release);
 }
 
 /**
@@ -1304,13 +1316,13 @@ static void batadv_tp_receiver_shutdown(struct timer_list *t)
 	if (batadv_tp_list_detach(&tp_vars->common))
 		batadv_tp_receiver_put(tp_vars);
 
-	spin_lock_bh(&tp_vars->common.unacked_lock);
-	list_for_each_entry_safe(un, safe, &tp_vars->common.unacked_list, list) {
+	spin_lock_bh(&tp_vars->unacked_lock);
+	list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) {
 		list_del(&un->list);
 		kfree(un);
-		tp_vars->common.unacked_count--;
+		tp_vars->unacked_count--;
 	}
-	spin_unlock_bh(&tp_vars->common.unacked_lock);
+	spin_unlock_bh(&tp_vars->unacked_lock);
 
 	/* drop reference of timer */
 	if (WARN_ON(atomic_xchg(&tp_vars->receiving, 0) != 1))
@@ -1403,7 +1415,7 @@ static int batadv_tp_send_ack(struct batadv_priv *bat_priv, const u8 *dst,
  */
 static bool batadv_tp_handle_out_of_order(struct batadv_tp_receiver *tp_vars,
 					  u32 seqno, u32 payload_len)
-	__must_hold(&tp_vars->common.unacked_lock)
+	__must_hold(&tp_vars->unacked_lock)
 {
 	struct batadv_tp_unacked *un, *new;
 	struct batadv_tp_unacked *safe;
@@ -1417,9 +1429,9 @@ static bool batadv_tp_handle_out_of_order(struct batadv_tp_receiver *tp_vars,
 	new->len = payload_len;
 
 	/* if the list is empty immediately attach this new object */
-	if (list_empty(&tp_vars->common.unacked_list)) {
-		list_add(&new->list, &tp_vars->common.unacked_list);
-		tp_vars->common.unacked_count++;
+	if (list_empty(&tp_vars->unacked_list)) {
+		list_add(&new->list, &tp_vars->unacked_list);
+		tp_vars->unacked_count++;
 		return true;
 	}
 
@@ -1430,7 +1442,7 @@ static bool batadv_tp_handle_out_of_order(struct batadv_tp_receiver *tp_vars,
 	 * the last received packet (the one being processed now) has a bigger
 	 * seqno than all the others already stored.
 	 */
-	list_for_each_entry_reverse(un, &tp_vars->common.unacked_list, list) {
+	list_for_each_entry_reverse(un, &tp_vars->unacked_list, list) {
 		/* look for the right position - an un which is smaller */
 		if (batadv_seq_before(new->seqno, un->seqno))
 			continue;
@@ -1476,19 +1488,19 @@ static bool batadv_tp_handle_out_of_order(struct batadv_tp_receiver *tp_vars,
 		 */
 		list_add(&new->list, &un->list);
 		added = true;
-		tp_vars->common.unacked_count++;
+		tp_vars->unacked_count++;
 		break;
 	}
 
 	/* received packet with smallest seqno out of order; add it to front */
 	if (!added) {
-		list_add(&new->list, &tp_vars->common.unacked_list);
-		tp_vars->common.unacked_count++;
+		list_add(&new->list, &tp_vars->unacked_list);
+		tp_vars->unacked_count++;
 	}
 
 	/* check if new filled the gap to the next list entries */
 	un = new;
-	list_for_each_entry_safe_continue(un, safe, &tp_vars->common.unacked_list, list) {
+	list_for_each_entry_safe_continue(un, safe, &tp_vars->unacked_list, list) {
 		if (batadv_seq_before(new->seqno + new->len, un->seqno))
 			break;
 
@@ -1499,16 +1511,16 @@ static bool batadv_tp_handle_out_of_order(struct batadv_tp_receiver *tp_vars,
 
 		list_del(&un->list);
 		kfree(un);
-		tp_vars->common.unacked_count--;
+		tp_vars->unacked_count--;
 	}
 
 	/* remove the last (biggest) unacked seqno when list is too large */
-	if (tp_vars->common.unacked_count > BATADV_TP_MAX_UNACKED) {
-		un = list_last_entry(&tp_vars->common.unacked_list,
+	if (tp_vars->unacked_count > BATADV_TP_MAX_UNACKED) {
+		un = list_last_entry(&tp_vars->unacked_list,
 				     struct batadv_tp_unacked, list);
 		list_del(&un->list);
 		kfree(un);
-		tp_vars->common.unacked_count--;
+		tp_vars->unacked_count--;
 	}
 
 	return true;
@@ -1520,7 +1532,7 @@ static bool batadv_tp_handle_out_of_order(struct batadv_tp_receiver *tp_vars,
  * @tp_vars: the private data of the current TP meter session
  */
 static void batadv_tp_ack_unordered(struct batadv_tp_receiver *tp_vars)
-	__must_hold(&tp_vars->common.unacked_lock)
+	__must_hold(&tp_vars->unacked_lock)
 {
 	struct batadv_tp_unacked *un, *safe;
 	u32 to_ack;
@@ -1528,7 +1540,7 @@ static void batadv_tp_ack_unordered(struct batadv_tp_receiver *tp_vars)
 	/* go through the unacked packet list and possibly ACK them as
 	 * well
 	 */
-	list_for_each_entry_safe(un, safe, &tp_vars->common.unacked_list, list) {
+	list_for_each_entry_safe(un, safe, &tp_vars->unacked_list, list) {
 		/* the list is ordered, therefore it is possible to stop as soon
 		 * there is a gap between the last acked seqno and the seqno of
 		 * the packet under inspection
@@ -1543,7 +1555,7 @@ static void batadv_tp_ack_unordered(struct batadv_tp_receiver *tp_vars)
 
 		list_del(&un->list);
 		kfree(un);
-		tp_vars->common.unacked_count--;
+		tp_vars->unacked_count--;
 	}
 }
 
@@ -1590,9 +1602,9 @@ batadv_tp_init_recv(struct batadv_priv *bat_priv,
 	tp_vars->common.bat_priv = bat_priv;
 	kref_init(&tp_vars->common.refcount);
 
-	spin_lock_init(&tp_vars->common.unacked_lock);
-	INIT_LIST_HEAD(&tp_vars->common.unacked_list);
-	tp_vars->common.unacked_count = 0;
+	spin_lock_init(&tp_vars->unacked_lock);
+	INIT_LIST_HEAD(&tp_vars->unacked_list);
+	tp_vars->unacked_count = 0;
 
 	kref_get(&tp_vars->common.refcount);
 	timer_setup(&tp_vars->common.timer, batadv_tp_receiver_shutdown, 0);
@@ -1652,7 +1664,7 @@ static void batadv_tp_recv_msg(struct batadv_priv *bat_priv,
 		WRITE_ONCE(tp_vars->last_recv_time, jiffies);
 	}
 
-	spin_lock_bh(&tp_vars->common.unacked_lock);
+	spin_lock_bh(&tp_vars->unacked_lock);
 
 	/* if the packet is a duplicate, it may be the case that an ACK has been
 	 * lost. Resend the ACK
@@ -1668,7 +1680,7 @@ static void batadv_tp_recv_msg(struct batadv_priv *bat_priv,
 		 * not been enqueued correctly
 		 */
 		if (!batadv_tp_handle_out_of_order(tp_vars, seqno, payload_len)) {
-			spin_unlock_bh(&tp_vars->common.unacked_lock);
+			spin_unlock_bh(&tp_vars->unacked_lock);
 			goto out;
 		}
 
@@ -1684,7 +1696,7 @@ static void batadv_tp_recv_msg(struct batadv_priv *bat_priv,
 
 send_ack:
 	to_ack = tp_vars->last_recv;
-	spin_unlock_bh(&tp_vars->common.unacked_lock);
+	spin_unlock_bh(&tp_vars->unacked_lock);
 
 	/* send the ACK. If the received packet was out of order, the ACK that
 	 * is going to be sent is a duplicate (the sender will count them and
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index c2ab00d8ef160..c194d8069774c 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -1334,7 +1334,7 @@ struct batadv_tp_unacked {
 	/** @len: length of the packet */
 	u32 len;
 
-	/** @list: list node for &batadv_tp_vars_common.unacked_list */
+	/** @list: list node for &batadv_tp_receiver.unacked_list */
 	struct list_head list;
 };
 
@@ -1357,15 +1357,6 @@ struct batadv_tp_vars_common {
 	/** @session: TP session identifier */
 	u8 session[2];
 
-	/** @unacked_list: list of unacked packets (meta-info only) */
-	struct list_head unacked_list;
-
-	/** @unacked_lock: protect unacked_list + &batadv_tp_receiver.last_recv */
-	spinlock_t unacked_lock;
-
-	/** @unacked_count: number of unacked entries */
-	size_t unacked_count;
-
 	/** @refcount: number of context where the object is used */
 	struct kref refcount;
 
@@ -1479,6 +1470,15 @@ struct batadv_tp_receiver {
 
 	/** @last_recv_time: time (jiffies) a msg was received */
 	unsigned long last_recv_time;
+
+	/** @unacked_list: list of unacked packets (meta-info only) */
+	struct list_head unacked_list;
+
+	/** @unacked_lock: protect unacked_list + &batadv_tp_receiver.last_recv */
+	spinlock_t unacked_lock;
+
+	/** @unacked_count: number of unacked entries */
+	size_t unacked_count;
 };
 
 /**
-- 
2.47.3