4 files changed, 69 insertions, 12 deletions

diff --git a/net/mac802154/cfg.c b/net/mac802154/cfg.c
index 1e4a9f74ed43..b51100fd9e3f 100644
--- a/net/mac802154/cfg.c
+++ b/net/mac802154/cfg.c
@@ -46,7 +46,7 @@ static int ieee802154_suspend(struct wpan_phy *wpan_phy)
 	if (!local->open_count)
 		goto suspend;
 
-	ieee802154_stop_queue(&local->hw);
+	ieee802154_hold_queue(local);
 	synchronize_net();
 
 	/* stop hardware - this must stop RX */
@@ -72,7 +72,7 @@ static int ieee802154_resume(struct wpan_phy *wpan_phy)
 		return ret;
 
 wake_up:
-	ieee802154_wake_queue(&local->hw);
+	ieee802154_release_queue(local);
 	local->suspended = false;
 	return 0;
 }
diff --git a/net/mac802154/ieee802154_i.h b/net/mac802154/ieee802154_i.h
index a8b7b9049f14..0c7ff9e0b632 100644
--- a/net/mac802154/ieee802154_i.h
+++ b/net/mac802154/ieee802154_i.h
@@ -130,6 +130,25 @@ netdev_tx_t
 ieee802154_subif_start_xmit(struct sk_buff *skb, struct net_device *dev);
 enum hrtimer_restart ieee802154_xmit_ifs_timer(struct hrtimer *timer);
 
+/**
+ * ieee802154_hold_queue - hold ieee802154 queue
+ * @local: main mac object
+ *
+ * Hold a queue by incrementing an atomic counter and requesting the netif
+ * queues to be stopped. The queues cannot be woken up while the counter has not
+ * been reset with as any ieee802154_release_queue() calls as needed.
+ */
+void ieee802154_hold_queue(struct ieee802154_local *local);
+
+/**
+ * ieee802154_release_queue - release ieee802154 queue
+ * @local: main mac object
+ *
+ * Release a queue which is held by decrementing an atomic counter and wake it
+ * up only if the counter reaches 0.
+ */
+void ieee802154_release_queue(struct ieee802154_local *local);
+
 /* MIB callbacks */
 void mac802154_dev_set_page_channel(struct net_device *dev, u8 page, u8 chan);
 
diff --git a/net/mac802154/tx.c b/net/mac802154/tx.c
index 33f64ecd96c7..6a53c83cf039 100644
--- a/net/mac802154/tx.c
+++ b/net/mac802154/tx.c
@@ -43,7 +43,7 @@ void ieee802154_xmit_sync_worker(struct work_struct *work)
 
 err_tx:
 	/* Restart the netif queue on each sub_if_data object. */
-	ieee802154_wake_queue(&local->hw);
+	ieee802154_release_queue(local);
 	atomic_dec(&local->phy->ongoing_txs);
 	kfree_skb(skb);
 	netdev_dbg(dev, "transmission failed\n");
@@ -75,7 +75,7 @@ ieee802154_tx(struct ieee802154_local *local, struct sk_buff *skb)
 	}
 
 	/* Stop the netif queue on each sub_if_data object. */
-	ieee802154_stop_queue(&local->hw);
+	ieee802154_hold_queue(local);
 	atomic_inc(&local->phy->ongoing_txs);
 
 	/* Drivers should preferably implement the async callback. In some rare
@@ -99,7 +99,7 @@ ieee802154_tx(struct ieee802154_local *local, struct sk_buff *skb)
 	return NETDEV_TX_OK;
 
 err_wake_netif_queue:
-	ieee802154_wake_queue(&local->hw);
+	ieee802154_release_queue(local);
 	atomic_dec(&local->phy->ongoing_txs);
 err_free_skb:
 	kfree_skb(skb);
diff --git a/net/mac802154/util.c b/net/mac802154/util.c
index 76dc663e2af4..0ed8b5bcbe8a 100644
--- a/net/mac802154/util.c
+++ b/net/mac802154/util.c
@@ -13,7 +13,17 @@
 /* privid for wpan_phys to determine whether they belong to us or not */
 const void *const mac802154_wpan_phy_privid = &mac802154_wpan_phy_privid;
 
-void ieee802154_wake_queue(struct ieee802154_hw *hw)
+/**
+ * ieee802154_wake_queue - wake ieee802154 queue
+ * @local: main mac object
+ *
+ * Tranceivers usually have either one transmit framebuffer or one framebuffer
+ * for both transmitting and receiving. Hence, the core currently only handles
+ * one frame at a time for each phy, which means we had to stop the queue to
+ * avoid new skb to come during the transmission. The queue then needs to be
+ * woken up after the operation.
+ */
+static void ieee802154_wake_queue(struct ieee802154_hw *hw)
 {
 	struct ieee802154_local *local = hw_to_local(hw);
 	struct ieee802154_sub_if_data *sdata;
@@ -27,9 +37,18 @@ void ieee802154_wake_queue(struct ieee802154_hw *hw)
 	}
 	rcu_read_unlock();
 }
-EXPORT_SYMBOL(ieee802154_wake_queue);
 
-void ieee802154_stop_queue(struct ieee802154_hw *hw)
+/**
+ * ieee802154_stop_queue - stop ieee802154 queue
+ * @local: main mac object
+ *
+ * Tranceivers usually have either one transmit framebuffer or one framebuffer
+ * for both transmitting and receiving. Hence, the core currently only handles
+ * one frame at a time for each phy, which means we need to tell upper layers to
+ * stop giving us new skbs while we are busy with the transmitted one. The queue
+ * must then be stopped before transmitting.
+ */
+static void ieee802154_stop_queue(struct ieee802154_hw *hw)
 {
 	struct ieee802154_local *local = hw_to_local(hw);
 	struct ieee802154_sub_if_data *sdata;
@@ -43,14 +62,33 @@ void ieee802154_stop_queue(struct ieee802154_hw *hw)
 	}
 	rcu_read_unlock();
 }
-EXPORT_SYMBOL(ieee802154_stop_queue);
+
+void ieee802154_hold_queue(struct ieee802154_local *local)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&local->phy->queue_lock, flags);
+	if (!atomic_fetch_inc(&local->phy->hold_txs))
+		ieee802154_stop_queue(&local->hw);
+	spin_unlock_irqrestore(&local->phy->queue_lock, flags);
+}
+
+void ieee802154_release_queue(struct ieee802154_local *local)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&local->phy->queue_lock, flags);
+	if (!atomic_dec_and_test(&local->phy->hold_txs))
+		ieee802154_wake_queue(&local->hw);
+	spin_unlock_irqrestore(&local->phy->queue_lock, flags);
+}
 
 enum hrtimer_restart ieee802154_xmit_ifs_timer(struct hrtimer *timer)
 {
 	struct ieee802154_local *local =
 		container_of(timer, struct ieee802154_local, ifs_timer);
 
-	ieee802154_wake_queue(&local->hw);
+	ieee802154_release_queue(local);
 
 	return HRTIMER_NORESTART;
 }
@@ -84,7 +122,7 @@ void ieee802154_xmit_complete(struct ieee802154_hw *hw, struct sk_buff *skb,
 				      hw->phy->sifs_period * NSEC_PER_USEC,
 				      HRTIMER_MODE_REL);
 	} else {
-		ieee802154_wake_queue(hw);
+		ieee802154_release_queue(local);
 	}
 
 	dev_consume_skb_any(skb);
@@ -98,7 +136,7 @@ void ieee802154_xmit_error(struct ieee802154_hw *hw, struct sk_buff *skb,
 	struct ieee802154_local *local = hw_to_local(hw);
 
 	local->tx_result = reason;
-	ieee802154_wake_queue(hw);
+	ieee802154_release_queue(local);
 	dev_kfree_skb_any(skb);
 	atomic_dec(&hw->phy->ongoing_txs);
 }