mac802154: rx: use tasklet instead workqueue

Tasklets have much less overhead than workqueues. This patch also
removes the heap allocation for the worker on receiving path.
Like mac80211 we should prefer use a tasklet here instead a workqueue to
getting fast out of interrupt context when ieee802154_rx_irqsafe is
called by driver. Like wireless inside the tasklet context we should
call netif_receive_skb instead netif_rx_ni anymore.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/include/net/mac802154.h b/include/net/mac802154.h
index 942dd53d4658b73d298ada73441127c63318623d..4c4642ef244f6f4fb5a98eab851ccc8aa42e1f76 100644 (file)
--- a/include/net/mac802154.h
+++ b/include/net/mac802154.h
@@ -202,6 +202,7 @@ void ieee802154_free_hw(struct ieee802154_hw *hw);
 int ieee802154_register_hw(struct ieee802154_hw *hw);
 void ieee802154_unregister_hw(struct ieee802154_hw *hw);
 
+void ieee802154_rx(struct ieee802154_hw *hw, struct sk_buff *skb);
 void ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb,
                           u8 lqi);
 

diff --git a/net/mac802154/ieee802154_i.h b/net/mac802154/ieee802154_i.h
index ef29c10eeb6642c85a83500ba2fcfbd7a2430667..603509a94a8670f7630f310b9491241fa5273140 100644 (file)
--- a/net/mac802154/ieee802154_i.h
+++ b/net/mac802154/ieee802154_i.h
@@ -55,11 +55,18 @@ struct ieee802154_local {
         * read them using any of protection methods.
         */
        bool running;
+
+       struct tasklet_struct tasklet;
+       struct sk_buff_head skb_queue;
 };
 
 #define        MAC802154_DEVICE_STOPPED        0x00
 #define MAC802154_DEVICE_RUN           0x01
 
+enum {
+       IEEE802154_RX_MSG        = 1,
+};
+
 /* Slave interface definition.
  *
  * Slaves represent typical network interfaces available from userspace.

diff --git a/net/mac802154/iface.c b/net/mac802154/iface.c
index be45dc9257b3818993288af31bf7552e58abd3c2..311f60c8629b7aa7f734ccac37dae1116aa22e89 100644 (file)
--- a/net/mac802154/iface.c
+++ b/net/mac802154/iface.c
@@ -376,7 +376,7 @@ void mac802154_wpan_setup(struct net_device *dev)
 
 static int mac802154_process_data(struct net_device *dev, struct sk_buff *skb)
 {
-       return netif_rx_ni(skb);
+       return netif_receive_skb(skb);
 }
 
 static int

diff --git a/net/mac802154/main.c b/net/mac802154/main.c
index 3c0a824d24ac6fa7cedbc900a5ecad46d33b1e6b..ff0de0f990cb42dc3dd58ba5ec929cb82a5c255e 100644 (file)
--- a/net/mac802154/main.c
+++ b/net/mac802154/main.c
@@ -222,6 +222,29 @@ static int mac802154_set_frame_retries(struct wpan_phy *phy, s8 retries)
        return local->ops->set_frame_retries(&local->hw, retries);
 }
 
+static void ieee802154_tasklet_handler(unsigned long data)
+{
+       struct ieee802154_local *local = (struct ieee802154_local *)data;
+       struct sk_buff *skb;
+
+       while ((skb = skb_dequeue(&local->skb_queue))) {
+               switch (skb->pkt_type) {
+               case IEEE802154_RX_MSG:
+                       /* Clear skb->pkt_type in order to not confuse kernel
+                        * netstack.
+                        */
+                       skb->pkt_type = 0;
+                       ieee802154_rx(&local->hw, skb);
+                       break;
+               default:
+                       WARN(1, "mac802154: Packet is of unknown type %d\n",
+                            skb->pkt_type);
+                       kfree_skb(skb);
+                       break;
+               }
+       }
+}
+
 struct ieee802154_hw *
 ieee802154_alloc_hw(size_t priv_data_len, struct ieee802154_ops *ops)
 {
@@ -270,6 +293,12 @@ ieee802154_alloc_hw(size_t priv_data_len, struct ieee802154_ops *ops)
        INIT_LIST_HEAD(&local->interfaces);
        mutex_init(&local->iflist_mtx);
 
+       tasklet_init(&local->tasklet,
+                    ieee802154_tasklet_handler,
+                    (unsigned long)local);
+
+       skb_queue_head_init(&local->skb_queue);
+
        return &local->hw;
 }
 EXPORT_SYMBOL(ieee802154_alloc_hw);
@@ -371,6 +400,7 @@ void ieee802154_unregister_hw(struct ieee802154_hw *hw)
        struct ieee802154_local *local = hw_to_local(hw);
        struct ieee802154_sub_if_data *sdata, *next;
 
+       tasklet_kill(&local->tasklet);
        flush_workqueue(local->workqueue);
        destroy_workqueue(local->workqueue);
 

diff --git a/net/mac802154/rx.c b/net/mac802154/rx.c
index 53c9e0c10a872a19df0ff6a8b43f13dfb79c81cc..2851a3f7ac0b2d527521490af060bc387e26d300 100644 (file)
--- a/net/mac802154/rx.c
+++ b/net/mac802154/rx.c
@@ -19,7 +19,6 @@
 
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/workqueue.h>
 #include <linux/netdevice.h>
 #include <linux/crc-ccitt.h>
 
@@ -28,30 +27,11 @@
 
 #include "ieee802154_i.h"
 
-/* The IEEE 802.15.4 standard defines 4 MAC packet types:
- * - beacon frame
- * - MAC command frame
- * - acknowledgement frame
- * - data frame
- *
- * and only the data frame should be pushed to the upper layers, other types
- * are just internal MAC layer management information. So only data packets
- * are going to be sent to the networking queue, all other will be processed
- * right here by using the device workqueue.
- */
-struct rx_work {
-       struct sk_buff *skb;
-       struct work_struct work;
-       struct ieee802154_hw *hw;
-       u8 lqi;
-};
-
 static void
-mac802154_subif_rx(struct ieee802154_hw *hw, struct sk_buff *skb, u8 lqi)
+mac802154_subif_rx(struct ieee802154_hw *hw, struct sk_buff *skb)
 {
        struct ieee802154_local *local = hw_to_local(hw);
 
-       mac_cb(skb)->lqi = lqi;
        skb->protocol = htons(ETH_P_IEEE802154);
        skb_reset_mac_header(skb);
 
@@ -79,32 +59,20 @@ fail:
        kfree_skb(skb);
 }
 
-static void mac802154_rx_worker(struct work_struct *work)
+void ieee802154_rx(struct ieee802154_hw *hw, struct sk_buff *skb)
 {
-       struct rx_work *rw = container_of(work, struct rx_work, work);
-
-       mac802154_subif_rx(rw->hw, rw->skb, rw->lqi);
-       kfree(rw);
+       mac802154_subif_rx(hw, skb);
 }
+EXPORT_SYMBOL(ieee802154_rx);
 
 void
 ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb, u8 lqi)
 {
        struct ieee802154_local *local = hw_to_local(hw);
-       struct rx_work *work;
 
-       if (!skb)
-               return;
-
-       work = kzalloc(sizeof(*work), GFP_ATOMIC);
-       if (!work)
-               return;
-
-       INIT_WORK(&work->work, mac802154_rx_worker);
-       work->skb = skb;
-       work->hw = hw;
-       work->lqi = lqi;
-
-       queue_work(local->workqueue, &work->work);
+       mac_cb(skb)->lqi = lqi;
+       skb->pkt_type = IEEE802154_RX_MSG;
+       skb_queue_tail(&local->skb_queue, skb);
+       tasklet_schedule(&local->tasklet);
 }
 EXPORT_SYMBOL(ieee802154_rx_irqsafe);