Commit c5c47e67 authored by Alexander Aring's avatar Alexander Aring Committed by Marcel Holtmann
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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: default avatarAlexander Aring <alex.aring@gmail.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent 61a22814

include/net/mac802154.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

net/mac802154/ieee802154_i.h

+7 −0
Original line number Diff line number Diff line
@@ -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.

net/mac802154/iface.c

+1 −1
Original line number Diff line number Diff line
@@ -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

net/mac802154/main.c

+30 −0
Original line number Diff line number Diff line
@@ -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);

net/mac802154/rx.c

+8 −40
Original line number Diff line number Diff line
@@ -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);

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