net/mac80211/work.c - arm/linux-arm64-legacy - Git at Google

 /*
  * mac80211 work implementation
  *
  * Copyright 2003-2008, Jouni Malinen <j@w1.fi>
  * Copyright 2004, Instant802 Networks, Inc.
  * Copyright 2005, Devicescape Software, Inc.
  * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
  * Copyright 2009, Johannes Berg <johannes@sipsolutions.net>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 #include <linux/delay.h>
 #include <linux/if_ether.h>
 #include <linux/skbuff.h>
 #include <linux/if_arp.h>
 #include <linux/etherdevice.h>
 #include <linux/crc32.h>
 #include <linux/slab.h>
 #include <net/mac80211.h>
 #include <asm/unaligned.h>

 #include "ieee80211_i.h"
 #include "rate.h"
 #include "driver-ops.h"

 enum work_action {
 	WORK_ACT_NONE,
 	WORK_ACT_TIMEOUT,
 };


 /* utils */
 static inline void ASSERT_WORK_MTX(struct ieee80211_local *local)
 {
 	lockdep_assert_held(&local->mtx);
 }

 /*
  * We can have multiple work items (and connection probing)
  * scheduling this timer, but we need to take care to only
  * reschedule it when it should fire _earlier_ than it was
  * asked for before, or if it's not pending right now. This
  * function ensures that. Note that it then is required to
  * run this function for all timeouts after the first one
  * has happened -- the work that runs from this timer will
  * do that.
  */
 static void run_again(struct ieee80211_local *local,
 		      unsigned long timeout)
 {
 	ASSERT_WORK_MTX(local);

 	if (!timer_pending(&local->work_timer) ||
 	    time_before(timeout, local->work_timer.expires))
 		mod_timer(&local->work_timer, timeout);
 }

 void free_work(struct ieee80211_work *wk)
 {
 	kfree_rcu(wk, rcu_head);
 }

 static enum work_action __must_check
 ieee80211_remain_on_channel_timeout(struct ieee80211_work *wk)
 {
 	/*
 	 * First time we run, do nothing -- the generic code will
 	 * have switched to the right channel etc.
 	 */
 	if (!wk->started) {
 		wk->timeout = jiffies + msecs_to_jiffies(wk->remain.duration);

 		cfg80211_ready_on_channel(wk->sdata->dev, (unsigned long) wk,
 					  wk->chan, wk->chan_type,
 					  wk->remain.duration, GFP_KERNEL);

 		return WORK_ACT_NONE;
 	}

 	return WORK_ACT_TIMEOUT;
 }

 static enum work_action __must_check
 ieee80211_offchannel_tx(struct ieee80211_work *wk)
 {
 	if (!wk->started) {
 		wk->timeout = jiffies + msecs_to_jiffies(wk->offchan_tx.wait);

 		/*
 		 * After this, offchan_tx.frame remains but now is no
 		 * longer a valid pointer -- we still need it as the
 		 * cookie for canceling this work/status matching.
 		 */
 		ieee80211_tx_skb(wk->sdata, wk->offchan_tx.frame);

 		return WORK_ACT_NONE;
 	}

 	return WORK_ACT_TIMEOUT;
 }

 static void ieee80211_work_timer(unsigned long data)
 {
 	struct ieee80211_local *local = (void *) data;

 	if (local->quiescing)
 		return;

 	ieee80211_queue_work(&local->hw, &local->work_work);
 }

 static void ieee80211_work_work(struct work_struct *work)
 {
 	struct ieee80211_local *local =
 		container_of(work, struct ieee80211_local, work_work);
 	struct ieee80211_work *wk, *tmp;
 	LIST_HEAD(free_work);
 	enum work_action rma;
 	bool remain_off_channel = false;

 	/*
 	 * ieee80211_queue_work() should have picked up most cases,
 	 * here we'll pick the rest.
 	 */
 	if (WARN(local->suspended, "work scheduled while going to suspend\n"))
 		return;

 	mutex_lock(&local->mtx);

 	if (local->scanning) {
 		mutex_unlock(&local->mtx);
 		return;
 	}

 	ieee80211_recalc_idle(local);

 	list_for_each_entry_safe(wk, tmp, &local->work_list, list) {
 		bool started = wk->started;

 		/* mark work as started if it's on the current off-channel */
 		if (!started && local->tmp_channel &&
 		    wk->chan == local->tmp_channel &&
 		    wk->chan_type == local->tmp_channel_type) {
 			started = true;
 			wk->timeout = jiffies;
 		}

 		if (!started && !local->tmp_channel) {
 			ieee80211_offchannel_stop_vifs(local, true);

 			local->tmp_channel = wk->chan;
 			local->tmp_channel_type = wk->chan_type;

 			ieee80211_hw_config(local, 0);

 			started = true;
 			wk->timeout = jiffies;
 		}

 		/* don't try to work with items that aren't started */
 		if (!started)
 			continue;

 		if (time_is_after_jiffies(wk->timeout)) {
 			/*
 			 * This work item isn't supposed to be worked on
 			 * right now, but take care to adjust the timer
 			 * properly.
 			 */
 			run_again(local, wk->timeout);
 			continue;
 		}

 		switch (wk->type) {
 		default:
 			WARN_ON(1);
 			/* nothing */
 			rma = WORK_ACT_NONE;
 			break;
 		case IEEE80211_WORK_ABORT:
 			rma = WORK_ACT_TIMEOUT;
 			break;
 		case IEEE80211_WORK_REMAIN_ON_CHANNEL:
 			rma = ieee80211_remain_on_channel_timeout(wk);
 			break;
 		case IEEE80211_WORK_OFFCHANNEL_TX:
 			rma = ieee80211_offchannel_tx(wk);
 			break;
 		}

 		wk->started = started;

 		switch (rma) {
 		case WORK_ACT_NONE:
 			/* might have changed the timeout */
 			run_again(local, wk->timeout);
 			break;
 		case WORK_ACT_TIMEOUT:
 			list_del_rcu(&wk->list);
 			synchronize_rcu();
 			list_add(&wk->list, &free_work);
 			break;
 		default:
 			WARN(1, "unexpected: %d", rma);
 		}
 	}

 	list_for_each_entry(wk, &local->work_list, list) {
 		if (!wk->started)
 			continue;
 		if (wk->chan != local->tmp_channel ||
 		    wk->chan_type != local->tmp_channel_type)
 			continue;
 		remain_off_channel = true;
 	}

 	if (!remain_off_channel && local->tmp_channel) {
 		local->tmp_channel = NULL;
 		ieee80211_hw_config(local, 0);

 		ieee80211_offchannel_return(local, true);

 		/* give connection some time to breathe */
 		run_again(local, jiffies + HZ/2);
 	}

 	ieee80211_recalc_idle(local);
 	ieee80211_run_deferred_scan(local);

 	mutex_unlock(&local->mtx);

 	list_for_each_entry_safe(wk, tmp, &free_work, list) {
 		wk->done(wk, NULL);
 		list_del(&wk->list);
 		kfree(wk);
 	}
 }

 void ieee80211_add_work(struct ieee80211_work *wk)
 {
 	struct ieee80211_local *local;

 	if (WARN_ON(!wk->chan))
 		return;

 	if (WARN_ON(!wk->sdata))
 		return;

 	if (WARN_ON(!wk->done))
 		return;

 	if (WARN_ON(!ieee80211_sdata_running(wk->sdata)))
 		return;

 	wk->started = false;

 	local = wk->sdata->local;
 	mutex_lock(&local->mtx);
 	list_add_tail(&wk->list, &local->work_list);
 	mutex_unlock(&local->mtx);

 	ieee80211_queue_work(&local->hw, &local->work_work);
 }

 void ieee80211_work_init(struct ieee80211_local *local)
 {
 	INIT_LIST_HEAD(&local->work_list);
 	setup_timer(&local->work_timer, ieee80211_work_timer,
 		    (unsigned long)local);
 	INIT_WORK(&local->work_work, ieee80211_work_work);
 }

 void ieee80211_work_purge(struct ieee80211_sub_if_data *sdata)
 {
 	struct ieee80211_local *local = sdata->local;
 	struct ieee80211_work *wk;
 	bool cleanup = false;

 	mutex_lock(&local->mtx);
 	list_for_each_entry(wk, &local->work_list, list) {
 		if (wk->sdata != sdata)
 			continue;
 		cleanup = true;
 		wk->type = IEEE80211_WORK_ABORT;
 		wk->started = true;
 		wk->timeout = jiffies;
 	}
 	mutex_unlock(&local->mtx);

 	/* run cleanups etc. */
 	if (cleanup)
 		ieee80211_work_work(&local->work_work);

 	mutex_lock(&local->mtx);
 	list_for_each_entry(wk, &local->work_list, list) {
 		if (wk->sdata != sdata)
 			continue;
 		WARN_ON(1);
 		break;
 	}
 	mutex_unlock(&local->mtx);
 }

 static enum work_done_result ieee80211_remain_done(struct ieee80211_work *wk,
 						   struct sk_buff *skb)
 {
 	/*
 	 * We are done serving the remain-on-channel command.
 	 */
 	cfg80211_remain_on_channel_expired(wk->sdata->dev, (unsigned long) wk,
 					   wk->chan, wk->chan_type,
 					   GFP_KERNEL);

 	return WORK_DONE_DESTROY;
 }

 int ieee80211_wk_remain_on_channel(struct ieee80211_sub_if_data *sdata,
 				   struct ieee80211_channel *chan,
 				   enum nl80211_channel_type channel_type,
 				   unsigned int duration, u64 *cookie)
 {
 	struct ieee80211_work *wk;

 	wk = kzalloc(sizeof(*wk), GFP_KERNEL);
 	if (!wk)
 		return -ENOMEM;

 	wk->type = IEEE80211_WORK_REMAIN_ON_CHANNEL;
 	wk->chan = chan;
 	wk->chan_type = channel_type;
 	wk->sdata = sdata;
 	wk->done = ieee80211_remain_done;

 	wk->remain.duration = duration;

 	*cookie = (unsigned long) wk;

 	ieee80211_add_work(wk);

 	return 0;
 }

 int ieee80211_wk_cancel_remain_on_channel(struct ieee80211_sub_if_data *sdata,
 					  u64 cookie)
 {
 	struct ieee80211_local *local = sdata->local;
 	struct ieee80211_work *wk, *tmp;
 	bool found = false;

 	mutex_lock(&local->mtx);
 	list_for_each_entry_safe(wk, tmp, &local->work_list, list) {
 		if ((unsigned long) wk == cookie) {
 			wk->timeout = jiffies;
 			found = true;
 			break;
 		}
 	}
 	mutex_unlock(&local->mtx);

 	if (!found)
 		return -ENOENT;

 	ieee80211_queue_work(&local->hw, &local->work_work);

 	return 0;
 }
	/*
	* mac80211 work implementation
	*
	* Copyright 2003-2008, Jouni Malinen <j@w1.fi>
	* Copyright 2004, Instant802 Networks, Inc.
	* Copyright 2005, Devicescape Software, Inc.
	* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
	* Copyright 2007, Michael Wu <flamingice@sourmilk.net>
	* Copyright 2009, Johannes Berg <johannes@sipsolutions.net>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <linux/delay.h>
	#include <linux/if_ether.h>
	#include <linux/skbuff.h>
	#include <linux/if_arp.h>
	#include <linux/etherdevice.h>
	#include <linux/crc32.h>
	#include <linux/slab.h>
	#include <net/mac80211.h>
	#include <asm/unaligned.h>

	#include "ieee80211_i.h"
	#include "rate.h"
	#include "driver-ops.h"

	enum work_action {
	WORK_ACT_NONE,
	WORK_ACT_TIMEOUT,
	};


	/* utils */
	static inline void ASSERT_WORK_MTX(struct ieee80211_local *local)
	{
	lockdep_assert_held(&local->mtx);
	}

	/*
	* We can have multiple work items (and connection probing)
	* scheduling this timer, but we need to take care to only
	* reschedule it when it should fire _earlier_ than it was
	* asked for before, or if it's not pending right now. This
	* function ensures that. Note that it then is required to
	* run this function for all timeouts after the first one
	* has happened -- the work that runs from this timer will
	* do that.
	*/
	static void run_again(struct ieee80211_local *local,
	unsigned long timeout)
	{
	ASSERT_WORK_MTX(local);

	if (!timer_pending(&local->work_timer) \|\|
	time_before(timeout, local->work_timer.expires))
	mod_timer(&local->work_timer, timeout);
	}

	void free_work(struct ieee80211_work *wk)
	{
	kfree_rcu(wk, rcu_head);
	}

	static enum work_action __must_check
	ieee80211_remain_on_channel_timeout(struct ieee80211_work *wk)
	{
	/*
	* First time we run, do nothing -- the generic code will
	* have switched to the right channel etc.
	*/
	if (!wk->started) {
	wk->timeout = jiffies + msecs_to_jiffies(wk->remain.duration);

	cfg80211_ready_on_channel(wk->sdata->dev, (unsigned long) wk,
	wk->chan, wk->chan_type,
	wk->remain.duration, GFP_KERNEL);

	return WORK_ACT_NONE;
	}

	return WORK_ACT_TIMEOUT;
	}

	static enum work_action __must_check
	ieee80211_offchannel_tx(struct ieee80211_work *wk)
	{
	if (!wk->started) {
	wk->timeout = jiffies + msecs_to_jiffies(wk->offchan_tx.wait);

	/*
	* After this, offchan_tx.frame remains but now is no
	* longer a valid pointer -- we still need it as the
	* cookie for canceling this work/status matching.
	*/
	ieee80211_tx_skb(wk->sdata, wk->offchan_tx.frame);

	return WORK_ACT_NONE;
	}

	return WORK_ACT_TIMEOUT;
	}

	static void ieee80211_work_timer(unsigned long data)
	{
	struct ieee80211_local local = (void ) data;

	if (local->quiescing)
	return;

	ieee80211_queue_work(&local->hw, &local->work_work);
	}

	static void ieee80211_work_work(struct work_struct *work)
	{
	struct ieee80211_local *local =
	container_of(work, struct ieee80211_local, work_work);
	struct ieee80211_work wk, tmp;
	LIST_HEAD(free_work);
	enum work_action rma;
	bool remain_off_channel = false;

	/*
	* ieee80211_queue_work() should have picked up most cases,
	* here we'll pick the rest.
	*/
	if (WARN(local->suspended, "work scheduled while going to suspend\n"))
	return;

	mutex_lock(&local->mtx);

	if (local->scanning) {
	mutex_unlock(&local->mtx);
	return;
	}

	ieee80211_recalc_idle(local);

	list_for_each_entry_safe(wk, tmp, &local->work_list, list) {
	bool started = wk->started;

	/* mark work as started if it's on the current off-channel */
	if (!started && local->tmp_channel &&
	wk->chan == local->tmp_channel &&
	wk->chan_type == local->tmp_channel_type) {
	started = true;
	wk->timeout = jiffies;
	}

	if (!started && !local->tmp_channel) {
	ieee80211_offchannel_stop_vifs(local, true);

	local->tmp_channel = wk->chan;
	local->tmp_channel_type = wk->chan_type;

	ieee80211_hw_config(local, 0);

	started = true;
	wk->timeout = jiffies;
	}

	/* don't try to work with items that aren't started */
	if (!started)
	continue;

	if (time_is_after_jiffies(wk->timeout)) {
	/*
	* This work item isn't supposed to be worked on
	* right now, but take care to adjust the timer
	* properly.
	*/
	run_again(local, wk->timeout);
	continue;
	}

	switch (wk->type) {
	default:
	WARN_ON(1);
	/* nothing */
	rma = WORK_ACT_NONE;
	break;
	case IEEE80211_WORK_ABORT:
	rma = WORK_ACT_TIMEOUT;
	break;
	case IEEE80211_WORK_REMAIN_ON_CHANNEL:
	rma = ieee80211_remain_on_channel_timeout(wk);
	break;
	case IEEE80211_WORK_OFFCHANNEL_TX:
	rma = ieee80211_offchannel_tx(wk);
	break;
	}

	wk->started = started;

	switch (rma) {
	case WORK_ACT_NONE:
	/* might have changed the timeout */
	run_again(local, wk->timeout);
	break;
	case WORK_ACT_TIMEOUT:
	list_del_rcu(&wk->list);
	synchronize_rcu();
	list_add(&wk->list, &free_work);
	break;
	default:
	WARN(1, "unexpected: %d", rma);
	}
	}

	list_for_each_entry(wk, &local->work_list, list) {
	if (!wk->started)
	continue;
	if (wk->chan != local->tmp_channel \|\|
	wk->chan_type != local->tmp_channel_type)
	continue;
	remain_off_channel = true;
	}

	if (!remain_off_channel && local->tmp_channel) {
	local->tmp_channel = NULL;
	ieee80211_hw_config(local, 0);

	ieee80211_offchannel_return(local, true);

	/* give connection some time to breathe */
	run_again(local, jiffies + HZ/2);
	}

	ieee80211_recalc_idle(local);
	ieee80211_run_deferred_scan(local);

	mutex_unlock(&local->mtx);

	list_for_each_entry_safe(wk, tmp, &free_work, list) {
	wk->done(wk, NULL);
	list_del(&wk->list);
	kfree(wk);
	}
	}

	void ieee80211_add_work(struct ieee80211_work *wk)
	{
	struct ieee80211_local *local;

	if (WARN_ON(!wk->chan))
	return;

	if (WARN_ON(!wk->sdata))
	return;

	if (WARN_ON(!wk->done))
	return;

	if (WARN_ON(!ieee80211_sdata_running(wk->sdata)))
	return;

	wk->started = false;

	local = wk->sdata->local;
	mutex_lock(&local->mtx);
	list_add_tail(&wk->list, &local->work_list);
	mutex_unlock(&local->mtx);

	ieee80211_queue_work(&local->hw, &local->work_work);
	}

	void ieee80211_work_init(struct ieee80211_local *local)
	{
	INIT_LIST_HEAD(&local->work_list);
	setup_timer(&local->work_timer, ieee80211_work_timer,
	(unsigned long)local);
	INIT_WORK(&local->work_work, ieee80211_work_work);
	}

	void ieee80211_work_purge(struct ieee80211_sub_if_data *sdata)
	{
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_work *wk;
	bool cleanup = false;

	mutex_lock(&local->mtx);
	list_for_each_entry(wk, &local->work_list, list) {
	if (wk->sdata != sdata)
	continue;
	cleanup = true;
	wk->type = IEEE80211_WORK_ABORT;
	wk->started = true;
	wk->timeout = jiffies;
	}
	mutex_unlock(&local->mtx);

	/* run cleanups etc. */
	if (cleanup)
	ieee80211_work_work(&local->work_work);

	mutex_lock(&local->mtx);
	list_for_each_entry(wk, &local->work_list, list) {
	if (wk->sdata != sdata)
	continue;
	WARN_ON(1);
	break;
	}
	mutex_unlock(&local->mtx);
	}

	static enum work_done_result ieee80211_remain_done(struct ieee80211_work *wk,
	struct sk_buff *skb)
	{
	/*
	* We are done serving the remain-on-channel command.
	*/
	cfg80211_remain_on_channel_expired(wk->sdata->dev, (unsigned long) wk,
	wk->chan, wk->chan_type,
	GFP_KERNEL);

	return WORK_DONE_DESTROY;
	}

	int ieee80211_wk_remain_on_channel(struct ieee80211_sub_if_data *sdata,
	struct ieee80211_channel *chan,
	enum nl80211_channel_type channel_type,
	unsigned int duration, u64 *cookie)
	{
	struct ieee80211_work *wk;

	wk = kzalloc(sizeof(*wk), GFP_KERNEL);
	if (!wk)
	return -ENOMEM;

	wk->type = IEEE80211_WORK_REMAIN_ON_CHANNEL;
	wk->chan = chan;
	wk->chan_type = channel_type;
	wk->sdata = sdata;
	wk->done = ieee80211_remain_done;

	wk->remain.duration = duration;

	*cookie = (unsigned long) wk;

	ieee80211_add_work(wk);

	return 0;
	}

	int ieee80211_wk_cancel_remain_on_channel(struct ieee80211_sub_if_data *sdata,
	u64 cookie)
	{
	struct ieee80211_local *local = sdata->local;
	struct ieee80211_work wk, tmp;
	bool found = false;

	mutex_lock(&local->mtx);
	list_for_each_entry_safe(wk, tmp, &local->work_list, list) {
	if ((unsigned long) wk == cookie) {
	wk->timeout = jiffies;
	found = true;
	break;
	}
	}
	mutex_unlock(&local->mtx);

	if (!found)
	return -ENOENT;

	ieee80211_queue_work(&local->hw, &local->work_work);

	return 0;
	}