mac80211: unify SW/offload remain-on-channel

Redesign all the off-channel code, getting rid of
the generic off-channel work concept, replacing
it with a simple remain-on-channel list.

This fixes a number of small issues with the ROC
implementation:
 * offloaded remain-on-channel couldn't be queued,
   now we can queue it as well, if needed
 * in iwlwifi (the only user) offloaded ROC is
   mutually exclusive with scanning, use the new
   queue to handle that case -- I expect that it
   will later depend on a HW flag

The bigger issue though is that there's a bad bug
in the current implementation: if we get a mgmt
TX request while HW roc is active, and this new
request has a wait time, we actually schedule a
software ROC instead since we can't guarantee the
existing offloaded ROC will still be that long.
To fix this, the queuing mechanism was needed.

The queuing mechanism for offloaded ROC isn't yet
optimal, ideally we should add API to have the HW
extend the ROC if needed. We could add that later
but for now use a software implementation.

Overall, this unifies the behaviour between the
offloaded and software-implemented case as much
as possible.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 0 insertions, 370 deletions

diff --git a/net/mac80211/work.c b/net/mac80211/work.c
deleted file mode 100644
index b2650a9d45f..00000000000
--- a/net/mac80211/work.c
+++ /dev/null
@@ -1,370 +0,0 @@
-/*
- * 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;
-}