Date:	Tue, 5 Oct 2010 14:13:34 +1100
From:	Stephen Rothwell <sfr@...b.auug.org.au>
To:	Tejun Heo <tj@...nel.org>
Cc:	linux-next@...r.kernel.org, linux-kernel@...r.kernel.org,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	Peter Zijlstra <peterz@...radead.org>
Subject: linux-next: manual merge of the lost-spurious-irq tree with the tip
 tree

Hi Tejun,

Today's linux-next merge of the lost-spurious-irq tree got a conflict in
kernel/irq/spurious.c between commits
6b8ff3120c758340505dddf08ad685ebb841d5d5 ("genirq: Convert core code to
irq_data") and bd151412263a67b5321e9dd1d5b4bf6d96fdebf3 ("genirq: Provide
config option to disable deprecated code") from the tip tree and commits
32b5d378f49485f3ae172eb0ac2bfc4ebbbdb060 ("irq: cleanup irqfixup") and
80f97e2b33c3e66c11b10abd2890506a3abeb320 ("irq: make spurious poll timer
per desc") from the lost-spurious-irq tree.

I think I fixed it all up (see below).  I can carry this fix (or a better
one) as necessary.
-- 
Cheers,
Stephen Rothwell                    sfr@...b.auug.org.au

diff --cc kernel/irq/spurious.c
index 3089d3b,b34b023..0000000
--- a/kernel/irq/spurious.c
+++ b/kernel/irq/spurious.c
@@@ -16,14 -75,558 +75,558 @@@
  
  #include "internals.h"
  
- static int irqfixup __read_mostly;
+ /*
+  * I spent quite some time thinking about each parameter but they
+  * still are just numbers pulled out of my ass.  If you think your ass
+  * is prettier than mine, please go ahead and suggest better ones.
+  *
+  * Most parameters are intentionally fixed constants and not
+  * adjustable through API.  The nature of IRQ delivery failures isn't
+  * usually dependent on specific drivers and the timing parameters are
+  * more about human perceivable latencies rather than any specific
+  * controller timing details, so figuring out constant values which
+  * can work for most cases shouldn't be too hard.  This allows tighter
+  * control over polling behaviors, eases future changes and makes the
+  * interface easy for drivers.
+  */
+ enum {
+ 	/* irqfixup levels */
+ 	IRQFIXUP_SPURIOUS		= 0,		/* spurious storm detection */
+ 	IRQFIXUP_MISROUTED		= 1,		/* misrouted IRQ fixup */
+ 	IRQFIXUP_POLL			= 2,		/* enable polling by default */
+ 
+ 	/* IRQ polling common parameters */
+ 	IRQ_POLL_SLOW_INTV		= 3 * HZ,	/* not too slow for ppl, slow enough for machine */
+ 	IRQ_POLL_INTV			= HZ / 100,	/* from the good ol' 100HZ tick */
+ 	IRQ_POLL_QUICK_INTV		= HZ / 1000,	/* on every tick, basically */
+ 
+ 	IRQ_POLL_SLOW_SLACK		= HZ,
+ 	IRQ_POLL_SLACK			= HZ / 250,	/* 1 tick slack w/ the popular 250HZ config */
+ 	IRQ_POLL_QUICK_SLACK		= HZ / 10000,	/* no slack, basically */
+ 
+ 	/*
+ 	 * IRQ expect parameters.
+ 	 *
+ 	 * Because IRQ expecting is tightly coupled with the actual
+ 	 * activity of the controller, we can be slightly aggressive
+ 	 * and try to minimize the effect of lost interrupts.
+ 	 *
+ 	 * An irqaction must accumulate VERIFY_GOAL good deliveries,
+ 	 * where one bad delivery (delivered by polling) costs
+ 	 * BAD_FACTOR good ones, before reaching the verified state.
+ 	 *
+ 	 * QUICK_SAMPLES IRQ deliveries are examined and if
+ 	 * >=QUICK_THRESHOLD of them are polled on the first poll, the
+ 	 * IRQ is considered to be quick and QUICK_INTV is used
+ 	 * instead.
+ 	 *
+ 	 * Keep QUICK_SAMPLES much higher than VERIFY_GOAL so that
+ 	 * quick polling doesn't interfact with the initial
+ 	 * verification attempt (quicker polling increases the chance
+ 	 * of polled deliveries).
+ 	 */
+ 	IRQ_EXP_BAD_FACTOR		= 10,
+ 	IRQ_EXP_VERIFY_GOAL		= 256,
+ 	IRQ_EXP_QUICK_SAMPLES		= IRQ_EXP_VERIFY_GOAL * 4,
+ 	IRQ_EXP_QUICK_THRESHOLD		= IRQ_EXP_QUICK_SAMPLES * 8 / 10,
+ 
+ 	/* IRQ expect flags */
+ 	IRQ_EXPECTING			= (1 << 0),	/* expecting in progress */
+ 	IRQ_EXP_VERIFIED		= (1 << 1),	/* delivery verified, use slow interval */
+ 	IRQ_EXP_QUICK			= (1 << 2),	/* quick polling enabled */
+ 	IRQ_EXP_WARNED			= (1 << 3),	/* already whined */
+ 
+ 	/*
+ 	 * IRQ watch parameters.
+ 	 *
+ 	 * As IRQ watching has much less information about what's
+ 	 * going on, the parameters are more conservative.  It will
+ 	 * terminate unless it can reliably determine that IRQ
+ 	 * delivery isn't working.
+ 	 *
+ 	 * IRQs are watched in timed intervals which is BASE_PERIOD
+ 	 * long by default.  Polling interval starts at BASE_INTV and
+ 	 * grows upto SLOW_INTV if no bad delivery is detected.
+ 	 *
+ 	 * If a period contains zero sample and no bad delivery was
+ 	 * seen since watch started, watch terminates.
+ 	 *
+ 	 * If a period contains >=1 but <MIN_SAMPLES deliveries,
+ 	 * collected samples are inherited to the next period.
+ 	 *
+ 	 * If it contains enough samples, the ratio between good and
+ 	 * bad deliveries are examined, if >=BAD_PCT% are bad, the
+ 	 * irqaction is tagged bad and watched indefinitely.  if
+ 	 * BAD_PCT% > nr_bad >= WARY_PCT%, WARY_PERIOD is used instead
+ 	 * of BASE_PERIOD and the whole process is restarted.  If
+ 	 * <WARY_PCT% are bad, watch terminates.
+ 	 */
+ 	IRQ_WAT_MIN_SAMPLES		= 10,
+ 	IRQ_WAT_BASE_INTV		= HZ / 2,
+ 	IRQ_WAT_BASE_PERIOD		= 60 * HZ,
+ 	IRQ_WAT_WARY_PERIOD		= 600 * HZ,
+ 	IRQ_WAT_WARY_PCT		= 1,
+ 	IRQ_WAT_BAD_PCT			= 10,
+ 
+ 	/* IRQ watch flags */
+ 	IRQ_WATCHING			= (1 << 0),
+ 	IRQ_WAT_POLLED			= (1 << 1),
+ 	IRQ_WAT_WARY			= (1 << 2),
+ 	IRQ_WAT_BAD			= (1 << 3),
+ 
+ 	/*
+ 	 * Spurious IRQ handling parameters.
+ 	 *
+ 	 * As this per-IRQ spurious handling is cheaper than the
+ 	 * previous system wide spurious handling, it can afford to
+ 	 * use more responsive settings but these parameters are still
+ 	 * pretty conservative.  If ever necessary, making it more
+ 	 * responsive shouldn't cause any problem.
+ 	 *
+ 	 * Spurious IRQs are monitored in segments of PERIOD_SAMPLES
+ 	 * IRQs which can stretch PERIOD_DURATION at maximum.  If
+ 	 * there are less than PERIOD_SAMPLES IRQs per
+ 	 * PERIOD_DURATION, the period is considered good.
+ 	 *
+ 	 * If >=BAD_THRESHOLD IRQs are bad ones, the period is
+ 	 * considered bad and spurious IRQ handling kicks in - the IRQ
+ 	 * is disabled and polled.  The IRQ is given another shot
+ 	 * after certain number IRQs are handled, which is at minimum
+ 	 * POLL_CNT_MIN, increased by 1 << POLL_CNT_INC_SHIFT times
+ 	 * after each bad period and decreased by factor of
+ 	 * POLL_CNT_INC_DEC_SHIFT after each good one.
+ 	 */
+ 	IRQ_SPR_PERIOD_DURATION		= 10 * HZ,
+ 	IRQ_SPR_PERIOD_SAMPLES		= 10000,
+ 	IRQ_SPR_BAD_THRESHOLD		= 9900,
+ 	IRQ_SPR_POLL_CNT_MIN		= 10000,
+ 	IRQ_SPR_POLL_CNT_INF		= UINT_MAX,
+ 	IRQ_SPR_POLL_CNT_INC_SHIFT	= 3,
+ 	IRQ_SPR_POLL_CNT_DEC_SHIFT	= 1,
+ 	IRQ_SPR_POLL_CNT_MAX_DEC_SHIFT	= BITS_PER_BYTE * sizeof(int) / 4,
+ };
+ 
+ struct irq_expect {
+ 	struct irq_expect	*next;
+ 	struct irq_desc		*desc;		/* the associated IRQ desc */
+ 	struct irqaction	*act;		/* the associated IRQ action */
+ 
+ 	unsigned int		flags;		/* IRQ_EXP_* flags */
+ 	unsigned int		nr_samples;	/* nr of collected samples in this period */
+ 	unsigned int		nr_quick;	/* nr of polls completed after single attempt */
+ 	unsigned int		nr_good;	/* nr of good IRQ deliveries */
+ 	unsigned long		started;	/* when this period started */
+ };
+ 
+ int noirqdebug __read_mostly;
+ static int irqfixup __read_mostly = IRQFIXUP_SPURIOUS;
+ 
+ static struct irqaction *find_irq_action(struct irq_desc *desc, void *dev_id)
+ {
+ 	struct irqaction *act;
+ 
+ 	for (act = desc->action; act; act = act->next)
+ 		if (act->dev_id == dev_id)
+ 			return act;
+ 	return NULL;
+ }
+ 
+ static void print_irq_handlers(struct irq_desc *desc)
+ {
+ 	struct irqaction *action;
+ 
+ 	printk(KERN_ERR "handlers:\n");
+ 
+ 	action = desc->action;
+ 	while (action) {
+ 		printk(KERN_ERR "[<%p>]", action->handler);
+ 		print_symbol(" (%s)", (unsigned long)action->handler);
+ 		printk("\n");
+ 		action = action->next;
+ 	}
+ }
+ 
+ static void warn_irq_poll(struct irq_desc *desc, struct irqaction *act)
+ {
+ 	if (desc->poll_warned)
+ 		return;
+ 
+ 	desc->poll_warned = true;
+ 
+ 	printk(KERN_WARNING "IRQ %u: %s: can't verify IRQ, will keep polling\n",
 -	       desc->irq, act->name);
++	       desc->irq_data.irq, act->name);
+ 	printk(KERN_WARNING "IRQ %u: %s: system performance may be affected\n",
 -	       desc->irq, act->name);
++	       desc->irq_data.irq, act->name);
+ }
+ 
+ static unsigned long irq_poll_slack(unsigned long intv)
+ {
+ 	if (intv >= IRQ_POLL_SLOW_INTV)
+ 		return IRQ_POLL_SLOW_SLACK;
+ 	else if (intv >= IRQ_POLL_INTV)
+ 		return IRQ_POLL_SLACK;
+ 	else
+ 		return IRQ_POLL_QUICK_SLACK;
+ }
+ 
+ /**
+  * irq_schedule_poll - schedule IRQ poll
+  * @desc: IRQ desc to schedule poll for
+  * @intv: poll interval
+  *
+  * Schedules @desc->poll_timer.  If the timer is already scheduled,
+  * it's modified iff jiffies + @intv + slack is before the timer's
+  * expires.  poll_timers aren't taken offline behind this function's
+  * back and the users of this function are guaranteed that poll_irq()
+  * will be called at or before jiffies + @intv + slack.
+  *
+  * CONTEXT:
+  * desc->lock
+  */
+ static void irq_schedule_poll(struct irq_desc *desc, unsigned long intv)
+ {
+ 	unsigned long expires = jiffies + intv;
+ 	int slack = irq_poll_slack(intv);
+ 
+ 	if (timer_pending(&desc->poll_timer) &&
+ 	    time_before_eq(desc->poll_timer.expires, expires + slack))
+ 		return;
+ 
+ 	set_timer_slack(&desc->poll_timer, slack);
+ 	mod_timer(&desc->poll_timer, expires);
+ }
+ 
+ static unsigned long irq_exp_intv(struct irq_expect *exp)
+ {
+ 	if (!(exp->flags & IRQ_EXPECTING))
+ 		return MAX_JIFFY_OFFSET;
+ 	if (exp->flags & IRQ_EXP_VERIFIED)
+ 		return IRQ_POLL_SLOW_INTV;
+ 	if (exp->flags & IRQ_EXP_QUICK)
+ 		return IRQ_POLL_QUICK_INTV;
+ 	return IRQ_POLL_INTV;
+ }
+ 
+ /**
+  * init_irq_expect - initialize IRQ expecting
+  * @irq: IRQ to expect
+  * @dev_id: dev_id of the irqaction to expect
+  *
+  * Initializes IRQ expecting and returns expect token to use.  This
+  * function can be called multiple times for the same irqaction and
+  * each token can be used independently.
+  *
+  * CONTEXT:
+  * Does GFP_KERNEL allocation.
+  *
+  * RETURNS:
+  * irq_expect token to use on success, %NULL on failure.
+  */
+ struct irq_expect *init_irq_expect(unsigned int irq, void *dev_id)
+ {
+ 	struct irq_desc *desc = irq_to_desc(irq);
+ 	struct irqaction *act;
+ 	struct irq_expect *exp;
+ 	unsigned long flags;
+ 
+ 	if (noirqdebug || WARN_ON_ONCE(!desc))
+ 		return NULL;
+ 
+ 	exp = kzalloc(sizeof(*exp), GFP_KERNEL);
+ 	if (!exp) {
+ 		printk(KERN_WARNING "IRQ %u: failed to initialize IRQ expect, "
+ 		       "allocation failed\n", irq);
+ 		return NULL;
+ 	}
+ 
+ 	exp->desc = desc;
+ 
+ 	raw_spin_lock_irqsave(&desc->lock, flags);
+ 
+ 	act = find_irq_action(desc, dev_id);
+ 	if (!WARN_ON_ONCE(!act)) {
+ 		exp->act = act;
+ 		exp->next = act->expects;
+ 		act->expects = exp;
+ 	} else {
+ 		kfree(exp);
+ 		exp = NULL;
+ 	}
+ 
+ 	raw_spin_unlock_irqrestore(&desc->lock, flags);
+ 
+ 	return exp;
+ }
+ EXPORT_SYMBOL_GPL(init_irq_expect);
+ 
+ /**
+  * expect_irq - expect IRQ
+  * @exp: expect token acquired from init_irq_expect(), %NULL is allowed
+  *
+  * Tell IRQ subsystem to expect an IRQ.  The IRQ might be polled until
+  * unexpect_irq() is called on @exp.  If @exp is %NULL, this function
+  * becomes noop.
+  *
+  * This function is fairly cheap and drivers can call it for each
+  * interrupt driven operation without adding noticeable overhead in
+  * most cases.
+  *
+  * CONTEXT:
+  * Don't care.  The caller is responsible for ensuring
+  * [un]expect_irq() calls don't overlap.  Overlapping may lead to
+  * unexpected polling behaviors but won't directly cause a failure.
+  */
+ void expect_irq(struct irq_expect *exp)
+ {
+ 	struct irq_desc *desc;
+ 	unsigned long intv, deadline;
+ 	unsigned long flags;
+ 
+ 	/* @exp is NULL if noirqdebug */
+ 	if (unlikely(!exp))
+ 		return;
+ 
+ 	desc = exp->desc;
+ 	exp->flags |= IRQ_EXPECTING;
+ 
+ 	/*
+ 	 * Paired with mb in poll_irq().  Either we see timer pending
+ 	 * cleared or poll_irq() sees IRQ_EXPECTING.
+ 	 */
+ 	smp_mb();
+ 
+ 	exp->started = jiffies;
+ 	intv = irq_exp_intv(exp);
+ 	deadline = exp->started + intv + irq_poll_slack(intv);
+ 
+ 	/*
+ 	 * poll_timer is never explicitly killed unless there's no
+ 	 * action left on the irq; also, while it's online, timer
+ 	 * duration is only shortened, which means that if we see
+ 	 * ->expires in the future and not later than our deadline,
+ 	 * the timer is guaranteed to fire before it.
+ 	 */
+ 	if (!timer_pending(&desc->poll_timer) ||
+ 	    time_after_eq(jiffies, desc->poll_timer.expires) ||
+ 	    time_before(deadline, desc->poll_timer.expires)) {
+ 		raw_spin_lock_irqsave(&desc->lock, flags);
+ 		irq_schedule_poll(desc, intv);
+ 		raw_spin_unlock_irqrestore(&desc->lock, flags);
+ 	}
+ }
+ EXPORT_SYMBOL_GPL(expect_irq);
+ 
+ /**
+  * unexpect_irq - unexpect IRQ
+  * @exp: expect token acquired from init_irq_expect(), %NULL is allowed
+  * @timedout: did the IRQ timeout?
+  *
+  * Tell IRQ subsystem to stop expecting an IRQ.  Set @timedout to
+  * %true if the expected IRQ never arrived.  If @exp is %NULL, this
+  * function becomes noop.
+  *
+  * This function is fairly cheap and drivers can call it for each
+  * interrupt driven operation without adding noticeable overhead in
+  * most cases.
+  *
+  * CONTEXT:
+  * Don't care.  The caller is responsible for ensuring
+  * [un]expect_irq() calls don't overlap.  Overlapping may lead to
+  * unexpected polling behaviors but won't directly cause a failure.
+  */
+ void unexpect_irq(struct irq_expect *exp, bool timedout)
+ {
+ 	struct irq_desc *desc;
+ 
+ 	/* @exp is NULL if noirqdebug */
+ 	if (unlikely(!exp) || (!(exp->flags & IRQ_EXPECTING) && !timedout))
+ 		return;
+ 
+ 	desc = exp->desc;
+ 	exp->flags &= ~IRQ_EXPECTING;
+ 
+ 	/* succesful completion from IRQ? */
+ 	if (likely(!(desc->status & IRQ_IN_POLLING) && !timedout)) {
+ 		/*
+ 		 * IRQ seems a bit more trustworthy.  Allow nr_good to
+ 		 * increase till VERIFY_GOAL + BAD_FACTOR - 1 so that
+ 		 * single succesful delivery can recover verified
+ 		 * state after an accidental polling hit.
+ 		 */
+ 		if (unlikely(exp->nr_good <
+ 			     IRQ_EXP_VERIFY_GOAL + IRQ_EXP_BAD_FACTOR - 1) &&
+ 		    ++exp->nr_good >= IRQ_EXP_VERIFY_GOAL) {
+ 			exp->flags |= IRQ_EXP_VERIFIED;
+ 			exp->nr_samples = 0;
+ 			exp->nr_quick = 0;
+ 		}
+ 		return;
+ 	}
+ 
+ 	/* timedout or polled */
+ 	if (timedout) {
+ 		exp->nr_good = 0;
+ 	} else {
+ 		exp->nr_good -= min_t(unsigned int,
+ 				      exp->nr_good, IRQ_EXP_BAD_FACTOR);
+ 
+ 		if (time_before_eq(jiffies, exp->started + IRQ_POLL_INTV))
+ 			exp->nr_quick++;
+ 
+ 		if (++exp->nr_samples >= IRQ_EXP_QUICK_SAMPLES) {
+ 			/*
+ 			 * Use quick sampling checkpoints as warning
+ 			 * checkpoints too.
+ 			 */
+ 			if (!(exp->flags & IRQ_EXP_WARNED) &&
+ 			    !desc->spr.poll_rem) {
+ 				warn_irq_poll(desc, exp->act);
+ 				exp->flags |= IRQ_EXP_WARNED;
+ 			}
+ 
+ 			exp->flags &= ~IRQ_EXP_QUICK;
+ 			if (exp->nr_quick >= IRQ_EXP_QUICK_THRESHOLD)
+ 				exp->flags |= IRQ_EXP_QUICK;
+ 			exp->nr_samples = 0;
+ 			exp->nr_quick = 0;
+ 		}
+ 	}
+ 
+ 	exp->flags &= ~IRQ_EXP_VERIFIED;
+ }
+ EXPORT_SYMBOL_GPL(unexpect_irq);
+ 
+ /**
+  * irq_update_watch - IRQ handled, update watch state
+  * @desc: IRQ desc of interest
+  * @act: IRQ action of interest
+  * @via_poll: IRQ was handled via poll
+  *
+  * Called after IRQ is successfully delievered or polled.  Updates
+  * watch state accordingly and determines which watch interval to use.
+  *
+  * CONTEXT:
+  * desc->lock
+  *
+  * RETURNS:
+  * Watch poll interval to use, MAX_JIFFY_OFFSET if watch polling isn't
+  * necessary.
+  */
+ static unsigned long irq_update_watch(struct irq_desc *desc,
+ 				      struct irqaction *act, bool via_poll)
+ {
+ 	struct irq_watch *wat = &act->watch;
+ 	unsigned long period = wat->flags & IRQ_WAT_WARY ?
+ 		IRQ_WAT_WARY_PERIOD : IRQ_WAT_BASE_PERIOD;
+ 
+ 	/* if not watching or already determined to be bad, it's easy */
+ 	if (!(wat->flags & IRQ_WATCHING))
+ 		return MAX_JIFFY_OFFSET;
+ 	if (wat->flags & IRQ_WAT_BAD)
+ 		return IRQ_POLL_INTV;
+ 
+ 	/* don't expire watch period while spurious polling is in effect */
+ 	if (desc->spr.poll_rem) {
+ 		wat->started = jiffies;
+ 		return IRQ_POLL_INTV;
+ 	}
+ 
+ 	/* IRQ was handled, record whether it was a good or bad delivery */
+ 	if (wat->last_ret == IRQ_HANDLED) {
+ 		wat->nr_samples++;
+ 		if (via_poll) {
+ 			wat->nr_polled++;
+ 			wat->flags |= IRQ_WAT_POLLED;
+ 		}
+ 	}
+ 
+ 	/* is this watch period over? */
+ 	if (time_after(jiffies, wat->started + period)) {
+ 		unsigned int wry_thr = wat->nr_samples * IRQ_WAT_WARY_PCT / 100;
+ 		unsigned int bad_thr = wat->nr_samples * IRQ_WAT_BAD_PCT / 100;
+ 
+ 		if (wat->nr_samples >= IRQ_WAT_MIN_SAMPLES) {
+ 			/* have enough samples, determine what to do */
+ 			if (wat->nr_polled <= wry_thr)
+ 				wat->flags &= ~IRQ_WATCHING;
+ 			else if (wat->nr_polled <= bad_thr)
+ 				wat->flags |= IRQ_WAT_WARY;
+ 			else {
+ 				warn_irq_poll(desc, act);
+ 				wat->flags |= IRQ_WAT_BAD;
+ 			}
+ 			wat->nr_samples = 0;
+ 			wat->nr_polled = 0;
+ 		} else if (!wat->nr_samples || !(wat->flags & IRQ_WAT_POLLED)) {
+ 			/* not sure but let's not hold onto it */
+ 			wat->flags &= ~IRQ_WATCHING;
+ 		}
+ 
+ 		wat->started = jiffies;
+ 	}
+ 
+ 	if (!(wat->flags & IRQ_WATCHING))
+ 		return MAX_JIFFY_OFFSET;
+ 	if (wat->flags & IRQ_WAT_POLLED)
+ 		return IRQ_POLL_INTV;
+ 	/* every delivery upto this point has been successful, grow interval */
+ 	return clamp_t(unsigned long, jiffies - wat->started,
+ 		       IRQ_WAT_BASE_INTV, IRQ_POLL_SLOW_INTV);
+ }
+ 
+ /**
+  * watch_irq - watch an irqaction
+  * @irq: IRQ the irqaction to watch belongs to
+  * @dev_id: dev_id for the irqaction to watch
+  *
+  * LOCKING:
+  * Grabs and releases desc->lock.
+  */
+ void watch_irq(unsigned int irq, void *dev_id)
+ {
+ 	struct irq_desc *desc = irq_to_desc(irq);
+ 	struct irqaction *act;
+ 	unsigned long flags;
+ 
+ 	if (WARN_ON_ONCE(!desc))
+ 		return;
+ 
+ 	raw_spin_lock_irqsave(&desc->lock, flags);
+ 
+ 	act = find_irq_action(desc, dev_id);
+ 	if (!WARN_ON_ONCE(!act)) {
+ 		struct irq_watch *wat = &act->watch;
+ 
+ 		wat->flags |= IRQ_WATCHING;
+ 		wat->started = jiffies;
+ 		wat->nr_samples = 0;
+ 		wat->nr_polled = 0;
+ 		desc->status |= IRQ_CHECK_WATCHES;
+ 		irq_schedule_poll(desc, IRQ_WAT_BASE_INTV);
+ 	}
+ 
+ 	raw_spin_unlock_irqrestore(&desc->lock, flags);
+ }
+ EXPORT_SYMBOL_GPL(watch_irq);
+ 
+ /* start a new spurious handling period */
+ static void irq_spr_new_period(struct irq_spr *spr)
+ {
+ 	spr->period_start = jiffies;
+ 	spr->nr_samples = 0;
+ 	spr->nr_bad = 0;
+ }
  
- #define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
- static void poll_spurious_irqs(unsigned long dummy);
- static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);
+ /* Reset spurious handling.  After this, poll_timer will offline itself soon. */
+ static void irq_spr_reset(struct irq_spr *spr)
+ {
+ 	irq_spr_new_period(spr);
+ 	spr->poll_cnt = IRQ_SPR_POLL_CNT_MIN;
+ 	spr->poll_rem = 0;
+ }
  
  /*
-  * Recovery handler for misrouted interrupts.
+  * Perform an actual poll.
   */
  static int try_one_irq(int irq, struct irq_desc *desc)
  {
@@@ -80,9 -682,8 +682,8 @@@
  	 * If we did actual work for the real IRQ line we must let the
  	 * IRQ controller clean up too
  	 */
 -	if (work && desc->chip && desc->chip->end)
 -		desc->chip->end(irq);
 +	if (work)
 +		irq_end(irq, desc);
- 	raw_spin_unlock(&desc->lock);
  
  	return ok;
  }
@@@ -106,165 -709,266 +709,266 @@@ static int misrouted_irq(int irq
  	return ok;
  }
  
- static void poll_spurious_irqs(unsigned long dummy)
+ /*
+  * IRQ delivery notification function.  Called after each IRQ delivery.
+  */
+ void __note_interrupt(unsigned int irq, struct irq_desc *desc,
+ 		      irqreturn_t action_ret)
  {
- 	struct irq_desc *desc;
- 	int i;
+ 	struct irq_spr *spr = &desc->spr;
+ 	unsigned long dur;
+ 	unsigned int cnt, abbr;
+ 	char unit = 'k';
  
- 	for_each_irq_desc(i, desc) {
- 		unsigned int status;
+ 	/* first, take care of IRQ watches */
+ 	if (unlikely(desc->status & IRQ_CHECK_WATCHES)) {
+ 		unsigned long intv = MAX_JIFFY_OFFSET;
+ 		struct irqaction *act;
  
- 		if (!i)
- 			 continue;
+ 		raw_spin_lock(&desc->lock);
  
- 		/* Racy but it doesn't matter */
- 		status = desc->status;
- 		barrier();
- 		if (!(status & IRQ_SPURIOUS_DISABLED))
- 			continue;
+ 		for (act = desc->action; act; act = act->next)
+ 			intv = min(intv, irq_update_watch(desc, act, false));
  
- 		local_irq_disable();
- 		try_one_irq(i, desc);
- 		local_irq_enable();
+ 		if (intv < MAX_JIFFY_OFFSET)
+ 			irq_schedule_poll(desc, intv);
+ 		else
+ 			desc->status &= ~IRQ_CHECK_WATCHES;
+ 
+ 		raw_spin_unlock(&desc->lock);
+ 	}
+ 
+ 	/*
+ 	 * Account for unhandled interrupt.  We don't care whether
+ 	 * spurious accounting update races with irq open/close and
+ 	 * gets some values wrong.  Do it w/o locking.
+ 	 */
+ 	if (unlikely(action_ret != IRQ_HANDLED)) {
+ 		static int bogus_count = 100;
+ 
+ 		spr->last_bad = jiffies - INITIAL_JIFFIES;
+ 		spr->nr_bad++;
+ 		if (likely(action_ret == IRQ_NONE)) {
+ 			if (unlikely(irqfixup >= IRQFIXUP_MISROUTED &&
+ 				     misrouted_irq(irq)))
+ 				spr->nr_bad--;
+ 		} else if (bogus_count > 0) {
+ 			bogus_count--;
+ 			printk(KERN_ERR "IRQ %u: bogus return value %x\n",
+ 			       irq, action_ret);
+ 			dump_stack();
+ 			print_irq_handlers(desc);
+ 		}
  	}
  
- 	mod_timer(&poll_spurious_irq_timer,
- 		  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
+ 	/* did we finish this spurious period? */
+ 	spr->nr_samples++;
+ 	if (likely(spr->nr_samples < IRQ_SPR_PERIOD_SAMPLES))
+ 		return;
+ 
+ 	/* if so, was it a good one? */
+ 	dur = jiffies - spr->period_start;
+ 	if (likely(spr->nr_bad < IRQ_SPR_BAD_THRESHOLD ||
+ 		   dur > IRQ_SPR_PERIOD_DURATION)) {
+ 		/*
+ 		 * If longer than PERIOD_DURATION has passed, consider
+ 		 * multiple good periods have happened.
+ 		 */
+ 		int sft = IRQ_SPR_POLL_CNT_DEC_SHIFT *
+ 			(dur >> order_base_2(IRQ_SPR_PERIOD_DURATION));
+ 
+ 		/* but don't kill poll_cnt at once */
+ 		sft = clamp(sft, 1, IRQ_SPR_POLL_CNT_MAX_DEC_SHIFT);
+ 
+ 		spr->poll_cnt >>= sft;
+ 		irq_spr_new_period(spr);
+ 		return;
+ 	}
+ 
+ 	/*
+ 	 * It was a bad one, start polling.  This is a slow path and
+ 	 * we're gonna be changing states which require proper
+ 	 * synchronization, grab desc->lock.
+ 	 */
+ 	raw_spin_lock(&desc->lock);
+ 
+ 	irq_spr_new_period(spr);
+ 
+ 	/* update spr_poll_cnt considering the lower and upper bounds */
+ 	cnt = max_t(unsigned int, spr->poll_cnt, IRQ_SPR_POLL_CNT_MIN);
+ 	spr->poll_cnt = cnt << IRQ_SPR_POLL_CNT_INC_SHIFT;
+ 	if (spr->poll_cnt < cnt)	/* did it overflow? */
+ 		spr->poll_cnt = IRQ_SPR_POLL_CNT_INF;
+ 
+ 	/* whine, plug IRQ and kick poll timer */
+ 	abbr = cnt / 1000;
+ 	if (abbr > 1000) {
+ 		abbr /= 1000;
+ 		unit = 'm';
+ 	}
+ 	printk(KERN_ERR "IRQ %u: too many spurious IRQs, disabling and "
+ 	       "polling for %u%c %umsec intervals.\n",
 -	       desc->irq, abbr, unit, jiffies_to_msecs(IRQ_POLL_INTV));
++	       desc->irq_data.irq, abbr, unit, jiffies_to_msecs(IRQ_POLL_INTV));
+ 	printk(KERN_ERR "IRQ %u: system performance may be affected\n",
 -	       desc->irq);
++	       desc->irq_data.irq);
+ 	print_irq_handlers(desc);
+ 
+ 	desc->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
+ 	desc->depth++;
 -	desc->chip->disable(desc->irq);
++	desc->irq_data.chip->irq_disable(&desc->irq_data);
+ 
+ 	spr->poll_rem = cnt;
+ 	irq_schedule_poll(desc, IRQ_POLL_INTV);
+ 
+ 	raw_spin_unlock(&desc->lock);
  }
  
  /*
-  * If 99,900 of the previous 100,000 interrupts have not been handled
-  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
-  * and try to turn the IRQ off.
-  *
-  * (The other 100-of-100,000 interrupts may have been a correctly
-  *  functioning device sharing an IRQ with the failing one)
-  *
-  * Called under desc->lock
+  * IRQ poller.  Called from desc->poll_timer.
   */
- 
- static void
- __report_bad_irq(unsigned int irq, struct irq_desc *desc,
- 		 irqreturn_t action_ret)
+ void poll_irq(unsigned long arg)
  {
- 	struct irqaction *action;
+ 	struct irq_desc *desc = (void *)arg;
+ 	struct irq_spr *spr = &desc->spr;
+ 	unsigned long intv = MAX_JIFFY_OFFSET;
+ 	bool reenable_irq = false;
+ 	struct irqaction *act;
+ 	struct irq_expect *exp;
+ 
+ 	raw_spin_lock_irq(&desc->lock);
+ 
+ 	/* poll the IRQ */
+ 	desc->status |= IRQ_IN_POLLING;
 -	try_one_irq(desc->irq, desc);
++	try_one_irq(desc->irq_data.irq, desc);
+ 	desc->status &= ~IRQ_IN_POLLING;
+ 
+ 	/* take care of spurious handling */
+ 	if (spr->poll_rem) {
+ 		if (spr->poll_rem != IRQ_SPR_POLL_CNT_INF)
+ 			spr->poll_rem--;
+ 		if (spr->poll_rem)
+ 			intv = IRQ_POLL_INTV;
+ 		else
+ 			irq_spr_new_period(spr);
+ 	}
+ 	if (!spr->poll_rem)
+ 		reenable_irq = desc->status & IRQ_SPURIOUS_DISABLED;
  
- 	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
- 		printk(KERN_ERR "irq event %d: bogus return value %x\n",
- 				irq, action_ret);
- 	} else {
- 		printk(KERN_ERR "irq %d: nobody cared (try booting with "
- 				"the \"irqpoll\" option)\n", irq);
+ 	/*
+ 	 * Paired with mb in expect_irq() so that either they see
+ 	 * timer pending cleared or irq_exp_intv() below sees
+ 	 * IRQ_EXPECTING.
+ 	 */
+ 	smp_mb();
+ 
+ 	/* take care of expects and watches */
+ 	for (act = desc->action; act; act = act->next) {
+ 		intv = min(irq_update_watch(desc, act, true), intv);
+ 		for (exp = act->expects; exp; exp = exp->next)
+ 			intv = min(irq_exp_intv(exp), intv);
  	}
- 	dump_stack();
- 	printk(KERN_ERR "handlers:\n");
  
- 	action = desc->action;
- 	while (action) {
- 		printk(KERN_ERR "[<%p>]", action->handler);
- 		print_symbol(" (%s)",
- 			(unsigned long)action->handler);
- 		printk("\n");
- 		action = action->next;
+ 	/* need to poll again? */
+ 	if (intv < MAX_JIFFY_OFFSET)
+ 		irq_schedule_poll(desc, intv);
+ 
+ 	raw_spin_unlock_irq(&desc->lock);
+ 
+ 	if (!reenable_irq)
+ 		return;
+ 
+ 	/* need to do locking dance for chip_bus_lock() to reenable IRQ */
 -	chip_bus_lock(desc->irq, desc);
++	chip_bus_lock(desc->irq_data.irq, desc);
+ 	raw_spin_lock_irq(&desc->lock);
+ 
+ 	/* make sure we haven't raced with anyone inbetween */
+ 	if (!spr->poll_rem && (desc->status & IRQ_SPURIOUS_DISABLED)) {
+ 		printk(KERN_INFO "IRQ %u: spurious polling finished, "
 -		       "reenabling IRQ\n", desc->irq);
 -		__enable_irq(desc, desc->irq, false);
++		       "reenabling IRQ\n", desc->irq_data.irq);
++		__enable_irq(desc, desc->irq_data.irq, false);
+ 		desc->status &= ~IRQ_SPURIOUS_DISABLED;
  	}
+ 
+ 	raw_spin_unlock_irq(&desc->lock);
 -	chip_bus_sync_unlock(desc->irq, desc);
++	chip_bus_sync_unlock(desc->irq_data.irq, desc);
  }
  
- static void
- report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
+ void irq_poll_action_added(struct irq_desc *desc, struct irqaction *action)
  {
- 	static int count = 100;
+ 	struct irq_spr *spr = &desc->spr;
+ 	unsigned long flags;
  
- 	if (count > 0) {
- 		count--;
- 		__report_bad_irq(irq, desc, action_ret);
+ 	raw_spin_lock_irqsave(&desc->lock, flags);
+ 
+ 	if ((action->flags & IRQF_SHARED) && irqfixup >= IRQFIXUP_POLL) {
+ 		if (!spr->poll_rem)
+ 			printk(KERN_INFO "IRQ %u: starting IRQFIXUP_POLL\n",
 -			       desc->irq);
++			       desc->irq_data.irq);
+ 		spr->poll_rem = IRQ_SPR_POLL_CNT_INF;
+ 		irq_schedule_poll(desc, IRQ_POLL_INTV);
+ 	} else {
+ 		/* new irqaction registered, give the IRQ another chance */
+ 		irq_spr_reset(spr);
  	}
+ 
+ 	raw_spin_unlock_irqrestore(&desc->lock, flags);
  }
  
- static inline int
- try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
- 		  irqreturn_t action_ret)
+ void irq_poll_action_removed(struct irq_desc *desc, struct irqaction *action)
  {
- 	struct irqaction *action;
+ 	bool irq_enabled = false, timer_killed = false;
+ 	struct irq_expect *exp, *next;
+ 	unsigned long flags;
+ 	int rc;
  
- 	if (!irqfixup)
- 		return 0;
+ 	raw_spin_lock_irqsave(&desc->lock, flags);
  
- 	/* We didn't actually handle the IRQ - see if it was misrouted? */
- 	if (action_ret == IRQ_NONE)
- 		return 1;
+ 	/* give the IRQ another chance */
+ 	if (irqfixup < IRQFIXUP_POLL)
+ 		irq_spr_reset(&desc->spr);
  
  	/*
- 	 * But for 'irqfixup == 2' we also do it for handled interrupts if
- 	 * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
- 	 * traditional PC timer interrupt.. Legacy)
+ 	 * Make sure the timer is offline if no irqaction is left as
+ 	 * the irq_desc will be reinitialized when the next irqaction
+ 	 * is added; otherwise, the timer can be left alone.  It will
+ 	 * offline itself if no longer necessary.
  	 */
- 	if (irqfixup < 2)
- 		return 0;
- 
- 	if (!irq)
- 		return 1;
+ 	while (!desc->action) {
+ 		rc = try_to_del_timer_sync(&desc->poll_timer);
+ 		if (rc >= 0) {
+ 			timer_killed = rc > 0;
+ 			break;
+ 		}
+ 		raw_spin_unlock_irqrestore(&desc->lock, flags);
+ 		cpu_relax();
+ 		raw_spin_lock_irqsave(&desc->lock, flags);
+ 	}
  
  	/*
- 	 * Since we don't get the descriptor lock, "action" can
- 	 * change under us.  We don't really care, but we don't
- 	 * want to follow a NULL pointer. So tell the compiler to
- 	 * just load it once by using a barrier.
+ 	 * If the timer was forcefully shut down, it might not have
+ 	 * had the chance to reenable IRQ.  Make sure it's enabled.
  	 */
- 	action = desc->action;
- 	barrier();
- 	return action && (action->flags & IRQF_IRQPOLL);
- }
- 
- void note_interrupt(unsigned int irq, struct irq_desc *desc,
- 		    irqreturn_t action_ret)
- {
- 	if (unlikely(action_ret != IRQ_HANDLED)) {
- 		/*
- 		 * If we are seeing only the odd spurious IRQ caused by
- 		 * bus asynchronicity then don't eventually trigger an error,
- 		 * otherwise the counter becomes a doomsday timer for otherwise
- 		 * working systems
- 		 */
- 		if (time_after(jiffies, desc->last_unhandled + HZ/10))
- 			desc->irqs_unhandled = 1;
- 		else
- 			desc->irqs_unhandled++;
- 		desc->last_unhandled = jiffies;
- 		if (unlikely(action_ret != IRQ_NONE))
- 			report_bad_irq(irq, desc, action_ret);
+ 	if (timer_killed && (desc->status & IRQ_SPURIOUS_DISABLED)) {
 -		__enable_irq(desc, desc->irq, false);
++		__enable_irq(desc, desc->irq_data.irq, false);
+ 		desc->status &= ~IRQ_SPURIOUS_DISABLED;
+ 		irq_enabled = true;
  	}
  
- 	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
- 		int ok = misrouted_irq(irq);
- 		if (action_ret == IRQ_NONE)
- 			desc->irqs_unhandled -= ok;
- 	}
- 
- 	desc->irq_count++;
- 	if (likely(desc->irq_count < 100000))
- 		return;
+ 	if (timer_killed || irq_enabled)
 -		printk(KERN_INFO "IRQ %u:%s%s%s\n", desc->irq,
++		printk(KERN_INFO "IRQ %u:%s%s%s\n", desc->irq_data.irq,
+ 		       timer_killed ? " polling stopped" : "",
+ 		       timer_killed && irq_enabled ? " and" : "",
+ 		       irq_enabled ? " IRQ reenabled" : "");
  
- 	desc->irq_count = 0;
- 	if (unlikely(desc->irqs_unhandled > 99900)) {
- 		/*
- 		 * The interrupt is stuck
- 		 */
- 		__report_bad_irq(irq, desc, action_ret);
- 		/*
- 		 * Now kill the IRQ
- 		 */
- 		printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
- 		desc->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
- 		desc->depth++;
- 		desc->irq_data.chip->irq_disable(&desc->irq_data);
- 
- 		mod_timer(&poll_spurious_irq_timer,
- 			  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
+ 	/* free expect tokens */
+ 	for (exp = action->expects; exp; exp = next) {
+ 		next = exp->next;
+ 		kfree(exp);
  	}
- 	desc->irqs_unhandled = 0;
- }
+ 	action->expects = NULL;
  
- int noirqdebug __read_mostly;
+ 	raw_spin_unlock_irqrestore(&desc->lock, flags);
+ }
  
  int noirqdebug_setup(char *str)
  {
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists