1 files changed, 104 insertions, 59 deletions

diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c
index 3089d3b..dd586eb 100644
--- a/kernel/irq/spurious.c
+++ b/kernel/irq/spurious.c
@@ -21,70 +21,94 @@ static int irqfixup __read_mostly;
 #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);
+static int irq_poll_cpu;
+static atomic_t irq_poll_active;
+
+/*
+ * We wait here for a poller to finish.
+ *
+ * If the poll runs on this CPU, then we yell loudly and return
+ * false. That will leave the interrupt line disabled in the worst
+ * case, but it should never happen.
+ *
+ * We wait until the poller is done and then recheck disabled and
+ * action (about to be disabled). Only if it's still active, we return
+ * true and let the handler run.
+ */
+bool irq_wait_for_poll(struct irq_desc *desc)
+{
+	if (WARN_ONCE(irq_poll_cpu == smp_processor_id(),
+		      "irq poll in progress on cpu %d for irq %d\n",
+		      smp_processor_id(), desc->irq_data.irq))
+		return false;
+
+#ifdef CONFIG_SMP
+	do {
+		raw_spin_unlock(&desc->lock);
+		while (desc->istate & IRQS_INPROGRESS)
+			cpu_relax();
+		raw_spin_lock(&desc->lock);
+	} while (desc->istate & IRQS_INPROGRESS);
+	/* Might have been disabled in meantime */
+	return !(desc->istate & IRQS_DISABLED) && desc->action;
+#else
+	return false;
+#endif
+}
+
 
 /*
  * Recovery handler for misrouted interrupts.
  */
-static int try_one_irq(int irq, struct irq_desc *desc)
+static int try_one_irq(int irq, struct irq_desc *desc, bool force)
 {
+	irqreturn_t ret = IRQ_NONE;
 	struct irqaction *action;
-	int ok = 0, work = 0;
 
 	raw_spin_lock(&desc->lock);
-	/* Already running on another processor */
-	if (desc->status & IRQ_INPROGRESS) {
-		/*
-		 * Already running: If it is shared get the other
-		 * CPU to go looking for our mystery interrupt too
-		 */
-		if (desc->action && (desc->action->flags & IRQF_SHARED))
-			desc->status |= IRQ_PENDING;
-		raw_spin_unlock(&desc->lock);
-		return ok;
-	}
-	/* Honour the normal IRQ locking */
-	desc->status |= IRQ_INPROGRESS;
-	action = desc->action;
-	raw_spin_unlock(&desc->lock);
 
-	while (action) {
-		/* Only shared IRQ handlers are safe to call */
-		if (action->flags & IRQF_SHARED) {
-			if (action->handler(irq, action->dev_id) ==
-				IRQ_HANDLED)
-				ok = 1;
-		}
-		action = action->next;
-	}
-	local_irq_disable();
-	/* Now clean up the flags */
-	raw_spin_lock(&desc->lock);
-	action = desc->action;
+	/* PER_CPU and nested thread interrupts are never polled */
+	if (irq_settings_is_per_cpu(desc) || irq_settings_is_nested_thread(desc))
+		goto out;
 
 	/*
-	 * While we were looking for a fixup someone queued a real
-	 * IRQ clashing with our walk:
+	 * Do not poll disabled interrupts unless the spurious
+	 * disabled poller asks explicitely.
 	 */
-	while ((desc->status & IRQ_PENDING) && action) {
+	if ((desc->istate & IRQS_DISABLED) && !force)
+		goto out;
+
+	/*
+	 * All handlers must agree on IRQF_SHARED, so we test just the
+	 * first. Check for action->next as well.
+	 */
+	action = desc->action;
+	if (!action || !(action->flags & IRQF_SHARED) ||
+	    (action->flags & __IRQF_TIMER) || !action->next)
+		goto out;
+
+	/* Already running on another processor */
+	if (desc->istate & IRQS_INPROGRESS) {
 		/*
-		 * Perform real IRQ processing for the IRQ we deferred
+		 * Already running: If it is shared get the other
+		 * CPU to go looking for our mystery interrupt too
 		 */
-		work = 1;
-		raw_spin_unlock(&desc->lock);
-		handle_IRQ_event(irq, action);
-		raw_spin_lock(&desc->lock);
-		desc->status &= ~IRQ_PENDING;
+		irq_compat_set_pending(desc);
+		desc->istate |= IRQS_PENDING;
+		goto out;
 	}
-	desc->status &= ~IRQ_INPROGRESS;
-	/*
-	 * If we did actual work for the real IRQ line we must let the
-	 * IRQ controller clean up too
-	 */
-	if (work)
-		irq_end(irq, desc);
-	raw_spin_unlock(&desc->lock);
 
-	return ok;
+	/* Mark it poll in progress */
+	desc->istate |= IRQS_POLL_INPROGRESS;
+	do {
+		if (handle_irq_event(desc) == IRQ_HANDLED)
+			ret = IRQ_HANDLED;
+		action = desc->action;
+	} while ((desc->istate & IRQS_PENDING) && action);
+	desc->istate &= ~IRQS_POLL_INPROGRESS;
+out:
+	raw_spin_unlock(&desc->lock);
+	return ret == IRQ_HANDLED;
 }
 
 static int misrouted_irq(int irq)
@@ -92,6 +116,11 @@ static int misrouted_irq(int irq)
 	struct irq_desc *desc;
 	int i, ok = 0;
 
+	if (atomic_inc_return(&irq_poll_active) == 1)
+		goto out;
+
+	irq_poll_cpu = smp_processor_id();
+
 	for_each_irq_desc(i, desc) {
 		if (!i)
 			 continue;
@@ -99,9 +128,11 @@ static int misrouted_irq(int irq)
 		if (i == irq)	/* Already tried */
 			continue;
 
-		if (try_one_irq(i, desc))
+		if (try_one_irq(i, desc, false))
 			ok = 1;
 	}
+out:
+	atomic_dec(&irq_poll_active);
 	/* So the caller can adjust the irq error counts */
 	return ok;
 }
@@ -111,23 +142,28 @@ static void poll_spurious_irqs(unsigned long dummy)
 	struct irq_desc *desc;
 	int i;
 
+	if (atomic_inc_return(&irq_poll_active) != 1)
+		goto out;
+	irq_poll_cpu = smp_processor_id();
+
 	for_each_irq_desc(i, desc) {
-		unsigned int status;
+		unsigned int state;
 
 		if (!i)
 			 continue;
 
 		/* Racy but it doesn't matter */
-		status = desc->status;
+		state = desc->istate;
 		barrier();
-		if (!(status & IRQ_SPURIOUS_DISABLED))
+		if (!(state & IRQS_SPURIOUS_DISABLED))
 			continue;
 
 		local_irq_disable();
-		try_one_irq(i, desc);
+		try_one_irq(i, desc, true);
 		local_irq_enable();
 	}
-
+out:
+	atomic_dec(&irq_poll_active);
 	mod_timer(&poll_spurious_irq_timer,
 		  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
 }
@@ -139,15 +175,13 @@ static void poll_spurious_irqs(unsigned long dummy)
  *
  * (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
  */
-
 static void
 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
 		 irqreturn_t action_ret)
 {
 	struct irqaction *action;
+	unsigned long flags;
 
 	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
 		printk(KERN_ERR "irq event %d: bogus return value %x\n",
@@ -159,6 +193,13 @@ __report_bad_irq(unsigned int irq, struct irq_desc *desc,
 	dump_stack();
 	printk(KERN_ERR "handlers:\n");
 
+	/*
+	 * We need to take desc->lock here. note_interrupt() is called
+	 * w/o desc->lock held, but IRQ_PROGRESS set. We might race
+	 * with something else removing an action. It's ok to take
+	 * desc->lock here. See synchronize_irq().
+	 */
+	raw_spin_lock_irqsave(&desc->lock, flags);
 	action = desc->action;
 	while (action) {
 		printk(KERN_ERR "[<%p>]", action->handler);
@@ -167,6 +208,7 @@ __report_bad_irq(unsigned int irq, struct irq_desc *desc,
 		printk("\n");
 		action = action->next;
 	}
+	raw_spin_unlock_irqrestore(&desc->lock, flags);
 }
 
 static void
@@ -218,6 +260,9 @@ try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
 void note_interrupt(unsigned int irq, struct irq_desc *desc,
 		    irqreturn_t action_ret)
 {
+	if (desc->istate & IRQS_POLL_INPROGRESS)
+		return;
+
 	if (unlikely(action_ret != IRQ_HANDLED)) {
 		/*
 		 * If we are seeing only the odd spurious IRQ caused by
@@ -254,9 +299,9 @@ void note_interrupt(unsigned int irq, struct irq_desc *desc,
 		 * Now kill the IRQ
 		 */
 		printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
-		desc->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
+		desc->istate |= IRQS_SPURIOUS_DISABLED;
 		desc->depth++;
-		desc->irq_data.chip->irq_disable(&desc->irq_data);
+		irq_disable(desc);
 
 		mod_timer(&poll_spurious_irq_timer,
 			  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);