genirq: Mark polled irqs and defer the real handler

With the chip.end() function gone we might run into a situation where
a poll call runs and the real interrupt comes in, sees IRQ_INPROGRESS
and disables the line. That might be a perfect working one, which will
then be masked forever.

So mark them polled while the poll runs. When the real handler sees
IRQ_INPROGRESS it checks the poll flag and waits for the polling to
complete. Add the necessary amount of sanity checks to it to avoid
deadlocks.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 20 insertions, 6 deletions

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 622b55ac0e09..31258782742c 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -448,6 +448,13 @@ out_unlock:
 }
 EXPORT_SYMBOL_GPL(handle_nested_irq);
 
+static bool irq_check_poll(struct irq_desc *desc)
+{
+        if (!(desc->status & IRQ_POLL_INPROGRESS))
+                return false;
+        return irq_wait_for_poll(desc);
+}
+
 /**
  *      handle_simple_irq - Simple and software-decoded IRQs.
  *      @irq:   the interrupt number
@@ -469,7 +476,9 @@ handle_simple_irq(unsigned int irq, struct irq_desc *desc)
         raw_spin_lock(&desc->lock);
 
         if (unlikely(desc->status & IRQ_INPROGRESS))
-                goto out_unlock;
+                if (!irq_check_poll(desc))
+                        goto out_unlock;
+
         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
         kstat_incr_irqs_this_cpu(irq, desc);
 
@@ -510,7 +519,9 @@ handle_level_irq(unsigned int irq, struct irq_desc *desc)
         mask_ack_irq(desc);
 
         if (unlikely(desc->status & IRQ_INPROGRESS))
-                goto out_unlock;
+                if (!irq_check_poll(desc))
+                        goto out_unlock;
+
         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
         kstat_incr_irqs_this_cpu(irq, desc);
 
@@ -558,7 +569,8 @@ handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
         raw_spin_lock(&desc->lock);
 
         if (unlikely(desc->status & IRQ_INPROGRESS))
-                goto out;
+                if (!irq_check_poll(desc))
+                        goto out;
 
         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
         kstat_incr_irqs_this_cpu(irq, desc);
@@ -620,9 +632,11 @@ handle_edge_irq(unsigned int irq, struct irq_desc *desc)
          */
         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
                     !desc->action)) {
-                desc->status |= (IRQ_PENDING | IRQ_MASKED);
-                mask_ack_irq(desc);
-                goto out_unlock;
+                if (!irq_check_poll(desc)) {
+                        desc->status |= (IRQ_PENDING | IRQ_MASKED);
+                        mask_ack_irq(desc);
+                        goto out_unlock;
+                }
         }
         kstat_incr_irqs_this_cpu(irq, desc);