irq: Handle spurios irq detection for threaded irqs

The detection of spurios interrupts is currently limited to first level
handler. In force-threaded mode we never notice if the threaded irq does
not feel responsible.
This patch catches the return value of the threaded handler and forwards
it to the spurious detector. If the primary handler returns only
IRQ_WAKE_THREAD then the spourious detector ignores it because it gets
called again from the threaded handler.

[ tglx: Report the erroneous return value early and bail out ]

Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Link: http://lkml.kernel.org/r/1306824972-27067-2-git-send-email-sebastian@breakpoint.cc
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 18 insertions, 4 deletions

diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c
index c9a78ba30b6f..aa57d5da18c1 100644
--- a/kernel/irq/spurious.c
+++ b/kernel/irq/spurious.c
@@ -167,6 +167,13 @@ out:
                   jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
 }
 
+static inline int bad_action_ret(irqreturn_t action_ret)
+{
+        if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
+                return 0;
+        return 1;
+}
+
 /*
  * 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
@@ -182,7 +189,7 @@ __report_bad_irq(unsigned int irq, struct irq_desc *desc,
         struct irqaction *action;
         unsigned long flags;
 
-        if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
+        if (bad_action_ret(action_ret)) {
                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
                                 irq, action_ret);
         } else {
@@ -263,7 +270,16 @@ void note_interrupt(unsigned int irq, struct irq_desc *desc,
         if (desc->istate & IRQS_POLL_INPROGRESS)
                 return;
 
-        if (unlikely(action_ret != IRQ_HANDLED)) {
+        /* we get here again via the threaded handler */
+        if (action_ret == IRQ_WAKE_THREAD)
+                return;
+
+        if (bad_action_ret(action_ret)) {
+                report_bad_irq(irq, desc, action_ret);
+                return;
+        }
+
+        if (unlikely(action_ret == IRQ_NONE)) {
                 /*
                  * If we are seeing only the odd spurious IRQ caused by
                  * bus asynchronicity then don't eventually trigger an error,
@@ -275,8 +291,6 @@ void note_interrupt(unsigned int irq, struct irq_desc *desc,
                 else
                         desc->irqs_unhandled++;
                 desc->last_unhandled = jiffies;
-                if (unlikely(action_ret != IRQ_NONE))
-                        report_bad_irq(irq, desc, action_ret);
         }
 
         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {