return action && (action->flags & IRQF_IRQPOLL);
}
+#define SPURIOUS_DEFERRED 0x80000000
+
void note_interrupt(unsigned int irq, struct irq_desc *desc,
irqreturn_t action_ret)
{
irq_settings_is_polled(desc))
return;
- /* 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;
}
+ /*
+ * We cannot call note_interrupt from the threaded handler
+ * because we need to look at the compound of all handlers
+ * (primary and threaded). Aside of that in the threaded
+ * shared case we have no serialization against an incoming
+ * hardware interrupt while we are dealing with a threaded
+ * result.
+ *
+ * So in case a thread is woken, we just note the fact and
+ * defer the analysis to the next hardware interrupt.
+ *
+ * The threaded handlers store whether they sucessfully
+ * handled an interrupt and we check whether that number
+ * changed versus the last invocation.
+ *
+ * We could handle all interrupts with the delayed by one
+ * mechanism, but for the non forced threaded case we'd just
+ * add pointless overhead to the straight hardirq interrupts
+ * for the sake of a few lines less code.
+ */
+ if (action_ret & IRQ_WAKE_THREAD) {
+ /*
+ * There is a thread woken. Check whether one of the
+ * shared primary handlers returned IRQ_HANDLED. If
+ * not we defer the spurious detection to the next
+ * interrupt.
+ */
+ if (action_ret == IRQ_WAKE_THREAD) {
+ int handled;
+ /*
+ * We use bit 31 of thread_handled_last to
+ * denote the deferred spurious detection
+ * active. No locking necessary as
+ * thread_handled_last is only accessed here
+ * and we have the guarantee that hard
+ * interrupts are not reentrant.
+ */
+ if (!(desc->threads_handled_last & SPURIOUS_DEFERRED)) {
+ desc->threads_handled_last |= SPURIOUS_DEFERRED;
+ return;
+ }
+ /*
+ * Check whether one of the threaded handlers
+ * returned IRQ_HANDLED since the last
+ * interrupt happened.
+ *
+ * For simplicity we just set bit 31, as it is
+ * set in threads_handled_last as well. So we
+ * avoid extra masking. And we really do not
+ * care about the high bits of the handled
+ * count. We just care about the count being
+ * different than the one we saw before.
+ */
+ handled = atomic_read(&desc->threads_handled);
+ handled |= SPURIOUS_DEFERRED;
+ if (handled != desc->threads_handled_last) {
+ action_ret = IRQ_HANDLED;
+ /*
+ * Note: We keep the SPURIOUS_DEFERRED
+ * bit set. We are handling the
+ * previous invocation right now.
+ * Keep it for the current one, so the
+ * next hardware interrupt will
+ * account for it.
+ */
+ desc->threads_handled_last = handled;
+ } else {
+ /*
+ * None of the threaded handlers felt
+ * responsible for the last interrupt
+ *
+ * We keep the SPURIOUS_DEFERRED bit
+ * set in threads_handled_last as we
+ * need to account for the current
+ * interrupt as well.
+ */
+ action_ret = IRQ_NONE;
+ }
+ } else {
+ /*
+ * One of the primary handlers returned
+ * IRQ_HANDLED. So we don't care about the
+ * threaded handlers on the same line. Clear
+ * the deferred detection bit.
+ *
+ * In theory we could/should check whether the
+ * deferred bit is set and take the result of
+ * the previous run into account here as
+ * well. But it's really not worth the
+ * trouble. If every other interrupt is
+ * handled we never trigger the spurious
+ * detector. And if this is just the one out
+ * of 100k unhandled ones which is handled
+ * then we merily delay the spurious detection
+ * by one hard interrupt. Not a real problem.
+ */
+ desc->threads_handled_last &= ~SPURIOUS_DEFERRED;
+ }
+ }
+
if (unlikely(action_ret == IRQ_NONE)) {
/*
* If we are seeing only the odd spurious IRQ caused by
projects / platform / adaptation / renesas_rcar / renesas_kernel.git / blobdiff