[PATCH 2/2] genirq: Resend nested irq's ancestor irq

[Ning Jiang]

We'll set IRQS_PENDING for handle_nested_irq if it's disabled. When
it's re-enabled later on, check_irq_resend() will detect this flag
and trigger the software resend mechanism. resend_irqs() will call
desc->handle_irq() directly to process this interrupt, hence the
irq_nested_primary_handler() will be called for the nested irq which
gives us a warning.

If we need to resend a nested interrupt, we have to trace all the
way back to its ancestor and trigger ancestor's irq flow handler.

Signed-off-by: Ning Jiang <ning.n.jiang@xxxxxxxxx>
---
 kernel/irq/resend.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/kernel/irq/resend.c b/kernel/irq/resend.c
index 6454db7..dcfc1b5 100644
--- a/kernel/irq/resend.c
+++ b/kernel/irq/resend.c
@@ -74,6 +74,11 @@ void check_irq_resend(struct irq_desc *desc, unsigned int irq)
 		if (!desc->irq_data.chip->irq_retrigger ||
 		    !desc->irq_data.chip->irq_retrigger(&desc->irq_data)) {
 #ifdef CONFIG_HARDIRQS_SW_RESEND
+			while (irq_settings_is_nested_thread(desc) &&
+				(desc->irq_data.parent_irq != NO_IRQ)) {
+				irq = desc->irq_data.parent_irq;
+				desc = irq_to_desc(irq);
+			}
 			/* Set it pending and activate the softirq: */
 			set_bit(irq, irqs_resend);
 			tasklet_schedule(&resend_tasklet);
-- 
1.7.1

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