linux-kernel - genirq: Consider domain hierarchy when checking for IRQCHIP_ONESHOT

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Date:   Fri, 3 Aug 2018 21:12:14 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Marc Zyngier <marc.zyngier@....com>
Subject: genirq: Consider domain hierarchy when checking for
 IRQCHIP_ONESHOT_SAFE

In case of a domain hierarchy we may miss the IRQCHIP_ONESHOT_SAFE
flag because we look at top of the stack only. See also discussion
here: https://marc.info/?l=linux-kernel&m=153301773524685&w=2

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
 kernel/irq/manage.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index a66c58f9..1a28f068 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1156,6 +1156,16 @@ setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary)
 	return 0;
 }
 
+static bool irq_data_oneshot_safe(struct irq_data *data)
+{
+#ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
+	/* check topmost irq_chip only */
+	while (data->parent_data)
+		data = data->parent_data;
+#endif
+	return !!(data->chip->flags & IRQCHIP_ONESHOT_SAFE);
+}
+
 /*
  * Internal function to register an irqaction - typically used to
  * allocate special interrupts that are part of the architecture.
@@ -1243,7 +1253,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 	 * chip flags, so we can avoid the unmask dance at the end of
 	 * the threaded handler for those.
 	 */
-	if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
+	if (irq_data_oneshot_safe(&desc->irq_data))
 		new->flags &= ~IRQF_ONESHOT;
 
 	/*
-- 
2.18.0