[tip:irq/urgent] genirq: Skip chained interrupt trigger setup if type is IRQ_TYPE_NONE

[tip-bot for Marc Zyngier <tipbot@zytor.com>]

Commit-ID:  e2a5069355e5e3c0644a831d3e690049c4d0624b
Gitweb:     http://git.kernel.org/tip/e2a5069355e5e3c0644a831d3e690049c4d0624b
Author:     Marc Zyngier <marc.zyngier@arm.com>
AuthorDate: Mon, 19 Sep 2016 09:49:27 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 20 Sep 2016 01:04:49 +0200

genirq: Skip chained interrupt trigger setup if type is IRQ_TYPE_NONE

There is no point in trying to configure the trigger of a chained
interrupt if no trigger information has been configured. At best
this is ignored, and at the worse this confuses the underlying
irqchip (which is likely not to handle such a thing), and
unnecessarily alarms the user.

Only apply the configuration if type is not IRQ_TYPE_NONE.

Fixes: 1e12c4a9393b ("genirq: Correctly configure the trigger on chained interrupts")
Reported-and-tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/CAMuHMdVW1eTn20=EtYcJ8hkVwohaSuH_yQXrY2MGBEvZ8fpFOg@mail.gmail.com
Link: http://lkml.kernel.org/r/1474274967-15984-1-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 drivers/irqchip/irq-gic-v3.c | 7 ++++---
 kernel/irq/chip.c            | 8 ++++++--
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index ede5672..da6c0ba 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -548,7 +548,7 @@ static int gic_starting_cpu(unsigned int cpu)
 static u16 gic_compute_target_list(int *base_cpu, const struct cpumask *mask,
 				   unsigned long cluster_id)
 {
-	int cpu = *base_cpu;
+	int next_cpu, cpu = *base_cpu;
 	unsigned long mpidr = cpu_logical_map(cpu);
 	u16 tlist = 0;
 
@@ -562,9 +562,10 @@ static u16 gic_compute_target_list(int *base_cpu, const struct cpumask *mask,
 
 		tlist |= 1 << (mpidr & 0xf);
 
-		cpu = cpumask_next(cpu, mask);
-		if (cpu >= nr_cpu_ids)
+		next_cpu = cpumask_next(cpu, mask);
+		if (next_cpu >= nr_cpu_ids)
 			goto out;
+		cpu = next_cpu;
 
 		mpidr = cpu_logical_map(cpu);
 
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 6373890..26ba565 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -820,6 +820,8 @@ __irq_do_set_handler(struct irq_desc *desc, irq_flow_handler_t handle,
 	desc->name = name;
 
 	if (handle != handle_bad_irq && is_chained) {
+		unsigned int type = irqd_get_trigger_type(&desc->irq_data);
+
 		/*
 		 * We're about to start this interrupt immediately,
 		 * hence the need to set the trigger configuration.
@@ -828,8 +830,10 @@ __irq_do_set_handler(struct irq_desc *desc, irq_flow_handler_t handle,
 		 * chained interrupt. Reset it immediately because we
 		 * do know better.
 		 */
-		__irq_set_trigger(desc, irqd_get_trigger_type(&desc->irq_data));
-		desc->handle_irq = handle;
+		if (type != IRQ_TYPE_NONE) {
+			__irq_set_trigger(desc, type);
+			desc->handle_irq = handle;
+		}
 
 		irq_settings_set_noprobe(desc);
 		irq_settings_set_norequest(desc);