[GIT pull] irq fixes for 4.18

[Thomas Gleixner]

Linus,

please pull the latest irq-urgent-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git irq-urgent-for-linus

A single bugfix for the irq core to prevent silent data corruption and
malfunction of threaded interrupts under certain conditions.

Thanks,

	tglx

------------------>
Thomas Gleixner (1):
      genirq: Make force irq threading setup more robust


 kernel/irq/manage.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index daeabd791d58..9a8b7ba9aa88 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1068,6 +1068,13 @@ static int irq_setup_forced_threading(struct irqaction *new)
 	if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
 		return 0;
 
+	/*
+	 * No further action required for interrupts which are requested as
+	 * threaded interrupts already
+	 */
+	if (new->handler == irq_default_primary_handler)
+		return 0;
+
 	new->flags |= IRQF_ONESHOT;
 
 	/*
@@ -1075,7 +1082,7 @@ static int irq_setup_forced_threading(struct irqaction *new)
 	 * thread handler. We force thread them as well by creating a
 	 * secondary action.
 	 */
-	if (new->handler != irq_default_primary_handler && new->thread_fn) {
+	if (new->handler && new->thread_fn) {
 		/* Allocate the secondary action */
 		new->secondary = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
 		if (!new->secondary)