From 89d694b9dbe769ca1004e01db0ca43964806a611 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 18 Feb 2008 18:25:17 +0100
Subject: [PATCH] genirq: do not leave interupts enabled on free_irq
The default_disable() function was changed in commit:
76d2160147f43f982dfe881404cfde9fd0a9da21
genirq: do not mask interrupts by default
It removed the mask function in favour of the default delayed
interrupt disabling. Unfortunately this also broke the shutdown in
free_irq() when the last handler is removed from the interrupt for
those architectures which rely on the default implementations. Now we
can end up with a enabled interrupt line after the last handler was
removed, which can result in spurious interrupts.
Fix this by adding a default_shutdown function, which is only
installed, when the irqchip implementation does provide neither a
shutdown nor a disable function.
[@stable: affected versions: .21 - .24 ]
Pointed-out-by: Michael Hennerich <Michael.Hennerich@analog.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: stable@kernel.org
Tested-by: Michael Hennerich <Michael.Hennerich@analog.com>
---
kernel/irq/chip.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index cc54c627635..fdb3fbe2b0c 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -245,6 +245,17 @@ static unsigned int default_startup(unsigned int irq)
return 0;
}
+/*
+ * default shutdown function
+ */
+static void default_shutdown(unsigned int irq)
+{
+ struct irq_desc *desc = irq_desc + irq;
+
+ desc->chip->mask(irq);
+ desc->status |= IRQ_MASKED;
+}
+
/*
* Fixup enable/disable function pointers
*/
@@ -256,8 +267,15 @@ void irq_chip_set_defaults(struct irq_chip *chip)
chip->disable = default_disable;
if (!chip->startup)
chip->startup = default_startup;
+ /*
+ * We use chip->disable, when the user provided its own. When
+ * we have default_disable set for chip->disable, then we need
+ * to use default_shutdown, otherwise the irq line is not
+ * disabled on free_irq():
+ */
if (!chip->shutdown)
- chip->shutdown = chip->disable;
+ chip->shutdown = chip->disable != default_disable ?
+ chip->disable : default_shutdown;
if (!chip->name)
chip->name = chip->typename;
if (!chip->end)
--
2.41.3