From ec7099fdea8025988710ee6fecfd4e4210c29ab5 Mon Sep 17 00:00:00 2001
From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Date: Fri, 2 Jul 2021 15:37:12 +0200
Subject: [PATCH] Revert "gpio: mpc8xxx: change the gpio interrupt flags."
Git-commit: ec7099fdea8025988710ee6fecfd4e4210c29ab5
Patch-mainline: v5.14-rc5
References: git-fixes
This reverts commit 3d5bfbd9716318b1ca5c38488aa69f64d38a9aa5.
When booting with threadirqs, it causes a splat
WARNING: CPU: 0 PID: 29 at kernel/irq/handle.c:159 __handle_irq_event_percpu+0x1ec/0x27c
irq 66 handler irq_default_primary_handler+0x0/0x1c enabled interrupts
That splat later went away with commit 81e2073c175b ("genirq: Disable
interrupts for force threaded handlers"), which got backported to
-stable. However, when running an -rt kernel, the splat still
exists. Moreover, quoting Thomas Gleixner [1]
But 3d5bfbd97163 ("gpio: mpc8xxx: change the gpio interrupt flags.")
has nothing to do with that:
"Delete the interrupt IRQF_NO_THREAD flags in order to gpio interrupts
can be threaded to allow high-priority processes to preempt."
This changelog is blatantly wrong. In mainline forced irq threads
have always been invoked with softirqs disabled, which obviously
makes them non-preemptible.
So the patch didn't even do what its commit log said.
[1] https://lore.kernel.org/lkml/871r8zey88.ffs@nanos.tec.linutronix.de/
Cc: stable@vger.kernel.org # v5.9+
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpio/gpio-mpc8xxx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/gpio/gpio-mpc8xxx.c
+++ b/drivers/gpio/gpio-mpc8xxx.c
@@ -396,7 +396,7 @@ static int mpc8xxx_probe(struct platform
ret = devm_request_irq(&pdev->dev, mpc8xxx_gc->irqn,
mpc8xxx_gpio_irq_cascade,
- IRQF_SHARED, "gpio-cascade",
+ IRQF_NO_THREAD | IRQF_SHARED, "gpio-cascade",
mpc8xxx_gc);
if (ret) {
dev_err(&pdev->dev, "%s: failed to devm_request_irq(%d), ret = %d\n",