This is a note to let you know that I've just added the patch titled
genirq: Add IRQF_NO_AUTOEN for request_irq/nmi()
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
genirq-add-irqf_no_autoen-for-request_irq-nmi.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 238632ec9b3ae3daca6155bc92358be3c59b3d54
Author: Barry Song <song.bao.hua@xxxxxxxxxxxxx>
Date: Wed Mar 3 11:49:15 2021 +1300
genirq: Add IRQF_NO_AUTOEN for request_irq/nmi()
[ Upstream commit cbe16f35bee6880becca6f20d2ebf6b457148552 ]
Many drivers don't want interrupts enabled automatically via request_irq().
So they are handling this issue by either way of the below two:
(1)
irq_set_status_flags(irq, IRQ_NOAUTOEN);
request_irq(dev, irq...);
(2)
request_irq(dev, irq...);
disable_irq(irq);
The code in the second way is silly and unsafe. In the small time gap
between request_irq() and disable_irq(), interrupts can still come.
The code in the first way is safe though it's subobtimal.
Add a new IRQF_NO_AUTOEN flag which can be handed in by drivers to
request_irq() and request_nmi(). It prevents the automatic enabling of the
requested interrupt/nmi in the same safe way as #1 above. With that the
various usage sites of #1 and #2 above can be simplified and corrected.
Signed-off-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: dmitry.torokhov@xxxxxxxxx
Link: https://lore.kernel.org/r/20210302224916.13980-2-song.bao.hua@xxxxxxxxxxxxx
Stable-dep-of: 99c05e4283a1 ("iio: adis: add '__adis_enable_irq()' implementation")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index ee8299eb1f52..0652b4858ba6 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -61,6 +61,9 @@
* interrupt handler after suspending interrupts. For system
* wakeup devices users need to implement wakeup detection in
* their interrupt handlers.
+ * IRQF_NO_AUTOEN - Don't enable IRQ or NMI automatically when users request it.
+ * Users will enable it explicitly by enable_irq() or enable_nmi()
+ * later.
*/
#define IRQF_SHARED 0x00000080
#define IRQF_PROBE_SHARED 0x00000100
@@ -74,6 +77,7 @@
#define IRQF_NO_THREAD 0x00010000
#define IRQF_EARLY_RESUME 0x00020000
#define IRQF_COND_SUSPEND 0x00040000
+#define IRQF_NO_AUTOEN 0x00080000
#define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 3cb29835632f..437b073dc487 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1667,7 +1667,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
}
- if (irq_settings_can_autoenable(desc)) {
+ if (!(new->flags & IRQF_NO_AUTOEN) &&
+ irq_settings_can_autoenable(desc)) {
irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
} else {
/*
@@ -2054,10 +2055,15 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler,
* which interrupt is which (messes up the interrupt freeing
* logic etc).
*
+ * Also shared interrupts do not go well with disabling auto enable.
+ * The sharing interrupt might request it while it's still disabled
+ * and then wait for interrupts forever.
+ *
* Also IRQF_COND_SUSPEND only makes sense for shared interrupts and
* it cannot be set along with IRQF_NO_SUSPEND.
*/
if (((irqflags & IRQF_SHARED) && !dev_id) ||
+ ((irqflags & IRQF_SHARED) && (irqflags & IRQF_NO_AUTOEN)) ||
(!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||
((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))
return -EINVAL;
@@ -2213,7 +2219,8 @@ int request_nmi(unsigned int irq, irq_handler_t handler,
desc = irq_to_desc(irq);
- if (!desc || irq_settings_can_autoenable(desc) ||
+ if (!desc || (irq_settings_can_autoenable(desc) &&
+ !(irqflags & IRQF_NO_AUTOEN)) ||
!irq_settings_can_request(desc) ||
WARN_ON(irq_settings_is_per_cpu_devid(desc)) ||
!irq_supports_nmi(desc))
