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Commit f5ce428e authored by Barry Song's avatar Barry Song Committed by Greg Kroah-Hartman
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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: default avatarBarry Song <song.bao.hua@hisilicon.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: dmitry.torokhov@gmail.com
Link: https://lore.kernel.org/r/20210302224916.13980-2-song.bao.hua@hisilicon.com


Stable-dep-of: 39db65a0a17b ("ASoC: es8316: Handle optional IRQ assignment")
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 0f319937

include/linux/interrupt.h

+4 −0
Original line number Original line Diff line number Diff line
@@ -61,6 +61,9 @@ 
 *                interrupt handler after suspending interrupts. For system

 *                interrupt handler after suspending interrupts. For system

 *                wakeup devices users need to implement wakeup detection in

 *                wakeup devices users need to implement wakeup detection in

 *                their interrupt handlers.

 *                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_SHARED		0x00000080

#define IRQF_PROBE_SHARED	0x00000100

#define IRQF_PROBE_SHARED	0x00000100
@@ -74,6 +77,7 @@ 
#define IRQF_NO_THREAD		0x00010000

#define IRQF_NO_THREAD		0x00010000

#define IRQF_EARLY_RESUME	0x00020000

#define IRQF_EARLY_RESUME	0x00020000

#define IRQF_COND_SUSPEND	0x00040000

#define IRQF_COND_SUSPEND	0x00040000

#define IRQF_NO_AUTOEN		0x00080000





#define IRQF_TIMER		(__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)

#define IRQF_TIMER		(__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)

kernel/irq/manage.c

+9 −2
Original line number Original line Diff line number Diff line
@@ -1610,7 +1610,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) 
			irqd_set(&desc->irq_data, IRQD_NO_BALANCING);

			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);

			irq_startup(desc, IRQ_RESEND, IRQ_START_COND);

		} else {

		} else {

			/*

			/*
@@ -2041,10 +2042,15 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler, 
	 * which interrupt is which (messes up the interrupt freeing

	 * which interrupt is which (messes up the interrupt freeing

	 * logic etc).

	 * 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

	 * Also IRQF_COND_SUSPEND only makes sense for shared interrupts and

	 * it cannot be set along with IRQF_NO_SUSPEND.

	 * it cannot be set along with IRQF_NO_SUSPEND.

	 */

	 */

	if (((irqflags & IRQF_SHARED) && !dev_id) ||

	if (((irqflags & IRQF_SHARED) && !dev_id) ||

	    ((irqflags & IRQF_SHARED) && (irqflags & IRQF_NO_AUTOEN)) ||

	    (!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||

	    (!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||

	    ((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))

	    ((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))

		return -EINVAL;

		return -EINVAL;
@@ -2200,7 +2206,8 @@ int request_nmi(unsigned int irq, irq_handler_t handler, 




	desc = irq_to_desc(irq);

	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) ||

	    !irq_settings_can_request(desc) ||

	    WARN_ON(irq_settings_is_per_cpu_devid(desc)) ||

	    WARN_ON(irq_settings_is_per_cpu_devid(desc)) ||

	    !irq_supports_nmi(desc))

	    !irq_supports_nmi(desc))