linux-kernel - [PATCH v2] genirq: Skip suspended irqs when restoring affinity

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Date: Wed, 24 Apr 2024 18:03:41 +0900
From: David Stevens <stevensd@...omium.org>
To: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-kernel@...r.kernel.org,
	David Stevens <stevensd@...omium.org>
Subject: [PATCH v2] genirq: Skip suspended irqs when restoring affinity

In irq_restore_affinity_of_irq(), skip suspended interrupts and let
resume_device_irqs() deal with restoring them. This ensures that irqs
are not delivered to drivers during the noirq phase of resuming from S3,
after non-boot CPUs are brought back online.

Signed-off-by: David Stevens <stevensd@...omium.org>
---
 kernel/irq/cpuhotplug.c | 11 ++++++++---
 kernel/irq/manage.c     | 12 ++++++++----
 2 files changed, 16 insertions(+), 7 deletions(-)

v1 -> v2:
 - Completely defer irq_startup() until __enable_irq().
diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c
index 1ed2b1739363..43340e0b6df0 100644
--- a/kernel/irq/cpuhotplug.c
+++ b/kernel/irq/cpuhotplug.c
@@ -195,10 +195,15 @@ static void irq_restore_affinity_of_irq(struct irq_desc *desc, unsigned int cpu)
 	    !irq_data_get_irq_chip(data) || !cpumask_test_cpu(cpu, affinity))
 		return;
 
-	if (irqd_is_managed_and_shutdown(data)) {
-		irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
+	/*
+	 * Don't restore suspended interrupts here when a system comes back
+	 * from S3. They are reenabled via resume_device_irqs().
+	 */
+	if (desc->istate & IRQS_SUSPENDED)
 		return;
-	}
+
+	if (irqd_is_managed_and_shutdown(data))
+		irq_startup(desc, IRQ_RESEND, IRQ_START_COND);
 
 	/*
 	 * If the interrupt can only be directed to a single target
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 1782f90cd8c6..82124f5bbe03 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -796,10 +796,14 @@ void __enable_irq(struct irq_desc *desc)
 		irq_settings_set_noprobe(desc);
 		/*
 		 * Call irq_startup() not irq_enable() here because the
-		 * interrupt might be marked NOAUTOEN. So irq_startup()
-		 * needs to be invoked when it gets enabled the first
-		 * time. If it was already started up, then irq_startup()
-		 * will invoke irq_enable() under the hood.
+		 * interrupt might be marked NOAUTOEN so irq_startup()
+		 * needs to be invoked when it gets enabled the first time.
+		 * This is also required when __enable_irq() is invoked for
+		 * a managed and shutdown interrupt from the S3 resume
+		 * path.
+		 *
+		 * If it was already started up, then irq_startup() will
+		 * invoke irq_enable() under the hood.
 		 */
 		irq_startup(desc, IRQ_RESEND, IRQ_START_FORCE);
 		break;

base-commit: e8f897f4afef0031fe618a8e94127a0934896aba
-- 
2.44.0.769.g3c40516874-goog