linux-kernel - [tip:irq/core] genirq/cpuhotplug: Do not migrated shutdown irqs

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Date:   Thu, 22 Jun 2017 09:55:28 -0700
From:   tip-bot for Thomas Gleixner <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     mpe@...erman.id.au, marc.zyngier@....com, axboe@...nel.dk,
        hpa@...or.com, hch@....de, linux-kernel@...r.kernel.org,
        peterz@...radead.org, keith.busch@...el.com, tglx@...utronix.de,
        mingo@...nel.org
Subject: [tip:irq/core] genirq/cpuhotplug: Do not migrated shutdown irqs

Commit-ID:  91f26cb4cd3c22bd656ab46c49329aacaaab5504
Gitweb:     http://git.kernel.org/tip/91f26cb4cd3c22bd656ab46c49329aacaaab5504
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Tue, 20 Jun 2017 01:37:28 +0200
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Thu, 22 Jun 2017 18:21:17 +0200

genirq/cpuhotplug: Do not migrated shutdown irqs

Interrupts, which are shut down are tried to be migrated as well. That's
pointless because the interrupt cannot fire and the next startup will move
it to the proper place anyway.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Jens Axboe <axboe@...nel.dk>
Cc: Marc Zyngier <marc.zyngier@....com>
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: Keith Busch <keith.busch@...el.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Christoph Hellwig <hch@....de>
Link: http://lkml.kernel.org/r/20170619235445.447550992@linutronix.de

---
 kernel/irq/cpuhotplug.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c
index 41fe1e0..09b20e1 100644
--- a/kernel/irq/cpuhotplug.c
+++ b/kernel/irq/cpuhotplug.c
@@ -33,10 +33,15 @@ static bool migrate_one_irq(struct irq_desc *desc)
 	}
 
 	/*
-	 * If this is a per-CPU interrupt, or the affinity does not
-	 * include this CPU, then we have nothing to do.
+	 * No move required, if:
+	 * - Interrupt is per cpu
+	 * - Interrupt is not started
+	 * - Affinity mask does not include this CPU.
+	 *
+	 * Note: Do not check desc->action as this might be a chained
+	 * interrupt.
 	 */
-	if (irqd_is_per_cpu(d) ||
+	if (irqd_is_per_cpu(d) || !irqd_is_started(d) ||
 	    !cpumask_test_cpu(smp_processor_id(), affinity))
 		return false;