linux-kernel - [GIT PULL] IRQ fixes

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Date:   Sat, 14 Oct 2017 17:57:08 +0200
From:   Ingo Molnar <mingo@...nel.org>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] IRQ fixes

Linus,

Please pull the latest irq-urgent-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git irq-urgent-for-linus

   # HEAD: e43b3b58548051f8809391eb7bec7a27ed3003ea genirq/cpuhotplug: Enforce affinity setting on startup of managed irqs

A CPU hotplug related fix, plus two related sanity checks.

 Thanks,

	Ingo

------------------>
Thomas Gleixner (3):
      genirq: Warn when effective affinity is not updated
      genirq/cpuhotplug: Add sanity check for effective affinity mask
      genirq/cpuhotplug: Enforce affinity setting on startup of managed irqs


 kernel/irq/chip.c       |  2 +-
 kernel/irq/cpuhotplug.c | 28 +++++++++++++++++++++++++++-
 kernel/irq/manage.c     | 17 +++++++++++++++++
 3 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 6fc89fd93824..5a2ef92c2782 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -265,8 +265,8 @@ int irq_startup(struct irq_desc *desc, bool resend, bool force)
 			irq_setup_affinity(desc);
 			break;
 		case IRQ_STARTUP_MANAGED:
+			irq_do_set_affinity(d, aff, false);
 			ret = __irq_startup(desc);
-			irq_set_affinity_locked(d, aff, false);
 			break;
 		case IRQ_STARTUP_ABORT:
 			return 0;
diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c
index 638eb9c83d9f..9eb09aef0313 100644
--- a/kernel/irq/cpuhotplug.c
+++ b/kernel/irq/cpuhotplug.c
@@ -18,8 +18,34 @@
 static inline bool irq_needs_fixup(struct irq_data *d)
 {
 	const struct cpumask *m = irq_data_get_effective_affinity_mask(d);
+	unsigned int cpu = smp_processor_id();
 
-	return cpumask_test_cpu(smp_processor_id(), m);
+#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	/*
+	 * The cpumask_empty() check is a workaround for interrupt chips,
+	 * which do not implement effective affinity, but the architecture has
+	 * enabled the config switch. Use the general affinity mask instead.
+	 */
+	if (cpumask_empty(m))
+		m = irq_data_get_affinity_mask(d);
+
+	/*
+	 * Sanity check. If the mask is not empty when excluding the outgoing
+	 * CPU then it must contain at least one online CPU. The outgoing CPU
+	 * has been removed from the online mask already.
+	 */
+	if (cpumask_any_but(m, cpu) < nr_cpu_ids &&
+	    cpumask_any_and(m, cpu_online_mask) >= nr_cpu_ids) {
+		/*
+		 * If this happens then there was a missed IRQ fixup at some
+		 * point. Warn about it and enforce fixup.
+		 */
+		pr_warn("Eff. affinity %*pbl of IRQ %u contains only offline CPUs after offlining CPU %u\n",
+			cpumask_pr_args(m), d->irq, cpu);
+		return true;
+	}
+#endif
+	return cpumask_test_cpu(cpu, m);
 }
 
 static bool migrate_one_irq(struct irq_desc *desc)
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index d00132b5c325..4bff6a10ae8e 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -168,6 +168,19 @@ void irq_set_thread_affinity(struct irq_desc *desc)
 			set_bit(IRQTF_AFFINITY, &action->thread_flags);
 }
 
+static void irq_validate_effective_affinity(struct irq_data *data)
+{
+#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	const struct cpumask *m = irq_data_get_effective_affinity_mask(data);
+	struct irq_chip *chip = irq_data_get_irq_chip(data);
+
+	if (!cpumask_empty(m))
+		return;
+	pr_warn_once("irq_chip %s did not update eff. affinity mask of irq %u\n",
+		     chip->name, data->irq);
+#endif
+}
+
 int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
 			bool force)
 {
@@ -175,12 +188,16 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
 	struct irq_chip *chip = irq_data_get_irq_chip(data);
 	int ret;
 
+	if (!chip || !chip->irq_set_affinity)
+		return -EINVAL;
+
 	ret = chip->irq_set_affinity(data, mask, force);
 	switch (ret) {
 	case IRQ_SET_MASK_OK:
 	case IRQ_SET_MASK_OK_DONE:
 		cpumask_copy(desc->irq_common_data.affinity, mask);
 	case IRQ_SET_MASK_OK_NOCOPY:
+		irq_validate_effective_affinity(data);
 		irq_set_thread_affinity(desc);
 		ret = 0;
 	}