[GIT PULL] IRQ fixes

From: Ingo Molnar
Date: Sat Oct 14 2017 - 11:57:16 EST


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;
}