Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq fixes from Ingo Molnar:
 "A CPU hotplug related fix, plus two related sanity checks"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq/cpuhotplug: Enforce affinity setting on startup of managed irqs
  genirq/cpuhotplug: Add sanity check for effective affinity mask
  genirq: Warn when effective affinity is not updated

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;
         }