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

Pull irq fixes from Ingo Molnar:
 "Affinity fixes and a nested threaded IRQ handling fix."

* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Always force thread affinity
  irq: Set CPU affinity right on thread creation
  genirq: Provide means to retrigger parent

3 files changed, 48 insertions, 2 deletions

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 57d86d07221..3aca9f29d30 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -272,6 +272,7 @@ void handle_nested_irq(unsigned int irq)
 
         raw_spin_lock_irq(&desc->lock);
 
+        desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
         kstat_incr_irqs_this_cpu(irq, desc);
 
         action = desc->action;
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 4c69326aa77..35c70c9e24d 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -616,6 +616,22 @@ int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
         return ret;
 }
 
+#ifdef CONFIG_HARDIRQS_SW_RESEND
+int irq_set_parent(int irq, int parent_irq)
+{
+        unsigned long flags;
+        struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
+
+        if (!desc)
+                return -EINVAL;
+
+        desc->parent_irq = parent_irq;
+
+        irq_put_desc_unlock(desc, flags);
+        return 0;
+}
+#endif
+
 /*
  * Default primary interrupt handler for threaded interrupts. Is
  * assigned as primary handler when request_threaded_irq is called
@@ -716,6 +732,7 @@ static void
 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
 {
         cpumask_var_t mask;
+        bool valid = true;
 
         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
                 return;
@@ -730,10 +747,18 @@ irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
         }
 
         raw_spin_lock_irq(&desc->lock);
-        cpumask_copy(mask, desc->irq_data.affinity);
+        /*
+         * This code is triggered unconditionally. Check the affinity
+         * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
+         */
+        if (desc->irq_data.affinity)
+                cpumask_copy(mask, desc->irq_data.affinity);
+        else
+                valid = false;
         raw_spin_unlock_irq(&desc->lock);
 
-        set_cpus_allowed_ptr(current, mask);
+        if (valid)
+                set_cpus_allowed_ptr(current, mask);
         free_cpumask_var(mask);
 }
 #else
@@ -833,6 +858,8 @@ static int irq_thread(void *data)
         init_task_work(&on_exit_work, irq_thread_dtor);
         task_work_add(current, &on_exit_work, false);
 
+        irq_thread_check_affinity(desc, action);
+
         while (!irq_wait_for_interrupt(action)) {
                 irqreturn_t action_ret;
 
@@ -936,6 +963,16 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
                  */
                 get_task_struct(t);
                 new->thread = t;
+                /*
+                 * Tell the thread to set its affinity. This is
+                 * important for shared interrupt handlers as we do
+                 * not invoke setup_affinity() for the secondary
+                 * handlers as everything is already set up. Even for
+                 * interrupts marked with IRQF_NO_BALANCE this is
+                 * correct as we want the thread to move to the cpu(s)
+                 * on which the requesting code placed the interrupt.
+                 */
+                set_bit(IRQTF_AFFINITY, &new->thread_flags);
         }
 
         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
diff --git a/kernel/irq/resend.c b/kernel/irq/resend.c
index 6454db7b6a4..9065107f083 100644
--- a/kernel/irq/resend.c
+++ b/kernel/irq/resend.c
@@ -74,6 +74,14 @@ void check_irq_resend(struct irq_desc *desc, unsigned int irq)
                 if (!desc->irq_data.chip->irq_retrigger ||
                     !desc->irq_data.chip->irq_retrigger(&desc->irq_data)) {
 #ifdef CONFIG_HARDIRQS_SW_RESEND
+                        /*
+                         * If the interrupt has a parent irq and runs
+                         * in the thread context of the parent irq,
+                         * retrigger the parent.
+                         */
+                        if (desc->parent_irq &&
+                            irq_settings_is_nested_thread(desc))
+                                irq = desc->parent_irq;
                         /* Set it pending and activate the softirq: */
                         set_bit(irq, irqs_resend);
                         tasklet_schedule(&resend_tasklet);