1 files changed, 64 insertions, 18 deletions

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 50da67672901..0ec9ed831737 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -80,14 +80,22 @@ int irq_can_set_affinity(unsigned int irq)
         return 1;
 }
 
-void
-irq_set_thread_affinity(struct irq_desc *desc, const struct cpumask *cpumask)
+/**
+ *      irq_set_thread_affinity - Notify irq threads to adjust affinity
+ *      @desc:          irq descriptor which has affitnity changed
+ *
+ *      We just set IRQTF_AFFINITY and delegate the affinity setting
+ *      to the interrupt thread itself. We can not call
+ *      set_cpus_allowed_ptr() here as we hold desc->lock and this
+ *      code can be called from hard interrupt context.
+ */
+void irq_set_thread_affinity(struct irq_desc *desc)
 {
         struct irqaction *action = desc->action;
 
         while (action) {
                 if (action->thread)
-                        set_cpus_allowed_ptr(action->thread, cpumask);
+                        set_bit(IRQTF_AFFINITY, &action->thread_flags);
                 action = action->next;
         }
 }
@@ -112,7 +120,7 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
         if (desc->status & IRQ_MOVE_PCNTXT) {
                 if (!desc->chip->set_affinity(irq, cpumask)) {
                         cpumask_copy(desc->affinity, cpumask);
-                        irq_set_thread_affinity(desc, cpumask);
+                        irq_set_thread_affinity(desc);
                 }
         }
         else {
@@ -122,7 +130,7 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
 #else
         if (!desc->chip->set_affinity(irq, cpumask)) {
                 cpumask_copy(desc->affinity, cpumask);
-                irq_set_thread_affinity(desc, cpumask);
+                irq_set_thread_affinity(desc);
         }
 #endif
         desc->status |= IRQ_AFFINITY_SET;
@@ -176,7 +184,7 @@ int irq_select_affinity_usr(unsigned int irq)
         spin_lock_irqsave(&desc->lock, flags);
         ret = setup_affinity(irq, desc);
         if (!ret)
-                irq_set_thread_affinity(desc, desc->affinity);
+                irq_set_thread_affinity(desc);
         spin_unlock_irqrestore(&desc->lock, flags);
 
         return ret;
@@ -443,6 +451,39 @@ static int irq_wait_for_interrupt(struct irqaction *action)
         return -1;
 }
 
+#ifdef CONFIG_SMP
+/*
+ * Check whether we need to change the affinity of the interrupt thread.
+ */
+static void
+irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
+{
+        cpumask_var_t mask;
+
+        if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
+                return;
+
+        /*
+         * In case we are out of memory we set IRQTF_AFFINITY again and
+         * try again next time
+         */
+        if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
+                set_bit(IRQTF_AFFINITY, &action->thread_flags);
+                return;
+        }
+
+        spin_lock_irq(&desc->lock);
+        cpumask_copy(mask, desc->affinity);
+        spin_unlock_irq(&desc->lock);
+
+        set_cpus_allowed_ptr(current, mask);
+        free_cpumask_var(mask);
+}
+#else
+static inline void
+irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
+#endif
+
 /*
  * Interrupt handler thread
  */
@@ -458,6 +499,8 @@ static int irq_thread(void *data)
 
         while (!irq_wait_for_interrupt(action)) {
 
+                irq_thread_check_affinity(desc, action);
+
                 atomic_inc(&desc->threads_active);
 
                 spin_lock_irq(&desc->lock);
@@ -564,7 +607,6 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
                  */
                 get_task_struct(t);
                 new->thread = t;
-                wake_up_process(t);
         }
 
         /*
@@ -647,6 +689,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
                                 (int)(new->flags & IRQF_TRIGGER_MASK));
         }
 
+        new->irq = irq;
         *old_ptr = new;
 
         /* Reset broken irq detection when installing new handler */
@@ -664,7 +707,13 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 
         spin_unlock_irqrestore(&desc->lock, flags);
 
-        new->irq = irq;
+        /*
+         * Strictly no need to wake it up, but hung_task complains
+         * when no hard interrupt wakes the thread up.
+         */
+        if (new->thread)
+                wake_up_process(new->thread);
+
         register_irq_proc(irq, desc);
         new->dir = NULL;
         register_handler_proc(irq, new);
@@ -718,7 +767,6 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
 {
         struct irq_desc *desc = irq_to_desc(irq);
         struct irqaction *action, **action_ptr;
-        struct task_struct *irqthread;
         unsigned long flags;
 
         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
@@ -766,9 +814,6 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
                         desc->chip->disable(irq);
         }
 
-        irqthread = action->thread;
-        action->thread = NULL;
-
         spin_unlock_irqrestore(&desc->lock, flags);
 
         unregister_handler_proc(irq, action);
@@ -776,12 +821,6 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
         /* Make sure it's not being used on another CPU: */
         synchronize_irq(irq);
 
-        if (irqthread) {
-                if (!test_bit(IRQTF_DIED, &action->thread_flags))
-                        kthread_stop(irqthread);
-                put_task_struct(irqthread);
-        }
-
 #ifdef CONFIG_DEBUG_SHIRQ
         /*
          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
@@ -797,6 +836,13 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
                 local_irq_restore(flags);
         }
 #endif
+
+        if (action->thread) {
+                if (!test_bit(IRQTF_DIED, &action->thread_flags))
+                        kthread_stop(action->thread);
+                put_task_struct(action->thread);
+        }
+
         return action;
 }