1 files changed, 113 insertions, 31 deletions

diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 3540a719012..517561fc731 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -51,30 +51,92 @@ static void warn_no_thread(unsigned int irq, struct irqaction *action)
                "but no thread function available.", irq, action->name);
 }
 
-/**
- * handle_IRQ_event - irq action chain handler
- * @irq:        the interrupt number
- * @action:     the interrupt action chain for this irq
- *
- * Handles the action chain of an irq event
- */
-irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
+static void irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
+{
+        /*
+         * Wake up the handler thread for this action. In case the
+         * thread crashed and was killed we just pretend that we
+         * handled the interrupt. The hardirq handler has disabled the
+         * device interrupt, so no irq storm is lurking. If the
+         * RUNTHREAD bit is already set, nothing to do.
+         */
+        if (test_bit(IRQTF_DIED, &action->thread_flags) ||
+            test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags))
+                return;
+
+        /*
+         * It's safe to OR the mask lockless here. We have only two
+         * places which write to threads_oneshot: This code and the
+         * irq thread.
+         *
+         * This code is the hard irq context and can never run on two
+         * cpus in parallel. If it ever does we have more serious
+         * problems than this bitmask.
+         *
+         * The irq threads of this irq which clear their "running" bit
+         * in threads_oneshot are serialized via desc->lock against
+         * each other and they are serialized against this code by
+         * IRQS_INPROGRESS.
+         *
+         * Hard irq handler:
+         *
+         *      spin_lock(desc->lock);
+         *      desc->state |= IRQS_INPROGRESS;
+         *      spin_unlock(desc->lock);
+         *      set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
+         *      desc->threads_oneshot |= mask;
+         *      spin_lock(desc->lock);
+         *      desc->state &= ~IRQS_INPROGRESS;
+         *      spin_unlock(desc->lock);
+         *
+         * irq thread:
+         *
+         * again:
+         *      spin_lock(desc->lock);
+         *      if (desc->state & IRQS_INPROGRESS) {
+         *              spin_unlock(desc->lock);
+         *              while(desc->state & IRQS_INPROGRESS)
+         *                      cpu_relax();
+         *              goto again;
+         *      }
+         *      if (!test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
+         *              desc->threads_oneshot &= ~mask;
+         *      spin_unlock(desc->lock);
+         *
+         * So either the thread waits for us to clear IRQS_INPROGRESS
+         * or we are waiting in the flow handler for desc->lock to be
+         * released before we reach this point. The thread also checks
+         * IRQTF_RUNTHREAD under desc->lock. If set it leaves
+         * threads_oneshot untouched and runs the thread another time.
+         */
+        desc->threads_oneshot |= action->thread_mask;
+        wake_up_process(action->thread);
+}
+
+irqreturn_t
+handle_irq_event_percpu(struct irq_desc *desc, struct irqaction *action)
 {
-        irqreturn_t ret, retval = IRQ_NONE;
-        unsigned int status = 0;
+        irqreturn_t retval = IRQ_NONE;
+        unsigned int random = 0, irq = desc->irq_data.irq;
 
         do {
+                irqreturn_t res;
+
                 trace_irq_handler_entry(irq, action);
-                ret = action->handler(irq, action->dev_id);
-                trace_irq_handler_exit(irq, action, ret);
+                res = action->handler(irq, action->dev_id);
+                trace_irq_handler_exit(irq, action, res);
 
-                switch (ret) {
+                if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pF enabled interrupts\n",
+                              irq, action->handler))
+                        local_irq_disable();
+
+                switch (res) {
                 case IRQ_WAKE_THREAD:
                         /*
                          * Set result to handled so the spurious check
                          * does not trigger.
                          */
-                        ret = IRQ_HANDLED;
+                        res = IRQ_HANDLED;
 
                         /*
                          * Catch drivers which return WAKE_THREAD but
@@ -85,36 +147,56 @@ irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
                                 break;
                         }
 
-                        /*
-                         * Wake up the handler thread for this
-                         * action. In case the thread crashed and was
-                         * killed we just pretend that we handled the
-                         * interrupt. The hardirq handler above has
-                         * disabled the device interrupt, so no irq
-                         * storm is lurking.
-                         */
-                        if (likely(!test_bit(IRQTF_DIED,
-                                             &action->thread_flags))) {
-                                set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
-                                wake_up_process(action->thread);
-                        }
+                        irq_wake_thread(desc, action);
 
                         /* Fall through to add to randomness */
                 case IRQ_HANDLED:
-                        status |= action->flags;
+                        random |= action->flags;
                         break;
 
                 default:
                         break;
                 }
 
-                retval |= ret;
+                retval |= res;
                 action = action->next;
         } while (action);
 
-        if (status & IRQF_SAMPLE_RANDOM)
+        if (random & IRQF_SAMPLE_RANDOM)
                 add_interrupt_randomness(irq);
-        local_irq_disable();
 
+        if (!noirqdebug)
+                note_interrupt(irq, desc, retval);
         return retval;
 }
+
+irqreturn_t handle_irq_event(struct irq_desc *desc)
+{
+        struct irqaction *action = desc->action;
+        irqreturn_t ret;
+
+        irq_compat_clr_pending(desc);
+        desc->istate &= ~IRQS_PENDING;
+        irq_compat_set_progress(desc);
+        desc->istate |= IRQS_INPROGRESS;
+        raw_spin_unlock(&desc->lock);
+
+        ret = handle_irq_event_percpu(desc, action);
+
+        raw_spin_lock(&desc->lock);
+        desc->istate &= ~IRQS_INPROGRESS;
+        irq_compat_clr_progress(desc);
+        return ret;
+}
+
+/**
+ * handle_IRQ_event - irq action chain handler
+ * @irq:        the interrupt number
+ * @action:     the interrupt action chain for this irq
+ *
+ * Handles the action chain of an irq event
+ */
+irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
+{
+        return handle_irq_event_percpu(irq_to_desc(irq), action);
+}