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

Pull irq/core changes for v3.4 from Ingo Molnar

* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Remove paranoid warnons and bogus fixups
  genirq: Flush the irq thread on synchronization
  genirq: Get rid of unnecessary IRQTF_DIED flag
  genirq: No need to check IRQTF_DIED before stopping a thread handler
  genirq: Get rid of unnecessary irqaction field in task_struct
  genirq: Fix incorrect check for forced IRQ thread handler
  softirq: Reduce invoke_softirq() code duplication
  genirq: Fix long-term regression in genirq irq_set_irq_type() handling
  x86-32/irq: Don't switch to irq stack for a user-mode irq

1 files changed, 13 insertions, 1 deletions

diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 470d08c82bbe..6ff84e6a954c 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -60,7 +60,7 @@ static void irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
 	 * 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) ||
+	if ((action->thread->flags & PF_EXITING) ||
 	    test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 		return;
 
@@ -110,6 +110,18 @@ static void irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
 	 * threads_oneshot untouched and runs the thread another time.
 	 */
 	desc->threads_oneshot |= action->thread_mask;
+
+	/*
+	 * We increment the threads_active counter in case we wake up
+	 * the irq thread. The irq thread decrements the counter when
+	 * it returns from the handler or in the exit path and wakes
+	 * up waiters which are stuck in synchronize_irq() when the
+	 * active count becomes zero. synchronize_irq() is serialized
+	 * against this code (hard irq handler) via IRQS_INPROGRESS
+	 * like the finalize_oneshot() code. See comment above.
+	 */
+	atomic_inc(&desc->threads_active);
+
 	wake_up_process(action->thread);
 }