Merge 4.4-rc6 into usb-next

We want the USB and PHY fixes in here as well to make things easier for
testing and development.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 13 insertions, 1 deletions

diff --git a/arch/powerpc/platforms/powernv/opal-irqchip.c b/arch/powerpc/platforms/powernv/opal-irqchip.c
index 0a00e2aed393..e505223b4ec5 100644
--- a/arch/powerpc/platforms/powernv/opal-irqchip.c
+++ b/arch/powerpc/platforms/powernv/opal-irqchip.c
@@ -83,7 +83,19 @@ static void opal_event_unmask(struct irq_data *d)
 	set_bit(d->hwirq, &opal_event_irqchip.mask);
 
 	opal_poll_events(&events);
-	opal_handle_events(be64_to_cpu(events));
+	last_outstanding_events = be64_to_cpu(events);
+
+	/*
+	 * We can't just handle the events now with opal_handle_events().
+	 * If we did we would deadlock when opal_event_unmask() is called from
+	 * handle_level_irq() with the irq descriptor lock held, because
+	 * calling opal_handle_events() would call generic_handle_irq() and
+	 * then handle_level_irq() which would try to take the descriptor lock
+	 * again. Instead queue the events for later.
+	 */
+	if (last_outstanding_events & opal_event_irqchip.mask)
+		/* Need to retrigger the interrupt */
+		irq_work_queue(&opal_event_irq_work);
 }
 
 static int opal_event_set_type(struct irq_data *d, unsigned int flow_type)