Merge branch 'kvm-amd-pmu-fixes' into HEAD

[linux-2.6-microblaze.git] / drivers / gpio / gpiolib.c

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e59884c..085348e 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1404,6 +1404,16 @@ static int gpiochip_to_irq(struct gpio_chip *gc, unsigned int offset)
 {
        struct irq_domain *domain = gc->irq.domain;
 
+#ifdef CONFIG_GPIOLIB_IRQCHIP
+       /*
+        * Avoid race condition with other code, which tries to lookup
+        * an IRQ before the irqchip has been properly registered,
+        * i.e. while gpiochip is still being brought up.
+        */
+       if (!gc->irq.initialized)
+               return -EPROBE_DEFER;
+#endif
+
        if (!gpiochip_irqchip_irq_valid(gc, offset))
                return -ENXIO;
 
@@ -1593,6 +1603,15 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc,
 
        acpi_gpiochip_request_interrupts(gc);
 
+       /*
+        * Using barrier() here to prevent compiler from reordering
+        * gc->irq.initialized before initialization of above
+        * GPIO chip irq members.
+        */
+       barrier();
+
+       gc->irq.initialized = true;
+
        return 0;
 }