Input: omap-keypad - use disable_irq_nosync() in irq handler

disable_irq() waits for all running handlers to complete before
returning.  As such, if it's used to disable an interrupt from
that interrupt's handler it will deadlock.  This replaces the
dangerous instances with the _nosync() variant which doesn't have
this problem.

Signed-off-by: Ben Nizette <bn@niasdigital.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

diff --git a/drivers/input/keyboard/omap-keypad.c b/drivers/input/keyboard/omap-keypad.c
index 058fa8b02c21ee1b939085c024c23884e2f6ca1d..87ec7b18ac69dbca67065b51891c1c9afb028982 100644 (file)
--- a/drivers/input/keyboard/omap-keypad.c
+++ b/drivers/input/keyboard/omap-keypad.c
@@ -100,8 +100,20 @@ static irqreturn_t omap_kp_interrupt(int irq, void *dev_id)
        /* disable keyboard interrupt and schedule for handling */
        if (cpu_is_omap24xx()) {
                int i;
-               for (i = 0; i < omap_kp->rows; i++)
-                       disable_irq(gpio_to_irq(row_gpios[i]));
+
+               for (i = 0; i < omap_kp->rows; i++) {
+                       int gpio_irq = gpio_to_irq(row_gpios[i]);
+                       /*
+                        * The interrupt which we're currently handling should
+                        * be disabled _nosync() to avoid deadlocks waiting
+                        * for this handler to complete.  All others should
+                        * be disabled the regular way for SMP safety.
+                        */
+                       if (gpio_irq == irq)
+                               disable_irq_nosync(gpio_irq);
+                       else
+                               disable_irq(gpio_irq);
+               }
        } else
                /* disable keyboard interrupt and schedule for handling */
                omap_writew(1, OMAP_MPUIO_BASE + OMAP_MPUIO_KBD_MASKIT);