generic irqs: handle failure of irqchip->set_type in setup_irq

set_type returns an int indicating success or failure, but up to now
setup_irq ignores that.

In my case this resulted in a machine hang:

gpio-keys requested IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, but
arm/ns9xxx can only trigger on one direction so set_type didn't touch
the configuration which happens do default to a level sensitiveness and
returned -EINVAL.  setup_irq ignored that and unmasked the irq.  This
resulted in an endless triggering of the gpio-key interrupt service
routine which effectively killed the machine.

With this patch applied setup_irq propagates the error to the caller.

Note that before in the case

	chip && !chip->set_type && !chip->name

a NULL pointer was feed to printk.  This is fixed, too.

Signed-off-by: Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 42 insertions, 22 deletions

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 3cfc0fefb5ee..5bc6e5ecc493 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -308,6 +308,30 @@ void compat_irq_chip_set_default_handler(struct irq_desc *desc)
                 desc->handle_irq = NULL;
 }
 
+static int __irq_set_trigger(struct irq_chip *chip, unsigned int irq,
+                unsigned long flags)
+{
+        int ret;
+
+        if (!chip || !chip->set_type) {
+                /*
+                 * IRQF_TRIGGER_* but the PIC does not support multiple
+                 * flow-types?
+                 */
+                pr_warning("No set_type function for IRQ %d (%s)\n", irq,
+                                chip ? (chip->name ? : "unknown") : "unknown");
+                return 0;
+        }
+
+        ret = chip->set_type(irq, flags & IRQF_TRIGGER_MASK);
+
+        if (ret)
+                pr_err("setting flow type for irq %u failed (%pF)\n",
+                                irq, chip->set_type);
+
+        return ret;
+}
+
 /*
  * Internal function to register an irqaction - typically used to
  * allocate special interrupts that are part of the architecture.
@@ -319,6 +343,7 @@ int setup_irq(unsigned int irq, struct irqaction *new)
         const char *old_name = NULL;
         unsigned long flags;
         int shared = 0;
+        int ret;
 
         if (irq >= NR_IRQS)
                 return -EINVAL;
@@ -376,35 +401,23 @@ int setup_irq(unsigned int irq, struct irqaction *new)
                 shared = 1;
         }
 
-        *p = new;
-
-        /* Exclude IRQ from balancing */
-        if (new->flags & IRQF_NOBALANCING)
-                desc->status |= IRQ_NO_BALANCING;
-
         if (!shared) {
                 irq_chip_set_defaults(desc->chip);
 
-#if defined(CONFIG_IRQ_PER_CPU)
-                if (new->flags & IRQF_PERCPU)
-                        desc->status |= IRQ_PER_CPU;
-#endif
-
                 /* Setup the type (level, edge polarity) if configured: */
                 if (new->flags & IRQF_TRIGGER_MASK) {
-                        if (desc->chip->set_type)
-                                desc->chip->set_type(irq,
-                                                new->flags & IRQF_TRIGGER_MASK);
-                        else
-                                /*
-                                 * IRQF_TRIGGER_* but the PIC does not support
-                                 * multiple flow-types?
-                                 */
-                                printk(KERN_WARNING "No IRQF_TRIGGER set_type "
-                                       "function for IRQ %d (%s)\n", irq,
-                                       desc->chip->name);
+                        ret = __irq_set_trigger(desc->chip, irq, new->flags);
+
+                        if (ret) {
+                                spin_unlock_irqrestore(&desc->lock, flags);
+                                return ret;
+                        }
                 } else
                         compat_irq_chip_set_default_handler(desc);
+#if defined(CONFIG_IRQ_PER_CPU)
+                if (new->flags & IRQF_PERCPU)
+                        desc->status |= IRQ_PER_CPU;
+#endif
 
                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
                                   IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
@@ -423,6 +436,13 @@ int setup_irq(unsigned int irq, struct irqaction *new)
                 /* Set default affinity mask once everything is setup */
                 irq_select_affinity(irq);
         }
+
+        *p = new;
+
+        /* Exclude IRQ from balancing */
+        if (new->flags & IRQF_NOBALANCING)
+                desc->status |= IRQ_NO_BALANCING;
+
         /* Reset broken irq detection when installing new handler */
         desc->irq_count = 0;
         desc->irqs_unhandled = 0;