genirq: Add internal state field to irq_desc

That field will contain internal state information which is not going
to be exposed to anything outside the core code - except via accessor
functions. I'm tired of everyone fiddling in irq_desc.status.

core_internal_state__do_not_mess_with_it is clear enough, annoying to
type and easy to grep for. Offenders will be tracked down and slapped
with stinking trouts.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 8 insertions, 1 deletions

diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
index 64794dec93b6..782bf9851a9f 100644
--- a/include/linux/irqdesc.h
+++ b/include/linux/irqdesc.h
@@ -19,6 +19,7 @@ struct timer_rand_state;
  * @handle_irq:         highlevel irq-events handler [if NULL, __do_IRQ()]
  * @action:             the irq action chain
  * @status:             status information
+ * @core_internal_state__do_not_mess_with_it: core internal status information
  * @depth:              disable-depth, for nested irq_disable() calls
  * @wake_depth:         enable depth, for multiple set_irq_wake() callers
  * @irq_count:          stats field to detect stalled irqs
@@ -63,7 +64,7 @@ struct irq_desc {
         irq_flow_handler_t      handle_irq;
         struct irqaction        *action;        /* IRQ action list */
         unsigned int            status;         /* IRQ status */
-
+        unsigned int            core_internal_state__do_not_mess_with_it;
         unsigned int            depth;          /* nested irq disables */
         unsigned int            wake_depth;     /* nested wake enables */
         unsigned int            irq_count;      /* For detecting broken IRQs */
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index b61824cdadc6..ae96e688f4e1 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -1,5 +1,9 @@
 /*
  * IRQ subsystem internal functions and variables:
+ *
+ * Do not ever include this file from anything else than
+ * kernel/irq/. Do not even think about using any information outside
+ * of this file for your non core code.
  */
 #include <linux/irqdesc.h>
 
@@ -9,6 +13,8 @@
 # define IRQ_BITMAP_BITS        NR_IRQS
 #endif
 
+#define istate core_internal_state__do_not_mess_with_it
+
 extern int noirqdebug;
 
 /*