---

yaml
---
r: 142760
b: refs/heads/master
c: 3aa551c
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 80c5520811d3805adcb15c570ea5e2d489fa5d0b
+refs/heads/master: 3aa551c9b4c40018f0e261a178e3d25478dc04a9

trunk/include/linux/hardirq.h

@@ -105,7 +105,7 @@
 # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
 #endif
 
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS)
 extern void synchronize_irq(unsigned int irq);
 #else
 # define synchronize_irq(irq)	barrier()

trunk/include/linux/interrupt.h

@@ -59,6 +59,16 @@
 #define IRQF_NOBALANCING	0x00000800
 #define IRQF_IRQPOLL		0x00001000
 
+/*
+ * Bits used by threaded handlers:
+ * IRQTF_RUNTHREAD - signals that the interrupt handler thread should run
+ * IRQTF_DIED      - handler thread died
+ */
+enum {
+	IRQTF_RUNTHREAD,
+	IRQTF_DIED,
+};
+
 typedef irqreturn_t (*irq_handler_t)(int, void *);
 
 /**
@@ -71,6 +81,9 @@ typedef irqreturn_t (*irq_handler_t)(int, void *);
  * @next:	pointer to the next irqaction for shared interrupts
  * @irq:	interrupt number
  * @dir:	pointer to the proc/irq/NN/name entry
+ * @thread_fn:	interupt handler function for threaded interrupts
+ * @thread:	thread pointer for threaded interrupts
+ * @thread_flags:	flags related to @thread
  */
 struct irqaction {
 	irq_handler_t handler;
@@ -81,11 +94,31 @@ struct irqaction {
 	struct irqaction *next;
 	int irq;
 	struct proc_dir_entry *dir;
+	irq_handler_t thread_fn;
+	struct task_struct *thread;
+	unsigned long thread_flags;
 };
 
 extern irqreturn_t no_action(int cpl, void *dev_id);
-extern int __must_check request_irq(unsigned int, irq_handler_t handler,
-		       unsigned long, const char *, void *);
+
+extern int __must_check
+request_threaded_irq(unsigned int irq, irq_handler_t handler,
+		     irq_handler_t thread_fn,
+		     unsigned long flags, const char *name, void *dev);
+
+static inline int __must_check
+request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
+	    const char *name, void *dev)
+{
+	return request_threaded_irq(irq, handler, NULL, flags, name, dev);
+}
+
+#ifdef CONFIG_GENERIC_HARDIRQS
+extern void exit_irq_thread(void);
+#else
+static inline void exit_irq_thread(void) { }
+#endif
+
 extern void free_irq(unsigned int, void *);
 
 struct device;

trunk/include/linux/irq.h

@@ -20,6 +20,7 @@
 #include <linux/irqreturn.h>
 #include <linux/irqnr.h>
 #include <linux/errno.h>
+#include <linux/wait.h>
 
 #include <asm/irq.h>
 #include <asm/ptrace.h>
@@ -155,6 +156,8 @@ struct irq_2_iommu;
  * @affinity:		IRQ affinity on SMP
  * @cpu:		cpu index useful for balancing
  * @pending_mask:	pending rebalanced interrupts
+ * @threads_active:	number of irqaction threads currently running
+ * @wait_for_threads:	wait queue for sync_irq to wait for threaded handlers
  * @dir:		/proc/irq/ procfs entry
  * @name:		flow handler name for /proc/interrupts output
  */
@@ -186,6 +189,8 @@ struct irq_desc {
 	cpumask_var_t		pending_mask;
 #endif
 #endif
+	atomic_t		threads_active;
+	wait_queue_head_t       wait_for_threads;
 #ifdef CONFIG_PROC_FS
 	struct proc_dir_entry	*dir;
 #endif

trunk/include/linux/irqreturn.h

@@ -5,10 +5,12 @@
  * enum irqreturn
  * @IRQ_NONE		interrupt was not from this device
  * @IRQ_HANDLED		interrupt was handled by this device
+ * @IRQ_WAKE_THREAD	handler requests to wake the handler thread
  */
 enum irqreturn {
 	IRQ_NONE,
 	IRQ_HANDLED,
+	IRQ_WAKE_THREAD,
 };
 
 typedef enum irqreturn irqreturn_t;

trunk/include/linux/sched.h

@@ -1292,6 +1292,11 @@ struct task_struct {
 /* Protection of (de-)allocation: mm, files, fs, tty, keyrings */
 	spinlock_t alloc_lock;
 
+#ifdef CONFIG_GENERIC_HARDIRQS
+	/* IRQ handler threads */
+	struct irqaction *irqaction;
+#endif
+
 	/* Protection of the PI data structures: */
 	spinlock_t pi_lock;
 

trunk/kernel/exit.c

@@ -1037,6 +1037,8 @@ NORET_TYPE void do_exit(long code)
 		schedule();
 	}
 
+	exit_irq_thread();
+
 	exit_signals(tsk);  /* sets PF_EXITING */
 	/*
 	 * tsk->flags are checked in the futex code to protect against

trunk/kernel/irq/handle.c

@@ -357,8 +357,37 @@ irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 
 	do {
 		ret = action->handler(irq, action->dev_id);
-		if (ret == IRQ_HANDLED)
+
+		switch (ret) {
+		case IRQ_WAKE_THREAD:
+			/*
+			 * Wake up the handler thread for this
+			 * action. In case the thread crashed and was
+			 * killed we just pretend that we handled the
+			 * interrupt. The hardirq handler above has
+			 * disabled the device interrupt, so no irq
+			 * storm is lurking.
+			 */
+			if (likely(!test_bit(IRQTF_DIED,
+					     &action->thread_flags))) {
+				set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
+				wake_up_process(action->thread);
+			}
+
+			/*
+			 * Set it to handled so the spurious check
+			 * does not trigger.
+			 */
+			ret = IRQ_HANDLED;
+			/* Fall through to add to randomness */
+		case IRQ_HANDLED:
 			status |= action->flags;
+			break;
+
+		default:
+			break;
+		}
+
 		retval |= ret;
 		action = action->next;
 	} while (action);