From 3aa551c9b4c40018f0e261a178e3d25478dc04a9 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 23 Mar 2009 18:28:15 +0100
Subject: [PATCH 1/5] genirq: add threaded interrupt handler support
Add support for threaded interrupt handlers:
A device driver can request that its main interrupt handler runs in a
thread. To achive this the device driver requests the interrupt with
request_threaded_irq() and provides additionally to the handler a
thread function. The handler function is called in hard interrupt
context and needs to check whether the interrupt originated from the
device. If the interrupt originated from the device then the handler
can either return IRQ_HANDLED or IRQ_WAKE_THREAD. IRQ_HANDLED is
returned when no further action is required. IRQ_WAKE_THREAD causes
the genirq code to invoke the threaded (main) handler. When
IRQ_WAKE_THREAD is returned handler must have disabled the interrupt
on the device level. This is mandatory for shared interrupt handlers,
but we need to do it as well for obscure x86 hardware where disabling
an interrupt on the IO_APIC level redirects the interrupt to the
legacy PIC interrupt lines.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
---
include/linux/hardirq.h | 2 +-
include/linux/interrupt.h | 37 +++++++-
include/linux/irq.h | 5 +
include/linux/irqreturn.h | 2 +
include/linux/sched.h | 5 +
kernel/exit.c | 2 +
kernel/irq/handle.c | 31 +++++-
kernel/irq/manage.c | 192 +++++++++++++++++++++++++++++++++++---
8 files changed, 259 insertions(+), 17 deletions(-)
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index f83288347dda3..2dfaadbdb2ac0 100644
--- a/include/linux/hardirq.h
+++ b/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()
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 0c9cb63e68953..6fc2b720c2312 100644
--- a/include/linux/interrupt.h
+++ b/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;
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 873e4ac11b813..8b1cf06302104 100644
--- a/include/linux/irq.h
+++ b/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
diff --git a/include/linux/irqreturn.h b/include/linux/irqreturn.h
index c5584ca5b8c94..819acaaac3f58 100644
--- a/include/linux/irqreturn.h
+++ b/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;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 46d680643f894..38b77b0f56e53 100644
--- a/include/linux/sched.h
+++ b/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;
diff --git a/kernel/exit.c b/kernel/exit.c
index 167e1e3ad7c61..ca0b3488c4a95 100644
--- a/kernel/exit.c
+++ b/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
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 9ebf779688715..fe8f45374e861 100644
--- a/kernel/irq/handle.c
+++ b/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);
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 6458e99984c08..a4c1ab86cd25a 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -8,16 +8,15 @@
*/
#include <linux/irq.h>
+#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
+#include <linux/sched.h>
#include "internals.h"
-#if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
-cpumask_var_t irq_default_affinity;
-
/**
* synchronize_irq - wait for pending IRQ handlers (on other CPUs)
* @irq: interrupt number to wait for
@@ -53,9 +52,18 @@ void synchronize_irq(unsigned int irq)
/* Oops, that failed? */
} while (status & IRQ_INPROGRESS);
+
+ /*
+ * We made sure that no hardirq handler is running. Now verify
+ * that no threaded handlers are active.
+ */
+ wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
}
EXPORT_SYMBOL(synchronize_irq);
+#ifdef CONFIG_SMP
+cpumask_var_t irq_default_affinity;
+
/**
* irq_can_set_affinity - Check if the affinity of a given irq can be set
* @irq: Interrupt to check
@@ -72,6 +80,18 @@ int irq_can_set_affinity(unsigned int irq)
return 1;
}
+static void
+irq_set_thread_affinity(struct irq_desc *desc, const struct cpumask *cpumask)
+{
+ struct irqaction *action = desc->action;
+
+ while (action) {
+ if (action->thread)
+ set_cpus_allowed_ptr(action->thread, cpumask);
+ action = action->next;
+ }
+}
+
/**
* irq_set_affinity - Set the irq affinity of a given irq
* @irq: Interrupt to set affinity
@@ -100,6 +120,7 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
cpumask_copy(desc->affinity, cpumask);
desc->chip->set_affinity(irq, cpumask);
#endif
+ irq_set_thread_affinity(desc, cpumask);
desc->status |= IRQ_AFFINITY_SET;
spin_unlock_irqrestore(&desc->lock, flags);
return 0;
@@ -150,6 +171,8 @@ int irq_select_affinity_usr(unsigned int irq)
spin_lock_irqsave(&desc->lock, flags);
ret = setup_affinity(irq, desc);
+ if (!ret)
+ irq_set_thread_affinity(desc, desc->affinity);
spin_unlock_irqrestore(&desc->lock, flags);
return ret;
@@ -384,6 +407,93 @@ int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
return ret;
}
+static inline int irq_thread_should_run(struct irqaction *action)
+{
+ return test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags);
+}
+
+static int irq_wait_for_interrupt(struct irqaction *action)
+{
+ while (!kthread_should_stop()) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (irq_thread_should_run(action)) {
+ __set_current_state(TASK_RUNNING);
+ return 0;
+ } else
+ schedule();
+ }
+ return -1;
+}
+
+/*
+ * Interrupt handler thread
+ */
+static int irq_thread(void *data)
+{
+ struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO/2, };
+ struct irqaction *action = data;
+ struct irq_desc *desc = irq_to_desc(action->irq);
+ int wake;
+
+ sched_setscheduler(current, SCHED_FIFO, ¶m);
+ current->irqaction = action;
+
+ while (!irq_wait_for_interrupt(action)) {
+
+ atomic_inc(&desc->threads_active);
+
+ spin_lock_irq(&desc->lock);
+ if (unlikely(desc->status & IRQ_DISABLED)) {
+ /*
+ * CHECKME: We might need a dedicated
+ * IRQ_THREAD_PENDING flag here, which
+ * retriggers the thread in check_irq_resend()
+ * but AFAICT IRQ_PENDING should be fine as it
+ * retriggers the interrupt itself --- tglx
+ */
+ desc->status |= IRQ_PENDING;
+ spin_unlock_irq(&desc->lock);
+ } else {
+ spin_unlock_irq(&desc->lock);
+
+ action->thread_fn(action->irq, action->dev_id);
+ }
+
+ wake = atomic_dec_and_test(&desc->threads_active);
+
+ if (wake && waitqueue_active(&desc->wait_for_threads))
+ wake_up(&desc->wait_for_threads);
+ }
+
+ /*
+ * Clear irqaction. Otherwise exit_irq_thread() would make
+ * fuzz about an active irq thread going into nirvana.
+ */
+ current->irqaction = NULL;
+ return 0;
+}
+
+/*
+ * Called from do_exit()
+ */
+void exit_irq_thread(void)
+{
+ struct task_struct *tsk = current;
+
+ if (!tsk->irqaction)
+ return;
+
+ printk(KERN_ERR
+ "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
+ tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq);
+
+ /*
+ * Set the THREAD DIED flag to prevent further wakeups of the
+ * soon to be gone threaded handler.
+ */
+ set_bit(IRQTF_DIED, &tsk->irqaction->flags);
+}
+
/*
* Internal function to register an irqaction - typically used to
* allocate special interrupts that are part of the architecture.
@@ -419,6 +529,26 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
rand_initialize_irq(irq);
}
+ /*
+ * Threaded handler ?
+ */
+ if (new->thread_fn) {
+ struct task_struct *t;
+
+ t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
+ new->name);
+ if (IS_ERR(t))
+ return PTR_ERR(t);
+ /*
+ * We keep the reference to the task struct even if
+ * the thread dies to avoid that the interrupt code
+ * references an already freed task_struct.
+ */
+ get_task_struct(t);
+ new->thread = t;
+ wake_up_process(t);
+ }
+
/*
* The following block of code has to be executed atomically
*/
@@ -456,15 +586,15 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
if (!shared) {
irq_chip_set_defaults(desc->chip);
+ init_waitqueue_head(&desc->wait_for_threads);
+
/* Setup the type (level, edge polarity) if configured: */
if (new->flags & IRQF_TRIGGER_MASK) {
ret = __irq_set_trigger(desc, irq,
new->flags & IRQF_TRIGGER_MASK);
- if (ret) {
- spin_unlock_irqrestore(&desc->lock, flags);
- return ret;
- }
+ if (ret)
+ goto out_thread;
} else
compat_irq_chip_set_default_handler(desc);
#if defined(CONFIG_IRQ_PER_CPU)
@@ -532,8 +662,19 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
dump_stack();
}
#endif
+ ret = -EBUSY;
+
+out_thread:
spin_unlock_irqrestore(&desc->lock, flags);
- return -EBUSY;
+ if (new->thread) {
+ struct task_struct *t = new->thread;
+
+ new->thread = NULL;
+ if (likely(!test_bit(IRQTF_DIED, &new->thread_flags)))
+ kthread_stop(t);
+ put_task_struct(t);
+ }
+ return ret;
}
/**
@@ -559,6 +700,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
{
struct irq_desc *desc = irq_to_desc(irq);
struct irqaction *action, **action_ptr;
+ struct task_struct *irqthread;
unsigned long flags;
WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
@@ -605,6 +747,10 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
else
desc->chip->disable(irq);
}
+
+ irqthread = action->thread;
+ action->thread = NULL;
+
spin_unlock_irqrestore(&desc->lock, flags);
unregister_handler_proc(irq, action);
@@ -612,6 +758,12 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
/* Make sure it's not being used on another CPU: */
synchronize_irq(irq);
+ if (irqthread) {
+ if (!test_bit(IRQTF_DIED, &action->thread_flags))
+ kthread_stop(irqthread);
+ put_task_struct(irqthread);
+ }
+
#ifdef CONFIG_DEBUG_SHIRQ
/*
* It's a shared IRQ -- the driver ought to be prepared for an IRQ
@@ -664,9 +816,12 @@ void free_irq(unsigned int irq, void *dev_id)
EXPORT_SYMBOL(free_irq);
/**
- * request_irq - allocate an interrupt line
+ * request_threaded_irq - allocate an interrupt line
* @irq: Interrupt line to allocate
- * @handler: Function to be called when the IRQ occurs
+ * @handler: Function to be called when the IRQ occurs.
+ * Primary handler for threaded interrupts
+ * @thread_fn: Function called from the irq handler thread
+ * If NULL, no irq thread is created
* @irqflags: Interrupt type flags
* @devname: An ascii name for the claiming device
* @dev_id: A cookie passed back to the handler function
@@ -678,6 +833,15 @@ EXPORT_SYMBOL(free_irq);
* raises, you must take care both to initialise your hardware
* and to set up the interrupt handler in the right order.
*
+ * If you want to set up a threaded irq handler for your device
+ * then you need to supply @handler and @thread_fn. @handler ist
+ * still called in hard interrupt context and has to check
+ * whether the interrupt originates from the device. If yes it
+ * needs to disable the interrupt on the device and return
+ * IRQ_THREAD_WAKE which will wake up the handler thread and run
+ * @thread_fn. This split handler design is necessary to support
+ * shared interrupts.
+ *
* Dev_id must be globally unique. Normally the address of the
* device data structure is used as the cookie. Since the handler
* receives this value it makes sense to use it.
@@ -693,8 +857,9 @@ EXPORT_SYMBOL(free_irq);
* IRQF_TRIGGER_* Specify active edge(s) or level
*
*/
-int request_irq(unsigned int irq, irq_handler_t handler,
- unsigned long irqflags, const char *devname, void *dev_id)
+int request_threaded_irq(unsigned int irq, irq_handler_t handler,
+ irq_handler_t thread_fn, unsigned long irqflags,
+ const char *devname, void *dev_id)
{
struct irqaction *action;
struct irq_desc *desc;
@@ -742,6 +907,7 @@ int request_irq(unsigned int irq, irq_handler_t handler,
return -ENOMEM;
action->handler = handler;
+ action->thread_fn = thread_fn;
action->flags = irqflags;
action->name = devname;
action->dev_id = dev_id;
@@ -771,4 +937,4 @@ int request_irq(unsigned int irq, irq_handler_t handler,
#endif
return retval;
}
-EXPORT_SYMBOL(request_irq);
+EXPORT_SYMBOL(request_threaded_irq);
From 935bd5b971f0df7c06d214d022cf8392e2f37952 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Mon, 23 Mar 2009 18:28:16 +0100
Subject: [PATCH 2/5] genirq: add support for threaded interrupts to devres
Some devices use devres_request_irq() for to install their interrupt
handler. Add support for threaded interrupts to devres as well.
[tglx - simplified and adapted to latest threadirq version]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/interrupt.h | 17 ++++++++++++++---
kernel/irq/devres.c | 16 ++++++++++------
2 files changed, 24 insertions(+), 9 deletions(-)
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 6fc2b720c2312..dbf6a6fd116c1 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -123,9 +123,20 @@ extern void free_irq(unsigned int, void *);
struct device;
-extern int __must_check devm_request_irq(struct device *dev, unsigned int irq,
- irq_handler_t handler, unsigned long irqflags,
- const char *devname, void *dev_id);
+extern int __must_check
+devm_request_threaded_irq(struct device *dev, unsigned int irq,
+ irq_handler_t handler, irq_handler_t thread_fn,
+ unsigned long irqflags, const char *devname,
+ void *dev_id);
+
+static inline int __must_check
+devm_request_irq(struct device *dev, unsigned int irq, irq_handler_t handler,
+ unsigned long irqflags, const char *devname, void *dev_id)
+{
+ return devm_request_threaded_irq(dev, irq, handler, NULL, irqflags,
+ devname, dev_id);
+}
+
extern void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id);
/*
diff --git a/kernel/irq/devres.c b/kernel/irq/devres.c
index 38a25b8d8bff6..d06df9c41cba2 100644
--- a/kernel/irq/devres.c
+++ b/kernel/irq/devres.c
@@ -26,10 +26,12 @@ static int devm_irq_match(struct device *dev, void *res, void *data)
}
/**
- * devm_request_irq - allocate an interrupt line for a managed device
+ * devm_request_threaded_irq - allocate an interrupt line for a managed device
* @dev: device to request interrupt for
* @irq: Interrupt line to allocate
* @handler: Function to be called when the IRQ occurs
+ * @thread_fn: function to be called in a threaded interrupt context. NULL
+ * for devices which handle everything in @handler
* @irqflags: Interrupt type flags
* @devname: An ascii name for the claiming device
* @dev_id: A cookie passed back to the handler function
@@ -42,9 +44,10 @@ static int devm_irq_match(struct device *dev, void *res, void *data)
* If an IRQ allocated with this function needs to be freed
* separately, dev_free_irq() must be used.
*/
-int devm_request_irq(struct device *dev, unsigned int irq,
- irq_handler_t handler, unsigned long irqflags,
- const char *devname, void *dev_id)
+int devm_request_threaded_irq(struct device *dev, unsigned int irq,
+ irq_handler_t handler, irq_handler_t thread_fn,
+ unsigned long irqflags, const char *devname,
+ void *dev_id)
{
struct irq_devres *dr;
int rc;
@@ -54,7 +57,8 @@ int devm_request_irq(struct device *dev, unsigned int irq,
if (!dr)
return -ENOMEM;
- rc = request_irq(irq, handler, irqflags, devname, dev_id);
+ rc = request_threaded_irq(irq, handler, thread_fn, irqflags, devname,
+ dev_id);
if (rc) {
devres_free(dr);
return rc;
@@ -66,7 +70,7 @@ int devm_request_irq(struct device *dev, unsigned int irq,
return 0;
}
-EXPORT_SYMBOL(devm_request_irq);
+EXPORT_SYMBOL(devm_request_threaded_irq);
/**
* devm_free_irq - free an interrupt
From f48fe81e5b032914183e9a17052313720c2cac56 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 24 Mar 2009 11:46:22 +0100
Subject: [PATCH 3/5] genirq: threaded irq handlers review fixups
Delta patch to address the review comments.
- Implement warning when IRQ_WAKE_THREAD is requested and no
thread handler installed
- coding style fixes
Pointed-out-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/interrupt.h | 2 ++
kernel/irq/handle.c | 29 ++++++++++++++++++++++++-----
kernel/irq/manage.c | 17 +++++++----------
3 files changed, 33 insertions(+), 15 deletions(-)
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index dbf6a6fd116c1..266a5f5f57cc5 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -63,10 +63,12 @@
* Bits used by threaded handlers:
* IRQTF_RUNTHREAD - signals that the interrupt handler thread should run
* IRQTF_DIED - handler thread died
+ * IRQTF_WARNED - warning "IRQ_WAKE_THREAD w/o thread_fn" has been printed
*/
enum {
IRQTF_RUNTHREAD,
IRQTF_DIED,
+ IRQTF_WARNED,
};
typedef irqreturn_t (*irq_handler_t)(int, void *);
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index fe8f45374e861..38b49a9e508a7 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -338,6 +338,15 @@ irqreturn_t no_action(int cpl, void *dev_id)
return IRQ_NONE;
}
+static void warn_no_thread(unsigned int irq, struct irqaction *action)
+{
+ if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
+ return;
+
+ printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
+ "but no thread function available.", irq, action->name);
+}
+
/**
* handle_IRQ_event - irq action chain handler
* @irq: the interrupt number
@@ -360,6 +369,21 @@ irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
switch (ret) {
case IRQ_WAKE_THREAD:
+ /*
+ * Set result to handled so the spurious check
+ * does not trigger.
+ */
+ ret = IRQ_HANDLED;
+
+ /*
+ * Catch drivers which return WAKE_THREAD but
+ * did not set up a thread function
+ */
+ if (unlikely(!action->thread_fn)) {
+ warn_no_thread(irq, action);
+ break;
+ }
+
/*
* Wake up the handler thread for this
* action. In case the thread crashed and was
@@ -374,11 +398,6 @@ irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
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;
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index a4c1ab86cd25a..a3eb7baf1e46f 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -407,20 +407,17 @@ int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
return ret;
}
-static inline int irq_thread_should_run(struct irqaction *action)
-{
- return test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags);
-}
-
static int irq_wait_for_interrupt(struct irqaction *action)
{
while (!kthread_should_stop()) {
set_current_state(TASK_INTERRUPTIBLE);
- if (irq_thread_should_run(action)) {
+
+ if (test_and_clear_bit(IRQTF_RUNTHREAD,
+ &action->thread_flags)) {
__set_current_state(TASK_RUNNING);
return 0;
- } else
- schedule();
+ }
+ schedule();
}
return -1;
}
@@ -820,8 +817,8 @@ EXPORT_SYMBOL(free_irq);
* @irq: Interrupt line to allocate
* @handler: Function to be called when the IRQ occurs.
* Primary handler for threaded interrupts
- * @thread_fn: Function called from the irq handler thread
- * If NULL, no irq thread is created
+ * @thread_fn: Function called from the irq handler thread
+ * If NULL, no irq thread is created
* @irqflags: Interrupt type flags
* @devname: An ascii name for the claiming device
* @dev_id: A cookie passed back to the handler function
From 3a38148f0488069cadb75c4a6909954072d648bf Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 24 Mar 2009 20:27:39 +0100
Subject: [PATCH 4/5] genirq: provide old request_irq() for
CONFIG_GENERIC_HARDIRQ=n
Impact: Undo compile breakage for archs with CONFIG_GENERIC_HARDIRQ=n
The threaded interrupt handler patches changed request_irq from extern
to inline. Architectures which do not use the generic irq code still
have request_irq() as a global function and therefor fail to compile.
Keep the extern declaration for CONFIG_GENERIC_HARDIRQ=n
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/interrupt.h | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 266a5f5f57cc5..7e63b824833f6 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -103,6 +103,7 @@ struct irqaction {
extern irqreturn_t no_action(int cpl, void *dev_id);
+#ifdef CONFIG_GENERIC_HARDIRQS
extern int __must_check
request_threaded_irq(unsigned int irq, irq_handler_t handler,
irq_handler_t thread_fn,
@@ -115,9 +116,13 @@ request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
return request_threaded_irq(irq, handler, NULL, flags, name, dev);
}
-#ifdef CONFIG_GENERIC_HARDIRQS
extern void exit_irq_thread(void);
#else
+
+extern int __must_check
+request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
+ const char *name, void *dev);
+
static inline void exit_irq_thread(void) { }
#endif
From de18836e447c2dc30120c0919b8db8ddc0401cc4 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 25 Mar 2009 17:33:38 +0100
Subject: [PATCH 5/5] genirq: fix devres.o build for GENERIC_HARDIRQS=n
kernel/irq/devres.c is built by sparc (32bit) and m68k via the obscure
../../../kernel/irq/devres.o reference in arch/[sparc/m68k]/kernel/Makefile
To avoid ifdeffery in devres.c provide request_threaded_irq as an
inline for these users.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/interrupt.h | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 7e63b824833f6..143192f48bf3d 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -123,6 +123,20 @@ extern int __must_check
request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
const char *name, void *dev);
+/*
+ * Special function to avoid ifdeffery in kernel/irq/devres.c which
+ * gets magically built by GENERIC_HARDIRQS=n architectures (sparc,
+ * m68k). I really love these $@%#!* obvious Makefile references:
+ * ../../../kernel/irq/devres.o
+ */
+static inline 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)
+{
+ return request_irq(irq, handler, flags, name, dev);
+}
+
static inline void exit_irq_thread(void) { }
#endif