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Merge branch 'irq/threaded' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

Browse source 
* 'irq/threaded' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  genirq: fix devres.o build for GENERIC_HARDIRQS=n
  genirq: provide old request_irq() for CONFIG_GENERIC_HARDIRQ=n
  genirq: threaded irq handlers review fixups
  genirq: add support for threaded interrupts to devres
  genirq: add threaded interrupt handler support
This commit is contained in:
Linus Torvalds 2009-04-07 14:07:52 -07:00
commit c61b79b6ef
9 changed files with 320 additions and 26 deletions
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2
include/linux/hardirq.h
View file

@ -116,7 +116,7 @@
# 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()

75
include/linux/interrupt.h
View file

@ -59,6 +59,18 @@
#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
* 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 *);
/**
@ -71,6 +83,9 @@ 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;
@ -81,18 +96,68 @@ 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 *);
#ifdef CONFIG_GENERIC_HARDIRQS
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);
}
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);
/*
* 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
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);
/*

5
include/linux/irq.h
View file

@ -22,6 +22,7 @@
#include <linux/irqnr.h>
#include <linux/errno.h>
#include <linux/topology.h>
#include <linux/wait.h>
#include <asm/irq.h>
#include <asm/ptrace.h>
@ -158,6 +159,8 @@ 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
*/
@ -189,6 +192,8 @@ 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

2
include/linux/irqreturn.h
View file

@ -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;

5
include/linux/sched.h
View file

@ -1294,6 +1294,11 @@ 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;

2
kernel/exit.c
View file

@ -923,6 +923,8 @@ 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

16
kernel/irq/devres.c
View file

@ -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

50
kernel/irq/handle.c
View file

@ -339,6 +339,15 @@ 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);
}
DEFINE_TRACE(irq_handler_entry);
DEFINE_TRACE(irq_handler_exit);
@ -363,8 +372,47 @@ irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
trace_irq_handler_entry(irq, action);
ret = action->handler(irq, action->dev_id);
trace_irq_handler_exit(irq, action, ret);
if (ret == IRQ_HANDLED)
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
* 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);
}
/* Fall through to add to randomness */
case IRQ_HANDLED:
status |= action->flags;
break;
default:
break;
}
retval |= ret;
action = action->next;
} while (action);

189
kernel/irq/manage.c
View file

@ -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;
@ -401,6 +424,90 @@ int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
return ret;
}
static int irq_wait_for_interrupt(struct irqaction *action)
{
while (!kthread_should_stop()) {
set_current_state(TASK_INTERRUPTIBLE);
if (test_and_clear_bit(IRQTF_RUNTHREAD,
&action->thread_flags)) {
__set_current_state(TASK_RUNNING);
return 0;
}
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, &param);
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.
@ -436,6 +543,26 @@ __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
*/
@ -473,15 +600,15 @@ __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)
@ -549,8 +676,19 @@ __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;
}
/**
@ -576,6 +714,7 @@ 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);
@ -622,6 +761,10 @@ 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);
@ -629,6 +772,12 @@ 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
@ -681,9 +830,12 @@ 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
@ -695,6 +847,15 @@ 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.
@ -710,8 +871,9 @@ 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;
@ -759,6 +921,7 @@ 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;
@ -788,4 +951,4 @@ int request_irq(unsigned int irq, irq_handler_t handler,
#endif
return retval;
}
EXPORT_SYMBOL(request_irq);
EXPORT_SYMBOL(request_threaded_irq);