From 18258f7239a61d8929b8e0c7b6d46c446459074c Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sat, 15 Feb 2014 00:55:18 +0000 Subject: genirq: Provide synchronize_hardirq() synchronize_irq() waits for hard irq and threaded handlers to complete before returning. For some special cases we only need to make sure that the hard interrupt part of the irq line is not in progress when we disabled the - possibly shared - interrupt at the device level. A proper use case for this was provided by Russell. The sdhci driver requires some irq triggered functions to be run in thread context. The current implementation of the thread context is a sdio private kthread construct, which has quite some shortcomings. These can be avoided when the thread is directly associated to the device interrupt via the generic threaded irq infrastructure. Though there is a corner case related to run time power management where one side disables the device interrupts at the device level and needs to make sure, that an already running hard interrupt handler has completed before proceeding further. Though that hard interrupt handler might wake the associated thread, which in turn can request the runtime PM to reenable the device. Using synchronize_irq() leads to an immediate deadlock of the irq thread waiting for the PM lock and the synchronize_irq() waiting for the irq thread to complete. Due to the fact that it is sufficient for this case to ensure that no hard irq handler is executing a new function which avoids the check for the thread is required. Add a function, which just monitors the hard irq parts and ignores the threaded handlers. Signed-off-by: Thomas Gleixner Tested-by: Russell King Cc: Chris Ball Acked-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20140215003823.653236081@linutronix.de --- kernel/irq/manage.c | 70 ++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 50 insertions(+), 20 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 481a13c43b17..274ba9238fb7 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -32,24 +32,10 @@ static int __init setup_forced_irqthreads(char *arg) early_param("threadirqs", setup_forced_irqthreads); #endif -/** - * synchronize_irq - wait for pending IRQ handlers (on other CPUs) - * @irq: interrupt number to wait for - * - * This function waits for any pending IRQ handlers for this interrupt - * to complete before returning. If you use this function while - * holding a resource the IRQ handler may need you will deadlock. - * - * This function may be called - with care - from IRQ context. - */ -void synchronize_irq(unsigned int irq) +static void __synchronize_hardirq(struct irq_desc *desc) { - struct irq_desc *desc = irq_to_desc(irq); bool inprogress; - if (!desc) - return; - do { unsigned long flags; @@ -67,12 +53,56 @@ void synchronize_irq(unsigned int irq) /* Oops, that failed? */ } while (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)); +/** + * synchronize_hardirq - wait for pending hard IRQ handlers (on other CPUs) + * @irq: interrupt number to wait for + * + * This function waits for any pending hard IRQ handlers for this + * interrupt to complete before returning. If you use this + * function while holding a resource the IRQ handler may need you + * will deadlock. It does not take associated threaded handlers + * into account. + * + * Do not use this for shutdown scenarios where you must be sure + * that all parts (hardirq and threaded handler) have completed. + * + * This function may be called - with care - from IRQ context. + */ +void synchronize_hardirq(unsigned int irq) +{ + struct irq_desc *desc = irq_to_desc(irq); + + if (desc) + __synchronize_hardirq(desc); +} +EXPORT_SYMBOL(synchronize_hardirq); + +/** + * synchronize_irq - wait for pending IRQ handlers (on other CPUs) + * @irq: interrupt number to wait for + * + * This function waits for any pending IRQ handlers for this interrupt + * to complete before returning. If you use this function while + * holding a resource the IRQ handler may need you will deadlock. + * + * This function may be called - with care - from IRQ context. + */ +void synchronize_irq(unsigned int irq) +{ + struct irq_desc *desc = irq_to_desc(irq); + + if (desc) { + __synchronize_hardirq(desc); + /* + * 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); -- cgit v1.2.3 From a92444c6b2225a9115d661c950cb48a22aeace20 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sat, 15 Feb 2014 00:55:19 +0000 Subject: genirq: Provide irq_wake_thread() In course of the sdhci/sdio discussion with Russell about killing the sdio kthread hackery we discovered the need to be able to wake an interrupt thread from software. The rationale for this is, that sdio hardware can lack proper interrupt support for certain features. So the driver needs to poll the status registers, but at the same time it needs to be woken up by an hardware interrupt. To be able to get rid of the home brewn kthread construct of sdio we need a way to wake an irq thread independent of an actual hardware interrupt. Provide an irq_wake_thread() function which wakes up the thread which is associated to a given dev_id. This allows sdio to invoke the irq thread from the hardware irq handler via the IRQ_WAKE_THREAD return value and provides a possibility to wake it via a timer for the polling scenarios. That allows to simplify the sdio logic significantly. Signed-off-by: Thomas Gleixner Cc: Russell King Cc: Chris Ball Acked-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20140215003823.772565780@linutronix.de --- kernel/irq/handle.c | 4 ++-- kernel/irq/internals.h | 1 + kernel/irq/manage.c | 27 +++++++++++++++++++++++++++ 3 files changed, 30 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c index 131ca176b497..bfec453557b4 100644 --- a/kernel/irq/handle.c +++ b/kernel/irq/handle.c @@ -51,7 +51,7 @@ static void warn_no_thread(unsigned int irq, struct irqaction *action) "but no thread function available.", irq, action->name); } -static void irq_wake_thread(struct irq_desc *desc, struct irqaction *action) +void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action) { /* * In case the thread crashed and was killed we just pretend that @@ -157,7 +157,7 @@ handle_irq_event_percpu(struct irq_desc *desc, struct irqaction *action) break; } - irq_wake_thread(desc, action); + __irq_wake_thread(desc, action); /* Fall through to add to randomness */ case IRQ_HANDLED: diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index 001fa5bab490..d61ac29e32d0 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -82,6 +82,7 @@ irqreturn_t handle_irq_event(struct irq_desc *desc); /* Resending of interrupts :*/ void check_irq_resend(struct irq_desc *desc, unsigned int irq); bool irq_wait_for_poll(struct irq_desc *desc); +void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action); #ifdef CONFIG_PROC_FS extern void register_irq_proc(unsigned int irq, struct irq_desc *desc); diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 274ba9238fb7..54eb5c99351b 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -911,6 +911,33 @@ static int irq_thread(void *data) return 0; } +/** + * irq_wake_thread - wake the irq thread for the action identified by dev_id + * @irq: Interrupt line + * @dev_id: Device identity for which the thread should be woken + * + */ +void irq_wake_thread(unsigned int irq, void *dev_id) +{ + struct irq_desc *desc = irq_to_desc(irq); + struct irqaction *action; + unsigned long flags; + + if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc))) + return; + + raw_spin_lock_irqsave(&desc->lock, flags); + for (action = desc->action; action; action = action->next) { + if (action->dev_id == dev_id) { + if (action->thread) + __irq_wake_thread(desc, action); + break; + } + } + raw_spin_unlock_irqrestore(&desc->lock, flags); +} +EXPORT_SYMBOL_GPL(irq_wake_thread); + static void irq_setup_forced_threading(struct irqaction *new) { if (!force_irqthreads) -- cgit v1.2.3 From b04c644e670f79417f1728e6be310cfd8e6a921b Mon Sep 17 00:00:00 2001 From: Chuansheng Liu Date: Mon, 10 Feb 2014 16:13:57 +0800 Subject: genirq: Update the a comment typo Change the comment "chasnge" to "change". Signed-off-by: Chuansheng Liu Link: http://lkml.kernel.org/r/1392020037-5484-2-git-send-email-chuansheng.liu@intel.com Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 54eb5c99351b..ada0c548c36a 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -757,7 +757,7 @@ out_unlock: #ifdef CONFIG_SMP /* - * Check whether we need to chasnge the affinity of the interrupt thread. + * Check whether we need to change the affinity of the interrupt thread. */ static void irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) -- cgit v1.2.3 From 792d0018a5fe31ef8ef9d07a7a02081d4abdf6b7 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 23 Feb 2014 21:40:14 +0000 Subject: genirq: Add a kstat helper to increment irq stats There is a common pattern all over the place: kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq)); This results in a call to core code anyway. So provide a function which does the same thing in core. While at it, replace the butt ugly macro with an inline. Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20140223212737.422068876@linutronix.de Signed-off-by: Thomas Gleixner --- kernel/irq/irqdesc.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'kernel') diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c index 8ab8e9390297..a7174617616b 100644 --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -489,6 +489,11 @@ void dynamic_irq_cleanup(unsigned int irq) raw_spin_unlock_irqrestore(&desc->lock, flags); } +void kstat_incr_irq_this_cpu(unsigned int irq) +{ + kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq)); +} + unsigned int kstat_irqs_cpu(unsigned int irq, int cpu) { struct irq_desc *desc = irq_to_desc(irq); -- cgit v1.2.3 From 8f945a3325bbe0dd651e2f496a53df9b06fc6d07 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 23 Feb 2014 21:40:23 +0000 Subject: genirq: Move kstat_incr_irqs_this_cpu() to core No more users outside the core code. Put it into the poison cabinet. That also gets rid of the linux/irq.h include in kernel_stat.h Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20140223212739.124207133@linutronix.de Signed-off-by: Thomas Gleixner --- kernel/irq/internals.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'kernel') diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index d61ac29e32d0..17b671713d5f 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -6,6 +6,7 @@ * of this file for your non core code. */ #include +#include #ifdef CONFIG_SPARSE_IRQ # define IRQ_BITMAP_BITS (NR_IRQS + 8196) @@ -180,3 +181,9 @@ static inline bool irqd_has_set(struct irq_data *d, unsigned int mask) { return d->state_use_accessors & mask; } + +static inline void kstat_incr_irqs_this_cpu(unsigned int irq, struct irq_desc *desc) +{ + __this_cpu_inc(*desc->kstat_irqs); + __this_cpu_inc(kstat.irqs_sum); +} -- cgit v1.2.3 From c1bacbae8192dd2a9ebadd22d793b68054f6c6e5 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sat, 8 Mar 2014 08:59:58 +0100 Subject: genirq: Provide irq_request/release_resources chip callbacks For certain irq types, e.g. gpios, it's necessary to request resources before starting up the irq. This might fail so we cannot use the irq_startup() callback because we might call the irq_set_type() callback before that which does not make sense when the resource is not available. Calling irq_startup() before irq_set_type() can lead to spurious interrupts which is not desired either. Signed-off-by: Thomas Gleixner Cc: Jean-Jacques Hiblot Cc: Grant Likely Cc: linux-arm-kernel@lists.infradead.org Reviewed-by: Linus Walleij Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1403080857160.18573@ionos.tec.linutronix.de Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index d3bf660cb57f..5d35cbe22896 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -896,6 +896,23 @@ static void irq_setup_forced_threading(struct irqaction *new) } } +static int irq_request_resources(struct irq_desc *desc) +{ + struct irq_data *d = &desc->irq_data; + struct irq_chip *c = d->chip; + + return c->irq_request_resources ? c->irq_request_resources(d) : 0; +} + +static void irq_release_resources(struct irq_desc *desc) +{ + struct irq_data *d = &desc->irq_data; + struct irq_chip *c = d->chip; + + if (c->irq_release_resources) + c->irq_release_resources(d); +} + /* * Internal function to register an irqaction - typically used to * allocate special interrupts that are part of the architecture. @@ -1091,6 +1108,13 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) } if (!shared) { + ret = irq_request_resources(desc); + if (ret) { + pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n", + new->name, irq, desc->irq_data.chip->name); + goto out_mask; + } + init_waitqueue_head(&desc->wait_for_threads); /* Setup the type (level, edge polarity) if configured: */ @@ -1261,8 +1285,10 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id) *action_ptr = action->next; /* If this was the last handler, shut down the IRQ line: */ - if (!desc->action) + if (!desc->action) { irq_shutdown(desc); + irq_release_resources(desc); + } #ifdef CONFIG_SMP /* make sure affinity_hint is cleaned up */ -- cgit v1.2.3 From 328a4978df833249b099c9875738d7b72042ffe1 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 13 Mar 2014 19:03:51 +0100 Subject: genirq: Add a new IRQCHIP_EOI_THREADED flag The flag is necessary for interrupt chips which require an ACK/EOI after the handler has run. In case of threaded handlers this needs to happen after the threaded handler has completed before the unmask of the interrupt. The flag is only unseful in combination with the handle_fasteoi_irq flow control handler. It can be combined with the flag IRQCHIP_EOI_IF_HANDLED, so the EOI is not issued when the interrupt is disabled or in progress. Tested-by: Hans de Goede Reviewed-by: Hans de Goede Cc: linux-arm-kernel@lists.infradead.org Cc: linux-sunxi@googlegroups.com Cc: Maxime Ripard Link: http://lkml.kernel.org/r/1394733834-26839-2-git-send-email-hdegoede@redhat.com Signed-off-by: Thomas Gleixner --- kernel/irq/chip.c | 48 ++++++++++++++++++++++++++++++++++++++++-------- kernel/irq/internals.h | 1 + kernel/irq/manage.c | 2 +- 3 files changed, 42 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index dc04c166c54d..6397df2d6945 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -281,6 +281,19 @@ void unmask_irq(struct irq_desc *desc) } } +void unmask_threaded_irq(struct irq_desc *desc) +{ + struct irq_chip *chip = desc->irq_data.chip; + + if (chip->flags & IRQCHIP_EOI_THREADED) + chip->irq_eoi(&desc->irq_data); + + if (chip->irq_unmask) { + chip->irq_unmask(&desc->irq_data); + irq_state_clr_masked(desc); + } +} + /* * handle_nested_irq - Handle a nested irq from a irq thread * @irq: the interrupt number @@ -435,6 +448,27 @@ static inline void preflow_handler(struct irq_desc *desc) static inline void preflow_handler(struct irq_desc *desc) { } #endif +static void cond_unmask_eoi_irq(struct irq_desc *desc, struct irq_chip *chip) +{ + if (!(desc->istate & IRQS_ONESHOT)) { + chip->irq_eoi(&desc->irq_data); + return; + } + /* + * We need to unmask in the following cases: + * - Oneshot irq which did not wake the thread (caused by a + * spurious interrupt or a primary handler handling it + * completely). + */ + if (!irqd_irq_disabled(&desc->irq_data) && + irqd_irq_masked(&desc->irq_data) && !desc->threads_oneshot) { + chip->irq_eoi(&desc->irq_data); + unmask_irq(desc); + } else if (!(chip->flags & IRQCHIP_EOI_THREADED)) { + chip->irq_eoi(&desc->irq_data); + } +} + /** * handle_fasteoi_irq - irq handler for transparent controllers * @irq: the interrupt number @@ -448,6 +482,8 @@ static inline void preflow_handler(struct irq_desc *desc) { } void handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc) { + struct irq_chip *chip = desc->irq_data.chip; + raw_spin_lock(&desc->lock); if (unlikely(irqd_irq_inprogress(&desc->irq_data))) @@ -473,18 +509,14 @@ handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc) preflow_handler(desc); handle_irq_event(desc); - if (desc->istate & IRQS_ONESHOT) - cond_unmask_irq(desc); + cond_unmask_eoi_irq(desc, chip); -out_eoi: - desc->irq_data.chip->irq_eoi(&desc->irq_data); -out_unlock: raw_spin_unlock(&desc->lock); return; out: - if (!(desc->irq_data.chip->flags & IRQCHIP_EOI_IF_HANDLED)) - goto out_eoi; - goto out_unlock; + if (!(chip->flags & IRQCHIP_EOI_IF_HANDLED)) + chip->irq_eoi(&desc->irq_data); + raw_spin_unlock(&desc->lock); } /** diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index 17b671713d5f..ddf1ffeb79f1 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -74,6 +74,7 @@ extern void irq_percpu_enable(struct irq_desc *desc, unsigned int cpu); extern void irq_percpu_disable(struct irq_desc *desc, unsigned int cpu); extern void mask_irq(struct irq_desc *desc); extern void unmask_irq(struct irq_desc *desc); +extern void unmask_threaded_irq(struct irq_desc *desc); extern void init_kstat_irqs(struct irq_desc *desc, int node, int nr); diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index de1a8ed29b40..2486a4c1a710 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -748,7 +748,7 @@ again: if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) && irqd_irq_masked(&desc->irq_data)) - unmask_irq(desc); + unmask_threaded_irq(desc); out_unlock: raw_spin_unlock_irq(&desc->lock); -- cgit v1.2.3 From d532676cc7329e1088702ccb0015942cc370b954 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 19 Mar 2014 11:19:52 +0100 Subject: softirq: Add linux/irq.h to make it compile again On Sparc and S390 the removal of irq.h from kernel_stat.h causes: kernel/softirq.c:774:9: error: 'NR_IRQS_LEGACY' undeclared Reported-by: Peter Zijlstra Signed-off-by: Thomas Gleixner --- kernel/softirq.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/softirq.c b/kernel/softirq.c index 490fcbb1dc5b..b50990a5bea0 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -25,6 +25,7 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include -- cgit v1.2.3 From bab5c790cc64adb1ede54b4077444375108ac8da Mon Sep 17 00:00:00 2001 From: Chema Gonzalez Date: Thu, 13 Mar 2014 19:50:55 -0700 Subject: genirq: procfs: Make smp_affinity values go+r Includes: - /proc/irq/default_smp_affinity - /proc/irq/*/affinity_hint - /proc/irq/*/smp_affinity - /proc/irq/*/smp_affinity_list Users can distill the same information by reading /proc/interrupts. Signed-off-by: Chema Gonzalez Cc: Eric Dumazet Link: http://lkml.kernel.org/r/1394765455-1217-1-git-send-email-chema@google.com Signed-off-by: Thomas Gleixner --- kernel/irq/proc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index 36f6ee181b0c..ac1ba2f11032 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -324,15 +324,15 @@ void register_irq_proc(unsigned int irq, struct irq_desc *desc) #ifdef CONFIG_SMP /* create /proc/irq//smp_affinity */ - proc_create_data("smp_affinity", 0600, desc->dir, + proc_create_data("smp_affinity", 0644, desc->dir, &irq_affinity_proc_fops, (void *)(long)irq); /* create /proc/irq//affinity_hint */ - proc_create_data("affinity_hint", 0400, desc->dir, + proc_create_data("affinity_hint", 0444, desc->dir, &irq_affinity_hint_proc_fops, (void *)(long)irq); /* create /proc/irq//smp_affinity_list */ - proc_create_data("smp_affinity_list", 0600, desc->dir, + proc_create_data("smp_affinity_list", 0644, desc->dir, &irq_affinity_list_proc_fops, (void *)(long)irq); proc_create_data("node", 0444, desc->dir, @@ -372,7 +372,7 @@ void unregister_handler_proc(unsigned int irq, struct irqaction *action) static void register_default_affinity_proc(void) { #ifdef CONFIG_SMP - proc_create("irq/default_smp_affinity", 0600, NULL, + proc_create("irq/default_smp_affinity", 0644, NULL, &default_affinity_proc_fops); #endif } -- cgit v1.2.3 From d6ee6d2325faeec3fb0122a4840678a2ba62b04b Mon Sep 17 00:00:00 2001 From: Alexander Shiyan Date: Sat, 22 Mar 2014 12:20:31 +0400 Subject: genirq: Export symbol no_action() This will allow to use the dummy IRQ handler no_action() from drivers compiled as module. Drivers which use ARM FIQ interrupts can use this to request the interrupt via the normal request_irq() mechanism w/o having to copy the dummy handler to their own code. Signed-off-by: Alexander Shiyan Link: http://lkml.kernel.org/r/1395476431-16070-1-git-send-email-shc_work@mail.ru Signed-off-by: Thomas Gleixner --- kernel/irq/handle.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c index bfec453557b4..635480270858 100644 --- a/kernel/irq/handle.c +++ b/kernel/irq/handle.c @@ -41,6 +41,7 @@ irqreturn_t no_action(int cpl, void *dev_id) { return IRQ_NONE; } +EXPORT_SYMBOL_GPL(no_action); static void warn_no_thread(unsigned int irq, struct irqaction *action) { -- cgit v1.2.3