From fe200ae48ef5c79bf7941fe8046ff9505c570ff6 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 7 Feb 2011 10:34:30 +0100 Subject: [PATCH] genirq: Mark polled irqs and defer the real handler With the chip.end() function gone we might run into a situation where a poll call runs and the real interrupt comes in, sees IRQ_INPROGRESS and disables the line. That might be a perfect working one, which will then be masked forever. So mark them polled while the poll runs. When the real handler sees IRQ_INPROGRESS it checks the poll flag and waits for the polling to complete. Add the necessary amount of sanity checks to it to avoid deadlocks. Signed-off-by: Thomas Gleixner --- include/linux/irq.h | 1 + kernel/irq/chip.c | 26 ++++++++++++++++----- kernel/irq/internals.h | 11 +-------- kernel/irq/spurious.c | 51 ++++++++++++++++++++++++++++++++---------- 4 files changed, 61 insertions(+), 28 deletions(-) diff --git a/include/linux/irq.h b/include/linux/irq.h index f5e900309d21..e32b64ccdc89 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -71,6 +71,7 @@ typedef void (*irq_flow_handler_t)(unsigned int irq, #define IRQ_SUSPENDED 0x04000000 /* IRQ has gone through suspend sequence */ #define IRQ_ONESHOT 0x08000000 /* IRQ is not unmasked after hardirq */ #define IRQ_NESTED_THREAD 0x10000000 /* IRQ is nested into another, no own handler thread */ +#define IRQ_POLL_INPROGRESS 0x20000000 /* IRQ poll is in progress */ #define IRQF_MODIFY_MASK \ (IRQ_TYPE_SENSE_MASK | IRQ_NOPROBE | IRQ_NOREQUEST | \ diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index 622b55ac0e09..31258782742c 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -448,6 +448,13 @@ out_unlock: } EXPORT_SYMBOL_GPL(handle_nested_irq); +static bool irq_check_poll(struct irq_desc *desc) +{ + if (!(desc->status & IRQ_POLL_INPROGRESS)) + return false; + return irq_wait_for_poll(desc); +} + /** * handle_simple_irq - Simple and software-decoded IRQs. * @irq: the interrupt number @@ -469,7 +476,9 @@ handle_simple_irq(unsigned int irq, struct irq_desc *desc) raw_spin_lock(&desc->lock); if (unlikely(desc->status & IRQ_INPROGRESS)) - goto out_unlock; + if (!irq_check_poll(desc)) + goto out_unlock; + desc->status &= ~(IRQ_REPLAY | IRQ_WAITING); kstat_incr_irqs_this_cpu(irq, desc); @@ -510,7 +519,9 @@ handle_level_irq(unsigned int irq, struct irq_desc *desc) mask_ack_irq(desc); if (unlikely(desc->status & IRQ_INPROGRESS)) - goto out_unlock; + if (!irq_check_poll(desc)) + goto out_unlock; + desc->status &= ~(IRQ_REPLAY | IRQ_WAITING); kstat_incr_irqs_this_cpu(irq, desc); @@ -558,7 +569,8 @@ handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc) raw_spin_lock(&desc->lock); if (unlikely(desc->status & IRQ_INPROGRESS)) - goto out; + if (!irq_check_poll(desc)) + goto out; desc->status &= ~(IRQ_REPLAY | IRQ_WAITING); kstat_incr_irqs_this_cpu(irq, desc); @@ -620,9 +632,11 @@ handle_edge_irq(unsigned int irq, struct irq_desc *desc) */ if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) || !desc->action)) { - desc->status |= (IRQ_PENDING | IRQ_MASKED); - mask_ack_irq(desc); - goto out_unlock; + if (!irq_check_poll(desc)) { + desc->status |= (IRQ_PENDING | IRQ_MASKED); + mask_ack_irq(desc); + goto out_unlock; + } } kstat_incr_irqs_this_cpu(irq, desc); diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index b5bfa24aa6a6..0eff7e92b1a9 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -28,6 +28,7 @@ extern void init_kstat_irqs(struct irq_desc *desc, int node, int nr); /* Resending of interrupts :*/ void check_irq_resend(struct irq_desc *desc, unsigned int irq); +bool irq_wait_for_poll(struct irq_desc *desc); #ifdef CONFIG_PROC_FS extern void register_irq_proc(unsigned int irq, struct irq_desc *desc); @@ -47,16 +48,6 @@ extern int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask); extern void irq_set_thread_affinity(struct irq_desc *desc); -#ifndef CONFIG_GENERIC_HARDIRQS_NO_DEPRECATED -static inline void irq_end(unsigned int irq, struct irq_desc *desc) -{ - if (desc->irq_data.chip && desc->irq_data.chip->end) - desc->irq_data.chip->end(irq); -} -#else -static inline void irq_end(unsigned int irq, struct irq_desc *desc) { } -#endif - /* Inline functions for support of irq chips on slow busses */ static inline void chip_bus_lock(struct irq_desc *desc) { diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c index 56ff8fffb8b0..f749d29bfd81 100644 --- a/kernel/irq/spurious.c +++ b/kernel/irq/spurious.c @@ -24,13 +24,45 @@ static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0); static int irq_poll_cpu; static atomic_t irq_poll_active; +/* + * We wait here for a poller to finish. + * + * If the poll runs on this CPU, then we yell loudly and return + * false. That will leave the interrupt line disabled in the worst + * case, but it should never happen. + * + * We wait until the poller is done and then recheck disabled and + * action (about to be disabled). Only if it's still active, we return + * true and let the handler run. + */ +bool irq_wait_for_poll(struct irq_desc *desc) +{ + if (WARN_ONCE(irq_poll_cpu == smp_processor_id(), + "irq poll in progress on cpu %d for irq %d\n", + smp_processor_id(), desc->irq_data.irq)) + return false; + +#ifdef CONFIG_SMP + do { + raw_spin_unlock(&desc->lock); + while (desc->status & IRQ_INPROGRESS) + cpu_relax(); + raw_spin_lock(&desc->lock); + } while (desc->status & IRQ_INPROGRESS); + /* Might have been disabled in meantime */ + return !(desc->status & IRQ_DISABLED) && desc->action; +#else + return false; +#endif +} + /* * Recovery handler for misrouted interrupts. */ static int try_one_irq(int irq, struct irq_desc *desc, bool force) { struct irqaction *action; - int ok = 0, work = 0; + int ok = 0; raw_spin_lock(&desc->lock); @@ -64,10 +96,9 @@ static int try_one_irq(int irq, struct irq_desc *desc, bool force) goto out; } - /* Honour the normal IRQ locking */ - desc->status |= IRQ_INPROGRESS; + /* Honour the normal IRQ locking and mark it poll in progress */ + desc->status |= IRQ_INPROGRESS | IRQ_POLL_INPROGRESS; do { - work++; desc->status &= ~IRQ_PENDING; raw_spin_unlock(&desc->lock); if (handle_IRQ_event(irq, action) != IRQ_NONE) @@ -76,14 +107,7 @@ static int try_one_irq(int irq, struct irq_desc *desc, bool force) action = desc->action; } while ((desc->status & IRQ_PENDING) && action); - desc->status &= ~IRQ_INPROGRESS; - /* - * If we did actual work for the real IRQ line we must let the - * IRQ controller clean up too - */ - if (work > 1) - irq_end(irq, desc); - + desc->status &= ~(IRQ_INPROGRESS | IRQ_POLL_INPROGRESS); out: raw_spin_unlock(&desc->lock); return ok; @@ -238,6 +262,9 @@ try_misrouted_irq(unsigned int irq, struct irq_desc *desc, void note_interrupt(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret) { + if (desc->status & IRQ_POLL_INPROGRESS) + return; + if (unlikely(action_ret != IRQ_HANDLED)) { /* * If we are seeing only the odd spurious IRQ caused by