From fe200ae48ef5c79bf7941fe8046ff9505c570ff6 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 7 Feb 2011 10:34:30 +0100 Subject: 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 --- kernel/irq/spurious.c | 51 +++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 39 insertions(+), 12 deletions(-) (limited to 'kernel/irq/spurious.c') 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 -- cgit v1.2.3