Commit fe200ae4 authored by Thomas Gleixner's avatar Thomas Gleixner

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: default avatarThomas Gleixner <tglx@linutronix.de>
parent d05c65ff
......@@ -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 | \
......
......@@ -448,6 +448,13 @@ void handle_nested_irq(unsigned int irq)
}
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);
......
......@@ -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)
{
......
......@@ -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
......
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