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Diffstat (limited to 'kernel/irq/manage.c')
-rw-r--r--kernel/irq/manage.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index eb6078ca60c7..398fda155f6e 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -382,6 +382,7 @@ int can_request_irq(unsigned int irq, unsigned long irqflags)
{
struct irq_desc *desc = irq_to_desc(irq);
struct irqaction *action;
+ unsigned long flags;
if (!desc)
return 0;
@@ -389,11 +390,14 @@ int can_request_irq(unsigned int irq, unsigned long irqflags)
if (desc->status & IRQ_NOREQUEST)
return 0;
+ raw_spin_lock_irqsave(&desc->lock, flags);
action = desc->action;
if (action)
if (irqflags & action->flags & IRQF_SHARED)
action = NULL;
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+
return !action;
}
@@ -483,8 +487,26 @@ static int irq_wait_for_interrupt(struct irqaction *action)
*/
static void irq_finalize_oneshot(unsigned int irq, struct irq_desc *desc)
{
+again:
chip_bus_lock(irq, desc);
raw_spin_lock_irq(&desc->lock);
+
+ /*
+ * Implausible though it may be we need to protect us against
+ * the following scenario:
+ *
+ * The thread is faster done than the hard interrupt handler
+ * on the other CPU. If we unmask the irq line then the
+ * interrupt can come in again and masks the line, leaves due
+ * to IRQ_INPROGRESS and the irq line is masked forever.
+ */
+ if (unlikely(desc->status & IRQ_INPROGRESS)) {
+ raw_spin_unlock_irq(&desc->lock);
+ chip_bus_sync_unlock(irq, desc);
+ cpu_relax();
+ goto again;
+ }
+
if (!(desc->status & IRQ_DISABLED) && (desc->status & IRQ_MASKED)) {
desc->status &= ~IRQ_MASKED;
desc->chip->unmask(irq);