genirq: Do not mask oneshot edge type interrupts

Masking oneshot edge type interrupts is wrong as we might lose an
interrupt which is issued when the threaded handler is handling the
device. We can keep the irq unmasked safely as with edge type
interrupts there is no danger of interrupt floods. If the threaded
handler has not yet finished then IRQTF_RUNTHREAD is set which will
keep the handler thread active.

Debugged and verified in preempt-rt.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 5765aad949989567c80a287b695a82221d20ccd2..c1660194d1153a4b55adda2263b752547daa8563 100644 (file)
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -548,13 +548,8 @@ handle_edge_irq(unsigned int irq, struct irq_desc *desc)
        kstat_incr_irqs_this_cpu(irq, desc);
 
        /* Start handling the irq */
-       if (unlikely(desc->status & IRQ_ONESHOT)) {
-               desc->status |= IRQ_MASKED;
-               mask_ack_irq(desc, irq);
-       } else {
-               if (desc->chip->ack)
-                       desc->chip->ack(irq);
-       }
+       if (desc->chip->ack)
+               desc->chip->ack(irq);
 
        /* Mark the IRQ currently in progress.*/
        desc->status |= IRQ_INPROGRESS;