Patchwork [v2,18/26] genirq: Bail out early in free_desc()

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Submitter Yinghai Lu
Date Feb. 8, 2013, 7:28 p.m.
Message ID <>
Download mbox | patch
Permalink /patch/219264/
State Not Applicable
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Yinghai Lu - Feb. 8, 2013, 7:28 p.m.
We pre-reserve irq range for hot-added ioapic, and later only
some are used via realloc.
So during hot-remove, we need to clear bits in allocated_irqs
for both case.

Check if the irq_desc is there at first, and bail out early if
irq_desc is not allocated yet.

So we can use irq_free_descs to clear allocated_irqs bits for
preserved irqs.

Signed-off-by: Yinghai Lu <>
 kernel/irq/irqdesc.c |    3 +++
 1 file changed, 3 insertions(+)


diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index b48f65b..32f099e 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -170,6 +170,9 @@  static void free_desc(unsigned int irq)
 	struct irq_desc *desc = irq_to_desc(irq);
+	if (!desc)
+		return;
 	unregister_irq_proc(irq, desc);