[PATCH] irq: clear kstat_irqs

From: Yinghai Lu
Date: Fri Feb 06 2009 - 16:51:47 EST



Impact: get correct kstat_irqs for msi etc

need to call clear_kstat_irqs(), so when reuse that irq_desc, could get correct
kstat in /proc/interrupts

also could make /proc/interrupts don't have none-<NULL> entries

don't need to worry about arch that doesn't support genirq, because they
will not call dynamic_irq_cleanup().

Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>

---
kernel/irq/chip.c | 1 +
kernel/irq/handle.c | 11 +++++++++++
kernel/irq/internals.h | 1 +
3 files changed, 13 insertions(+)

Index: linux-2.6/kernel/irq/chip.c
===================================================================
--- linux-2.6.orig/kernel/irq/chip.c
+++ linux-2.6/kernel/irq/chip.c
@@ -81,6 +81,7 @@ void dynamic_irq_cleanup(unsigned int ir
desc->handle_irq = handle_bad_irq;
desc->chip = &no_irq_chip;
desc->name = NULL;
+ clear_kstat_irqs(desc);
spin_unlock_irqrestore(&desc->lock, flags);
}

Index: linux-2.6/kernel/irq/handle.c
===================================================================
--- linux-2.6.orig/kernel/irq/handle.c
+++ linux-2.6/kernel/irq/handle.c
@@ -270,6 +270,17 @@ struct irq_desc *irq_to_desc_alloc_cpu(u
}
#endif /* !CONFIG_SPARSE_IRQ */

+void clear_kstat_irqs(struct irq_desc *desc)
+{
+ unsigned long bytes;
+ char *ptr;
+
+ ptr = (char *)desc->kstat_irqs;
+ /* Compute how many bytes we need to clear */
+ bytes = nr_cpu_ids * sizeof(unsigned int);
+ memset(ptr, 0, bytes);
+}
+
/*
* What should we do if we get a hw irq event on an illegal vector?
* Each architecture has to answer this themself.
Index: linux-2.6/kernel/irq/internals.h
===================================================================
--- linux-2.6.orig/kernel/irq/internals.h
+++ linux-2.6/kernel/irq/internals.h
@@ -15,6 +15,7 @@ extern int __irq_set_trigger(struct irq_

extern struct lock_class_key irq_desc_lock_class;
extern void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr);
+extern void clear_kstat_irqs(struct irq_desc *desc);
extern spinlock_t sparse_irq_lock;

#ifdef CONFIG_SPARSE_IRQ
--
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