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locking, irq: enclose irq_desc_lock_class in CONFIG_LOCKDEP

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Impact: simplify code

commit "08678b0: generic: sparse irqs: use irq_desc() [...]" introduced
the irq_desc_lock_class variable.

But it is used only if CONFIG_SPARSE_IRQ=Y or CONFIG_TRACE_IRQFLAGS=Y.
Otherwise, following warnings happen:

	CC      kernel/irq/handle.o
	kernel/irq/handle.c:26: warning: 'irq_desc_lock_class' defined but not used

Actually, current early_init_irq_lock_class has a bit strange and messy ifdef.
In addition, it is not valueable.

1. this function is protected by !CONFIG_SPARSE_IRQ, but that is not necessary.
   if CONFIG_SPARSE_IRQ=Y, desc of all irq number are initialized by NULL
   at first - then this function calling is safe.

2. this function protected by CONFIG_TRACE_IRQFLAGS too. but it is not
   necessary either, because lockdep_set_class() doesn't have bad side
   effect even if CONFIG_TRACE_IRQFLAGS=n.

This patch bloat kernel size a bit on CONFIG_TRACE_IRQFLAGS=n and
CONFIG_SPARSE_IRQ=Y - but that's ok. early_init_irq_lock_class() is not
a fastpatch at all.

To avoid messy ifdefs is more important than a few bytes diet.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
KOSAKI Motohiro 2008-12-17 19:40:33 +09:00 committed by Ingo Molnar
parent 6f8a0ed4e5
commit 74c8a61304
2 changed files with 1 additions and 6 deletions
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2
include/linux/lockdep.h
View file

@ -377,7 +377,7 @@ do { \
#endif /* CONFIG_LOCK_STAT */
#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_GENERIC_HARDIRQS)
#ifdef CONFIG_GENERIC_HARDIRQS
extern void early_init_irq_lock_class(void);
#else
static inline void early_init_irq_lock_class(void)

5
kernel/irq/handle.c
View file

@ -422,11 +422,8 @@ unsigned int __do_IRQ(unsigned int irq)
}
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
void early_init_irq_lock_class(void)
{
#ifndef CONFIG_SPARSE_IRQ
struct irq_desc *desc;
int i;
@ -436,9 +433,7 @@ void early_init_irq_lock_class(void)
lockdep_set_class(&desc->lock, &irq_desc_lock_class);
}
#endif
}
#endif
#ifdef CONFIG_SPARSE_IRQ
unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)