locking, irq: enclose irq_desc_lock_class in CONFIG_LOCKDEP
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>
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 29aec6e..9dba554 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -377,7 +377,7 @@
#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)
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index f1a2306..6492400 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -422,11 +422,8 @@
}
#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 @@
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)