On Thu, 2008-10-23 at 18:06 +0200, Petr Tesarik wrote:
> The new macro LOCK_CONTENDED_FLAGS expands to the correct implementation
> depending on the config options, so that IRQ's are re-enabled when
> possible, but they remain disabled if CONFIG_LOCKDEP is set.
>
> Signed-off-by: Petr Tesarik <ptesarik@xxxxxxx>
Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Sorry, got lost in the inbox...
> ---
> include/linux/lockdep.h | 17 +++++++++++++++++
> kernel/spinlock.c | 12 ++----------
> 2 files changed, 19 insertions(+), 10 deletions(-)
>
> diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
> index 331e5f1..1e6e578 100644
> --- a/include/linux/lockdep.h
> +++ b/include/linux/lockdep.h
> @@ -376,6 +376,23 @@ do
> { \
>
> #endif /* CONFIG_LOCK_STAT */
>
> +#ifdef CONFIG_LOCKDEP
> +
> +/*
> + * On lockdep we dont want the hand-coded irq-enable of
> + * _raw_*_lock_flags() code, because lockdep assumes
> + * that interrupts are not re-enabled during lock-acquire:
> + */
> +#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
> + LOCK_CONTENDED((_lock), (try), (lock))
> +
> +#else /* CONFIG_LOCKDEP */
> +
> +#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
> + lockfl((_lock), (flags))
> +
> +#endif /* CONFIG_LOCKDEP */
> +
> #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_GENERIC_HARDIRQS)
> extern void early_init_irq_lock_class(void);
> #else
> diff --git a/kernel/spinlock.c b/kernel/spinlock.c
> index 29ab207..cf41b87 100644
> --- a/kernel/spinlock.c
> +++ b/kernel/spinlock.c
> @@ -299,16 +299,8 @@ unsigned long __lockfunc
> _spin_lock_irqsave_nested(spinlock_t *lock, int subclas
> local_irq_save(flags);
> preempt_disable();
> spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
> - /*
> - * On lockdep we dont want the hand-coded irq-enable of
> - * _raw_spin_lock_flags() code, because lockdep assumes
> - * that interrupts are not re-enabled during lock-acquire:
> - */
> -#ifdef CONFIG_LOCKDEP
> - LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
> -#else
> - _raw_spin_lock_flags(lock, &flags);
> -#endif
> + LOCK_CONTENDED_FLAGS(lock, _raw_spin_trylock, _raw_spin_lock,
> + _raw_spin_lock_flags, &flags);
> return flags;
> }
> EXPORT_SYMBOL(_spin_lock_irqsave_nested);
>
>
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