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SubjectRe: [PATCH 1/2] lockdep: spin_lock_irqsave_nested()
Here are some doubts...

Jarek P.

On 30-10-2006 10:03, Peter Zijlstra wrote:
> From: Arjan van de Ven <arjan@linux.intel.com>
> Subject: spin_lock_irqsave_nested()
>
> Introduce spin_lock_irqsave_nested(); implementation from:
> http://lkml.org/lkml/2006/6/1/122
> Patch from:
> http://lkml.org/lkml/2006/9/13/258
>
> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
> Signed-off-by: Jiri Kosina <jikos@jikos.cz>
> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
> ---
> include/linux/spinlock.h | 5 +++++
> include/linux/spinlock_api_smp.h | 2 ++
> include/linux/spinlock_api_up.h | 1 +
> kernel/spinlock.c | 21 +++++++++++++++++++++
> 4 files changed, 29 insertions(+)
>
> Index: linux-2.6/include/linux/spinlock_api_smp.h
> ===================================================================
> --- linux-2.6.orig/include/linux/spinlock_api_smp.h
> +++ linux-2.6/include/linux/spinlock_api_smp.h
> @@ -32,6 +32,8 @@ void __lockfunc _read_lock_irq(rwlock_t
> void __lockfunc _write_lock_irq(rwlock_t *lock) __acquires(lock);
> unsigned long __lockfunc _spin_lock_irqsave(spinlock_t *lock)
> __acquires(lock);
> +unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclass)
> + __acquires(spinlock_t);

According to neighbours rather:
+ __acquires(lock);

> unsigned long __lockfunc _read_lock_irqsave(rwlock_t *lock)
> __acquires(lock);
> unsigned long __lockfunc _write_lock_irqsave(rwlock_t *lock)
> Index: linux-2.6/include/linux/spinlock_api_up.h
> ===================================================================
> --- linux-2.6.orig/include/linux/spinlock_api_up.h
> +++ linux-2.6/include/linux/spinlock_api_up.h
> @@ -59,6 +59,7 @@
> #define _read_lock_irq(lock) __LOCK_IRQ(lock)
> #define _write_lock_irq(lock) __LOCK_IRQ(lock)
> #define _spin_lock_irqsave(lock, flags) __LOCK_IRQSAVE(lock, flags)
> +#define _spin_lock_irqsave_nested(lock, flags, subclass) __LOCK_IRQSAVE(lock, flags, subclass)

Is __LOCK_IRQSAVE() with 3 args defined?

> #define _read_lock_irqsave(lock, flags) __LOCK_IRQSAVE(lock, flags)
> #define _write_lock_irqsave(lock, flags) __LOCK_IRQSAVE(lock, flags)
> #define _spin_trylock(lock) ({ __LOCK(lock); 1; })
> Index: linux-2.6/include/linux/spinlock.h
> ===================================================================
> --- linux-2.6.orig/include/linux/spinlock.h
> +++ linux-2.6/include/linux/spinlock.h
> @@ -186,6 +186,11 @@ do { \
> #define spin_lock_irqsave(lock, flags) flags = _spin_lock_irqsave(lock)
> #define read_lock_irqsave(lock, flags) flags = _read_lock_irqsave(lock)
> #define write_lock_irqsave(lock, flags) flags = _write_lock_irqsave(lock)
> +#ifdef CONFIG_DEBUG_LOCK_ALLOC
> +#define spin_lock_irqsave_nested(lock, flags, subclass) flags = _spin_lock_irqsave_nested(lock, subclass)
> +#else
> +#define spin_lock_irqsave_nested(lock, flags, subclass) flags = _spin_lock_irqsave(lock)
> +#endif
> #else

Plus for api_up:

+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+#define spin_lock_irqsave_nested(lock, flags, subclass) _spin_lock_irqsave_nested(lock, flags, subclass)
+#else
+#define spin_lock_irqsave_nested(lock, flags, subclass) _spin_lock_irqsave(lock, flags)
+#endif

> #define spin_lock_irqsave(lock, flags) _spin_lock_irqsave(lock, flags)
> #define read_lock_irqsave(lock, flags) _read_lock_irqsave(lock, flags)
> Index: linux-2.6/kernel/spinlock.c
> ===================================================================
> --- linux-2.6.orig/kernel/spinlock.c
> +++ linux-2.6/kernel/spinlock.c
> @@ -293,6 +293,27 @@ void __lockfunc _spin_lock_nested(spinlo
> }
>
> EXPORT_SYMBOL(_spin_lock_nested);
> +unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclass)
> +{
> + unsigned long flags;
> +
> + 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_PROVE_SPIN_LOCKING
> + _raw_spin_lock(lock);
> +#else
> + _raw_spin_lock_flags(lock, &flags);
> +#endif
> + return flags;
> +}
> +
> +EXPORT_SYMBOL(_spin_lock_irqsave_nested);
>
> #endif
>
>

Shouldn't this _nested locks be considered in:
#else /* CONFIG_PREEMPT: */
part?
-
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