Re: [PATCH 3/3] lglock: add DEFINE_STATIC_LGLOCK()

From: Andrew Morton
Date: Tue Oct 09 2012 - 17:48:35 EST


On Tue, 9 Oct 2012 11:46:40 +0800
Lai Jiangshan <laijs@xxxxxxxxxxxxxx> wrote:

> When if the lglock don't to be exported,
> we can use DEFINE_STATIC_LGLOCK().
>
> --- a/include/linux/lglock.h
> +++ b/include/linux/lglock.h
> @@ -32,7 +32,8 @@
> #define br_write_lock(name) lg_global_lock(name)
> #define br_write_unlock(name) lg_global_unlock(name)
>
> -#define DEFINE_BRLOCK(name) DEFINE_LGLOCK(name)
> +#define DEFINE_BRLOCK(name) DEFINE_LGLOCK(name)
> +#define DEFINE_STATIC_BRLOCK(name) DEFINE_STATIC_LGLOCK(name)
>
> #ifdef CONFIG_DEBUG_LOCK_ALLOC
> #define LOCKDEP_INIT_MAP lockdep_init_map
> @@ -53,6 +54,11 @@ struct lglock {
> = __ARCH_SPIN_LOCK_UNLOCKED; \
> struct lglock name = { .lock = &name ## _lock }
>
> +#define DEFINE_STATIC_LGLOCK(name) \
> + static DEFINE_PER_CPU(arch_spinlock_t, name ## _lock) \
> + = __ARCH_SPIN_LOCK_UNLOCKED; \
> + static struct lglock name = { .lock = &name ## _lock }
> +
> void lg_lock_init(struct lglock *lg, char *name);
> void lg_local_lock(struct lglock *lg);
> void lg_local_unlock(struct lglock *lg);

hm, this is a bit sad. It would be better if we could do

static DEFINE_LGLOCK(foo);

but I don't immediately see a way in which we can rework
DEFINE_LGLOCK() to permit that.

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