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

[Andrew Morton]

On Tue, 9 Oct 2012 11:46:40 +0800
Lai Jiangshan  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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[PATCH 3/3] lglock: add DEFINE_STATIC_LGLOCK()

[Lai Jiangshan]

When if the lglock don't to be exported,
we can use DEFINE_STATIC_LGLOCK().

Signed-off-by: Lai Jiangshan 
---
 fs/file_table.c|2 +-
 include/linux/lglock.h |8 +++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/fs/file_table.c b/fs/file_table.c
index 701985e..e26fd31 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -36,7 +36,7 @@ struct files_stat_struct files_stat = {
.max_files = NR_FILE
 };
 
-DEFINE_LGLOCK(files_lglock);
+DEFINE_STATIC_LGLOCK(files_lglock);
 
 /* SLAB cache for file structures */
 static struct kmem_cache *filp_cachep __read_mostly;
diff --git a/include/linux/lglock.h b/include/linux/lglock.h
index 8f97451..0d24e93 100644
--- 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);
-- 
1.7.4.4

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