On 03/19/2013 10:16 PM, Sebastian Andrzej Siewior wrote:
> There are macros for static initializer for the three out of four
> possible notifier types, that are:
> ATOMIC_NOTIFIER_HEAD()
> BLOCKING_NOTIFIER_HEAD()
> RAW_NOTIFIER_HEAD()
>
> This patch provides a static initilizer for the forth type to make it
> complete.
>
> Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
> ---
> include/linux/notifier.h | 26 +++++++++++++++++++++-----
> include/linux/srcu.h | 6 +++---
> 2 files changed, 24 insertions(+), 8 deletions(-)
>
> diff --git a/include/linux/notifier.h b/include/linux/notifier.h
> index d65746e..6bfd703 100644
> --- a/include/linux/notifier.h
> +++ b/include/linux/notifier.h
> @@ -42,9 +42,7 @@
> * in srcu_notifier_call_chain(): no cache bounces and no memory barriers.
> * As compensation, srcu_notifier_chain_unregister() is rather expensive.
> * SRCU notifier chains should be used when the chain will be called very
> - * often but notifier_blocks will seldom be removed. Also, SRCU notifier
> - * chains are slightly more difficult to use because they require special
> - * runtime initialization.
> + * often but notifier_blocks will seldom be removed.
> */
>
> struct notifier_block {
> @@ -85,7 +83,7 @@ struct srcu_notifier_head {
> (name)->head = NULL; \
> } while (0)
>
> -/* srcu_notifier_heads must be initialized and cleaned up dynamically */
> +/* srcu_notifier_heads must be cleaned up dynamically */
> extern void srcu_init_notifier_head(struct srcu_notifier_head *nh);
> #define srcu_cleanup_notifier_head(name) \
> cleanup_srcu_struct(&(name)->srcu);
> @@ -98,7 +96,13 @@ extern void srcu_init_notifier_head(struct
> srcu_notifier_head *nh);
> .head = NULL }
> #define RAW_NOTIFIER_INIT(name) { \
> .head = NULL }
> -/* srcu_notifier_heads cannot be initialized statically */
> +
> +#define SRCU_NOTIFIER_INIT(name, pcpu) \
> + { \
> + .mutex = __MUTEX_INITIALIZER(name.mutex), \
> + .head = NULL, \
> + .srcu = __SRCU_STRUCT_INIT(name.srcu, pcpu), \
> + }
Hi, Sebastian
I don't want to expose __SRCU_STRUCT_INIT(),
due to it has strong coupling with the percpu array.
I hope other structure which uses SRCU should use init_srcu_struct().
Thanks,
Lai
>
> #define ATOMIC_NOTIFIER_HEAD(name) \
> struct atomic_notifier_head name = \
> @@ -110,6 +114,18 @@ extern void srcu_init_notifier_head(struct
> srcu_notifier_head *nh);
> struct raw_notifier_head name = \
> RAW_NOTIFIER_INIT(name)
>
> +#define _SRCU_NOTIFIER_HEAD(name, mod) \
> + static DEFINE_PER_CPU(struct srcu_struct_array, \
> + name##_head_srcu_array); \
> + mod struct srcu_notifier_head name = \
> + SRCU_NOTIFIER_INIT(name, name##_head_srcu_array)
> +
> +#define SRCU_NOTIFIER_HEAD(name) \
> + _SRCU_NOTIFIER_HEAD(name, )
> +
> +#define SRCU_NOTIFIER_HEAD_STATIC(name) \
> + _SRCU_NOTIFIER_HEAD(name, static)
> +
> #ifdef __KERNEL__
>
> extern int atomic_notifier_chain_register(struct atomic_notifier_head *nh,
> diff --git a/include/linux/srcu.h b/include/linux/srcu.h
> index d04acb8..fe9efd4 100644
> --- a/include/linux/srcu.h
> +++ b/include/linux/srcu.h
> @@ -84,10 +84,10 @@ int init_srcu_struct(struct srcu_struct *sp);
>
> void process_srcu(struct work_struct *work);
>
> -#define __SRCU_STRUCT_INIT(name) \
> +#define __SRCU_STRUCT_INIT(name, pcpu_name) \
> { \
> .completed = -300, \
> - .per_cpu_ref = &name##_srcu_array, \
> + .per_cpu_ref = &pcpu_name, \
> .queue_lock = __SPIN_LOCK_UNLOCKED(name.queue_lock), \
> .running = false, \
> .batch_queue = RCU_BATCH_INIT(name.batch_queue), \
> @@ -105,7 +105,7 @@ void process_srcu(struct work_struct *work);
> #define _DEFINE_SRCU(name, mod)
> \
> static DEFINE_PER_CPU(struct srcu_struct_array, name##_srcu_array);\
> mod struct srcu_struct name = \
> - __SRCU_STRUCT_INIT(name);
> + __SRCU_STRUCT_INIT(name, name##_srcu_array);
>
> #define DEFINE_SRCU(name) _DEFINE_SRCU(name, )
> #define DEFINE_STATIC_SRCU(name) _DEFINE_SRCU(name, static)
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