| From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| Date: Tue, 19 Mar 2013 14:44:30 +0100 |
| Subject: kernel/SRCU: provide a static initializer |
| |
| 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 <bigeasy@linutronix.de> |
| --- |
| include/linux/notifier.h | 34 +++++++++++++++++++++++++--------- |
| include/linux/srcu.h | 6 +++--- |
| 2 files changed, 28 insertions(+), 12 deletions(-) |
| |
| --- a/include/linux/notifier.h |
| +++ b/include/linux/notifier.h |
| @@ -6,7 +6,7 @@ |
| * |
| * Alan Cox <Alan.Cox@linux.org> |
| */ |
| - |
| + |
| #ifndef _LINUX_NOTIFIER_H |
| #define _LINUX_NOTIFIER_H |
| #include <linux/errno.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; |
| @@ -90,7 +88,7 @@ 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); |
| @@ -103,7 +101,13 @@ extern void srcu_init_notifier_head(stru |
| .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), \ |
| + } |
| |
| #define ATOMIC_NOTIFIER_HEAD(name) \ |
| struct atomic_notifier_head name = \ |
| @@ -115,6 +119,18 @@ extern void srcu_init_notifier_head(stru |
| 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, |
| @@ -184,12 +200,12 @@ static inline int notifier_to_errno(int |
| |
| /* |
| * Declared notifiers so far. I can imagine quite a few more chains |
| - * over time (eg laptop power reset chains, reboot chain (to clean |
| + * over time (eg laptop power reset chains, reboot chain (to clean |
| * device units up), device [un]mount chain, module load/unload chain, |
| - * low memory chain, screenblank chain (for plug in modular screenblankers) |
| + * low memory chain, screenblank chain (for plug in modular screenblankers) |
| * VC switch chains (for loadable kernel svgalib VC switch helpers) etc... |
| */ |
| - |
| + |
| /* CPU notfiers are defined in include/linux/cpu.h. */ |
| |
| /* netdevice notifiers are defined in include/linux/netdevice.h */ |
| --- a/include/linux/srcu.h |
| +++ b/include/linux/srcu.h |
| @@ -84,10 +84,10 @@ int init_srcu_struct(struct srcu_struct |
| |
| 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), \ |
| @@ -119,7 +119,7 @@ void process_srcu(struct work_struct *wo |
| */ |
| #define __DEFINE_SRCU(name, is_static) \ |
| static DEFINE_PER_CPU(struct srcu_struct_array, name##_srcu_array);\ |
| - is_static struct srcu_struct name = __SRCU_STRUCT_INIT(name) |
| + is_static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name##_srcu_array) |
| #define DEFINE_SRCU(name) __DEFINE_SRCU(name, /* not static */) |
| #define DEFINE_STATIC_SRCU(name) __DEFINE_SRCU(name, static) |
| |