From: Sebastian Andrzej Siewior 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 --- include/linux/notifier.h | 42 +++++++++++++++++++++++++++++++++--------- include/linux/srcutiny.h | 6 +++--- include/linux/srcutree.h | 6 +++--- 3 files changed, 39 insertions(+), 15 deletions(-) --- a/include/linux/notifier.h +++ b/include/linux/notifier.h @@ -7,7 +7,7 @@ * * Alan Cox */ - + #ifndef _LINUX_NOTIFIER_H #define _LINUX_NOTIFIER_H #include @@ -43,9 +43,7 @@ * 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; @@ -91,7 +89,7 @@ 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); @@ -104,7 +102,13 @@ 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 = \ @@ -116,6 +120,26 @@ extern void srcu_init_notifier_head(stru struct raw_notifier_head name = \ RAW_NOTIFIER_INIT(name) +#ifdef CONFIG_TREE_SRCU +#define _SRCU_NOTIFIER_HEAD(name, mod) \ + static DEFINE_PER_CPU(struct srcu_data, \ + name##_head_srcu_data); \ + mod struct srcu_notifier_head name = \ + SRCU_NOTIFIER_INIT(name, name##_head_srcu_data) + +#else +#define _SRCU_NOTIFIER_HEAD(name, mod) \ + mod struct srcu_notifier_head name = \ + SRCU_NOTIFIER_INIT(name, name) + +#endif + +#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, @@ -185,12 +209,12 @@ 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/srcutiny.h +++ b/include/linux/srcutiny.h @@ -43,7 +43,7 @@ struct srcu_struct { void srcu_drive_gp(struct work_struct *wp); -#define __SRCU_STRUCT_INIT(name) \ +#define __SRCU_STRUCT_INIT(name, __ignored) \ { \ .srcu_wq = __SWAIT_QUEUE_HEAD_INITIALIZER(name.srcu_wq), \ .srcu_cb_tail = &name.srcu_cb_head, \ @@ -56,9 +56,9 @@ void srcu_drive_gp(struct work_struct *w * Tree SRCU, which needs some per-CPU data. */ #define DEFINE_SRCU(name) \ - struct srcu_struct name = __SRCU_STRUCT_INIT(name) + struct srcu_struct name = __SRCU_STRUCT_INIT(name, name) #define DEFINE_STATIC_SRCU(name) \ - static struct srcu_struct name = __SRCU_STRUCT_INIT(name) + static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name) void synchronize_srcu(struct srcu_struct *sp); --- a/include/linux/srcutree.h +++ b/include/linux/srcutree.h @@ -104,9 +104,9 @@ struct srcu_struct { #define SRCU_STATE_SCAN1 1 #define SRCU_STATE_SCAN2 2 -#define __SRCU_STRUCT_INIT(name) \ +#define __SRCU_STRUCT_INIT(name, pcpu_name) \ { \ - .sda = &name##_srcu_data, \ + .sda = &pcpu_name, \ .lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \ .srcu_gp_seq_needed = 0 - 1, \ __SRCU_DEP_MAP_INIT(name) \ @@ -133,7 +133,7 @@ struct srcu_struct { */ #define __DEFINE_SRCU(name, is_static) \ static DEFINE_PER_CPU(struct srcu_data, name##_srcu_data);\ - is_static struct srcu_struct name = __SRCU_STRUCT_INIT(name) + is_static struct srcu_struct name = __SRCU_STRUCT_INIT(name, name##_srcu_data) #define DEFINE_SRCU(name) __DEFINE_SRCU(name, /* not static */) #define DEFINE_STATIC_SRCU(name) __DEFINE_SRCU(name, static)