From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Tue, 19 Mar 2013 14:44:30 +0100
Subject: kernel/SRCU: provide a static initializer
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git
Git-commit: a0b0a24539ca3eb9a1cc0ead6c5441cb8343aec6
Patch-mainline: Queued in subsystem maintainer repository
References: SLE Realtime Extension
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>
Signed-off-by: Mike Galbraith <mgalbraith@suse.de>
---
include/linux/notifier.h | 46 +++++++++++++++++++++++++++++++++++---------
include/linux/srcuclassic.h | 6 ++---
include/linux/srcutiny.h | 6 ++---
include/linux/srcutree.h | 6 ++---
4 files changed, 46 insertions(+), 18 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 +119,30 @@ extern void srcu_init_notifier_head(stru
struct raw_notifier_head name = \
RAW_NOTIFIER_INIT(name)
+#if defined(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)
+#elif defined(CONFIG_CLASSIC_SRCU)
+#define _SRCU_NOTIFIER_HEAD(name, mod) \
+ static DEFINE_PER_CPU(struct srcu_array, \
+ name##_head_srcu_array); \
+ mod struct srcu_notifier_head name = \
+ SRCU_NOTIFIER_INIT(name, name##_head_srcu_array)
+#elif defined(CONFIG_TINY_SRCU)
+#define _SRCU_NOTIFIER_HEAD(name, mod) \
+ mod struct srcu_notifier_head name = \
+ SRCU_NOTIFIER_INIT(name, /* unused */)
+#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,
@@ -184,12 +212,12 @@ 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/srcuclassic.h
+++ b/include/linux/srcuclassic.h
@@ -55,10 +55,10 @@ 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), \
@@ -90,7 +90,7 @@ void process_srcu(struct work_struct *wo
*/
#define __DEFINE_SRCU(name, is_static) \
static DEFINE_PER_CPU(struct srcu_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)
--- a/include/linux/srcutiny.h
+++ b/include/linux/srcutiny.h
@@ -44,7 +44,7 @@ struct srcu_struct {
void srcu_drive_gp(struct work_struct *wp);
-#define __SRCU_STRUCT_INIT(name) \
+#define __SRCU_STRUCT_INIT(name, pcpu_name) \
{ \
.srcu_wq = __SWAIT_QUEUE_HEAD_INITIALIZER(name.srcu_wq), \
.srcu_cblist = RCU_SEGCBLIST_INITIALIZER(name.srcu_cblist), \
@@ -57,9 +57,9 @@ 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, /* unused */)
#define DEFINE_STATIC_SRCU(name) \
- static struct srcu_struct name = __SRCU_STRUCT_INIT(name)
+ static struct srcu_struct name = __SRCU_STRUCT_INIT(name, /* unused */)
void synchronize_srcu(struct srcu_struct *sp);
--- a/include/linux/srcutree.h
+++ b/include/linux/srcutree.h
@@ -106,9 +106,9 @@ struct srcu_struct {
void process_srcu(struct work_struct *work);
-#define __SRCU_STRUCT_INIT(name) \
+#define __SRCU_STRUCT_INIT(name, pcpu_name) \
{ \
- .sda = &name##_srcu_data, \
+ .sda = &pcpu_name, \
.gp_lock = __SPIN_LOCK_UNLOCKED(name.gp_lock), \
.srcu_gp_seq_needed = 0 - 1, \
__SRCU_DEP_MAP_INIT(name) \
@@ -135,7 +135,7 @@ void process_srcu(struct work_struct *wo
*/
#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)