brlocks/lglocks: turn into functions

lglocks and brlocks are currently generated with some complicated macros
in lglock.h.  But there's no reason to not just use common utility
functions and put all the data into a common data structure.

Since there are at least two users it makes sense to share this code in a
library.  This is also easier maintainable than a macro forest.

This will also make it later possible to dynamically allocate lglocks and
also use them in modules (this would both still need some additional, but
now straightforward, code)

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/file_table.c

@@ -34,7 +34,6 @@ struct files_stat_struct files_stat = {
 	.max_files = NR_FILE
 };
 
-DECLARE_LGLOCK(files_lglock);
 DEFINE_LGLOCK(files_lglock);
 
 /* SLAB cache for file structures */

fs/internal.h

@@ -56,7 +56,7 @@ extern int sb_prepare_remount_readonly(struct super_block *);
 
 extern void __init mnt_init(void);
 
-DECLARE_BRLOCK(vfsmount_lock);
+extern struct lglock vfsmount_lock;
 
 
 /*

include/linux/lglock.h

@@ -23,26 +23,17 @@
 #include <linux/lockdep.h>
 #include <linux/percpu.h>
 #include <linux/cpu.h>
+#include <linux/notifier.h>
 
 /* can make br locks by using local lock for read side, global lock for write */
-#define br_lock_init(name)	name##_lock_init()
-#define br_read_lock(name)	name##_local_lock()
-#define br_read_unlock(name)	name##_local_unlock()
-#define br_write_lock(name)	name##_global_lock()
-#define br_write_unlock(name)	name##_global_unlock()
+#define br_lock_init(name)	lg_lock_init(name, #name)
+#define br_read_lock(name)	lg_local_lock(name)
+#define br_read_unlock(name)	lg_local_unlock(name)
+#define br_write_lock(name)	lg_global_lock(name)
+#define br_write_unlock(name)	lg_global_unlock(name)
 
-#define DECLARE_BRLOCK(name)	DECLARE_LGLOCK(name)
 #define DEFINE_BRLOCK(name)	DEFINE_LGLOCK(name)
 
-
-#define lg_lock_init(name)	name##_lock_init()
-#define lg_local_lock(name)	name##_local_lock()
-#define lg_local_unlock(name)	name##_local_unlock()
-#define lg_local_lock_cpu(name, cpu)	name##_local_lock_cpu(cpu)
-#define lg_local_unlock_cpu(name, cpu)	name##_local_unlock_cpu(cpu)
-#define lg_global_lock(name)	name##_global_lock()
-#define lg_global_unlock(name)	name##_global_unlock()
-
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 #define LOCKDEP_INIT_MAP lockdep_init_map
 
@@ -57,90 +48,26 @@
 #define DEFINE_LGLOCK_LOCKDEP(name)
 #endif
 
-
-#define DECLARE_LGLOCK(name)						\
- extern void name##_lock_init(void);					\
- extern void name##_local_lock(void);					\
- extern void name##_local_unlock(void);					\
- extern void name##_local_lock_cpu(int cpu);				\
- extern void name##_local_unlock_cpu(int cpu);				\
- extern void name##_global_lock(void);					\
- extern void name##_global_unlock(void);				\
+struct lglock {
+	arch_spinlock_t __percpu *lock;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lock_class_key lock_key;
+	struct lockdep_map    lock_dep_map;
+#endif
+};
 
 #define DEFINE_LGLOCK(name)						\
-									\
- DEFINE_SPINLOCK(name##_cpu_lock);					\
- DEFINE_PER_CPU(arch_spinlock_t, name##_lock);				\
 	DEFINE_LGLOCK_LOCKDEP(name);					\
-									\
- void name##_lock_init(void) {						\
-	int i;								\
-	LOCKDEP_INIT_MAP(&name##_lock_dep_map, #name, &name##_lock_key, 0); \
-	for_each_possible_cpu(i) {					\
-		arch_spinlock_t *lock;					\
-		lock = &per_cpu(name##_lock, i);			\
-		*lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;	\
-	}								\
- }									\
- EXPORT_SYMBOL(name##_lock_init);					\
-									\
- void name##_local_lock(void) {						\
-	arch_spinlock_t *lock;						\
-	preempt_disable();						\
-	rwlock_acquire_read(&name##_lock_dep_map, 0, 0, _THIS_IP_);	\
-	lock = &__get_cpu_var(name##_lock);				\
-	arch_spin_lock(lock);						\
- }									\
- EXPORT_SYMBOL(name##_local_lock);					\
-									\
- void name##_local_unlock(void) {					\
-	arch_spinlock_t *lock;						\
-	rwlock_release(&name##_lock_dep_map, 1, _THIS_IP_);		\
-	lock = &__get_cpu_var(name##_lock);				\
-	arch_spin_unlock(lock);						\
-	preempt_enable();						\
- }									\
- EXPORT_SYMBOL(name##_local_unlock);					\
-									\
- void name##_local_lock_cpu(int cpu) {					\
-	arch_spinlock_t *lock;						\
-	preempt_disable();						\
-	rwlock_acquire_read(&name##_lock_dep_map, 0, 0, _THIS_IP_);	\
-	lock = &per_cpu(name##_lock, cpu);				\
-	arch_spin_lock(lock);						\
- }									\
- EXPORT_SYMBOL(name##_local_lock_cpu);					\
-									\
- void name##_local_unlock_cpu(int cpu) {				\
-	arch_spinlock_t *lock;						\
-	rwlock_release(&name##_lock_dep_map, 1, _THIS_IP_);		\
-	lock = &per_cpu(name##_lock, cpu);				\
-	arch_spin_unlock(lock);						\
-	preempt_enable();						\
- }									\
- EXPORT_SYMBOL(name##_local_unlock_cpu);				\
-									\
- void name##_global_lock(void) {					\
-	int i;								\
-	preempt_disable();						\
-	rwlock_acquire(&name##_lock_dep_map, 0, 0, _RET_IP_);		\
-	for_each_possible_cpu(i) {					\
-		arch_spinlock_t *lock;					\
-		lock = &per_cpu(name##_lock, i);			\
-		arch_spin_lock(lock);					\
-	}								\
- }									\
- EXPORT_SYMBOL(name##_global_lock);					\
-									\
- void name##_global_unlock(void) {					\
-	int i;								\
-	rwlock_release(&name##_lock_dep_map, 1, _RET_IP_);		\
-	for_each_possible_cpu(i) {					\
-		arch_spinlock_t *lock;					\
-		lock = &per_cpu(name##_lock, i);			\
-		arch_spin_unlock(lock);					\
-	}								\
-	preempt_enable();						\
- }									\
- EXPORT_SYMBOL(name##_global_unlock);
+	DEFINE_PER_CPU(arch_spinlock_t, name ## _lock)			\
+	= __ARCH_SPIN_LOCK_UNLOCKED;					\
+	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);
+void lg_local_lock_cpu(struct lglock *lg, int cpu);
+void lg_local_unlock_cpu(struct lglock *lg, int cpu);
+void lg_global_lock(struct lglock *lg);
+void lg_global_unlock(struct lglock *lg);
+
 #endif

kernel/Makefile

@@ -10,7 +10,7 @@ obj-y     = fork.o exec_domain.o panic.o printk.o \
 	    kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
 	    hrtimer.o rwsem.o nsproxy.o srcu.o semaphore.o \
 	    notifier.o ksysfs.o cred.o \
-	    async.o range.o groups.o
+	    async.o range.o groups.o lglock.o
 
 ifdef CONFIG_FUNCTION_TRACER
 # Do not trace debug files and internal ftrace files

kernel/lglock.c

+/* See include/linux/lglock.h for description */
+#include <linux/module.h>
+#include <linux/lglock.h>
+#include <linux/cpu.h>
+#include <linux/string.h>
+
+/*
+ * Note there is no uninit, so lglocks cannot be defined in
+ * modules (but it's fine to use them from there)
+ * Could be added though, just undo lg_lock_init
+ */
+
+void lg_lock_init(struct lglock *lg, char *name)
+{
+	LOCKDEP_INIT_MAP(&lg->lock_dep_map, name, &lg->lock_key, 0);
+}
+EXPORT_SYMBOL(lg_lock_init);
+
+void lg_local_lock(struct lglock *lg)
+{
+	arch_spinlock_t *lock;
+
+	preempt_disable();
+	rwlock_acquire_read(&lg->lock_dep_map, 0, 0, _RET_IP_);
+	lock = this_cpu_ptr(lg->lock);
+	arch_spin_lock(lock);
+}
+EXPORT_SYMBOL(lg_local_lock);
+
+void lg_local_unlock(struct lglock *lg)
+{
+	arch_spinlock_t *lock;
+
+	rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
+	lock = this_cpu_ptr(lg->lock);
+	arch_spin_unlock(lock);
+	preempt_enable();
+}
+EXPORT_SYMBOL(lg_local_unlock);
+
+void lg_local_lock_cpu(struct lglock *lg, int cpu)
+{
+	arch_spinlock_t *lock;
+
+	preempt_disable();
+	rwlock_acquire_read(&lg->lock_dep_map, 0, 0, _RET_IP_);
+	lock = per_cpu_ptr(lg->lock, cpu);
+	arch_spin_lock(lock);
+}
+EXPORT_SYMBOL(lg_local_lock_cpu);
+
+void lg_local_unlock_cpu(struct lglock *lg, int cpu)
+{
+	arch_spinlock_t *lock;
+
+	rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
+	lock = per_cpu_ptr(lg->lock, cpu);
+	arch_spin_unlock(lock);
+	preempt_enable();
+}
+EXPORT_SYMBOL(lg_local_unlock_cpu);
+
+void lg_global_lock(struct lglock *lg)
+{
+	int i;
+
+	preempt_disable();
+	rwlock_acquire(&lg->lock_dep_map, 0, 0, _RET_IP_);
+	for_each_possible_cpu(i) {
+		arch_spinlock_t *lock;
+		lock = per_cpu_ptr(lg->lock, i);
+		arch_spin_lock(lock);
+	}
+}
+EXPORT_SYMBOL(lg_global_lock);
+
+void lg_global_unlock(struct lglock *lg)
+{
+	int i;
+
+	rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
+	for_each_possible_cpu(i) {
+		arch_spinlock_t *lock;
+		lock = per_cpu_ptr(lg->lock, i);
+		arch_spin_unlock(lock);
+	}
+	preempt_enable();
+}
+EXPORT_SYMBOL(lg_global_unlock);