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Commit 9dd6fa03 authored by Rusty Russell's avatar Rusty Russell Committed by Al Viro
Browse files

lglock: remove online variants of lock 



Optimizing the slow paths adds a lot of complexity.  If you need to
grab every lock often, you have other problems.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Acked-by: default avatarNick Piggin <npiggin@kernel.dk>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent ea022dfb

include/linux/lglock.h

+2 −56
Original line number Diff line number Diff line
@@ -28,8 +28,8 @@ 
#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_online()

#define br_write_unlock(name)	name##_global_unlock_online()

#define br_write_lock(name)	name##_global_lock()

#define br_write_unlock(name)	name##_global_unlock()



#define DECLARE_BRLOCK(name)	DECLARE_LGLOCK(name)

#define DEFINE_BRLOCK(name)	DEFINE_LGLOCK(name)
@@ -42,8 +42,6 @@ 
#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()

#define lg_global_lock_online(name) name##_global_lock_online()

#define lg_global_unlock_online(name) name##_global_unlock_online()



#ifdef CONFIG_DEBUG_LOCK_ALLOC

#define LOCKDEP_INIT_MAP lockdep_init_map
@@ -68,36 +66,13 @@ 
 extern void name##_local_unlock_cpu(int cpu);				\

 extern void name##_global_lock(void);					\

 extern void name##_global_unlock(void);				\

 extern void name##_global_lock_online(void);				\

 extern void name##_global_unlock_online(void);				\



#define DEFINE_LGLOCK(name)						\

									\

 DEFINE_SPINLOCK(name##_cpu_lock);					\

 cpumask_t name##_cpus __read_mostly;					\

 DEFINE_PER_CPU(arch_spinlock_t, name##_lock);				\

 DEFINE_LGLOCK_LOCKDEP(name);						\

									\

 static int								\

 name##_lg_cpu_callback(struct notifier_block *nb,			\

				unsigned long action, void *hcpu)	\

 {									\

	switch (action & ~CPU_TASKS_FROZEN) {				\

	case CPU_UP_PREPARE:						\

		spin_lock(&name##_cpu_lock);				\

		cpu_set((unsigned long)hcpu, name##_cpus);		\

		spin_unlock(&name##_cpu_lock);				\

		break;							\

	case CPU_UP_CANCELED: case CPU_DEAD:				\

		spin_lock(&name##_cpu_lock);				\

		cpu_clear((unsigned long)hcpu, name##_cpus);		\

		spin_unlock(&name##_cpu_lock);				\

	}								\

	return NOTIFY_OK;						\

 }									\

 static struct notifier_block name##_lg_cpu_notifier = {		\

	.notifier_call = name##_lg_cpu_callback,			\

 };									\

 void name##_lock_init(void) {						\

	int i;								\

	LOCKDEP_INIT_MAP(&name##_lock_dep_map, #name, &name##_lock_key, 0); \
@@ -106,11 +81,6 @@ 
		lock = &per_cpu(name##_lock, i);			\

		*lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;	\

	}								\

	register_hotcpu_notifier(&name##_lg_cpu_notifier);		\

	get_online_cpus();						\

	for_each_online_cpu(i)						\

		cpu_set(i, name##_cpus);				\

	put_online_cpus();						\

 }									\

 EXPORT_SYMBOL(name##_lock_init);					\

									\
@@ -150,30 +120,6 @@ 
 }									\

 EXPORT_SYMBOL(name##_local_unlock_cpu);				\

									\

 void name##_global_lock_online(void) {					\

	int i;								\

	spin_lock(&name##_cpu_lock);					\

	rwlock_acquire(&name##_lock_dep_map, 0, 0, _RET_IP_);		\

	for_each_cpu(i, &name##_cpus) {					\

		arch_spinlock_t *lock;					\

		lock = &per_cpu(name##_lock, i);			\

		arch_spin_lock(lock);					\

	}								\

 }									\

 EXPORT_SYMBOL(name##_global_lock_online);				\

									\

 void name##_global_unlock_online(void) {				\

	int i;								\

	rwlock_release(&name##_lock_dep_map, 1, _RET_IP_);		\

	for_each_cpu(i, &name##_cpus) {					\

		arch_spinlock_t *lock;					\

		lock = &per_cpu(name##_lock, i);			\

		arch_spin_unlock(lock);					\

	}								\

	spin_unlock(&name##_cpu_lock);					\

 }									\

 EXPORT_SYMBOL(name##_global_unlock_online);				\

									\

 void name##_global_lock(void) {					\

	int i;								\

	preempt_disable();						\