lglock.c

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/* 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);