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#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/fs_pin.h>
#include "internal.h"
#include "mount.h"
static void pin_free_rcu(struct rcu_head *head)
{
kfree(container_of(head, struct fs_pin, rcu));
}
static DEFINE_SPINLOCK(pin_lock);
void pin_put(struct fs_pin *p)
{
if (atomic_long_dec_and_test(&p->count))
call_rcu(&p->rcu, pin_free_rcu);
}
void pin_remove(struct fs_pin *pin)
{
spin_lock(&pin_lock);
hlist_del_init(&pin->m_list);
hlist_del_init(&pin->s_list);
spin_unlock(&pin_lock);
}
void pin_insert(struct fs_pin *pin, struct vfsmount *m)
{
spin_lock(&pin_lock);
hlist_add_head(&pin->s_list, &m->mnt_sb->s_pins);
hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins);
spin_unlock(&pin_lock);
}
void mnt_pin_kill(struct mount *m)
{
while (1) {
struct hlist_node *p;
struct fs_pin *pin;
rcu_read_lock();
p = ACCESS_ONCE(m->mnt_pins.first);
if (!p) {
rcu_read_unlock();
break;
}
pin = hlist_entry(p, struct fs_pin, m_list);
if (!atomic_long_inc_not_zero(&pin->count)) {
rcu_read_unlock();
cpu_relax();
continue;
}
rcu_read_unlock();
pin->kill(pin);
}
}
void sb_pin_kill(struct super_block *sb)
{
while (1) {
struct hlist_node *p;
struct fs_pin *pin;
rcu_read_lock();
p = ACCESS_ONCE(sb->s_pins.first);
if (!p) {
rcu_read_unlock();
break;
}
pin = hlist_entry(p, struct fs_pin, s_list);
if (!atomic_long_inc_not_zero(&pin->count)) {
rcu_read_unlock();
cpu_relax();
continue;
}
rcu_read_unlock();
pin->kill(pin);
}
}
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