1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun #include <linux/fs.h>
3*4882a593Smuzhiyun #include <linux/sched.h>
4*4882a593Smuzhiyun #include <linux/slab.h>
5*4882a593Smuzhiyun #include "internal.h"
6*4882a593Smuzhiyun #include "mount.h"
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun static DEFINE_SPINLOCK(pin_lock);
9*4882a593Smuzhiyun
pin_remove(struct fs_pin * pin)10*4882a593Smuzhiyun void pin_remove(struct fs_pin *pin)
11*4882a593Smuzhiyun {
12*4882a593Smuzhiyun spin_lock(&pin_lock);
13*4882a593Smuzhiyun hlist_del_init(&pin->m_list);
14*4882a593Smuzhiyun hlist_del_init(&pin->s_list);
15*4882a593Smuzhiyun spin_unlock(&pin_lock);
16*4882a593Smuzhiyun spin_lock_irq(&pin->wait.lock);
17*4882a593Smuzhiyun pin->done = 1;
18*4882a593Smuzhiyun wake_up_locked(&pin->wait);
19*4882a593Smuzhiyun spin_unlock_irq(&pin->wait.lock);
20*4882a593Smuzhiyun }
21*4882a593Smuzhiyun
pin_insert(struct fs_pin * pin,struct vfsmount * m)22*4882a593Smuzhiyun void pin_insert(struct fs_pin *pin, struct vfsmount *m)
23*4882a593Smuzhiyun {
24*4882a593Smuzhiyun spin_lock(&pin_lock);
25*4882a593Smuzhiyun hlist_add_head(&pin->s_list, &m->mnt_sb->s_pins);
26*4882a593Smuzhiyun hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins);
27*4882a593Smuzhiyun spin_unlock(&pin_lock);
28*4882a593Smuzhiyun }
29*4882a593Smuzhiyun
pin_kill(struct fs_pin * p)30*4882a593Smuzhiyun void pin_kill(struct fs_pin *p)
31*4882a593Smuzhiyun {
32*4882a593Smuzhiyun wait_queue_entry_t wait;
33*4882a593Smuzhiyun
34*4882a593Smuzhiyun if (!p) {
35*4882a593Smuzhiyun rcu_read_unlock();
36*4882a593Smuzhiyun return;
37*4882a593Smuzhiyun }
38*4882a593Smuzhiyun init_wait(&wait);
39*4882a593Smuzhiyun spin_lock_irq(&p->wait.lock);
40*4882a593Smuzhiyun if (likely(!p->done)) {
41*4882a593Smuzhiyun p->done = -1;
42*4882a593Smuzhiyun spin_unlock_irq(&p->wait.lock);
43*4882a593Smuzhiyun rcu_read_unlock();
44*4882a593Smuzhiyun p->kill(p);
45*4882a593Smuzhiyun return;
46*4882a593Smuzhiyun }
47*4882a593Smuzhiyun if (p->done > 0) {
48*4882a593Smuzhiyun spin_unlock_irq(&p->wait.lock);
49*4882a593Smuzhiyun rcu_read_unlock();
50*4882a593Smuzhiyun return;
51*4882a593Smuzhiyun }
52*4882a593Smuzhiyun __add_wait_queue(&p->wait, &wait);
53*4882a593Smuzhiyun while (1) {
54*4882a593Smuzhiyun set_current_state(TASK_UNINTERRUPTIBLE);
55*4882a593Smuzhiyun spin_unlock_irq(&p->wait.lock);
56*4882a593Smuzhiyun rcu_read_unlock();
57*4882a593Smuzhiyun schedule();
58*4882a593Smuzhiyun rcu_read_lock();
59*4882a593Smuzhiyun if (likely(list_empty(&wait.entry)))
60*4882a593Smuzhiyun break;
61*4882a593Smuzhiyun /* OK, we know p couldn't have been freed yet */
62*4882a593Smuzhiyun spin_lock_irq(&p->wait.lock);
63*4882a593Smuzhiyun if (p->done > 0) {
64*4882a593Smuzhiyun spin_unlock_irq(&p->wait.lock);
65*4882a593Smuzhiyun break;
66*4882a593Smuzhiyun }
67*4882a593Smuzhiyun }
68*4882a593Smuzhiyun rcu_read_unlock();
69*4882a593Smuzhiyun }
70*4882a593Smuzhiyun
mnt_pin_kill(struct mount * m)71*4882a593Smuzhiyun void mnt_pin_kill(struct mount *m)
72*4882a593Smuzhiyun {
73*4882a593Smuzhiyun while (1) {
74*4882a593Smuzhiyun struct hlist_node *p;
75*4882a593Smuzhiyun rcu_read_lock();
76*4882a593Smuzhiyun p = READ_ONCE(m->mnt_pins.first);
77*4882a593Smuzhiyun if (!p) {
78*4882a593Smuzhiyun rcu_read_unlock();
79*4882a593Smuzhiyun break;
80*4882a593Smuzhiyun }
81*4882a593Smuzhiyun pin_kill(hlist_entry(p, struct fs_pin, m_list));
82*4882a593Smuzhiyun }
83*4882a593Smuzhiyun }
84*4882a593Smuzhiyun
group_pin_kill(struct hlist_head * p)85*4882a593Smuzhiyun void group_pin_kill(struct hlist_head *p)
86*4882a593Smuzhiyun {
87*4882a593Smuzhiyun while (1) {
88*4882a593Smuzhiyun struct hlist_node *q;
89*4882a593Smuzhiyun rcu_read_lock();
90*4882a593Smuzhiyun q = READ_ONCE(p->first);
91*4882a593Smuzhiyun if (!q) {
92*4882a593Smuzhiyun rcu_read_unlock();
93*4882a593Smuzhiyun break;
94*4882a593Smuzhiyun }
95*4882a593Smuzhiyun pin_kill(hlist_entry(q, struct fs_pin, s_list));
96*4882a593Smuzhiyun }
97*4882a593Smuzhiyun }
98