]> git.kernelconcepts.de Git - karo-tx-linux.git/blob - fs/fs_pin.c
Merge tag 'iwlwifi-for-kalle-2015-04-28' of https://git.kernel.org/pub/scm/linux...
[karo-tx-linux.git] / fs / fs_pin.c
1 #include <linux/fs.h>
2 #include <linux/sched.h>
3 #include <linux/slab.h>
4 #include "internal.h"
5 #include "mount.h"
6
7 static DEFINE_SPINLOCK(pin_lock);
8
9 void pin_remove(struct fs_pin *pin)
10 {
11         spin_lock(&pin_lock);
12         hlist_del_init(&pin->m_list);
13         hlist_del_init(&pin->s_list);
14         spin_unlock(&pin_lock);
15         spin_lock_irq(&pin->wait.lock);
16         pin->done = 1;
17         wake_up_locked(&pin->wait);
18         spin_unlock_irq(&pin->wait.lock);
19 }
20
21 void pin_insert_group(struct fs_pin *pin, struct vfsmount *m, struct hlist_head *p)
22 {
23         spin_lock(&pin_lock);
24         if (p)
25                 hlist_add_head(&pin->s_list, p);
26         hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins);
27         spin_unlock(&pin_lock);
28 }
29
30 void pin_insert(struct fs_pin *pin, struct vfsmount *m)
31 {
32         pin_insert_group(pin, m, &m->mnt_sb->s_pins);
33 }
34
35 void pin_kill(struct fs_pin *p)
36 {
37         wait_queue_t wait;
38
39         if (!p) {
40                 rcu_read_unlock();
41                 return;
42         }
43         init_wait(&wait);
44         spin_lock_irq(&p->wait.lock);
45         if (likely(!p->done)) {
46                 p->done = -1;
47                 spin_unlock_irq(&p->wait.lock);
48                 rcu_read_unlock();
49                 p->kill(p);
50                 return;
51         }
52         if (p->done > 0) {
53                 spin_unlock_irq(&p->wait.lock);
54                 rcu_read_unlock();
55                 return;
56         }
57         __add_wait_queue(&p->wait, &wait);
58         while (1) {
59                 set_current_state(TASK_UNINTERRUPTIBLE);
60                 spin_unlock_irq(&p->wait.lock);
61                 rcu_read_unlock();
62                 schedule();
63                 rcu_read_lock();
64                 if (likely(list_empty(&wait.task_list)))
65                         break;
66                 /* OK, we know p couldn't have been freed yet */
67                 spin_lock_irq(&p->wait.lock);
68                 if (p->done > 0) {
69                         spin_unlock_irq(&p->wait.lock);
70                         break;
71                 }
72         }
73         rcu_read_unlock();
74 }
75
76 void mnt_pin_kill(struct mount *m)
77 {
78         while (1) {
79                 struct hlist_node *p;
80                 rcu_read_lock();
81                 p = ACCESS_ONCE(m->mnt_pins.first);
82                 if (!p) {
83                         rcu_read_unlock();
84                         break;
85                 }
86                 pin_kill(hlist_entry(p, struct fs_pin, m_list));
87         }
88 }
89
90 void group_pin_kill(struct hlist_head *p)
91 {
92         while (1) {
93                 struct hlist_node *q;
94                 rcu_read_lock();
95                 q = ACCESS_ONCE(p->first);
96                 if (!q) {
97                         rcu_read_unlock();
98                         break;
99                 }
100                 pin_kill(hlist_entry(q, struct fs_pin, s_list));
101         }
102 }