new fs_pin killing logics
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/fs_pin.c b/fs/fs_pin.c
index 50ef7d2..0c77bdc 100644
--- a/fs/fs_pin.c
+++ b/fs/fs_pin.c
@@ -1,4 +1,5 @@
#include <linux/fs.h>
+#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fs_pin.h>
#include "internal.h"
@@ -12,6 +13,10 @@
hlist_del(&pin->m_list);
hlist_del(&pin->s_list);
spin_unlock(&pin_lock);
+ spin_lock_irq(&pin->wait.lock);
+ pin->done = 1;
+ wake_up_locked(&pin->wait);
+ spin_unlock_irq(&pin->wait.lock);
}
void pin_insert_group(struct fs_pin *pin, struct vfsmount *m, struct hlist_head *p)
@@ -28,19 +33,58 @@
pin_insert_group(pin, m, &m->mnt_sb->s_pins);
}
+void pin_kill(struct fs_pin *p)
+{
+ wait_queue_t wait;
+
+ if (!p) {
+ rcu_read_unlock();
+ return;
+ }
+ init_wait(&wait);
+ spin_lock_irq(&p->wait.lock);
+ if (likely(!p->done)) {
+ p->done = -1;
+ spin_unlock_irq(&p->wait.lock);
+ rcu_read_unlock();
+ p->kill(p);
+ return;
+ }
+ if (p->done > 0) {
+ spin_unlock_irq(&p->wait.lock);
+ rcu_read_unlock();
+ return;
+ }
+ __add_wait_queue(&p->wait, &wait);
+ while (1) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ spin_unlock_irq(&p->wait.lock);
+ rcu_read_unlock();
+ schedule();
+ rcu_read_lock();
+ if (likely(list_empty(&wait.task_list)))
+ break;
+ /* OK, we know p couldn't have been freed yet */
+ spin_lock_irq(&p->wait.lock);
+ if (p->done > 0) {
+ spin_unlock_irq(&p->wait.lock);
+ break;
+ }
+ }
+ rcu_read_unlock();
+}
+
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);
- pin->kill(pin);
+ pin_kill(hlist_entry(p, struct fs_pin, m_list));
}
}
@@ -48,14 +92,12 @@
{
while (1) {
struct hlist_node *q;
- struct fs_pin *pin;
rcu_read_lock();
q = ACCESS_ONCE(p->first);
if (!q) {
rcu_read_unlock();
break;
}
- pin = hlist_entry(q, struct fs_pin, s_list);
- pin->kill(pin);
+ pin_kill(hlist_entry(q, struct fs_pin, s_list));
}
}