Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / fs / fs_pin.c

diff --git a/kernel/fs/fs_pin.c b/kernel/fs/fs_pin.c
new file mode 100644 (file)
index 0000000..611b540
--- /dev/null
+++ b/kernel/fs/fs_pin.c
@@ -0,0 +1,102 @@
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include "internal.h"
+#include "mount.h"
+
+static DEFINE_SPINLOCK(pin_lock);
+
+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);
+       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)
+{
+       spin_lock(&pin_lock);
+       if (p)
+               hlist_add_head(&pin->s_list, p);
+       hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins);
+       spin_unlock(&pin_lock);
+}
+
+void pin_insert(struct fs_pin *pin, struct vfsmount *m)
+{
+       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;
+               rcu_read_lock();
+               p = ACCESS_ONCE(m->mnt_pins.first);
+               if (!p) {
+                       rcu_read_unlock();
+                       break;
+               }
+               pin_kill(hlist_entry(p, struct fs_pin, m_list));
+       }
+}
+
+void group_pin_kill(struct hlist_head *p)
+{
+       while (1) {
+               struct hlist_node *q;
+               rcu_read_lock();
+               q = ACCESS_ONCE(p->first);
+               if (!q) {
+                       rcu_read_unlock();
+                       break;
+               }
+               pin_kill(hlist_entry(q, struct fs_pin, s_list));
+       }
+}