sched/stat: Expose /proc/pid/schedstat if CONFIG_SCHED_INFO=y

[deliverable/linux.git] / fs / namespace.c

diff --git a/fs/namespace.c b/fs/namespace.c
index 1b9e11167baedc310b8f5b6585ac019abd78b915..9c1c43d0d4f10112bcf711068873a70e2a057200 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -590,24 +590,35 @@ static void delayed_free_vfsmnt(struct rcu_head *head)
 }
 
 /* call under rcu_read_lock */
-bool legitimize_mnt(struct vfsmount *bastard, unsigned seq)
+int __legitimize_mnt(struct vfsmount *bastard, unsigned seq)
 {
        struct mount *mnt;
        if (read_seqretry(&mount_lock, seq))
-               return false;
+               return 1;
        if (bastard == NULL)
-               return true;
+               return 0;
        mnt = real_mount(bastard);
        mnt_add_count(mnt, 1);
        if (likely(!read_seqretry(&mount_lock, seq)))
-               return true;
+               return 0;
        if (bastard->mnt_flags & MNT_SYNC_UMOUNT) {
                mnt_add_count(mnt, -1);
-               return false;
+               return 1;
+       }
+       return -1;
+}
+
+/* call under rcu_read_lock */
+bool legitimize_mnt(struct vfsmount *bastard, unsigned seq)
+{
+       int res = __legitimize_mnt(bastard, seq);
+       if (likely(!res))
+               return true;
+       if (unlikely(res < 0)) {
+               rcu_read_unlock();
+               mntput(bastard);
+               rcu_read_lock();
        }
-       rcu_read_unlock();
-       mntput(bastard);
-       rcu_read_lock();
        return false;
 }