1 files changed, 24 insertions, 7 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 48809e2..9f544f3 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -611,6 +611,21 @@ static void attach_mnt(struct vfsmount *mnt, struct path *path)
 	list_add_tail(&mnt->mnt_child, &path->mnt->mnt_mounts);
 }
 
+static inline void __mnt_make_longterm(struct vfsmount *mnt)
+{
+#ifdef CONFIG_SMP
+	atomic_inc(&mnt->mnt_longterm);
+#endif
+}
+
+/* needs vfsmount lock for write */
+static inline void __mnt_make_shortterm(struct vfsmount *mnt)
+{
+#ifdef CONFIG_SMP
+	atomic_dec(&mnt->mnt_longterm);
+#endif
+}
+
 /*
  * vfsmount lock must be held for write
  */
@@ -626,7 +641,7 @@ static void commit_tree(struct vfsmount *mnt)
 	list_add_tail(&head, &mnt->mnt_list);
 	list_for_each_entry(m, &head, mnt_list) {
 		m->mnt_ns = n;
-		atomic_inc(&m->mnt_longterm);
+		__mnt_make_longterm(m);
 	}
 
 	list_splice(&head, n->list.prev);
@@ -1189,7 +1204,7 @@ void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill)
 		list_del_init(&p->mnt_list);
 		__touch_mnt_namespace(p->mnt_ns);
 		p->mnt_ns = NULL;
-		atomic_dec(&p->mnt_longterm);
+		__mnt_make_shortterm(p);
 		list_del_init(&p->mnt_child);
 		if (p->mnt_parent != p) {
 			p->mnt_parent->mnt_ghosts++;
@@ -2243,16 +2258,18 @@ static struct mnt_namespace *alloc_mnt_ns(void)
 
 void mnt_make_longterm(struct vfsmount *mnt)
 {
-	atomic_inc(&mnt->mnt_longterm);
+	__mnt_make_longterm(mnt);
 }
 
 void mnt_make_shortterm(struct vfsmount *mnt)
 {
+#ifdef CONFIG_SMP
 	if (atomic_add_unless(&mnt->mnt_longterm, -1, 1))
 		return;
 	br_write_lock(vfsmount_lock);
 	atomic_dec(&mnt->mnt_longterm);
 	br_write_unlock(vfsmount_lock);
+#endif
 }
 
 /*
@@ -2292,17 +2309,17 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
 	q = new_ns->root;
 	while (p) {
 		q->mnt_ns = new_ns;
-		atomic_inc(&q->mnt_longterm);
+		__mnt_make_longterm(q);
 		if (fs) {
 			if (p == fs->root.mnt) {
 				fs->root.mnt = mntget(q);
-				atomic_inc(&q->mnt_longterm);
+				__mnt_make_longterm(q);
 				mnt_make_shortterm(p);
 				rootmnt = p;
 			}
 			if (p == fs->pwd.mnt) {
 				fs->pwd.mnt = mntget(q);
-				atomic_inc(&q->mnt_longterm);
+				__mnt_make_longterm(q);
 				mnt_make_shortterm(p);
 				pwdmnt = p;
 			}
@@ -2348,7 +2365,7 @@ struct mnt_namespace *create_mnt_ns(struct vfsmount *mnt)
 	new_ns = alloc_mnt_ns();
 	if (!IS_ERR(new_ns)) {
 		mnt->mnt_ns = new_ns;
-		atomic_inc(&mnt->mnt_longterm);
+		__mnt_make_longterm(mnt);
 		new_ns->root = mnt;
 		list_add(&new_ns->list, &new_ns->root->mnt_list);
 	}