5 files changed, 18 insertions, 12 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 89509b5a090e..8a75e3b0f49d 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -38,6 +38,7 @@
 #include <linux/prefetch.h>
 #include <linux/ratelimit.h>
 #include "internal.h"
+#include "mount.h"
 
 /*
  * Usage:
@@ -2460,9 +2461,8 @@ static int prepend_path(const struct path *path,
 
                 if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) {
                         /* Global root? */
-                        if (vfsmnt->mnt_parent == vfsmnt) {
+                        if (!mnt_has_parent(vfsmnt))
                                 goto global_root;
-                        }
                         dentry = vfsmnt->mnt_mountpoint;
                         vfsmnt = vfsmnt->mnt_parent;
                         continue;
@@ -2862,7 +2862,7 @@ int path_is_under(struct path *path1, struct path *path2)
         br_read_lock(vfsmount_lock);
         if (mnt != path2->mnt) {
                 for (;;) {
-                        if (mnt->mnt_parent == mnt) {
+                        if (!mnt_has_parent(mnt)) {
                                 br_read_unlock(vfsmount_lock);
                                 return 0;
                         }
diff --git a/fs/mount.h b/fs/mount.h
new file mode 100644
index 000000000000..7890e49f74ef
--- /dev/null
+++ b/fs/mount.h
@@ -0,0 +1,6 @@
+#include <linux/mount.h>
+
+static inline int mnt_has_parent(struct vfsmount *mnt)
+{
+        return mnt != mnt->mnt_parent;
+}
diff --git a/fs/namespace.c b/fs/namespace.c
index 31d357450f7f..ec8512478b04 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1182,7 +1182,7 @@ void release_mounts(struct list_head *head)
         while (!list_empty(head)) {
                 mnt = list_first_entry(head, struct vfsmount, mnt_hash);
                 list_del_init(&mnt->mnt_hash);
-                if (mnt->mnt_parent != mnt) {
+                if (mnt_has_parent(mnt)) {
                         struct dentry *dentry;
                         struct vfsmount *m;
 
@@ -1222,7 +1222,7 @@ void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill)
                 p->mnt_ns = NULL;
                 __mnt_make_shortterm(p);
                 list_del_init(&p->mnt_child);
-                if (p->mnt_parent != p) {
+                if (mnt_has_parent(p)) {
                         p->mnt_parent->mnt_ghosts++;
                         dentry_reset_mounted(p->mnt_parent, p->mnt_mountpoint);
                 }
@@ -1867,7 +1867,7 @@ static int do_move_mount(struct path *path, char *old_name)
         if (old_path.dentry != old_path.mnt->mnt_root)
                 goto out1;
 
-        if (old_path.mnt == old_path.mnt->mnt_parent)
+        if (!mnt_has_parent(old_path.mnt))
                 goto out1;
 
         if (S_ISDIR(path->dentry->d_inode->i_mode) !=
@@ -1887,7 +1887,7 @@ static int do_move_mount(struct path *path, char *old_name)
             tree_contains_unbindable(old_path.mnt))
                 goto out1;
         err = -ELOOP;
-        for (p = path->mnt; p->mnt_parent != p; p = p->mnt_parent)
+        for (p = path->mnt; mnt_has_parent(p); p = p->mnt_parent)
                 if (p == old_path.mnt)
                         goto out1;
 
@@ -2604,17 +2604,17 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
         error = -EINVAL;
         if (root.mnt->mnt_root != root.dentry)
                 goto out4; /* not a mountpoint */
-        if (root.mnt->mnt_parent == root.mnt)
+        if (!mnt_has_parent(root.mnt))
                 goto out4; /* not attached */
         if (new.mnt->mnt_root != new.dentry)
                 goto out4; /* not a mountpoint */
-        if (new.mnt->mnt_parent == new.mnt)
+        if (!mnt_has_parent(new.mnt))
                 goto out4; /* not attached */
         /* make sure we can reach put_old from new_root */
         tmp = old.mnt;
         if (tmp != new.mnt) {
                 for (;;) {
-                        if (tmp->mnt_parent == tmp)
+                        if (!mnt_has_parent(tmp))
                                 goto out4; /* already mounted on put_old */
                         if (tmp->mnt_parent == new.mnt)
                                 break;
diff --git a/fs/pnode.c b/fs/pnode.c
index d42514e32380..f1cd958b92e5 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -36,7 +36,7 @@ static inline struct vfsmount *next_slave(struct vfsmount *p)
 static bool is_path_reachable(struct vfsmount *mnt, struct dentry *dentry,
                          const struct path *root)
 {
-        while (mnt != root->mnt && mnt->mnt_parent != mnt) {
+        while (mnt != root->mnt && mnt_has_parent(mnt)) {
                 dentry = mnt->mnt_mountpoint;
                 mnt = mnt->mnt_parent;
         }
diff --git a/fs/pnode.h b/fs/pnode.h
index 391287110274..7f0c13ae9484 100644
--- a/fs/pnode.h
+++ b/fs/pnode.h
@@ -9,7 +9,7 @@
 #define _LINUX_PNODE_H
 
 #include <linux/list.h>
-#include <linux/mount.h>
+#include "mount.h"
 
 #define IS_MNT_SHARED(mnt) (mnt->mnt_flags & MNT_SHARED)
 #define IS_MNT_SLAVE(mnt) (mnt->mnt_master)