get rid of insanity with namespace roots in tomoyo

passing *any* namespace root to __d_path() as root is equivalent
to just passing it {NULL, NULL}; no need to bother with finding
the root of our namespace in there.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 4 insertions, 19 deletions

diff --git a/security/tomoyo/realpath.c b/security/tomoyo/realpath.c
index 18369d497eb8..6a4f8495f281 100644
--- a/security/tomoyo/realpath.c
+++ b/security/tomoyo/realpath.c
@@ -89,27 +89,12 @@ int tomoyo_realpath_from_path2(struct path *path, char *newname,
                 sp = dentry->d_op->d_dname(dentry, newname + offset,
                                            newname_len - offset);
         } else {
-                /* Taken from d_namespace_path(). */
-                struct path root;
-                struct path ns_root = { };
-                struct path tmp;
-
-                read_lock(&current->fs->lock);
-                root = current->fs->root;
-                path_get(&root);
-                read_unlock(&current->fs->lock);
-                spin_lock(&vfsmount_lock);
-                if (root.mnt && root.mnt->mnt_ns)
-                        ns_root.mnt = mntget(root.mnt->mnt_ns->root);
-                if (ns_root.mnt)
-                        ns_root.dentry = dget(ns_root.mnt->mnt_root);
-                spin_unlock(&vfsmount_lock);
+                struct path ns_root = {.mnt = NULL, .dentry = NULL};
+
                 spin_lock(&dcache_lock);
-                tmp = ns_root;
-                sp = __d_path(path, &tmp, newname, newname_len);
+                /* go to whatever namespace root we are under */
+                sp = __d_path(path, &ns_root, newname, newname_len);
                 spin_unlock(&dcache_lock);
-                path_put(&root);
-                path_put(&ns_root);
                 /* Prepend "/proc" prefix if using internal proc vfs mount. */
                 if (!IS_ERR(sp) && (path->mnt->mnt_parent == path->mnt) &&
                     (strcmp(path->mnt->mnt_sb->s_type->name, "proc") == 0)) {