[PATCH] reduce stack footprint in namespace.c
A lot of places misuse struct nameidata when they need struct path.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namespace.c b/fs/namespace.c
index 7953c96..6324dfc 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -155,15 +155,15 @@
}
}
-static void detach_mnt(struct vfsmount *mnt, struct nameidata *old_nd)
+static void detach_mnt(struct vfsmount *mnt, struct path *old_path)
{
- old_nd->path.dentry = mnt->mnt_mountpoint;
- old_nd->path.mnt = mnt->mnt_parent;
+ old_path->dentry = mnt->mnt_mountpoint;
+ old_path->mnt = mnt->mnt_parent;
mnt->mnt_parent = mnt;
mnt->mnt_mountpoint = mnt->mnt_root;
list_del_init(&mnt->mnt_child);
list_del_init(&mnt->mnt_hash);
- old_nd->path.dentry->d_mounted--;
+ old_path->dentry->d_mounted--;
}
void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry,
@@ -174,12 +174,12 @@
dentry->d_mounted++;
}
-static void attach_mnt(struct vfsmount *mnt, struct nameidata *nd)
+static void attach_mnt(struct vfsmount *mnt, struct path *path)
{
- mnt_set_mountpoint(nd->path.mnt, nd->path.dentry, mnt);
+ mnt_set_mountpoint(path->mnt, path->dentry, mnt);
list_add_tail(&mnt->mnt_hash, mount_hashtable +
- hash(nd->path.mnt, nd->path.dentry));
- list_add_tail(&mnt->mnt_child, &nd->path.mnt->mnt_mounts);
+ hash(path->mnt, path->dentry));
+ list_add_tail(&mnt->mnt_child, &path->mnt->mnt_mounts);
}
/*
@@ -744,7 +744,7 @@
int flag)
{
struct vfsmount *res, *p, *q, *r, *s;
- struct nameidata nd;
+ struct path path;
if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(mnt))
return NULL;
@@ -769,14 +769,14 @@
q = q->mnt_parent;
}
p = s;
- nd.path.mnt = q;
- nd.path.dentry = p->mnt_mountpoint;
+ path.mnt = q;
+ path.dentry = p->mnt_mountpoint;
q = clone_mnt(p, p->mnt_root, flag);
if (!q)
goto Enomem;
spin_lock(&vfsmount_lock);
list_add_tail(&q->mnt_list, &res->mnt_list);
- attach_mnt(q, &nd);
+ attach_mnt(q, &path);
spin_unlock(&vfsmount_lock);
}
}
@@ -876,11 +876,11 @@
* in allocations.
*/
static int attach_recursive_mnt(struct vfsmount *source_mnt,
- struct nameidata *nd, struct nameidata *parent_nd)
+ struct path *path, struct path *parent_path)
{
LIST_HEAD(tree_list);
- struct vfsmount *dest_mnt = nd->path.mnt;
- struct dentry *dest_dentry = nd->path.dentry;
+ struct vfsmount *dest_mnt = path->mnt;
+ struct dentry *dest_dentry = path->dentry;
struct vfsmount *child, *p;
if (propagate_mnt(dest_mnt, dest_dentry, source_mnt, &tree_list))
@@ -892,9 +892,9 @@
}
spin_lock(&vfsmount_lock);
- if (parent_nd) {
- detach_mnt(source_mnt, parent_nd);
- attach_mnt(source_mnt, nd);
+ if (parent_path) {
+ detach_mnt(source_mnt, parent_path);
+ attach_mnt(source_mnt, path);
touch_mnt_namespace(current->nsproxy->mnt_ns);
} else {
mnt_set_mountpoint(dest_mnt, dest_dentry, source_mnt);
@@ -930,7 +930,7 @@
err = -ENOENT;
if (IS_ROOT(nd->path.dentry) || !d_unhashed(nd->path.dentry))
- err = attach_recursive_mnt(mnt, nd, NULL);
+ err = attach_recursive_mnt(mnt, &nd->path, NULL);
out_unlock:
mutex_unlock(&nd->path.dentry->d_inode->i_mutex);
if (!err)
@@ -1059,7 +1059,8 @@
*/
static noinline int do_move_mount(struct nameidata *nd, char *old_name)
{
- struct nameidata old_nd, parent_nd;
+ struct nameidata old_nd;
+ struct path parent_path;
struct vfsmount *p;
int err = 0;
if (!capable(CAP_SYS_ADMIN))
@@ -1114,7 +1115,7 @@
if (p == old_nd.path.mnt)
goto out1;
- err = attach_recursive_mnt(old_nd.path.mnt, nd, &parent_nd);
+ err = attach_recursive_mnt(old_nd.path.mnt, &nd->path, &parent_path);
if (err)
goto out1;
@@ -1128,7 +1129,7 @@
out:
up_write(&namespace_sem);
if (!err)
- path_put(&parent_nd.path);
+ path_put(&parent_path);
path_put(&old_nd.path);
return err;
}
@@ -1683,7 +1684,7 @@
path_put(&old_pwd);
}
-static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd)
+static void chroot_fs_refs(struct path *old_root, struct path *new_root)
{
struct task_struct *g, *p;
struct fs_struct *fs;
@@ -1695,12 +1696,12 @@
if (fs) {
atomic_inc(&fs->count);
task_unlock(p);
- if (fs->root.dentry == old_nd->path.dentry
- && fs->root.mnt == old_nd->path.mnt)
- set_fs_root(fs, &new_nd->path);
- if (fs->pwd.dentry == old_nd->path.dentry
- && fs->pwd.mnt == old_nd->path.mnt)
- set_fs_pwd(fs, &new_nd->path);
+ if (fs->root.dentry == old_root->dentry
+ && fs->root.mnt == old_root->mnt)
+ set_fs_root(fs, new_root);
+ if (fs->pwd.dentry == old_root->dentry
+ && fs->pwd.mnt == old_root->mnt)
+ set_fs_pwd(fs, new_root);
put_fs_struct(fs);
} else
task_unlock(p);
@@ -1737,7 +1738,8 @@
const char __user * put_old)
{
struct vfsmount *tmp;
- struct nameidata new_nd, old_nd, parent_nd, root_parent, user_nd;
+ struct nameidata new_nd, old_nd, user_nd;
+ struct path parent_path, root_parent;
int error;
if (!capable(CAP_SYS_ADMIN))
@@ -1811,19 +1813,19 @@
goto out3;
} else if (!is_subdir(old_nd.path.dentry, new_nd.path.dentry))
goto out3;
- detach_mnt(new_nd.path.mnt, &parent_nd);
+ detach_mnt(new_nd.path.mnt, &parent_path);
detach_mnt(user_nd.path.mnt, &root_parent);
/* mount old root on put_old */
- attach_mnt(user_nd.path.mnt, &old_nd);
+ attach_mnt(user_nd.path.mnt, &old_nd.path);
/* mount new_root on / */
attach_mnt(new_nd.path.mnt, &root_parent);
touch_mnt_namespace(current->nsproxy->mnt_ns);
spin_unlock(&vfsmount_lock);
- chroot_fs_refs(&user_nd, &new_nd);
+ chroot_fs_refs(&user_nd.path, &new_nd.path);
security_sb_post_pivotroot(&user_nd, &new_nd);
error = 0;
- path_put(&root_parent.path);
- path_put(&parent_nd.path);
+ path_put(&root_parent);
+ path_put(&parent_path);
out2:
mutex_unlock(&old_nd.path.dentry->d_inode->i_mutex);
up_write(&namespace_sem);