From: Al Viro Date: Sat, 22 Mar 2008 00:48:19 +0000 (-0400) Subject: [PATCH] reduce stack footprint in namespace.c X-Git-Tag: v2.6.25-rc8~42^2~4 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1a39068954e33f4bf3e09375a8112dcc801c4688;p=linux-2.6 [PATCH] reduce stack footprint in namespace.c A lot of places misuse struct nameidata when they need struct path. Signed-off-by: Al Viro --- diff --git a/fs/namespace.c b/fs/namespace.c index 7953c96a20..6324dfc80d 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -155,15 +155,15 @@ static void __touch_mnt_namespace(struct mnt_namespace *ns) } } -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 @@ void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry, 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 @@ struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry, 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 @@ struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry, 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 @@ void drop_collected_mounts(struct vfsmount *mnt) * 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 @@ static int attach_recursive_mnt(struct vfsmount *source_mnt, } 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 @@ static int graft_tree(struct vfsmount *mnt, struct nameidata *nd) 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 inline int tree_contains_unbindable(struct vfsmount *mnt) */ 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 @@ static noinline int do_move_mount(struct nameidata *nd, char *old_name) 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 @@ out1: 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 @@ void set_fs_pwd(struct fs_struct *fs, struct path *path) 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 @@ static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd) 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 @@ asmlinkage long sys_pivot_root(const char __user * new_root, 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 @@ asmlinkage long sys_pivot_root(const char __user * new_root, 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);